JP7461284B2 - buffer - Google Patents

Description

The present invention relates to a shock absorber.

Shock absorbers, for example, are installed between the body and wheels of a vehicle to exert a damping force and suppress vibration between the body and wheels. The damping force exerted by the shock absorber is exerted by a damping valve and affects the ride comfort of the vehicle.

Such a shock absorber includes, for example, a cylinder, a rod movably inserted into the cylinder, and an expansion side chamber connected to the rod and movably inserted into the cylinder, and in which the cylinder is filled with hydraulic oil. a reservoir having a liquid chamber for storing liquid and an air chamber for pressurizing the liquid chamber, a first passage connecting the expansion side chamber and the liquid chamber, and the pressure side chamber and the liquid chamber. a second passage connecting the two, a rebound damping valve and a first check valve provided in parallel with the first passage, and a compression damping valve and a second check valve provided in parallel with the second passage. (For example, see Patent Document 1).

The first check valve only allows hydraulic oil to flow from the expansion side chamber to the reservoir, and the second check valve only allows hydraulic oil to flow from the compression side chamber to the reservoir.

Therefore, in a shock absorber configured in this way, during an extension operation in which the piston moves relative to the cylinder in a direction that compresses the extension side chamber, the hydraulic oil in the compressed extension side chamber moves through the extension side damping valve and the second check valve to the expanding compression side chamber, generating an extension side damping force in the extension side damping valve that impedes the extension operation.

In contrast, when the shock absorber is in a contraction operation in which the piston moves relative to the cylinder in a direction that compresses the compression side chamber, the hydraulic oil in the compressed compression side chamber moves through the compression side damping valve and the first check valve to the expanding extension side chamber, generating a compression side damping force in the compression side damping valve that impedes the contraction operation.

U.S. Patent No. 7,607,522

In this way, with conventional shock absorbers, even during contraction, it is possible to send an amount of hydraulic fluid equal to the volume variation of the pressure side chamber to be compressed to the compression side damping valve, and it is also effective in generating compression side damping force. The pressure receiving area of the piston can be increased. In a typical double-tube shock absorber, only the volume of hydraulic oil that the rod enters into the cylinder when it contracts can be sent to the pressure-side damping valve, and because the rod diameter is restricted, the pressure-receiving area of the piston is also large. It's tough.

Therefore, compared to a typical twin-tube shock absorber, the conventional shock absorber allows a larger amount of hydraulic oil to pass through the compression damping valve during compression, and also ensures a larger pressure-receiving area for the piston, providing an advantageous structure for exerting a large damping force.

Here, we want to set the damping force characteristics generated by the buffer against the piston speed using damping valves on the expansion side and compression side, but as the oil passage diameter becomes smaller, the pressure loss due to the resistance caused by the oil passage will override the damping force characteristics. This makes it difficult to design. Also, if you want to obtain a large damping force, it is necessary to increase the size of the damping valves on the rebound and compression sides.

However, in conventional shock absorbers, because a layout is adopted in which a reservoir is provided between the rebound damping valve and the compression damping valve, the oil passage communicating between the rebound chamber and the reservoir and the oil passage communicating between the compression chamber and the reservoir are required. In addition, it is necessary to install the damping valves on the expansion side and compression side, which are installed in these oil passages, in the narrow space between the cylinder and the reservoir. Therefore, in conventional shock absorbers, if the diameter of the oil passage is increased and the damping valves on the expansion side and compression side are made large, the entire shock absorber becomes extremely large, impairing its mountability on a vehicle.

Therefore, with conventional shock absorbers, it has been difficult to improve the degree of freedom in designing the damping force characteristics, increase the damping force, and downsize the shock absorber.

Therefore, the present invention aims to provide a shock absorber that can improve the design freedom of the damping force characteristics, and can not only increase the damping force but also be made smaller.

In order to solve the above problems, the shock absorber of the present invention comprises a cylinder, a rod movably inserted into the cylinder, a piston connected to the rod and movably inserted into the cylinder, which divides the cylinder into an extension side chamber and a compression side chamber filled with liquid, a reservoir for storing liquid, an extension side damping passage that allows liquid to flow from the extension side chamber to the reservoir, a compression side damping passage that allows liquid to flow from the compression side chamber to the reservoir, an extension side damping valve provided in the extension side damping passage to provide resistance to the flow of liquid passing through, a compression side damping valve provided in the compression side damping passage to provide resistance to the flow of liquid passing through, an extension side suction passage that allows liquid to flow only from the reservoir to the extension side chamber, and a compression side suction passage that allows liquid to flow only from the reservoir to the compression side chamber, and the reservoir is formed in the rod or in a housing provided in the rod.

Even if a shock absorber configured in this way adopts a layout with a reservoir between the extension side damping valve and the compression side damping valve, the reservoir is not located outside the cylinder, so the external shape can be slimmed down accordingly and made smaller. Also, even if a shock absorber configured in this way adopts a layout with a reservoir between the extension side damping valve and the compression side damping valve, the extension side damping passage, compression side reduction passage, extension side damping valve and compression side damping valve can be located inside the cylinder, so that the oil passage diameter can be increased and the extension side and compression side damping valves can be enlarged without resulting in an increase in the size of the entire shock absorber.

The extension side damping passage, compression side damping passage, extension side suction passage, and compression side suction passage in the shock absorber may be provided in the piston. In this way, a shock absorber that employs a structure in which the extension side damping passage, compression side damping passage, extension side suction passage, and compression side suction passage are provided in the piston can consolidate the extension side damping valve and compression side damping valve in the piston, making it possible to make the shock absorber more compact.

Furthermore, the piston in the shock absorber may include a first partition wall attached to the rod and sliding against the inner periphery of the cylinder to define an extension side chamber and having an extension side damping passage and an extension side suction passage, and a second partition wall attached to the rod at a distance from the first partition wall and sliding against the inner periphery of the cylinder to define a compression side chamber and having a compression side damping passage and a compression side suction passage, and the reservoir may be connected to the gap between the first partition wall and the second partition wall. With a shock absorber configured in this way, the extension side damping valve and the compression side damping valve can be easily installed in the shock absorber by using the first partition wall and the second partition wall as valve seat members.

In addition, the shock absorber includes a growth side secondary damping passage that communicates the growth side chamber and the compression side chamber without a reservoir and allows only the flow of liquid from the growth side chamber to the compression side chamber, and a reservoir between the compression side chamber and the compression side chamber. A compression side damping passage that communicates with each other without going through the compression side chamber and allowing only the flow of liquid from the compression side chamber to the growth side chamber, and a compression side secondary damping passage that is provided in the growth side secondary damping passage and can adjust the resistance given to the flow of the liquid passing through by external operation. It is also possible to provide a secondary damping valve on the compression side, which is capable of expansion, and a secondary damping valve on the compression side, which is provided in the compression secondary damping passage and whose resistance to the flow of liquid passing therethrough can be adjusted by external operation. According to the shock absorber configured in this manner, the resistance given to the flow of liquid between the expansion side secondary damping valve and the compression side secondary damping valve is adjusted from the outside to be suitable for suppressing vibrations of the vehicle body of the vehicle to which it is applied. The damping force on the rebound and compression sides can be easily adjusted independently.

As described above, according to the shock absorber of the present invention, the degree of freedom in designing the damping force characteristics can be improved, and not only the damping force can be increased, but also the size can be reduced.

FIG. 2 is a vertical cross-sectional view of the shock absorber according to the embodiment. 1 is a diagram showing a damping force characteristic of a shock absorber according to an embodiment; FIG. 2 is a diagram showing an example of a check valve of the shock absorber according to an embodiment; FIG. 11 is a cross-sectional view of a shock absorber according to a first modified example of the embodiment. FIG. 11 is a cross-sectional view of a shock absorber according to a second modified example of the embodiment.

The present invention will be described below based on the embodiment shown in the drawings. As shown in FIG. 1, the shock absorber D in one embodiment includes a cylinder 1, a rod 2 movably inserted into the cylinder 1, a piston 3 connected to the rod 2 and movably inserted into the cylinder 1, and dividing the cylinder 1 into an extension side chamber R1 and a compression side chamber R2 filled with liquid, a reservoir R for storing liquid, an extension side damping passage 4 that allows the flow of liquid from the extension side chamber R1 to the reservoir R, a compression side damping passage 5 that allows the flow of liquid from the compression side chamber R2 to the reservoir R, an extension side damping valve 6 provided in the extension side damping passage 4 to provide resistance to the flow of liquid passing through, a compression side damping valve 7 provided in the compression side damping passage 5 to provide resistance to the flow of liquid passing through, an extension side suction passage 8 that allows only the flow of liquid from the reservoir R to the extension side chamber R1, and a compression side suction passage 9 that allows only the flow of liquid from the reservoir R to the compression side chamber R2. This shock absorber D is installed between the body and axle of a vehicle (not shown) to suppress vibrations of the body and wheels.

The following describes each part of the shock absorber D in detail. As shown in Figure 1, the cylinder 1 is cylindrical, with the upper end in Figure 1 being closed by an annular rod guide 19 and the lower end in Figure 1 being closed by a cap 20.

The inside of the cylinder 1 is divided into an extension side chamber R1 at the top in FIG. 1 and a compression side chamber R2 at the bottom in FIG. 1 by a piston 3 inserted movably into the cylinder 1. The extension side chamber R1 and the compression side chamber R2 are filled with a liquid such as hydraulic oil. Note that the liquid may be other than hydraulic oil, such as water or an aqueous solution.

The rod 2 is inserted into the cylinder 1 through the inner circumference of the rod guide 19 so as to be movable in the vertical direction, which is the axial direction in FIG. 1, and the piston 3 is connected to the tip. Therefore, when the rod 2 moves axially relative to the cylinder 1, the piston 3 connected to the rod 2 also moves axially relative to the cylinder 1, compressing one of the extension side chamber R1 and the compression side chamber R2 and expanding the other of the extension side chamber R1 and the compression side chamber R2. The outer circumference of the rod 2 is in sliding contact with the inner circumference of the rod guide 19, and the axial movement of the rod 2 relative to the cylinder 1 is guided by the rod guide 19 and the piston 3. Note that the shock absorber D of this embodiment is configured as a so-called single-rod type shock absorber in which the rod 2 is inserted only into the extension side chamber R1, but it may also be configured as a so-called double-rod type shock absorber in which the rod 2 is inserted not only into the extension side chamber R1 but also into the compression side chamber R2.

The piston 3 is configured with a first partition wall 3a that is annular, attached to the outer periphery of the rod 2, and in sliding contact with the inner periphery of the cylinder 1 to define the expansion side chamber R1 at the top of the cylinder 1 in FIG. 1, and a second partition wall 3b that is also annular, attached to the outer periphery of the rod 2 with a gap between it and the first partition wall 3a, and in sliding contact with the inner periphery of the cylinder 1 to define the compression side chamber R2 at the bottom of the cylinder 1 in FIG. 1.

The rod 2 includes a hollow housing 11 that defines a reservoir R between the first partition 3a and the second partition 3b.
and a free piston 12 inserted into the housing 11 so as to be axially movable and dividing the housing 11 into a liquid chamber L filled with liquid and an air chamber G filled with gas. The liquid chamber L is connected to a gap A formed in the cylinder 1 between the first partition wall 3a and the second partition wall 3b by a through hole 11a provided in the housing 11. In addition, an inert high-pressure gas is sealed in the air chamber G, and the pressure in the air chamber G acts on the liquid chamber L via the free piston 12 to pressurize the liquid chamber L. In the shock absorber D of this embodiment, the reservoir R is divided into the liquid chamber L and the air chamber G by the free piston 12, but the reservoir R may be divided into the liquid chamber L and the air chamber G by a diaphragm or a bellows instead of the free piston 12. In addition, in the shock absorber D of this embodiment, a high-pressure gas is sealed in the air chamber G, but instead of sealing the high-pressure gas, an elastic body such as a spring that urges the free piston 12 in a direction to compress the liquid chamber L may be provided.

An outer cylinder 10 is provided on the outer periphery of the cylinder 1 to cover the outer periphery of the cylinder 1. Further, the upper end of the outer cylinder 10 in FIG. 1 is fitted with a rod guide 19 and is closed, and the lower end of the outer cylinder 10 in FIG. 1 is closed by a cap 20. The annular gap S formed between the cylinder 1 and the outer cylinder 10 is communicated with the expansion side chamber R1 inside the cylinder 1 through a through hole 1a provided near the upper end of the cylinder 1 in FIG. There is.

The extension-side damping passage 4 is provided with a port 3a1 that is provided in the first partition 3a of the piston 3 and communicates the extension-side chamber R1 with the gap A, and communicates the extension-side chamber R1 with the liquid chamber L in the reservoir R via the gap A and the through hole 11a. At the gap side end, which is the lower end of the first partition 3a in FIG. 1, an extension-side damping valve 6 is stacked, which is a laminated leaf valve composed of multiple stacked annular plates that open and close the outlet end of the port 3a1.

The expansion-side damping valve 6 has an inner circumferential side fixed to the rod 2 together with the first partition wall 3a, and is allowed to bend on the outer circumferential side. The growth side damping valve 6 uses the first partition wall 3a as a valve seat member, and when in contact with the first partition wall 3a, the port 3a1 is closed, and the pressure of the growth side chamber R1 acting on the front side through the port 3a1 is transferred to the back side. When the pressure of the reservoir R acting on the side via the gap A becomes greater and the differential pressure between the two reaches the valve opening pressure, the outer periphery is bent to open the port 3a1. Then, when the port 3a1 is opened, the growth-side damping valve 6 allows the flow of liquid from the growth-side chamber R1 toward the reservoir R, and provides resistance to the flow of the liquid. On the other hand, when the pressure in the reservoir R is higher than the growth side chamber R1, the growth side damping valve 6 comes into close contact with the first partition wall 3a to block the port 3a1 and prevent the flow of liquid from the reservoir R to the growth side chamber R1. prevent. In this way, the growth-side damping valve 6 that opens and closes the port 3a1 functions not only as a damping valve but also as a check valve, and the growth-side damping valve 6 directs the growth-side damping passage 4 from the growth-side chamber R1 to the reservoir R. It is set up as a one-way passageway that only allows the flow of liquid.

When the extension damping valve 6 is configured as a valve that allows two-way flow, such as an orifice or choke, a check valve that forces the flow of liquid only from the extension chamber R1 to the reservoir R may be provided in the extension damping passage 4. In this way, the extension damping passage 4 can be set as a one-way passage by using the extension damping valve 6 that allows the flow of liquid only in one direction, or a check valve may be provided separately when the extension damping valve 6 is a valve that allows the flow of liquid in both directions.

The extension-side suction passage 8 is provided with a port 3a2 in the first partition 3a of the piston 3 that communicates between the gap A and the extension-side chamber R1, and communicates between the liquid chamber L in the reservoir R and the extension-side chamber R1 via the gap A and the through hole 11a. At the end of the extension-side chamber side, which is the upper end of the first partition 3a in FIG. 1, an extension-side check valve 13 made of an annular plate that opens and closes the outlet end of the port 3a2 is stacked, with the first partition 3a as a valve seat member. The inner periphery of the extension-side check valve 13 is fixed to the rod 2 together with the first partition 3a, and deflection on the outer periphery is permitted.

The expansion side check valve 13 closes the port 3a2 when in contact with the first partition wall 3a, so that the pressure of the reservoir R acting on the front side through the port 3a2 is higher than the pressure of the expansion side chamber R1 acting on the rear side. When the size increases, the outer periphery is bent to open the port 3a2. When the growth side check valve 13 opens the port 3a2, it allows the liquid to flow from the reservoir R toward the growth side chamber R1. Note that the resistance that the expansion side check valve 13 provides to the flow of liquid passing through the port 3a2 is extremely small. On the other hand, when the pressure in the growth side chamber R1 is higher than the pressure in the reservoir R, the growth side check valve 13 comes into close contact with the first partition wall 3a to block the port 3a2 and prevent the liquid from flowing from the growth side chamber R1 to the reservoir R. block the flow. In this way, the growth side check valve 13 that opens and closes the port 3a2 sets the growth side suction passage 8 to be a one-way passageway that only allows the flow of liquid from the reservoir R to the growth side chamber R1.

The compression side damping passage 5 includes a port 3b1 provided in the second partition wall 3b of the piston 3 and communicating between the pressure side chamber R2 and the gap A, and communicates between the pressure side chamber R2 and the reservoir R via the gap A and the through hole 11a. It communicates with the liquid chamber L in. At the gap side end of the second partition wall 3b, which is the upper end in FIG. There is.

The compression side damping valve 7 is fixed to the rod 2 together with the second partition 3b on the inner periphery, and is allowed to bend on the outer periphery. The compression side damping valve 7 closes the port 3b1 when it is in contact with the second partition 3b, using the second partition 3b as a valve seat member, and when the pressure of the compression side chamber R2 acting on the front side through the port 3b1 becomes greater than the pressure of the reservoir R acting on the back side through the gap A, and the differential pressure between the two reaches the valve opening pressure, the compression side damping valve 7 bends the outer periphery and opens the port 3b1. When the compression side damping valve 7 opens the port 3b1, it allows the flow of liquid from the compression side chamber R2 to the reservoir R and provides resistance to the flow of the liquid. On the other hand, when the pressure of the reservoir R is higher than the compression side chamber R2, the compression side damping valve 7 comes into close contact with the second partition 3b to block the port 3b1 and prevent the flow of liquid from the reservoir R to the compression side chamber R2. In this way, the compression side damping valve 7 that opens and closes port 3b1 functions not only as a damping valve but also as a check valve, and the compression side damping valve 7 sets the compression side damping passage 5 as a one-way passage that only allows the flow of liquid from the compression side chamber R2 to the reservoir R.

When the compression side damping valve 7 is configured as a valve that allows two-way flow, such as an orifice or choke, a check valve that forces liquid to flow only from the compression side chamber R2 to the reservoir R may be provided in the compression side damping passage 5. In this way, the compression side damping passage 5 can be set as a one-way passage by using the compression side damping valve 7 that allows liquid to flow only in one direction, or a check valve may be provided separately if the compression side damping valve 7 is a valve that allows liquid to flow in both directions.

The pressure side suction passage 9 is provided with a port 3b2 provided in the second partition wall 3b of the piston 3 and communicates the gap A with the pressure side chamber R2, and is connected to the liquid chamber L in the reservoir R via the gap A and the through hole 11a. and the pressure side chamber R2 are communicated with each other. A pressure side check valve 14 made of an annular plate that opens and closes the outlet end of the port 3b2 is laminated on the pressure side chamber side end of the second partition wall 3b, which is the lower end in FIG. 1, using the second partition wall 3b as a valve seat member.

The compression side check valve 14 is fixed to the rod 2 on the inner periphery together with the second partition wall 3b, and is allowed to bend on the outer periphery. When the compression side check valve 14 abuts against the second partition wall 3b, it closes the port 3b2, and when the pressure of the reservoir R acting on the front side through the port 3b2 becomes greater than the pressure of the compression side chamber R2 acting on the back side, it bends the outer periphery and opens the port 3b2. When the compression side check valve 14 opens the port 3b2, it allows the flow of liquid from the reservoir R to the compression side chamber R2. The resistance that the compression side check valve 14 provides to the flow of liquid passing through the port 3b2 is extremely small. On the other hand, when the pressure of the compression side chamber R2 is higher than the pressure of the reservoir R, the compression side check valve 14 comes into close contact with the second partition wall 3b to block the port 3b2 and prevent the flow of liquid from the compression side chamber R2 to the reservoir R. In this way, the pressure-side check valve 14 that opens and closes port 3b2 sets the pressure-side suction passage 9 as a one-way passage that only allows liquid to flow from the reservoir R to the pressure-side chamber R2.

In addition to the above-described configuration, the shock absorber D of the present embodiment also includes a rebound side sub-damping passage 15 that communicates the growth side chamber R1 and the compression side chamber R2 without intervening the reservoir R, and a compression side chamber R2 and the expansion side chamber. A compression side sub-damping passage 16 that communicates with R1 without going through the reservoir R, a rebound side sub-damping valve 17 provided in the rebound side sub-damping passage 15, and a compression side sub-damping valve 18 provided in the compression side sub-damping passage 16. We are prepared.

The expansion-side auxiliary damping passage 15 is composed of an annular gap S that is connected to the expansion-side chamber R1 via a through hole 1a, and a conduit 20a that is provided in the cap 20 and connects the annular gap S to the compression-side chamber R2, and connects the expansion-side chamber R1 to the compression-side chamber R2 without going through the reservoir R. In addition, the conduit 20a is provided with a check valve 20b that allows only the flow of liquid from the expansion-side chamber R1 to the compression-side chamber R2. Therefore, the expansion-side auxiliary damping passage 15 is set as a one-way passage that allows only the flow of liquid from the expansion-side chamber R1 to the compression-side chamber R2 by the check valve 20b.

Moreover, the expansion side sub-damping valve 17 is provided in the conduit 20a in series with the check valve 20b. The expansion side secondary damping valve 17 is installed in the cap 20, and is a variable damping valve whose opening area can be adjusted by operating from the outside of the shock absorber D.

The compression side auxiliary damping passage 16 is composed of an annular gap S that is connected to the expansion side chamber R1 via a through hole 1a, and a conduit 20c that is provided in the cap 20 and connects the annular gap S to the compression side chamber R2, and connects the expansion side chamber R1 to the compression side chamber R2 without going through the reservoir R. In addition, the conduit 20c is provided with a check valve 20d that allows only the flow of liquid from the compression side chamber R2 to the expansion side chamber R1. Therefore, the compression side auxiliary damping passage 16 is set as a one-way passage that allows only the flow of liquid from the compression side chamber R2 to the expansion side chamber R1 by the check valve 20d.

In addition, the pipe 20c is provided with a compression auxiliary damping valve 18 in series with the check valve 20d. The compression auxiliary damping valve 18 is installed in the cap 20 and is a variable damping valve whose opening area can be adjusted by operating it from outside the shock absorber D.

The shock absorber D of this embodiment is configured as described above, and the operation of the shock absorber D will be described below. First, the operation of the shock absorber D during extension will be described. When the shock absorber D extends, the piston 3 moves upward in FIG. 1 relative to the cylinder 1, and the expansion side chamber R1 is compressed by the piston 3, and the compression side chamber R2 is expanded. The liquid in the compressed expansion side chamber R1 moves to the liquid chamber L side of the reservoir R through the expansion side damping passage 4 and moves to the compression side chamber R2 through the expansion side auxiliary damping passage 15 because the expansion side suction passage 8 is blocked by the expansion side check valve 13. In addition, liquid moves from the reservoir R through the compression side suction passage 9 to the expanded compression side chamber R2. Note that when the shock absorber D extends, the rod 2 retreats from the cylinder 1, so the amount of liquid that moves from the expansion side chamber R1 to the reservoir R is greater than the amount of liquid by the volume of the rod 2 retreating from the cylinder 1. Therefore, when the shock absorber D expands, the free piston 12 moves to reduce the fluid chamber L, and the fluid is discharged from the fluid chamber L of the reservoir R by the volume of the rod 2 that is withdrawn from the cylinder 1, and moves to the compression side chamber R2. Then, the expansion side damping valve 6 and the expansion side auxiliary damping valve 17 provide resistance to the flow of fluid passing through the expansion side damping passage 4 and the expansion side auxiliary damping passage 15, so that the pressure in the expansion side chamber R1 rises. In addition, the compression side check valve 14 of the compression side suction passage 9 opens and fluid is supplied from the reservoir R to the compression side chamber R2 that is expanded by the movement of the piston 3, so that the pressure in the compression side chamber R2 becomes almost equal to the pressure in the reservoir R (reservoir pressure). In this way, a difference in pressure is created between the expansion side chamber R1 and the compression side chamber R2, and the shock absorber D generates an expansion side damping force that hinders expansion by the expansion side damping valve 6 and the expansion side auxiliary damping valve 17. Here, when the piston speed of the shock absorber D is low and the pressure difference between the extension side chamber R1 and the reservoir R does not reach the valve opening pressure of the extension side damping valve 6, the extension side damping valve 6 does not open and the liquid passes only through the extension side auxiliary damping valve 17. Therefore, when the piston speed of the shock absorber D during extension is in the low speed range, the shock absorber D generates the extension side damping force by the extension side auxiliary damping valve 17. Therefore, as shown in FIG. 2, when the piston speed is in the low speed range, the damping force characteristic during extension of the shock absorber D shows the characteristic of the extension side auxiliary damping valve 17. When the piston speed of the shock absorber D during extension reaches the high speed range, the pressure difference between the extension side chamber R1 and the reservoir R reaches the valve opening pressure of the extension side damping valve 6 and the extension side damping valve 6 opens. When the piston speed reaches the high speed range, the resistance that the extension side auxiliary damping valve 17, which is a throttle valve, provides to the flow of the liquid increases abruptly and the liquid becomes difficult to pass through the extension side auxiliary damping valve 17. Therefore, when the piston speed during extension of the shock absorber D is in the high speed range, the liquid mainly passes through the extension damping valve 6. Therefore, as shown in FIG. 2, when the piston speed is in the high speed range, the damping force characteristics during extension of the shock absorber D show the characteristics of the extension damping valve 6. In addition, in this embodiment, by adjusting the opening area of the auxiliary extension damping valve 17, which is a variable throttle valve, the extension damping force of the shock absorber D when the piston speed is in the low speed range can be adjusted.

Next, the operation of the shock absorber D during contraction will be described. When the shock absorber D contracts, the piston 3 moves downward in FIG. 1 relative to the cylinder 1, and the piston 3 compresses the compression side chamber R2 and expands the extension side chamber R1. The liquid in the compressed compression side chamber R2 moves to the liquid chamber L of the reservoir R through the compression side damping passage 5 and to the extension side chamber R1 through the compression side auxiliary damping passage 16 because the compression side suction passage 9 is blocked by the compression side check valve 14. In addition, liquid moves from the reservoir R through the extension side suction passage 8 to the expanded extension side chamber R1. Note that when the shock absorber D contracts, the rod 2 enters the cylinder 1, so the amount of liquid moving from the reservoir R to the extension side chamber R1 is less than the amount of liquid moving from the compression side chamber R2 to the reservoir R by the amount of liquid that is equivalent to the volume of the rod 2 entering and exiting the cylinder 1. Therefore, when the shock absorber D contracts, the free piston 12 compresses the air chamber G to expand the liquid chamber L, and the reservoir R absorbs the volume of liquid that the rod 2 invades into the cylinder 1. The compression side damping valve 7 and the compression side auxiliary damping valve 18 provide resistance to the flow of liquid passing through the compression side damping passage 5 and the compression side auxiliary damping passage 16, so the pressure in the compression side chamber R2 rises. In addition, the expansion side check valve 13 of the expansion side suction passage 8 opens and liquid is supplied from the reservoir R to the expansion side chamber R1, which is expanded by the movement of the piston 3, so the pressure in the expansion side chamber R1 becomes almost equal to the pressure in the reservoir R (reservoir pressure). In this way, a difference in pressure is created between the compression side chamber R2 and the expansion side chamber R1, and the shock absorber D generates a compression side damping force that prevents contraction by the compression side damping valve 7 and the compression side auxiliary damping valve 18. Here, when the piston speed of the shock absorber D is low and the pressure difference between the compression side chamber R2 and the reservoir R does not reach the valve opening pressure of the compression side damping valve 7, the compression side damping valve 7 does not open and the liquid passes only through the compression side auxiliary damping valve 18. Therefore, when the piston speed of the shock absorber D during contraction is in the low speed range, the shock absorber D generates a compression side damping force by the compression side auxiliary damping valve 18. Therefore, as shown in FIG. 2, when the piston speed is in the low speed range, the damping force characteristic during contraction of the shock absorber D shows the characteristic of the compression side auxiliary damping valve 18. When the piston speed of the shock absorber D during contraction reaches the high speed range, the pressure difference between the compression side chamber R2 and the reservoir R reaches the valve opening pressure of the compression side damping valve 7 and the compression side damping valve 7 opens. When the piston speed reaches the high speed range, the compression side auxiliary damping valve 18 is a throttle valve, so the resistance to the flow of the liquid increases suddenly and it becomes difficult for the liquid to pass through the compression side auxiliary damping valve 18. Therefore, when the piston speed during contraction of the shock absorber D is in the high speed range, the liquid mainly passes through the compression side damping valve 7. Therefore, as shown in FIG. 2, when the piston speed is in the high speed range, the damping force characteristics during contraction of the shock absorber D exhibit the characteristics of the compression side damping valve 7. In addition, in this embodiment, by adjusting the opening area of the compression side auxiliary damping valve 18, which is a variable throttle valve, the compression side damping force of the shock absorber D when the piston speed is in the low speed range can be adjusted.

In this way, the shock absorber D generates a damping force as it expands and contracts. When the shock absorber D is extended, the liquid flows in one direction by directing the growth side damping valve 6 from the growth side chamber R1 to the liquid chamber L, and directing the growth side sub-damping valve 17 from the growth side chamber R1 to the compression side chamber R2. At the same time, it flows in one direction through the pressure side suction passage 9 from the liquid chamber L to the pressure side chamber R2. Furthermore, when the shock absorber D is contracted, the liquid flows in one direction by directing the compression side damping valve 7 from the pressure side chamber R2 to the liquid chamber L, and directing the compression side sub-damping valve 18 from the compression side chamber R2 to the expansion side chamber R1. At the same time, the liquid flows in one direction through the expansion side suction passage 8 from the liquid chamber L to the expansion side chamber R1. In this way, in the shock absorber D of this embodiment, when the shock absorber D is extended, the liquid flows in one direction through the rebound side damping passage 4, the growth side auxiliary damping passage 15, and the compression side suction passage 9; During contraction, the air flows in one direction through the compression side damping passage 5, the compression side sub-damping passage 16, and the expansion side suction passage 8. Therefore, when the buffer D is expanded and contracted, the liquid does not flow through the same passage in the opposite direction. Therefore, in the shock absorber D of this embodiment, unlike conventional shock absorbers, the flow does not flow in the same passage in reverse, and the various valves provided in each passage 4, 5, 8, 9, 15, 16 The problem of closing delay does not occur, and the shock absorber D can generate a damping force with good responsiveness when the telescopic operation is switched.

As explained above, the shock absorber D of this embodiment includes a cylinder 1, a rod 2 that is movably inserted into the cylinder 1, a rod 2 that is connected to the rod 2 and is movably inserted into the cylinder 1, and a rod 2 that is movably inserted into the cylinder 1. A piston 3 that divides the inside of the cylinder 1 into a growth side chamber R1 filled with liquid and a compression side chamber R2, a reservoir R that stores liquid, and a growth side damping passage that allows liquid to flow from the growth side chamber R1 to the reservoir R. 4, a compression side damping passage 5 that allows the flow of liquid from the compression side chamber R2 toward the reservoir R, a rebound damping valve 6 that is provided in the expansion side damping passage 4 and provides resistance to the flow of liquid passing therethrough, and a compression side damping passage 5 that allows the flow of liquid from the compression side chamber R2 to the reservoir R. A compression side damping valve 7 that is provided in the passage 5 and provides resistance to the flow of liquid passing through it, a growth side suction passage 8 that only allows the flow of liquid from the reservoir R to the growth side chamber R1, and from the reservoir R to the compression side chamber R2. A reservoir R is formed in a housing 11 provided on the rod 2.

In the shock absorber D configured in this manner, the reservoir R is formed within the housing 11 provided on the rod 2. Therefore, in the shock absorber D of this embodiment, even if a layout is adopted in which the reservoir R is provided between the rebound damping valve 6 and the compression damping valve 7, the reservoir R is not arranged outside the cylinder 1. The external shape can be made slimmer and more compact. Furthermore, even if the shock absorber D of the present embodiment adopts a layout in which the reservoir R is provided between the rebound damping valve 6 and the compression damping valve 7, The damping valve 6 and the compression side damping valve 7 can be arranged in the cylinder, and even if the oil passage diameter is increased and the expansion side and compression side damping valves 6 and 7 are enlarged, the overall size of the shock absorber does not increase.

In this way, in the shock absorber D of this embodiment, it is possible to increase the size of the rebound damping valve 6 and the compression damping valve 7 without increasing the size of the shock absorber D, so the damping force characteristics of the shock absorber D can be designed. The degree of freedom is improved and the damping force can also be increased. Therefore, according to the shock absorber D of this embodiment, the degree of freedom in designing the damping force characteristics can be improved, and not only the damping force can be increased, but also the size can be reduced.

In addition, the extension side damping passage 4, the compression side damping passage 5, the extension side suction passage 8, and the compression side suction passage 9 in the shock absorber D of this embodiment are provided in the piston 3. In this way, according to the shock absorber D that adopts a structure in which the extension side damping passage 4, the compression side damping passage 5, the extension side suction passage 8, and the compression side suction passage 9 are provided in the piston 3, the extension side damping valve 6 and the compression side damping valve 7 can be consolidated in the piston 3, making it possible to make the shock absorber more compact.

Further, the piston 3 in the shock absorber D of this embodiment is attached to the rod 2 and slides on the inner circumference of the cylinder 1 to define a growth side chamber R1, and has a growth side damping passage 4 and a growth side suction passage 8. It has a first partition wall 3a, a pressure side damping passage 5, and a pressure side suction passage 9, which are attached to the rod 2 at a distance from the first partition wall 3a and slide on the inner periphery of the cylinder 1 to define a pressure side chamber R2. and a second partition wall 3b, and the reservoir R is communicated with a gap A between the first partition wall 3a and the second partition wall 3b. According to the shock absorber D configured in this way, the piston 3 is divided into the first partition wall 3a having the expansion side damping passage 4 and the expansion side suction passage 8, and the second partition wall 3b having the compression side damping passage 5 and the compression side suction passage 9. Since a structure is adopted in which the gap A between the first partition wall 3a and the second partition wall 3b is communicated with the reservoir R, the rebound damping valve 6 and the compression damping valve 7 are connected to the first partition wall 3a and the second partition wall 3b. It can be easily installed in the shock absorber D by using the two partition walls 3b as a valve seat member.

In the shock absorber D of this embodiment, the expansion side damping valve 6 and the compression side damping valve 7 are leaf valves whose inner peripheries are fixed to the rod 2 and are stacked on the first partition wall 3a or the second partition wall 3b, respectively. A growth side check valve 13 made of an annular plate that sets the growth side suction passage 8 as a one-way passage is laminated with the first partition wall 3a as a valve seat member, and the compression side suction passage 9 is set as a one-way passage. A pressure side check valve 14 made of an annular plate set to 1 is laminated with the second partition wall 3b serving as a valve seat member. According to the shock absorber D configured in this way, even if the expansion side damping valve 6, the compression side damping valve 7, the expansion side check valve 13, and the compression side check valve 14 are integrated in the piston 3, the overall length of the piston portion can be shortened. be able to.

In the shock absorber D of this embodiment, the reservoir R is formed in the housing 11 provided between the first partition 3a and the second partition 3b of the rod 2, so that the shock absorber D can be formed compactly. However, as in the shock absorber D1 of the first modified example shown in FIG. 3, the rod 2 may be made hollow and the reservoir R may be formed in the hollow portion 2a within the rod 2. In this case, a free piston 21 may be slidably inserted into the hollow portion 2a of the rod 2, and the hollow portion 2a may be divided into a liquid chamber L, which is connected to the gap A between the first partition 3a and the second partition 3b by the free piston 21, and an air chamber G. In this way, when the reservoir R is formed within the rod 2, it is not necessary to provide a housing 11 between the first partition 3a and the second partition 3b, so that the axial distance between the first partition 3a and the second partition 3b can be shortened, and the stroke length of the shock absorber D1 can be increased. Furthermore, in the shock absorber D of this embodiment, the reservoir R is formed in a housing 11 provided between the first partition 3a and the second partition 3b of the rod 2, but as in a shock absorber D2 of a second modified example shown in Fig. 4, a housing 22 that is hollow and communicates with the gap A between the first partition 3a and the second partition 3b may be provided at the upper end of the rod 2, and a free piston 21 may be slidably inserted into the hollow portion 2a of the rod 2 to partition the inside of the housing 22 into a liquid chamber L that is communicated with the gap A via a passage 2b provided in the rod 2 by a free piston 23, and an air chamber G. In this way, when the housing 22 that forms the reservoir R is provided at the upper end of the rod 2, it is not necessary to provide a housing 11 between the first partition 3a and the second partition 3b, so that the axial distance between the first partition 3a and the second partition 3b can be shortened, the stroke length of the shock absorber D1 can be increased, and the volume of the reservoir R can be sufficiently secured. In the above-mentioned shock absorbers D1 and D2, the reservoir R is divided into a liquid chamber L and an air chamber G by the free pistons 21 and 23, but the liquid chamber L and the air chamber G may be divided by a diaphragm or bellows instead of the free pistons 21 and 23. In addition, in the shock absorbers D1 and D2, high-pressure gas is sealed in the air chamber G, but instead of sealing in the high-pressure gas, an elastic body such as a spring that biases the free pistons 21 and 23 in a direction that compresses the liquid chamber L may be provided.

Furthermore, the shock absorber D of the present embodiment communicates the growth side chamber R1 and the compression side chamber R2 without going through the reservoir R, and allows only the flow of liquid from the growth side chamber R1 to the compression side chamber R2. A passage 15, a compression side secondary damping passage 16 which communicates the compression side chamber R2 and the growth side chamber R1 without going through the reservoir R, and allows only the flow of liquid from the compression side chamber R2 to the growth side chamber R1, and a growth side secondary damping passage. 15 and is provided in the compression side sub-damping passage 16 and is capable of adjusting the resistance given to the flow of liquid passing through it by external operation. and an adjustable pressure side damping valve 18. According to the shock absorber D configured in this way, the vibration of the vehicle body to which it is applied can be suppressed by externally adjusting the resistance given to the flow of liquid between the expansion side secondary damping valve 17 and the compression side secondary damping valve 18. The damping force on the rebound and compression sides can be easily adjusted independently to suit the user's needs. In addition, in the above description, the expansion side secondary damping valve 17 and the compression side secondary damping valve 18 are variable throttle valves, but any variable damping valve that can adjust the resistance given to the flow of liquid may be used. In addition to the variable throttle valve whose flow path area can be adjusted, a variable relief valve whose opening pressure can be adjusted may also be used. In addition, since the shock absorber D can generate damping force by the rebound damping valve 6 provided in the rebound damping passage 4 and the compression damping valve 7 provided in the compression damping passage 5, there is no need to adjust the damping force by external operation. For example, one or both of the expansion secondary damping passage 15 and the compression secondary damping passage 16 can be eliminated.

Furthermore, if the extension side auxiliary damping valve 17 and the compression side auxiliary damping valve 18 are variable throttle valves and the extension side damping valve 6 and the compression side damping valve 7 are relief valves for which the valve opening pressure is set, the extension side auxiliary damping valve 17 and the compression side auxiliary damping valve 18 can adjust the damping force characteristics when the piston speed when the piston 3 moves relative to the cylinder 1 is in the low speed range, and the extension side damping valve 6 and the compression side damping valve 7 can set the damping force characteristics when the piston speed is in the high speed range that exceeds the low speed range.

In addition, in the above description, the piston 3 is composed of the first partition wall 3a and the second partition wall 3b, but it is composed of a single partition body connected to the rod 2 and in sliding contact with the inner circumference of the cylinder 1. Good too. Even if the piston 3 is composed of a single partition body, the expansion side damping passage 4, the compression side damping passage 5, the expansion side suction passage 8, the compression side suction passage 9, the expansion side damping valve 6, the compression side damping valve 7, the expansion side check The valve 13 and the pressure side check valve 14 may be provided on the piston 3, and the piston 3 may be used as a housing forming the reservoir R.

Although the preferred embodiment of the present invention has been described in detail above, modifications, variations, and changes are possible without departing from the scope of the claims.

1: Cylinder, 2: Rod, 3: Piston, 3a: First partition, 3b: Second partition, 4: Rebound damping passage, 5: Compression damping passage, 6: Rebound damping valve, 7: Compression damping valve, 8: Rebound suction passage, 9: Compression suction passage, 11, 22: Housing, 15: Rebound auxiliary damping passage, 16: Rebound auxiliary damping passage, 16: Rebound auxiliary damping valve, 17: Rebound auxiliary damping valve, A: Gap, D, D1, D2: Shock absorber, R: Reservoir, R1: Rebound chamber, R2: Compression chamber

Claims (4)

cylinder and
a rod movably inserted into the cylinder;
a piston connected to the rod and movably inserted into the cylinder and partitioning the cylinder into a expansion side chamber and a compression side chamber filled with liquid;
a reservoir for storing liquid;
a growth-side damping passageway that allows liquid to flow from the growth-side chamber toward the reservoir;
a pressure-side damping passage that allows liquid to flow from the pressure-side chamber toward the reservoir;
a growth-side damping valve that is provided in the growth-side damping passage and provides resistance to the flow of liquid passing therethrough;
a pressure side damping valve that is provided in the pressure side damping passage and provides resistance to the flow of liquid passing therethrough;
a growth-side suction passageway that only allows liquid to flow from the reservoir toward the growth-side chamber;
and a pressure side suction passageway that allows only the flow of liquid from the reservoir to the pressure side chamber,
The buffer is characterized in that the reservoir is formed within the rod or within a housing provided on the rod. The shock absorber according to claim 1, wherein the extension-side damping passage, the compression-side damping passage, the extension-side suction passage, and the compression-side suction passage are provided in the piston. The piston is
a first partition wall attached to the rod and in sliding contact with an inner periphery of the cylinder to define the expansion-side chamber, the first partition wall having the expansion-side damping passage and the expansion-side suction passage;
a second partition wall attached to the rod with a gap between the first partition wall and the rod, the second partition wall being in sliding contact with an inner periphery of the cylinder to define the compression side chamber, and the second partition wall having the compression side damping passage and the compression side suction passage,
The shock absorber according to claim 1 or 2, wherein the reservoir is in communication with a gap between the first partition and the second partition. a growth side secondary damping passage that communicates the growth side chamber and the compression side chamber without going through the reservoir and allows only the flow of liquid from the growth side chamber to the compression side chamber;
a compression side sub-damping passage that communicates the compression side chamber and the growth side chamber without going through the reservoir, and allows only the flow of liquid from the compression side chamber toward the growth side chamber;
an expansion side secondary damping valve that is provided in the expansion side secondary damping passage and is capable of adjusting resistance given to the flow of liquid passing therethrough by external operation;
4. The pressure side auxiliary damping valve is provided in the pressure side auxiliary damping passage and is capable of adjusting the resistance given to the flow of liquid passing therethrough by external operation. buffer.

Images