JP7110698B2 - vehicle suspension system - Google Patents

Description

The present invention relates to a vehicle suspension system using a damper with a coil spring coaxial arrangement, and more particularly, a damper comprising a piston whose upper end is attached to the vehicle body and a cylinder whose lower end is attached to the wheel, and the damper. The present invention relates to a vehicle suspension device comprising a coil-shaped main spring having its upper end attached to the outer periphery of the cylinder on the vehicle body side and having its lower end attached to the outer peripheral wall of the cylinder.

In general, coil springs for suspensions used in vehicles such as sports cars are usually so-called hard springs with a high spring constant in order to ensure steering stability.
On the other hand, in order to obtain a feeling of the grounding of the wheel when the piston of the damper reaches its maximum stroke (during full rebound), there is a problem of softening the coil spring characteristics near the maximum stroke.

A damper 70 as shown in FIG. 7 is conventionally known for this problem.
That is, a cylinder 72 to which a damper bushing 71 at the lower end is attached to the wheel side, an upper spring seat 73 provided at the upper end of the piston rod, a lower spring seat 74 fixed to the upper outer circumference of the cylinder 72, and a middle spring seat 74 in the vertical direction. a main spring 76 stretched between the upper spring seat 73 and the intermediate spring seat 75; and stretched between the intermediate spring seat 75 and the lower spring seat 74. and a suspended auxiliary spring 77 .

By setting the spring constant of the main spring 76 high and the spring constant of the auxiliary spring 77 low, the auxiliary spring 77 is made a so-called soft spring. is in a grounded state (line-to-line contact state), only the main spring 76 is operated to set a hard spring, and only in the vicinity of the maximum stroke, the auxiliary spring 77 is also operated to set a soft spring.

However, since the auxiliary spring 77 described above is positioned outside the damper 70, more specifically, on the outer circumference of the cylinder 72, and is used both in the grounded state and in the non-grounded state, during grounding (line-to-line contact) There is concern that the paint film that coats the spring will peel off due to sand getting caught in the spring, causing rust, and that abnormal noise (metallic noise) will occur when the wires contact each other. There is room for improvement. there were.

By the way, in Patent Document 1, in a strut-type suspension device, a main spring provided outside the bellows and an auxiliary spring which is pressed (line-to-line contact) in the normal stroke region of the piston and functions as a spring only in the vicinity of the maximum stroke. is disclosed.
Further, Patent Literature 2 discloses a vehicle suspension device provided with a rebound spring that is compressed at the time of rebound on the piston side in the cylinder.

Japanese Utility Model Laid-Open No. 62-56405 Japanese Patent Application Laid-Open No. 2003-118339

Therefore, the present invention can suppress the occurrence of rust and abnormal noise caused by peeling of the paint film due to sand bite by preventing pressure contact of the auxiliary spring. It is an object of the present invention to provide a suspension system for a vehicle capable of achieving the sum of characteristics and spring characteristics of an auxiliary spring.

A vehicle suspension system according to the present invention comprises a damper comprising a piston having an upper end attached to the vehicle body, a cylinder having a lower end attached to a wheel, and an upper end attached to the outer periphery of the damper on the vehicle body side, a coil-shaped main spring having a lower end attached to the outer peripheral wall of the cylinder, wherein the piston comes into contact with the inside of the cylinder when the piston moves downward by a predetermined distance from a maximum stroke position. An auxiliary spring is provided which is compressed as the piston moves downward , and a centering guide is provided at the inner bottom of the cylinder and on the outer peripheral side of the auxiliary spring .

According to the above configuration, since the auxiliary spring is arranged inside the cylinder, sand gets caught between the wires of the auxiliary spring, causing rust due to peeling of the paint film, and abnormal noise due to contact between the wires. can be suppressed.

Moreover, since the main spring is provided on the outer periphery of the damper and the auxiliary spring is provided inside the cylinder, the spring characteristics of the suspension are the sum of the spring characteristics of the main spring corresponding to the stroke and the spring characteristics of the auxiliary spring. can be set to a value.

Further, since a centering guide is provided on the inner bottom of the cylinder and on the outer peripheral side of the auxiliary spring, the centering guide can be used to position the auxiliary spring, particularly to position the auxiliary spring in the radial direction. is achieved, the quality of the damper is further stabilized.

In one embodiment of the present invention, there is provided a bump stopper that abuts against the upper portion of the cylinder before the auxiliary spring presses against the wheel when the wheel is fully bumped to prevent the press contact of the auxiliary spring.
According to the above configuration, it is possible to reliably prevent pressure contact (line-to-line contact) of the auxiliary spring with the bump stopper described above, thereby preventing the occurrence of rust and abnormal noise caused by peeling of the paint film. This can be prevented more reliably.

In one embodiment of the present invention, the cylinder is composed of a single wall, is filled with oil, and is expandable and compressible via an oil storage chamber communicating with the cylinder and a free piston. and an oil reservoir including a gas chamber.
According to the above configuration, it is possible to smoothly move the oil along with the movement of the piston while fixing the end of the auxiliary spring on the side opposite to the piston to the lower side of the cylinder in which the oil is sealed.

According to the present invention, by preventing the pressure contact of the auxiliary spring, it is possible to suppress the occurrence of rust and abnormal noise caused by the peeling of the paint film due to sand getting caught. There is an effect that can be achieved on the sum of the characteristic and the spring characteristic of the auxiliary spring.

FIG. 2 is a sectional view showing the vehicle suspension device of the present invention at the maximum stroke position; Sectional view showing the above suspension device at a position near the maximum stroke Cross-sectional view showing the suspension device at a predetermined stroke position Cross-sectional view of the suspension device at the time when it starts to hit the bump stopper Sectional view showing the suspension device in a full bump state Characteristic diagram showing the spring characteristics of the suspension device Side view showing a conventional vehicle suspension device

By preventing pressure contact of the auxiliary spring, it is possible to suppress the occurrence of rust and abnormal noise caused by peeling of the paint film due to sand getting caught. A damper composed of a piston whose upper end is attached to the vehicle body side and a cylinder whose lower end is attached to the wheel side, and its upper end is attached to the outer periphery of the damper on the vehicle body side. and a coil-shaped main spring whose lower end is attached to the outer peripheral wall of the cylinder, wherein when the piston moves downward by a predetermined distance from the maximum stroke position inside the cylinder, An auxiliary spring is provided that abuts and is compressed as the piston moves downward , and a centering guide is provided at the inner bottom of the cylinder and on the outer peripheral side of the auxiliary spring .

An embodiment of the invention will be described in detail below with reference to the drawings.
1 is a cross-sectional view showing the suspension system at the maximum stroke position, FIG. 2 is a cross-sectional view showing the suspension system at a position near the maximum stroke, and FIG. 3 is a suspension system at a predetermined stroke. FIG. 4 is a cross-sectional view of the suspension system at the point of starting contact with the bump stopper, and FIG. 5 is a cross-sectional view showing the suspension system in a full-bump state.

FIG. 6 is a characteristic diagram showing the spring characteristics of the suspension device, with the horizontal axis representing the stroke and the vertical axis representing the load acting on the damper. 1 to 2, 3, 4, and 5 show changes in the damper from full rebound (see FIG. 1) to full bump (see FIG. 5) in order.

As shown in FIGS. 1 to 5, the vehicle suspension system 10 of this embodiment includes a piston 12 whose upper end is attached to the vehicle body 11 side via a piston rod 16 described later, and a lower end which is attached to a wheel via a damper bush 13 . A damper 15 is configured with a cylinder 14 attached to the side (so-called tire side). The damper bushing 13 described above includes an inner cylinder 13a and an outer cylinder 13b.

The above-mentioned piston 12 incorporates a valve (not shown) therein, and is integrally attached with an upwardly extending piston rod 16 and a downwardly extending lower piston rod 17 . That is, the piston 12 is configured as a double rod type.

An upper spring seat 18 is attached to the lower surface of the vehicle body 11 described above, and a washer 20 is arranged on a radially inner upper portion of the upper spring seat 18 via a damper bush 19 .
Also, a washer 22 is arranged via a damper bush 21 at the radially inner lower portion of the upper spring seat 18 , and a bump stopper 23 is fixed to the lower surface of this washer 22 .

The piston rod 16 protrudes above the washer 20 through the central portions of the elements 23, 22, 21, 18, 19, and 20, and a nut 24 is screwed onto a threaded portion 16a formed on the upward protrusion. Together, the piston rod 16 and the vehicle body 11 are integrated.

The above-mentioned piston rod 16 vertically passes through a rod guide 25 at the upper end of the cylinder 14, and a rebound stopper receiver 26 is integrally provided at a portion of the piston rod 16 that is close to the upper surface of the piston 12. ing. In other words, the rebound stopper receiver 26 described above is fixed to the piston rod 16 .

Furthermore, a rebound stopper 27 (in FIG. 1, the rebound stopper 27 is shown in a compressed state corresponding to the maximum stroke position of the piston 12) is fixed to the lower surface of the rod guide 25 described above. A spring seat 28 (specifically, an upper movable spring seat) is loosely fitted on the lower piston rod 17 . The rebound stopper 27 and the bump stopper 23 described above are made of a rubber member.

A lower spring seat 29 is fixed to the upper outer peripheral wall of the cylinder 14. A coiled spring seat 29 is provided between the upper and lower spring seats 18, 29 with seat rubbers 30, 31 interposed therebetween. of the main spring 32 is stretched.
That is, the main spring 32 has its upper end attached to the outer periphery of the damper 15 on the side of the vehicle body 11 and its lower end attached to the outer peripheral wall of the cylinder 14 .

Here, a cylindrical dust cover 33 is provided inside the main spring 32 in the radial direction and is spaced apart from the main spring 32 . The length of the dust cover 33 in the vertical direction is set so that the lower end thereof does not contact the sheet rubber 31 at full bump (see FIG. 5).

Inside the cylinder 14, when the piston 12 moves downward from the maximum stroke position MAX (see FIG. 1) by a predetermined distance (see the predetermined stroke position B shown in FIG. and is compressed as the piston 12 moves downward (specifically, relative movement).

The auxiliary spring 34 is also formed of a coil spring like the main spring 32 described above.
A spring seat 35 (more specifically, a lower fixed spring seat) is fixed to the inner bottom of the cylinder 14, and the auxiliary spring 34 is stretched between the upper and lower spring seats 28,35.

The upper end of the auxiliary spring 34 and the spring seat 28 are fixed by caulking means or the like. Similarly, the lower end of the auxiliary spring 34 and the spring seat 35 are fixed by caulking means or the like.

A cylindrical centering guide 36 is provided on the inner bottom of the cylinder 14 and on the outer peripheral side of the auxiliary spring 34 . Thereby, the centering guide 36 positions the auxiliary spring 34 , in particular, positions the auxiliary spring 34 in the radial direction (so-called anti-vibration), thereby stabilizing the quality of the damper 15 .

When the wheel is fully bumped as shown in FIG. 5, the bump stopper 23 comes into contact with the upper part of the cylinder 14, more specifically, the upper part of the rod guide 25 before the auxiliary spring 34 makes pressure contact (line-to-line contact). This prevents the pressure contact of the spring 34, thereby reliably preventing the pressure contact (line-to-line contact) of the auxiliary spring 34 with the bump stopper 23, the occurrence of rust due to the peeling of the coating film, and the abnormal noise (metallic It is configured to prevent the occurrence of noise). In other words, the upper and lower lines of the auxiliary spring 34 are configured so as not to come into contact with each other during the full bump shown in FIG.
The cylinder 14 described above is composed of a single-walled so-called monotube, and the inside of the cylinder 14 is filled with oil OIL.

Further, an oil storage chamber 41 communicating with the lower portion of the cylinder 14 via an oil passage 40, and a gas chamber 43 expandable and compressible via a free piston 42 are provided. , and the gas chamber 43 , and the oil passage 40 and the sub-tank 44 together form an oil storage device 45 .

As a result, the end of the auxiliary spring 34 on the side opposite to the piston, that is, the lower end is fixed to the lower side of the cylinder 14 in which the oil OIL is sealed, and the movement of the oil OIL accompanying the movement of the piston 12 is smoothly performed. It is configured. The gas chamber 43 is filled with _N2 gas, which is an inert gas.

Here, the above-mentioned free piston 42 completely separates the _N2 gas in the gas chamber 43 from the oil OIL in the oil storage chamber 41. A completely separated _N2 gas (specifically, a high-pressure gas) can be enclosed in the gas chamber 43, thereby ensuring stable damping force characteristics.

The operation of the vehicle suspension system thus constructed will be described below.
FIG. 6 is a characteristic diagram showing the spring characteristics of the suspension device 10, with the horizontal axis representing the stroke and the vertical axis representing the load acting on the damper 15. The maximum stroke position (full rebound position) MAX shown in FIG. 1, the position near the maximum stroke (rebound stopper separation start position) A shown in FIG. 6 corresponds to FIG. The bump stopper contact start position C shown in FIG. 6 corresponds to FIG. 4, and the full bump position D shown in FIG. 6 corresponds to FIG.

6 shows the characteristic RE of the rebound stopper 27 between the position MAX and the position A, the characteristic MA shown by the solid line shows the characteristic of the main spring 32, and the characteristic HE shown by the dotted line shows the characteristic MA of the main spring and the auxiliary spring 34 , and the characteristic BU indicated by the phantom line indicates the characteristic HE plus the characteristic of the bump stopper 23 .

At the maximum stroke position MAX shown in FIG. 1, the rebound stopper 27 is pressed and compressed by the rebound stopper receiver 26, and further upward movement of the piston 12 and the piston rod 16 is restricted. A clearance CL2 is formed between . Also, in this case, the auxiliary spring 34 has a free length.

When the wheel slightly moves in the bump direction from the maximum stroke position MAX shown in FIG. 1, the piston 12 moves slightly downward as shown in FIG. Then, the maximum stroke vicinity position (the position where the rebound stopper 27 starts to separate from the rebound stopper receiver 26) A shown in FIG.

2, the lower surface of the rebound stopper 27 and the upper surface of the rebound stopper receiver 26 are shown in contact with each other.
In this case, the clearance CL1 between the lower surface of the piston 12 and the upper surface of the spring seat 28 is smaller than the clearance CL2 in FIG. 1 (CL1<CL2). Also at this point, the auxiliary spring 34 has a free length.

When the wheel moves further in the bump direction from the position A near the maximum stroke shown in FIG. 2, the piston 12 moves downward by a predetermined distance as shown in FIG. A predetermined stroke position B abutting against 34 is reached. In this case, the clearance CL between the lower surface of the piston 12 and the upper surface of the spring seat 28 becomes zero, and the compression of the auxiliary spring 34 starts at this point.

When the wheel further moves in the bump direction from the predetermined stroke position B shown in FIG. 3, as shown in FIG. 4, the lower surface of the bump stopper 23 contacts the upper surface of the rod guide 25 located at the upper end of the cylinder 14. As shown in FIG.

When the wheel further moves in the bump direction from the contact start position C of the bump stopper 23 shown in FIG. 4, the bump stopper 23 is compressed along the bump stopper characteristic BU shown in FIG. A full bump position D is reached in which further downward movement of the piston 12, the piston rod 16, and the lower piston rod 17 is restricted to prevent pressure contact (line-to-line contact).

The main spring 32 acts along the main spring characteristic MA during the entire stroke in the bump direction from the position A near the maximum stroke shown in FIG. Therefore, the spring characteristics of the suspension device 10 are the spring characteristics of the main spring 32 corresponding to the stroke (main spring characteristic MA) and the spring characteristics of the auxiliary spring 34. can be set to the added value (characteristic HE).

Further, the rebound stopper characteristic RE acts between the position MAX and the position A shown in FIG. 6, and the bump stopper characteristic BU acts between the position C and the position D.
Furthermore, by setting the spring constant of the main spring 32 low, it is configured to ensure the preload at the time of full rebound (see FIG. 1).

Also, in comparison between the main spring characteristic MA indicated by the solid line in FIG. 6 and the characteristic HE obtained by adding the auxiliary spring characteristic to the main spring characteristic indicated by the dotted line in FIG. , the load change rate with respect to the stroke is set to be small.

In the above description, the action corresponding to the stroke shortening change from the maximum stroke position MAX to the full bump position D has been described, but the action corresponding to the stroke expansion change from the full bump position D to the maximum stroke position MAX is shown in FIG. Along the characteristic indicated by 6, the action is opposite to that described above.

Thus, the vehicle suspension system of the above-described embodiment includes a damper 15 composed of a piston 12 whose upper end is attached to the vehicle body 11 side, a cylinder 14 whose lower end is attached to the wheel side, and an outer circumference of the damper 15. A coil-shaped main spring 32 whose upper end is attached to a vehicle body 11 side and whose lower end is attached to the outer peripheral wall of the cylinder 14, wherein the piston 12 is mounted inside the cylinder 14. is moved downward by a predetermined distance (see predetermined stroke position B in FIG. 3) from the maximum stroke position MAX (see FIG. 1), and is compressed as the piston 12 moves downward. (See Figures 1 and 3).

According to this configuration, since the auxiliary spring 34 is arranged inside the cylinder 14, sand gets caught between the wires of the auxiliary spring 34, which causes rust due to peeling of the paint film and contact between the wires. It is possible to suppress the generation of abnormal noise due to

Moreover, since the main spring 32 provided on the outer circumference of the damper 15 and the auxiliary spring 34 provided inside the cylinder 14 are provided, the spring characteristics of the suspension can be adjusted to the spring characteristics of the main spring 32 corresponding to the stroke (main spring 32 in FIG. 6). (see the spring characteristic MA) and the spring characteristic obtained by adding the spring characteristic of the auxiliary spring 34 to the spring characteristic of the main spring (see the characteristic HE in FIG. 6).

Further, in one embodiment of the present invention, when the wheel is fully bumped (see FIG. 5), before the auxiliary spring 34 is pressed against the upper part of the cylinder 14, the pressure contact of the auxiliary spring 34 is prevented by contacting the top of the cylinder 14. It is provided with a bump stopper 23 (see FIG. 5).
With this configuration, the bump stopper 23 can reliably prevent the auxiliary spring 34 from coming into pressure contact (line-to-line contact). The occurrence can be prevented more reliably.

Further, in one embodiment of the present invention, the cylinder 14 is composed of a single wall and filled with oil OIL, and has an oil storage chamber 41 communicating with the cylinder 14 and a free piston 42. An oil storage device 45 including a gas chamber 43 which can be expanded and compressed via the oil storage device 45 (see FIGS. 1 to 5).

According to this configuration, the end of the auxiliary spring 34 opposite to the piston is fixed to the lower side of the cylinder 14 in which the oil OIL is sealed, and the oil OIL can be smoothly moved along with the movement of the piston 12. can be done.

In addition, in one embodiment of the present invention, a centering guide 36 is provided on the inner bottom of the cylinder 14 and on the outer peripheral side of the auxiliary spring 34 (see FIGS. 1 to 5).
According to this configuration, the centering guide 36 positions the auxiliary spring 34, in particular, positions the auxiliary spring 34 in the radial direction, so that the quality of the damper 15 is further stabilized.

In the above embodiment, a monotube type gas damper provided with a cylinder 14 made of a single wall was exemplified. The present invention may be employed in the entry damper.

As described above, the present invention comprises a damper composed of a piston whose upper end is attached to the vehicle body, a cylinder whose lower end is attached to the wheel, and a damper whose upper end is attached to the outer periphery of the damper on the vehicle body side. , and a coil-shaped main spring whose lower end is attached to the outer peripheral wall of the cylinder.

DESCRIPTION OF SYMBOLS 11... Vehicle body 12... Piston 14... Cylinder 15... Damper 23... Bump stopper 32... Main spring 34... Auxiliary spring 36... Centering guide 41... Oil storage chamber 42... Free piston 43... Gas chamber 45... Oil storage device OIL... Oil

Claims (3)

a damper composed of a piston whose upper end is attached to the vehicle body and a cylinder whose lower end is attached to the wheel;
a coil-shaped main spring having an upper end attached to the outer periphery of the damper on the vehicle body side and having a lower end attached to the outer peripheral wall of the cylinder, the suspension device for a vehicle comprising:
An auxiliary spring is provided inside the cylinder, which abuts when the piston moves downward from the maximum stroke position by a predetermined distance and is compressed as the piston moves downward ,
A suspension device for a vehicle, wherein a centering guide is provided on the inner bottom of the cylinder and on the outer peripheral side of the auxiliary spring . 2. A suspension system for a vehicle according to claim 1, further comprising a bump stopper that abuts against the upper part of the cylinder to prevent pressure contact of the auxiliary spring before the auxiliary spring is pressed against the wheel when the wheel is fully bumped. The cylinder is composed of a single wall and is filled with oil,
3. A suspension system for a vehicle according to claim 1, further comprising an oil storage device including an oil storage chamber communicating with said cylinder and a gas chamber expandable and compressible via a free piston.

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