JP7487422B1 - Shock absorber - Google Patents

Abstract

The shock absorber (10; 10A; 10B) has a cylinder (17), a piston (30), a piston portion spring (25) that biases a flow path (31a) of the piston (30) in a direction to close the flow path, and a slide spring receiving member (40; 40A; 40B) that is provided between the piston portion spring (25) and the piston (30) so as to be displaceable in a direction along the axis (CL). The piston (30) has a piston body (31) and a stacked valve (33). The slide spring receiving member (40; 40A; 40B) includes an abutment surface (42a; 42Aa; 42Ba) against which the stacked valve (33) can abut. An imaginary plane (S1; S3) formed by connecting the part of the abutment surface (42a; 42Aa; 42Ba) closest to the axis (CL) to the radially outer end is inclined with respect to a vertical plane (S2) extending radially from the axis (CL).

Description

The present invention relates to a shock absorber.

For example, many vehicles, such as motorcycles, are equipped with shock absorbers to dampen vibrations from the road surface. Prior art related to shock absorbers is disclosed in Patent Document 1.

The shock absorber shown in Patent Document 1 comprises a cylindrical cylinder, a piston provided inside the cylinder, a spring that biases the piston in a direction to close the flow path, and a sliding spring support member that is disposed between the piston and the spring and is displaceable in the axial direction to transmit the biasing force of the spring to the piston.

The shock absorber shown in Patent Document 1 can provide characteristics that allow for a large rise in damping force at low speeds and a damping force that is as gentle as possible at high speeds.

Japanese Utility Model Application Publication No. 63-180751

It is known that damping force characteristics affect the ride comfort of a vehicle. If more arbitrary damping force characteristics could be generated, the ride comfort of the vehicle could be improved, which is preferable. The objective of the present invention is to provide a shock absorber that can generate more arbitrary damping force characteristics.

After extensive research, the inventors discovered that by tilting the contact surface of the slide spring receiving member with which the laminated valve can come into contact with respect to a vertical plane extending radially from the axis, it becomes possible to more finely adjust the amount of displacement of the laminated valve, thereby enabling more arbitrary damping force characteristics to be produced. The present invention was completed based on this discovery.

This disclosure is described below.

According to the present disclosure, there is provided a shock absorber comprising: a cylinder having a generally cylindrical shape and filled with a working fluid; a piston provided inside the cylinder and dividing the interior of the cylinder into a first chamber and a second chamber; a piston spring that biases a flow path formed inside the piston in a direction to close the flow path through which the working fluid flows; and a slide spring support member that is provided between the piston spring and the piston and is displaceable in a direction along the axis of the cylinder and transmits the biasing force of the piston spring to the piston; the piston comprises a piston body having a flow path through which the working fluid can pass, and a stacked valve that biases one end of the flow path in a direction to close the flow path and is formed by stacking a plurality of plate-shaped valves; the slide spring support member includes an abutment surface against which the stacked valve can abut; and when a surface formed by connecting a portion of the abutment surface closest to the axis to an end portion radially outward is taken as an imaginary surface, the imaginary surface is inclined with respect to a vertical plane extending in the radial direction about the axis.

The present invention makes it possible to provide a shock absorber that can produce more arbitrary damping force characteristics.

1 is a cross-sectional view of a main portion of a shock absorber according to a first embodiment of the present invention. FIG. 2 is an enlarged view of the piston and the spring receiving member shown in FIG. 1 . FIG. 3 is an enlarged view of the laminated valve shown in FIG. 2 in a deformed state. 2 is a diagram illustrating the damping force characteristics of the shock absorber shown in FIG. 1 . FIG. 6 is an enlarged view of a main portion of a shock absorber according to a second embodiment of the present invention. 6 is a diagram illustrating the damping force characteristic of the shock absorber shown in FIG. 5 . FIG. 11 is an enlarged view of a main portion of a shock absorber according to a third embodiment of the present invention.

An embodiment of the present invention will be described below with reference to the attached drawings. Note that the embodiment shown in the attached drawings is an example of the present invention, and the present invention is not limited to this embodiment.

Example 1
Please refer to Fig. 1. Fig. 1 shows a shock absorber 10 that constitutes a main part of a front fork. The front fork is provided at the front of a saddle-ride type vehicle and suppresses the transmission of vibrations received from the road surface to the vehicle body.

The shock absorber 10 is used by bridging the area around the head pipe of the motorcycle to the front wheel. When the motorcycle is traveling, vibrations are input from the front wheel due to the influence of unevenness in the road surface, etc. At this time, the shock absorber 10 compresses and expands, generating a damping force.

The shock absorber 10 has as its main components a cylindrical outer tube 11 that extends downward from the head pipe of the motorcycle toward the front wheel, a cylindrical inner tube 12 that extends upward from the front wheel toward the head pipe with its tip inserted inside the outer tube 11, and a coil spring 13 that biases the outer tube 11 and inner tube 12 in directions separating them from each other.

The space enclosed by the outer tube 11 and the inner tube 12 is filled with oil as a working fluid. In addition, seals 14 and 15 are provided between the inner surface of the tip of the outer tube 11 and the outer surface of the inner tube 12 to prevent the oil from leaking out.

The shock absorber 10 has an outer tube cover 16 that closes the upper end (terminal end) of the outer tube 11, and a cylindrical cylinder 17 that is arranged inside the outer tube 11 on the coaxial line CL.

The shock absorber 10 also has an axle holder closing the lower end (terminal end) of the inner tube 12, a piston rod 22 extending from the axle holder along the axis CL, and a piston 30 provided at the tip of the piston rod 22 and through which oil can pass during compression and extension. The tip of the piston rod 22 and the piston 30 are inserted inside the cylinder 17. When the shock absorber 10 expands and contracts, the piston rod 22 and the piston 30 are displaced relative to the cylinder 17. During displacement, oil flows inside the piston 30, generating a damping force.

Refer to Figure 2. On the outer periphery of the tip of the piston rod 22, there are provided a piston spring 25 that biases the piston 30 in the closing direction, a cylindrical collar 26, a slide spring support member 40 that can slide on the outer periphery of the collar 26 and transmits the biasing force of the piston spring 25 to the piston 30, a nut 28 that prevents the piston 30 from coming out, and a washer 29 that is sandwiched between the nut 28 and the piston 30.

Refer to Figure 1. The piston 30 divides the interior of the cylinder 17 into a first chamber R1 and a second chamber R2.

See Figure 2. The piston rod 22 has a hole drilled along the axis, allowing oil to pass through. The piston rod 22 is formed with a rod-side spring receiving portion 22a and a stopper portion 22b at a portion where the outer diameter changes. The rod-side spring receiving portion 22a and the stopper portion 22b each extend radially from the axis CL as the center, and are roughly O-shaped. The rod-side spring receiving portion 22a receives the end of the piston portion spring 25. The stopper portion 22b receives the end of the collar 26, and restricts movement when the slide spring receiving member 40 comes into contact with it.

The area between the rod-side spring receiving portion 22a and the stopper portion 22b of the piston rod 22 is a spring guide portion 22c that guides the piston spring 25 and prevents it from falling over. The outer diameter of the spring guide portion 22c is set slightly smaller than the inner diameter of the piston spring 25.

The tip of the piston rod 22 is male threaded and a nut 28 is fastened to it.

The piston 30 has a piston body 31 having a flow passage 31a therein through which the working fluid can pass, a seal 32 fixed to the outer peripheral surface of the piston body 31 and whose outer peripheral surface abuts the inner peripheral surface of the cylinder 17 (see Figure 1), a compression side laminated valve 33 (laminated valve 33) that is biased in a direction to close the end (one end) of the flow passage 31a and opens during the compression stroke, and an extension side laminated valve 34 that is biased in a direction to close the end (other end) of the flow passage 31a and opens during the extension stroke.

For example, when a motorcycle runs over a step, a compressive force is applied to the shock absorber 10, displacing the piston 30 as shown by the white arrow 51. This causes oil to flow into the flow passage 31a as shown by the arrow 52, displacing the compression side laminated valve 33 and/or the slide spring support member 40. At this time, a damping force is generated.

After the shock absorber 10 is compressed, the force of the coil spring 13 (see FIG. 1) exerts a force on the shock absorber 10 in the expansion direction, displacing the piston 30 as shown by the outlined arrow 53. This causes oil to flow into the flow passage 31a as shown by the arrow 54, displacing the compression side laminated valve 33 and/or the slide spring support member 40. At this time, a damping force is generated.

The compression side laminated valve 33 and the extension side laminated valve 34 can be well-known laminated valves, each of which is made of a plurality of laminated metal plate valves that are elastically deformable in the axial direction. The forces required for the compression side laminated valve 33 and the extension side laminated valve 34 to open the flow passage 31a may be set to be the same or different.

For example, a compression coil spring is used as the piston spring 25. The biasing force of the piston spring 25 may be set so that the compression side laminated valve 33 is displaced before the slide spring support member 40, or the slide spring support member 40 is displaced before the compression side laminated valve 33.

The collar 26 is formed, for example, of a resin cylinder. The collar 26 is sandwiched and fixed between the stopper portion 22b and the piston body 31. In addition to the slide spring receiving member 40, the compression side laminated valve 33 is provided on the outer periphery of the collar 26. In other words, the compression side laminated valve 33 and the slide spring receiving member 40 are provided slidably on the outer periphery of the collar 26.

The slide spring support member 40 has a spring support tubular portion 41 formed in a cylindrical shape to surround the collar 26, and a flange portion 42 extending radially from the tip of the spring support tubular portion 41.

The outer diameter of the spring receiving tubular portion 41 is approximately the same as the outer diameter of the spring guide portion 22c and is slightly smaller than the inner diameter of the piston spring 25. The spring receiving tubular portion 41 guides the piston spring 25 and prevents it from falling over.

One surface of the flange portion 42 is a contact surface 42a against which the compression side laminated valve 33 can contact, and the other surface is a slider side spring support portion 42b that supports the piston portion spring 25.

The contact surface 42a is configured by an inclined surface that continues radially outward from the axis CL and moves away from the piston body 31. In other words, the contact surface 42a includes a tapered portion that is inclined with respect to the vertical plane S2. In other words, if the surface formed by connecting the portion of the contact surface 42a closest to the axis CL to the radially outer end is taken as a virtual plane S1 (in the shock absorber 10, the virtual plane S1 coincides with the contact surface 42a), the virtual plane S1 can be said to be inclined with respect to the vertical plane S2 that spreads radially around the axis CL. The reason will be described later.

The abutment surface 42a may be inclined in the opposite direction. In other words, it may be inclined so as to approach the piston body 31 as it moves away radially outward from the axis CL. The abutment surface 42a may also be a curved surface whose inclination changes continuously or a stepped surface whose inclination changes in stages, and is not limited to a flat surface. Furthermore, these shapes can be combined, and any shape can be used to match the characteristics of the damping force to be generated.

The function of the shock absorber 10 will be explained.

For example, when the piston 30 rises inside the cylinder 17 (see FIG. 1), oil flows into the flow passage 31a as shown by the arrow 52. The oil pressure of this oil applies a downward force to the compression side laminated valve 33.

Please refer to Figure 3. Figure 3 shows the compression side laminated valve 33 in a state of elastic deformation due to hydraulic pressure. If the biasing force of the piston portion spring 25 is set so that the compression side laminated valve 33 displaces before the slide spring support member 40, the slide spring support member 40 is displaced by further application of hydraulic pressure.

Please also refer to Figure 4. Figure 4 shows a graph showing the relationship between piston speed and damping force. The horizontal axis represents piston speed, and the vertical axis represents damping force. Since the cross-sectional area of the flow path 31a (see Figure 2) inside the piston 30 is constant, it can also be said that the graph shows the relationship between oil flow rate and damping force. With shock absorber 10, the damping force is increased significantly in the area where piston 30 starts to move, and thereafter the damping force also increases in proportion to the increase in piston speed.

By making the contact surface 42a a tapered surface that moves away from the piston body 31 (see FIG. 2), the amount of displacement of the compression side laminated valve 33 can be made larger than when the contact surface 42a is a surface perpendicular to the axis (see vertical surface S2). By changing the amount of displacement of the compression side laminated valve 33, the characteristics of the damping force also change. In other words, the damping force can be adjusted by changing the shape of the contact surface 42a.

The damping force characteristics can also be changed by setting the spring force of the piston portion spring 25 so that the slide spring support member 40 displaces before the compression side stacked valve 33.

Example 2
Next, a second embodiment will be described with reference to the drawings.

Refer to Figure 5. In shock absorber 10A according to embodiment 2, the shape of flange portion 42A of slide spring receiving member 40A differs from the shape of flange portion 42 shown in Figure 3. The other basic configuration is the same as shock absorber 10 (see Figure 2). For configuration common to shock absorber 10, the same reference numerals are used and detailed description is omitted as appropriate.

The contact surface 42Aa that contacts the compression side laminated valve 33 has an outermost portion that protrudes toward the piston body 31 (see FIG. 2). In other words, the contact surface 42Aa includes a portion P2 that protrudes to a portion closer to the piston body 31 than the portion closest to the axis line CL (see FIG. 2).

If the surface formed by connecting the portion of the abutment surface 42Aa closest to the axis line CL to the radially outer end is defined as a virtual surface S3, it can be said that the virtual surface S3 is inclined with respect to a vertical surface S2 extending in the radial direction around the axis line CL.

Of the compression side stacked valves 33, the valves abutting the protruding portion P2 have their displacement restricted compared to when the abutment surface 42a is formed on the vertical surface S2.

As mentioned above, the abutment surface 42Aa may have multiple protruding portions P2 so as to have a stepped shape that gradually approaches the piston body 31.

Please also refer to Figure 6. Figure 6 shows a graph showing the relationship between piston speed and damping force. With shock absorber 10A, the change in damping force relative to changes in piston speed is large in the slow and fast piston speed regions, and the change in damping force relative to changes in piston speed is small in the region between these two.

Example 3
Next, a third embodiment will be described with reference to the drawings.

Refer to Figure 7. In shock absorber 10B according to Example 3, the shape of flange portion 42B of slide spring receiving member 40B differs from the shape of flange portion 42 shown in Figure 2 and flange portion 42A shown in Figure 5. The other basic configuration is common to shock absorbers 10 (see Figure 2) and 10A (see Figure 5) described above. For configuration common to shock absorbers 10 and 10A, the same reference numerals will be used and detailed explanations will be omitted as appropriate.

The contact surface 42Ba that contacts the compression side laminated valve 33 is composed of a tapered portion P1 and a protruding portion P2. This allows a damping force characteristic different from the damping force characteristic described above to be generated.

The shock absorbers 10, 10A, and 10B described above are summarized below.

Referring to Figure 1. First, the shock absorber 10 has a cylinder 17 that is substantially cylindrical and filled with a working fluid, and a piston 30 that is provided inside the cylinder 17 and divides the inside of the cylinder 17 into a first chamber R1 and a second chamber R2.

Refer to Figure 2. The shock absorber 10 further includes a piston spring 25 that is formed inside the piston 30 and biases the flow path 31a, through which the working fluid flows, in a direction to close the flow path, and a slide spring support member 40 that is disposed between the piston spring 25 and the piston 30 and is displaceable in a direction along the axis CL of the cylinder 17 and transmits the biasing force of the piston spring 25 to the piston 30.

The piston 30 has a piston body 31 having a flow passage 31a therein through which the working fluid can pass, and a compression side laminated valve 33 which is biased in a direction to close one end of the flow passage 31a and is made up of multiple plate-shaped valves stacked on top of each other.

The slide spring support member 40 includes an abutment surface 42a against which the compression side laminated valve 33 can abut. If a surface formed by connecting the portion of the abutment surface 42a closest to the axis line CL to the radially outer end is defined as an imaginary surface S1, the imaginary surface S1 is inclined with respect to a vertical surface S2 that extends in the radial direction around the axis line CL.

The imaginary plane S1 is inclined with respect to the vertical plane S2 that spreads in the radial direction around the axis line CL. This allows the displacement amount of the compression side laminated valve 33 to be set arbitrarily, compared to when the abutment surface 42a is along the vertical plane S2. The generated damping force can be adjusted by controlling the displacement amount of the compression side laminated valve 33. Specifically, the compression side laminated valve 33 is formed by stacking multiple plate-shaped valves with a large diameter on a plate-shaped valve with a small diameter that contacts the slide spring receiving member 40. By adjusting the size of the plate-shaped valve with a small diameter and the contact position with the abutment surface 42a, a complex damping force characteristic can be obtained compared to when a single plate-shaped valve is used. The imaginary plane S1 of the abutment surface 42a is inclined with respect to the vertical plane S2 that spreads in the radial direction around the axis line CL, so that the displacement amount of the compression side laminated valve 33 can be adjusted more arbitrarily. Furthermore, since the abutment surface 42a is provided on the slide spring receiving member 40, the slide spring receiving member 40 can slide while maintaining a large displacement amount of the compression side laminated valve 33. The synergistic effect of these factors makes it possible to generate more arbitrary damping force characteristics. It is possible to provide a shock absorber that can generate more arbitrary damping force characteristics. The same applies to the shock absorber 10A (see FIG. 5) and the shock absorber 10B (see FIG. 7).

Secondly, the first shock absorber 10 has a stopper portion 22b that is arranged to be able to abut against the slide spring support member 40 and that restricts the displacement of the slide spring support member 40 by the abutment of the slide spring support member 40.

The amount of displacement of the slide spring support member 40 can be set as desired by changing the position of the stopper portion 22b. This makes it possible to generate more desired damping force characteristics. The same applies to shock absorber 10A (see FIG. 5) and shock absorber 10B (see FIG. 7).

Third, in the first or second shock absorber 10, the contact surface 42a includes a tapered portion that is inclined with respect to the vertical plane S2. The tapered portion provides a proportional damping force characteristic.

See Figure 5. Fourthly, in any of the first to third shock absorbers 10A, the abutment surface 42Aa includes a portion P2 that protrudes to a portion closer to the piston body 31 (see Figure 2) than the portion closest to the axis CL. This suppresses the amount of opening of the compression side laminated valve 33, thereby obtaining a characteristic that makes it easier for the damping force to increase (progressive characteristic).

See FIG. 2. Fifth, in any one of the first to fourth shock absorbers 10, the biasing force of the piston spring 25 is set so that the compression side laminated valve 33 is displaced before the slide spring support member 40. This allows the compression side laminated valve 33 to open in the low piston speed range, making it possible to provide smooth damping force characteristics in the low piston speed range, and to meet such needs. In addition, in the high speed range, the slide spring support member 40 is displaced while maintaining the displacement of the compression side laminated valve 33, making it possible to provide damping force characteristics that are linked to the damping force characteristics in the low speed range. The same applies to shock absorbers 10A (see FIG. 5) and 10B (see FIG. 7).

Sixth, in any of the first to fourth shock absorbers 10, the biasing force of the piston spring 25 is set so that the slide spring support member 40 is displaced before the compression side laminated valve 33. As a result, the slide spring support member 40 is displaced in the low piston speed range, so that the damping force characteristics in the low piston speed range can be a single damping force characteristic. In the high piston speed range, the compression side laminated valve 33 is displaced, so that smooth damping force characteristics can be obtained and such needs can be met. The same applies to shock absorber 10A (see FIG. 5) and shock absorber 10B (see FIG. 7).

Seventh, in any one of the first to sixth shock absorbers 10, the slide spring receiving member 40 includes a spring receiving tubular portion 41 formed in a cylindrical shape so as to surround the axis line CL. The spring receiving tubular portion 41 extends along the inside of the piston portion spring 25.

Since the slide spring receiving member 40 can be displaced more reliably along the axis line CL, the set damping force characteristics can be more reliably generated. In addition, the collapse of the piston portion spring 25 can be suppressed. The same applies to the shock absorber 10A (see FIG. 5) and the shock absorber 10B (see FIG. 7).

Although the shock absorber according to the present invention has been described as being applied to an inverted front fork of a motorcycle, it can also be applied to an upright front fork or rear cushion. In addition, the vehicle on which it is mounted is not limited to motorcycles, but can also be applied to saddle-type vehicles such as three-wheeled vehicles and other vehicles.

In addition, the cylinder is not limited to being provided inside the inner tube. In other words, the outer tube or the inner tube may be the cylinder of the present invention as long as it is a cylindrical body with a piston abutting on its inner circumferential surface.

Although the piston has been described as being movable axially inside the cylinder, it may be fixed inside the cylinder, such as a piston provided at the end of a front fork or a piston used in the damping force generating section of a rear cushion.

In other words, as long as the action and effect of the present invention are achieved, the present invention is not limited to the examples.

The shock absorber of the present invention is suitable for the front fork of a motorcycle.

10; 10A; 10B... shock absorber, 17... cylinder, 22b... stopper portion, 25... piston portion spring, 30... piston, 31... piston body, 31a... flow path, 33... compression side laminated valve (laminated valve), 40; 40A; 40B... slide spring receiving member, 42a; 42Aa; 42Ba... abutment surface, R1... first chamber, R2... second chamber, S1; S3... imaginary surface, S2... vertical surface, P1... tapered portion, P2... protruding portion, CL... axis

Claims (4)

A cylinder having a generally cylindrical shape and filled with a working fluid;
a piston provided inside the cylinder and dividing the interior of the cylinder into a first chamber and a second chamber;
a piston spring that biases a flow path formed inside the piston in a direction to close the flow path through which the working fluid flows;
a slide spring receiving member disposed between the piston spring and the piston so as to be displaceable in a direction along the axis of the cylinder and transmitting the biasing force of the piston spring to the piston,
The piston is
A piston body having a flow passage therein through which the working fluid can pass;
a laminated valve configured by stacking a plurality of plate-shaped valves, the laminated valve being biased in a direction to close one end of the flow path;
The slide spring receiving member includes an abutment surface against which the laminated valve can abut,
when a surface formed by connecting a portion of the contact surface closest to the axis to an end portion on the radially outer side is defined as a virtual surface, the virtual surface is inclined with respect to a vertical plane extending in a radial direction about the axis,
The contact surface includes a portion that protrudes to a portion closer to the piston body than a portion closest to the axis. 2. The shock absorber according to claim 1,
The slide spring receiving member has a stopper portion that is capable of contacting the slide spring receiving member and that restricts the displacement of the slide spring receiving member by the slide spring receiving member contacting the stopper portion. 2. The shock absorber according to claim 1,
The biasing force of the piston spring is set so that the laminated valve is displaced before the slide spring receiving member. 2. The shock absorber according to claim 1,
The slide spring receiving member includes a spring receiving cylindrical portion formed in a cylindrical shape so as to surround the axis line,
The spring receiving cylindrical portion extends along the inside of the piston spring.

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