WO2017130919A1

WO2017130919A1 - Suspension

Info

Publication number: WO2017130919A1
Application number: PCT/JP2017/002190
Authority: WO
Inventors: 藤田　悦則; 大下　裕樹
Original assignee: デルタ工業株式会社
Priority date: 2016-01-31
Filing date: 2017-01-23
Publication date: 2017-08-03
Also published as: JPWO2017130919A1; JP6883333B2

Abstract

In order to make it possible to apply a greater damping force than with conventional suspensions while also decreasing thickness, a damper (60) is provided toward the side of an upper frame (10), which is a main vibration member supported at the tops of a front link (30) and a rear link (40) in a frame linking mechanism, so as to serve as an accessory vibration means that generates vibrations with a behavior different from the vibrations in the upper frame (10) which are generated by the rotational movements of the front link (30) and the rear link (40). When the upper frame vibrates due to input vibrations, the damper (60) exhibits a different vibrational behavior; thus, the energy of the input vibrations is not only dispersed as the vibrational energy of the upper frame (10) and the thermal energy generated by the expansions and contraction of the damper (60), but is also consumed as the energy that induces the vibration of the damper (60) itself, which is provided as a vibrating member. As a result of having such a structure, the damper (60) improves the basic performance of the suspension in terms of the vibration absorption characteristics and shock absorption characteristics thereof.

Description

suspension

The present invention relates to a suspension, and more particularly to a suspension suitable for use as a seat suspension for supporting a seat mounted on a vehicle such as an automobile.

In

Patent Documents

1 and 2, an upper frame provided to be movable up and down with respect to the lower frame is elastically supported by a magnetic spring and a torsion bar, and the magnetic spring has a negative spring constant in a predetermined displacement range. , And a combination of a torsion bar having a positive spring constant and a spring constant obtained by superimposing both in a predetermined displacement range is set to substantially zero (for example, a range from −50 N / mm to +50 N / mm). A suspension is disclosed.

JP 2010-179719 A JP 2010-179720 A

The seat suspensions of

Patent Documents

1 and 2 have characteristics that the spring constant obtained by superimposing both of them is substantially zero due to the configuration using the magnetic spring and the torsion bar for vibrations of a predetermined frequency and amplitude. Although it absorbs vibrations, a damper is also installed to absorb energy from larger vibrations and shocks.

As the damper, a telescopic type including a cylinder, a piston moving in the cylinder, and a piston rod connected to the piston is used. For example, the tip of the piston rod is connected to the lower frame via a shaft member. The rear end of the cylinder is rotatably connected to the upper frame via a shaft member. As a result, when the upper frame moves up and down relative to the lower frame, the piston connected to the piston rod moves relative to the cylinder by an amount corresponding thereto, and the energy is attenuated. Therefore, in such a configuration, the damper exhibits a predetermined damping force according to the displacement and speed of the upper frame.
However, it is always desired that vibration absorption characteristics and shock absorption characteristics can be more appropriately exhibited. In particular, in a thin suspension, it is desirable that a higher damping force can be exhibited while the stroke of the upper frame is limited.

The present invention has been made in view of the above points, and can further improve vibration absorption characteristics and shock absorption characteristics, and can exert a high damping force even if the stroke of the upper frame is short. It is an object of the present invention to provide a suspension that can contribute to thinning, particularly a suspension that is suitable as a thin sheet suspension.

In order to solve the above-mentioned problems, a suspension according to the present invention includes a lower frame, a front link and a rear link that are supported by the lower frame at a predetermined interval in the front-rear direction and perform a rotational motion around the lower portion. A link mechanism for a frame, an upper frame supported on top of the front link and the rear link, a spring mechanism for elastically urging the front link and the rear link, and the lower frame of the upper frame A suspension with a damper that attenuates energy at the time of separating operation with respect to
The damper is a telescopic type including a piston rod and a cylinder, and is attached to the upper frame side so as to expand and contract by the rotational movement of the front link and the rear link, and the damper itself is externally attached. A vibration having a behavior different from the vibration of the upper frame caused by the rotational motion of the front link and the rear link due to the input vibration from
The upper frame supported via the spring mechanism is a main vibration body, and the damper attached to the upper frame side is a sub vibration body.

The upper frame includes an upper front frame provided between the upper portions of the front links disposed on the left and right and an upper rear frame disposed between the upper portions of the rear links disposed on the left and right pairs. The damper is disposed between at least one of the upper front frame and the upper rear frame via at least one damper link, and the damper link. It is preferable that the damper itself functions as the sub-vibration body that generates a vibration having a behavior different from the vibration of the upper frame, which is the main vibration body, due to an external input vibration.
The damper has an axial center near the neutral position of the upper frame, a fulcrum on the upper side of the front link that supports the upper frame, and a fulcrum on the upper side of the rear link that supports the upper frame. However, it is preferable that it is set so as to be substantially in a straight line when viewed from the side.
One of a piston rod bracket to which the piston rod is connected and a cylinder bracket to which the cylinder is connected is provided on the upper front frame, and the other is provided on the upper rear frame. It is preferable that a link is interposed between at least one of the piston rod and the piston rod bracket and between the cylinder and the cylinder bracket.
In the vicinity of the neutral position of the upper frame, the fulcrums at both ends of the damper link are the upper fulcrum of the front link that supports the upper frame, or the upper side of the rear link that supports the upper frame. It is preferable to be provided in a posture that is substantially in line with the fulcrum.

The spring mechanism is a combination of a spring having a positive characteristic that biases the upper frame in a direction away from the lower frame and a spring having a negative characteristic in a predetermined displacement range. Preferably, in the vicinity of the neutral position of the upper frame, there is a region where the characteristics of the springs are superimposed and the spring constant becomes substantially zero.
It is preferable that the lower frame is fixed to the vehicle body side and used as a vehicle seat suspension in which a seat is supported by the upper frame.

According to the present invention, the damper has a rotational motion of the front link and the rear link on the upper frame side which is a main vibration body supported by the upper part of the front link and the rear link of the frame link mechanism via the spring mechanism. It is provided so as to be a sub-vibration body that generates a vibration having a behavior different from the vibration of the upper frame caused by. That is, when the upper frame, which is the main vibrating body, vibrates due to the input vibration, the damper, which is the sub-vibrating body, exhibits different vibration behavior, so the energy of the input vibration is the heat generated by the vibration energy of the upper frame and the expansion and contraction of the damper. In addition to being dispersed in energy, it is also consumed as energy that vibrates the damper itself. Therefore, such an arrangement structure of the damper improves the basic performance of the vibration absorption characteristics and shock absorption characteristics of the suspension. As a result, even if the stroke of the upper frame is short, predetermined vibration absorption characteristics and shock absorption characteristics can be exhibited, which can contribute to a thinner suspension. In addition, since the damper can be disposed substantially horizontally along the upper frame and does not need to be disposed across the upper frame and the lower frame, this point can also contribute to thinning of the suspension. In addition, by installing the damper on the upper frame side via at least one damper link, the amount of vibration of the damper itself that occurs as the upper frame moves up and down is increased, and the share of input energy is reduced. The vibration absorption characteristics can be further improved.

Further, the present invention preferably has a configuration in which the damper is substantially in a straight line when viewed from the side and the portion supporting the piston rod and cylinder near the neutral position of the upper frame. Therefore, when the upper frame is near the neutral position, the damper is near the dead center position, so that the damping force does not function so much and the upper frame is in the range of slight vibration, and the elasticity of the spring mechanism Can be isolated by force. Therefore, even if a damper with a high damping force is used, the damping force of the damper hardly functions in the range of slight vibration of the upper frame. Therefore, it is possible to use a damper that generates a stronger damping force, and the suspension is thin. It is suitable for planning. Further, by adopting a configuration using the rotational movement of the damper link, the damper can be expanded and contracted efficiently even if the displacement amount of the upper frame is small, and this also contributes to the thinning of the suspension.

FIG. 1 is a perspective view showing a schematic configuration of a seat suspension according to an embodiment of the present invention. FIG. 2 is a perspective view of the seat suspension shown in FIG. 1 with the attachment frame provided on the upper frame removed. FIG. 3A is a front view of the seat suspension according to the embodiment, and FIG. 3B is a plan view. FIG. 4A is a side view of the seat suspension according to the embodiment, and FIG. 4B is a bottom view. FIG. 5 is a view for explaining the positional relationship between the front link, the rear link, and the damper. 6 (a) to 6 (c) are views for explaining the operation of the seat suspension according to the embodiment, and FIG. 6 (a) is a side view of the upper frame in the lower limit position. 6B is a side view of the upper frame in the neutral position, and FIG. 6C is a side view of the upper frame in the upper limit position. FIG. 7A is a diagram showing the displacement-load characteristics of the seat suspension according to Test Example 1. FIG. 7B is a diagram showing the displacement amount of the upper frame (suspension displacement) and the displacement amount of the damper (damper displacement). ), And FIG. 7C is a diagram showing the relationship between suspension displacement and force transmission efficiency. FIG. 8A is a diagram showing temporal changes in the displacement amount (suspension displacement) of the upper frame and the displacement amount of the damper (damper displacement) of the seat suspension according to Test Example 1, and FIG. FIG. 8C is a diagram showing temporal changes in the displacement speed of the upper frame (suspension speed) and the displacement speed of the damper (damper speed). FIG. 8C shows the damping force of the damper alone and the damping force of the entire seat suspension. It is the figure shown by the relationship with the displacement amount (suspension displacement) of a flame | frame. FIG. 8D is a diagram showing the displacement-load characteristic diagram of FIG. 7A together with the damping force of the entire seat suspension in FIG. 8C. FIG. 9 is a diagram illustrating a measurement result of vibration transmissibility in Test Example 2.

Hereinafter, the present invention will be described in more detail based on the embodiments shown in the drawings. 1 to 6 show a structure of a seat suspension 1 for a vehicle such as a passenger car, a truck, a bus, and a forklift, which is a suspension according to an embodiment of the present invention. As shown in these drawings, the seat suspension 1 according to the present embodiment includes a substantially rectangular upper frame 10 and a lower frame 20, and a parallel link including a front link 30 and a rear link 40 in pairs. It is connected via a frame linking mechanism. A vehicle seat (not shown) is supported on the upper frame 10, and the lower frame 20 is fixed to the vehicle body side (for example, a floor (not shown)). The upper portions of the pair of left and right front links 30 and 30 are connected by an upper front frame 11 included in the upper frame 10, and the upper portion of the pair of left and right

rear links

40 and 40 is connected to the upper rear frame 12 included in the upper frame 10. It is connected by. Then, the end portions of the upper front frame 11 and the upper rear frame 12 are inserted into attachment holes (not shown) formed in the pair of

side frames

10a, 10a of the upper frame 10, and the

front links

30, 30 and The

rear links

40 and 40 are provided so as to be positioned near the side portions of the upper frame 10 and the lower frame 20. Accordingly, the upper frame 10 can move up and down with respect to the lower frame 20, more precisely, the frame link mechanism has a parallel link structure including the

front links

30 and 30 and the

rear links

40 and 40. Therefore, it moves up and down between the diagonally upper rear that is the upper limit position and the diagonally lower front that is the lower limit position along the rotation trajectories of the

front links

30 and 30 and the

rear links

40 and 40.

The upper front frame 11 and the upper rear frame 12 are both formed of a pipe material in the present embodiment, and the torsion bars 31 and 41 are inserted, respectively. One end of each of the torsion bars 31 and 41 is provided so as not to rotate relative to the upper front frame 11 and the upper rear frame 12, so that the torsion bars 31 and 41 can move the upper frame 10 to the lower frame 20. On the other hand, it is set so as to exert an elastic force biasing in a direction that is relatively separated from each other, that is, upward. The other ends of the torsion bars 31 and 41 are connected to an initial position adjusting member 15 including an adjusting shaft 15a, an adjusting dial 15b, and the like. The structure is the same as the structure disclosed in

Patent Documents

1 and 2, and when the adjustment dial 15b is rotated, the torsion bars 31 and 41 are twisted in either direction, and the initial elasticity of the torsion bars 31 and 41 is The force is adjusted so that the upper frame 10 can be adjusted to the neutral position regardless of the weight of the seated person. The arrangement positions of the torsion bars 31 and 41 are not limited to the upper part, and may be provided below the upper front frame 11 and the upper rear frame 12. In addition, the spring for biasing the upper frame 10 in the direction away from the lower frame 20 is not limited to the torsion bars 31 and 41, and a coil spring or the like may be used. However, in order to obtain a predetermined positive spring constant in a range where the stroke of the upper frame 10 is short, a torsion that can be incorporated at the fulcrum of the

front links

30 and 30 and the

rear links

40 and 40 as in this embodiment.

Bars

31 and 41 are preferably used.

The magnetic spring 50 includes a fixed magnet unit 51 and a moving magnet unit 52 as shown in FIGS. The fixed magnet unit 51 includes a fixed-side magnet support frame 511 attached to the lower frame 20, and fixed-

side magnets

512 and 512 supported by the fixed-side magnet support frame 511 and attached at predetermined intervals in the vertical direction. It becomes.

The moving magnet unit 52 includes a moving magnet 521 disposed in a gap 513 between fixed

magnets

512 and 512 that are arranged to face each other at a predetermined interval. Each end of the movement-side magnet 521 is connected to one end of a substantially L-shaped movement-

side magnet link

522, 522. The other ends of the moving-side magnet links 522 and 522 are pivotally supported by a mounting bracket 523 provided near the rear portion of the upper frame 20. As a result, when the upper frame 10 is displaced in the direction approaching the lower frame 20, that is, downward, the moving magnet 521 causes the gap 513 between the

fixed magnets

512 and 512 via the moving

magnet links

522 and 522. When the upper frame 10 is displaced away from the lower frame 20, that is, upward, the moving magnet 521 is moved between the

fixed magnets

512 and 512 via the moving

magnet links

522 and 522. The gap 513 is moved backward.

The magnetic spring 50 can be provided so that the moving side magnet 521 moves in a substantially vertical direction. However, if the moving side magnet 521 is configured to move in a substantially horizontal direction as in the present embodiment, the magnetic spring 50 can be provided. The overall thickness (vertical height) of the magnetic spring 50 can be reduced, which can contribute to a reduction in the overall thickness of the seat suspension 1.

The magnetic spring 50 exhibits a negative spring constant in a predetermined displacement amount range when the moving side magnet 521 moves. For example, as the fixed

side magnets

512 and 512 arranged to face each other, the magnetic spring 50 has a thickness direction. Two magnetized magnets are used, each being arranged so that the different poles are adjacent to each other along the moving direction of the moving magnet 521, while the magnetizing direction of the moving magnet 521 is the moving direction. By configuring in this way, a structure that exhibits a negative spring constant in the vicinity of a position that crosses between the

fixed magnets

512 and 512 can be obtained. In this specification, the characteristic in the direction in which the value of the restoring force increases as the torsion amount of the torsion bars 31 and 41 increases is referred to as “positive spring characteristic (the spring constant at that time is referred to as“ positive spring constant ”). When the torsion bars 31 and 41 are twisted so as to exert positive spring characteristics, the relative position of the moving side magnet 521 with respect to the fixed

side magnets

512 and 512 causes the magnetic spring 50 to move regardless of the increase in displacement. The characteristic of the displacement range (the range from about -10mm to about 10mm in Fig. 7 (a)) where the restoring force value becomes smaller is the "negative spring characteristic (the spring constant at that time is the" negative spring constant ")" It is said.

As a result, the spring mechanism of the present embodiment including the magnetic spring 50 and the above-described

torsion bars

31 and 41 has the above-described

torsion bars

31 and 41 in the range in which the negative spring constant of the magnetic spring 50 functions. A constant load region where the load characteristic does not change even if the amount of displacement increases, that is, a region where the spring constant becomes substantially zero (for example, the change of the spring constant changes from −50 N / mm to +50 N). / Mm range (a range from about −10 mm to about 10 mm in FIG. 7A). In order to effectively use the region where the spring constant is substantially zero as much as possible, the moving magnet 521 of the moving magnet unit 52 is positioned substantially in the center of the moving range at the neutral position of the upper frame 10. It is preferable to set so as to.

Here, in this embodiment, the damper 60 is provided on the upper frame 10 side. The damper 60 has a piston rod 61 and a cylinder 62 in which a piston 61b attached to the piston rod 61 reciprocates (see FIGS. 5 and 6). The upper front side attached to the upper frame 10 side ("upper frame side" means any part constituting the upper frame 10 and any part operating together with the upper frame 10). A piston rod bracket 35 as a part for supporting the front side of the damper 60 is provided on the part frame 11 so as to protrude rearward, and the upper rear frame is also attached to the upper frame 10 side. 12 is provided with a cylinder bracket 45 as a part for supporting the rear side of the damper 60 so as to protrude forward (see FIGS. 5 and 6). Since the damper 60 is thus spanned between the upper front frame 11 and the upper rear frame 12 constituting the upper frame 10, the damper 60 is disposed substantially horizontally.

For example, the upper frame 10 that is the main vibrating body vibrates up and down via the

front links

30 and 30 and the

rear links

40 and 40 due to vibration input from the vehicle body floor side during traveling, but the damper according to the present embodiment. Reference numeral 60 denotes a sub-vibrator that generates vibrations having behaviors different from the vibration of the upper frame 10. Therefore, the energy of the input vibration is also dissipated by the vibration energy of the damper 60 as a sub-vibration body, and the vibration absorption characteristics and shock absorption characteristics of the entire seat suspension 1 are improved.

As shown in FIGS. 5 and 6, the piston rod 61 of the damper 60 as the sub-vibration body of the present embodiment has its tip end portion 61 a pivotally supported by the piston bracket 35 via the first shaft member 63 a. The upper end 61a is pivotable up and down. On the other hand, the cylinder 62 is not directly connected to the cylinder bracket 45 but is connected via a damper link 70.

Specifically, a mounting frame 10b is spanned between the upper surfaces of the side frames 10a and 10a in the vicinity of the middle between the upper front frame 11 and the upper rear frame 12 of the upper frame 10. Support brackets 64 that are formed in a substantially U-shape when viewed from the front of the seat suspension 1 are attached to the mounting frame 10b back to back, and a cylinder 62 is disposed between the side surfaces of the substantially U-shaped support bracket 64. (See FIGS. 1, 2 and 5). Note that the support bracket 64 is formed in a substantially L-shape extending downward after hanging downward when viewed from the side. At the position corresponding to the axial center of the cylinder 62 at the rear portion of the cylinder 62, there is an upper portion of a substantially triangular link 65 that serves as a relay damper link connected to a damper link 70 described later. While being connected via the second shaft member 63b, the lower part of the substantially triangular link 65 is connected to the rear end 64a extending rearward in the support bracket 64 via the third shaft member 63c. The top portion 65a of the substantially triangular link 65 projects rearward from the rear end of the cylinder 62, and the top portion 65a and one end 70a of the damper link 70 are connected via a fourth shaft member 63d. The other end 70b of the damper link 70 and the cylinder bracket 45 are connected via a fifth shaft member 63e (see FIG. 5).

Thus, when the upper frame 10 is separated from and in contact with the lower frame 20, the piston rod 61 and the cylinder 62 of the damper 60 relatively expand and contract, but the upper frame 10 is in a neutral position (the upper frame 10 with respect to the lower frame 20). As shown in FIGS. 5 and 6 (b), the damper link 70 is a dead center (thinking) in the vicinity of the middle of the displacement range in the vicinity of a point determined by design as a position where a sufficient vertical stroke can be secured. It is attached so that it becomes the posture of the point) position. Specifically, as shown in FIGS. 5 and 6 (b), the damper link 70 is substantially straight with respect to the cylinder bracket 45 when viewed from the side, and more precisely when viewed from the side. The center of the upper rear frame 12 (torsion bar 41) to which the cylinder bracket 45 is attached, which is a fulcrum on the upper side of the rear link 40 that supports the upper frame 10, one of the damper link 70 and the cylinder bracket 45 The center of the fifth shaft member 63e, which is a fulcrum, and the center of the fourth shaft member 63d, which is the other fulcrum of the damper link 70 and the substantially triangular link 65, are attached in a substantially straight line.

By attaching in this way, the upper frame 10 is located above the lower frame 20 from near the neutral position (in the direction of displacement from the state of FIG. 6B to the state of FIG. 6C) or below (the figure The damper 60 fixed to the upper rear frame 12 with any change in the angle of the

rear links

40, 40, regardless of whether it is displaced from the state of 6 (b) to the state of FIG. 6 (a). When the angle of the cylinder bracket 45 as a part for supporting the rear side changes, that is, when the upper frame 10 is displaced upward, the tip of the cylinder bracket 45 is changed from the state of FIG. 6B to FIG. 6C. When the upper frame 10 is rotated downward (clockwise in FIGS. 6B and 6C) so that the upper frame 10 is displaced downward, the tip of the cylinder bracket 45 is in the state shown in FIG. State so as to lower et Figure 6 (a) (FIG. 6 (a), the counter-clockwise direction in (b)) is rotated to. The other end 70b of the damper link 70 is displaced in the same direction as the cylinder bracket 45 is rotated. Therefore, the one end 70a rotates in the opposite direction around the fifth shaft member 63e, and has a substantially triangular shape. The top portion 65a of the link 65 is pulled toward the rear side, that is, the cylinder bracket 45 side. As a result, the upper part of the substantially triangular link 65 rotates backward (clockwise in FIGS. 6A to 6C) around the third shaft member 63c connected to the support bracket 64, and the substantially triangular link 65 The cylinder 62 connected to the upper part of the 65 via the second shaft member 63 b is drawn rearward, and the piston rod 61 operates in the extending direction relative to the cylinder 62. Since the damper 60 is extended by the damper link 70 that rotates in this manner, the displacement speed (the cylinder 62 of the piston rod 61) of the damper 60, which is the amount of displacement (elongation) of the damper 60 per unit time. (Moving speed) increases as the amount of displacement of the upper frame 10 increases. Therefore, the damping force of the damper 60 increases rapidly until the upper frame 10 reaches a position separated by a predetermined amount upward or downward.

Further, as shown in FIGS. 5 and 6B, at the neutral position of the upper frame 10, the axis of the damper 60 (the center of the first shaft member 63a, which is a fulcrum between the piston bracket 35 and the piston rod 61). And a line connecting the center of the second shaft member 63b that is a fulcrum between the cylinder 62 and the substantially triangular link 65) is an upper front frame that is a fulcrum on the upper side of the front link 30 that supports the upper frame 10. 11 (torsion bar 31) and the center of upper rear frame 12 (torsion bar 41), which is a fulcrum on the upper side of rear link 40 that supports upper frame 10, are provided so as to substantially coincide with each other. Therefore, when the upper frame 10 is displaced vertically from the neutral position, the straight line connecting the center of the upper front frame 11 (center of the torsion bar 31) and the first shaft member 63a and the axis of the damper 60 are formed. The angle on one side (lower side when displaced downward (FIG. 6A) and upper side when displaced upward (FIG. 6C)) is less than 180 degrees. Further, the other side formed by the straight line connecting the center of the upper rear frame 12 (center of the torsion bar 41) and the second shaft member 63b and the axis of the damper 60 (when displaced downward (FIG. 6A)). Similarly, the angle when the lens is displaced upward and downward (lower side in FIG. 6C) is similarly less than 180 degrees. As a result, the piston rod 61 and the cylinder 62 are displaced in the opposite direction, that is, in the extending direction by the amount corresponding to this angle. Therefore, in the configuration of the present embodiment, even if the damper link 70 is not disposed, if the upper frame 10 vibrates up and down from the neutral position, the piston rod 61 increases as the displacement amount of the upper frame 10 increases due to these actions. The ratio of the amount of displacement increases. However, it is preferable to provide the damper link 70 in order to increase the relative movement amount of the piston rod 61 with respect to the cylinder 62 even when the displacement amount of the upper frame 10 is smaller.

Further, by arranging the damper 60 using the damper link 70 or the like in this way, when the upper frame 10 moves up and down, the cylinder is formed around the first shaft member 63a that is a fulcrum of the piston rod 61. The amount of vibration on the 62 side increases. In particular, in this embodiment, a substantially triangular link 65 is connected as an auxiliary damper link between the cylinder 62 and the damper link 70 using the second, third and fourth shaft members 63b to 63d. ing. Therefore, the damper 60 is supported via the articulated link structure including the damper link 70 and the substantially triangular link 65 as the auxiliary damper link. The resulting vibration of the damper 60 itself is noticeable. The vibration behavior of the damper 60 at this time does not coincide with the behavior of the upper frame 10 that vibrates up and down substantially in parallel, and the front end portion on the piston rod 61 side and the rear end portion on the cylinder 62 side operate in opposite directions. Show different behaviors (pendulum motion). As a result, the damper 60 serving as the sub-vibrating body can dissipate input energy not only by the expansion / contraction operation but also by the pendulum motion independent of the upper frame 10 serving as the main vibrating body, thereby improving vibration absorption characteristics and shock absorption characteristics. Since the damper 60 itself exhibits such independent vibration behavior, when the seat suspension 1 itself is regarded as a dynamic vibration absorber, the damper 60 functions as an auxiliary mass body. It can be said that it contributes to the improvement of the characteristics and shock absorption characteristics.

Further, in the vicinity of the neutral position of the upper frame 10, as described above, the axial center of the damper 60 is substantially in line with the center of the upper front frame 11 and the center of the upper rear frame 12 as viewed from the side, and The center of the fifth shaft member 63e and the center of the fourth shaft member 63d at both ends of the damper link 70 are substantially in line with the center of the upper rear frame 12 when viewed from the side surface. The posture at the point) position. Therefore, the damper 60 hardly expands and contracts near the neutral position of the upper frame 10. Accordingly, the damping force of the damper 60 does not substantially act at the neutral position of the upper frame 10, and the vibration is isolated by the characteristics of the spring mechanism of the present embodiment configured by the torsion bars 31 and 41 and the magnetic spring 50. . That is, in the vicinity of the neutral position of the upper frame 10, small amplitude and high frequency micro vibrations of the upper frame 10 can be absorbed without using the damping force of the damper 60. For this reason, as the damper 60, it is possible to use a damper having a high damping force that effectively absorbs a low-frequency vibration or impact force having a larger amplitude. As a result, even if the entire stroke of the upper frame 10 is small, high vibration absorption characteristics and shock absorption characteristics can be exhibited, which is suitable for reducing the thickness of the seat suspension 1.

Further, in the present embodiment, since the damper link 70 is provided, the rotational movement of the cylinder bracket 45 via the upper rear frame 12 accompanying the rotational movement of the

rear links

40, 40, the front link 30, In addition to the rotational motion of the piston rod bracket 35 associated with the rotational motion of 30, the rotational motion of the damper link 70 that accompanies the rotational motion acts synergistically. Therefore, in spite of the structure in which the damper 60 is provided substantially horizontally on the upper frame 10 side, the damper 70 quickly reacts sensitively to the upward or downward displacement from the vicinity of the neutral position of the upper frame 10. Works. Thereby, according to the seat suspension 1 of the present embodiment, a high damping force can be applied before the upper frame 10 reaches the upper limit position or the lower limit position, and the bottom frame and ceiling suppression effects of the upper frame 10 can be applied. Is expensive.

Here, the type of the damper 60 is not limited, and a displacement-dependent damper such as a friction damper using a spring element, a speed-dependent damper such as a magnetic damper or an oil damper, or a displacement or speed. Other dampers or the like having a small dependency can be used. However, as described above, in the present embodiment, the damper 60 is provided in a substantially horizontal posture on the upper frame 10 side, so that it is more than an oil damper using a viscous liquid. It is preferable to use a friction damper or a magnetic damper. As the displacement-dependent friction damper, for example, a rubber or resin ball disposed on the outer peripheral surface of the piston 61b or a rubber and resin ball used together and provided in an appropriate arrangement in the axial direction is used. Thus, a frictional resistance and an elastic deformation are generated between the inner peripheral surface of the cylinder 62 and a damping force is generated. As the speed-dependent magnetic damper, for example, a magnet having a structure in which a magnet is used as the piston 61b and a conductor made of copper is disposed on the inner peripheral surface as the cylinder 62 can be used. A displacement-dependent friction damper can employ a high damping force by increasing the frictional resistance and spring constant. Even in the case of a speed-dependent magnetic damper, in the present embodiment, as the amount of displacement of the upper frame 10 increases, the rate of displacement of the piston rod 61 increases as described above. A high damping force can be exerted at a displacement position separated by a predetermined amount.

Further, in this embodiment, the damper link 70 is provided between the cylinder 62 and the cylinder bracket 45, but instead, it may be provided between the piston rod 61 and the piston rod bracket 35. it can. Also, the damper link 70 can be disposed on both the piston rod 61 side and the cylinder 62 side. In this embodiment, the piston rod 61 is arranged on the front side and the cylinder 62 is arranged on the rear side. However, it is of course possible to arrange them in the reverse direction.

(Test Example 1)
7A to 7C are diagrams showing the static characteristics of the seat suspension 1 according to Test Example 1 that employs the structure of the present embodiment. As the damper 60, a speed-dependent magnetic damper in which a magnet is disposed as the piston 61b and copper is disposed on the inner peripheral surface of the cylinder 62 is used. Further, the distance (damper length) between the center of the first shaft member 63a on which the piston rod 61 is pivotally supported and the center of the second shaft member 63b, which is a fulcrum of the cylinder 62 and the substantially triangular link 65, is shown in FIG. When L1 is at the neutral position of 6 (b), L2 is at the lower limit position of FIG. 6 (a), and L3 is at the upper limit position of FIG. 6 (c), L2 = L1 + 3.1 mm and L3 = L1 + 5.3 mm. is there. In FIG. 7, the displacement amount 0 mm is the neutral position of the upper frame 10, a positive value of the displacement amount indicates a case where the upper frame 10 is displaced downward from the neutral position, and a negative value of the displacement amount is the upper frame. A case where 10 is displaced upward from the neutral position is shown. First, from the displacement-load characteristics shown in FIG. 7 (a), the seat suspension 1 of the present embodiment has a spring constant of an absolute value of about 20 N / mm or less (within an absolute value in a displacement amount range of ± about 10 mm centered on a displacement amount of 0 mm ( It can be seen that in the displacement range of ± 5 mm, the spring constant has an area of approximately zero with an absolute value of approximately 10 N / mm or less. Therefore, when a person is seated and the upper frame 10 is positioned near the neutral position, the vertical vibration transmitted from the vehicle body floor is effectively damped by the relative motion of the upper frame 10 and the lower frame 20.

On the other hand, from FIG. 7B, when the displacement amount (suspension displacement) of the upper frame 10 with respect to the lower frame 20 is compared with the displacement amount (damper displacement) of the piston 61b and the piston rod 61 with respect to the cylinder 62, As the amount of displacement increases, the ratio of the amount of displacement of the damper 60 increases. In particular, when the amount of displacement of the upper frame 10 exceeds about ± 10 mm, the proportion of the amount of displacement of the damper 60 increases rapidly. The effects of the rotational movements of the cylinder bracket 35, the damper link 70, and the piston rod bracket 35 are notable.

8 (a) to 8 (c) are diagrams showing dynamic characteristics when the upper frame 10 is moved up and down at 4 Hz with the displacement amount from the neutral position of the upper frame 10 being ± 15 mm. Comparing FIGS. 8A and 8B, the damper speed (moving speed of the piston 61b and the piston rod 61 in the cylinder 62) is highest when the displacement (suspension displacement) of the upper frame 10 is near +10 mm and near −10 mm. It has become. From FIG. 8C, the damping force of the damper 60 and the damping force of the seat suspension 1 are maximized in the vicinity of the displacement amount (suspension displacement) of the upper frame 10 +10 mm and in the vicinity of −10 mm. Therefore, according to the present embodiment, it can be seen that the upper frame 10 can be attenuated by applying a large damping force before reaching the upper limit position or the lower limit position. On the other hand, at the neutral position of the upper frame 10, the damper link 70 becomes a dead point (thought point) position, and the damping force of the damper 60 is hardly working. This is also apparent from FIG. 8 (d) showing the displacement-load characteristic of FIG. 7 (a) and the damping force of FIG. 8 (c). When the vibration is isolated by the characteristic that the spring constant becomes substantially zero and a larger vibration or impact is input, energy is absorbed by the damping force of the damper 60.

For the seat suspension 1 of Test Example 1, a SEAT value (Seat Effective Amplitude Transmissibility factor) was determined based on JIS A 8304: 2001 (ISO 7096: 2000). Assuming that the seat suspension 1 of Test Example 1 is used for a driver's seat of a forklift, an input spectrum class EM6 (excitation center frequency 7.6, PSD, which is a reference of a “50,000 kg or less crawler tractor dozer”) The maximum value of 0.34 (m / s ² ) ² / Hz) was tested. The test subjects were two persons weighing 63 kg and 72 kg. As a result, the obtained SEAT values were 0.34 and 0.28, respectively. Since the standard of SEAT value of EM6 was less than 0.7, the standard was satisfied. In addition, the test was performed with an input spectrum class EM8 (excitation center frequency 3.3, PSD maximum value 0.4 (m / s ² ) ² / Hz) which is a standard of “a compact loader of 4,500 kg or less”. The subjects were two persons weighing 63 kg and 72 kg. As a result, the obtained SEAT values were 0.52 and 0.52, respectively. Since the standard of SEAT value of EM8 was less than 0.8, the standard was satisfied.

(Test Example 2)
FIG. 9 shows a vibration transmissibility when an automobile seat is mounted on the upper frame 10 of the seat suspension 1 in which the lower frame 20 is set on a vibration exciter and the subject with a weight of 85 kg is seated on the seat. It is the figure which showed the measurement result. In the seat suspension 1 of Test Example 2, as the damper 60, a displacement-dependent friction damper that provides rubber on the peripheral surface of the piston 61 b and slides on the inner peripheral surface of the cylinder 62 is used. Moreover, the damping force of the displacement-dependent friction damper exceeds the damping force of the magnetic damper of Test Example 1. In FIG. 9, Comparative Example 1 is a measurement result when a seat suspension from which the displacement-dependent friction damper is removed is used.

FIG. 9 shows that the vibration transmissibility at the resonance point in Test Example 2 is significantly lower than that in Comparative Example 1. Further, in the region where the input frequency band is higher than the resonance point, Test Example 2 has almost the same vibration transmissibility as Comparative Example 1 even though the displacement-dependent friction damper having a high damping force is used. Thus, it can be seen that in the region of high frequency and small amplitude, the displacement-dependent friction damper does not act, and the vibration can be isolated by the action of a spring mechanism having a substantially zero spring constant characteristic.

Further, in Test Example 2 that employs the structure of the above-described embodiment, as described above, the damper 60 that is the sub-vibrating body includes the cylinder 62, the second shaft member 63b, the third shaft member 63c, and the fourth shaft member. It is supported by a substantially triangular link 65 and a damper link 70 as auxiliary damper links connected via 63d and the fifth shaft member 63e, that is, by a multi-joint structure link. Therefore, when the upper frame 10 that is the main vibrating body moves up and down, the cylinder 62 side swings around the first shaft member 63a that is the fulcrum of the piston rod 61.

From FIG. 9, the resonance peak in Test Example 2 is significantly lower than that in Comparative Example 1 due to the expansion / contraction operation of the damper 60 made of a friction damper, but the resonance of Comparative Example 1 that does not include the damper 60. While the frequency is about 1.8 Hz, in Test Example 2, it is about 1.9 Hz. That is, Test Example 2 is slightly shifted to the high frequency side. However, in Test Example 2, the vibration transmissibility is lower than that of Comparative Example 1 even in a higher frequency region exceeding the resonance frequency, particularly up to about 2.5 Hz, and no secondary resonance point is generated. Moreover, in the high frequency region above 2.5 Hz, both have substantially the same vibration transmissibility. Therefore, in Test Example 2, the frequency band of the attenuation region is increased as compared with Comparative Example 1. This is due to the action of the damper 60 which is a sub-vibration body in which the seat suspension 1 of Test Example 2 vibrates with a behavior different from the vibration of the upper frame 10 which is the main vibration body. That is, the energy of the input vibration is dissipated not only by the vibration of the upper frame 10 and the energy consumption of the input vibration accompanying the expansion / contraction operation of the damper 60 but also by the vibration of the damper 60 itself. . Also, the reason that the vibration transmissibility gradually falls without generating a secondary resonance point in the range exceeding 2 Hz is that the damper 60 is not a spring but a substantially triangular link 65, a damper link in the upper frame 10. By being supported through a plurality of links including 70.

DESCRIPTION OF SYMBOLS 1 Seat suspension 10 Upper frame 11 Upper front frame 12 Upper rear frame 15 Initial position adjusting member 20 Lower frame 30 Front link 31 Torsion bar 35 Piston rod bracket 40 Rear link 41 Torsion bar 45 Cylinder bracket 50 Magnetic spring 51 Fixed Magnet unit 512 Fixed magnet 52 Moving magnet unit 521 Moving magnet 60 Damper 61 Piston rod 61b Piston 62 Cylinder 63a to 63e Shaft member 65 Roughly triangular link 70 Damper link

Claims

A lower frame,
A frame link mechanism comprising a front link and a rear link that are supported on the lower frame at a predetermined interval in the front-rear direction and each perform a rotational movement back and forth around the lower part;
An upper frame supported on top of the front and rear links;
A spring mechanism that elastically biases the front link and the rear link;
A suspension comprising a damper for attenuating energy at the time of the separation operation of the upper frame with respect to the lower frame,
The damper is a telescopic type including a piston rod and a cylinder, and is attached to the upper frame side so as to expand and contract by the rotational movement of the front link and the rear link, and the damper itself is externally attached. A vibration having a behavior different from the vibration of the upper frame caused by the rotational motion of the front link and the rear link due to the input vibration from
The suspension is characterized in that the upper frame supported via the spring mechanism serves as a main vibration body, and the damper attached to the upper frame side serves as a sub vibration body.
The upper frame includes an upper front frame provided between the upper portions of the front links disposed on the left and right and an upper rear frame disposed between the upper portions of the rear links disposed on the left and right pairs. And
The damper is disposed between at least one damper link between the upper front frame and at least one of the upper rear frame,
2. The damper according to claim 1, wherein the damper itself functions as the sub-vibration body that generates a vibration having a behavior different from the vibration of the upper frame, which is the main vibration body, due to an input vibration from the outside due to the movement of the damper link. suspension.
The damper has an axial center near the neutral position of the upper frame, a fulcrum on the upper side of the front link that supports the upper frame, and a fulcrum on the upper side of the rear link that supports the upper frame. The suspension according to claim 1, wherein the suspension is set to be substantially in a straight line when viewed from the side.
One of the piston rod bracket to which the piston rod is connected and the cylinder bracket to which the cylinder is connected is provided on the upper front frame, and the other is provided on the upper rear frame.
The suspension according to claim 2 or 3, wherein the damper link is interposed between at least one of the piston rod and the piston rod bracket and between the cylinder and the cylinder bracket.
In the vicinity of the neutral position of the upper frame, the fulcrums at both ends of the damper link are the upper fulcrum of the front link that supports the upper frame, or the upper side of the rear link that supports the upper frame. The suspension according to claim 4, wherein the suspension is provided in a posture substantially in line with the fulcrum.
The spring mechanism is a combination of a spring having a positive characteristic that biases the upper frame in a direction away from the lower frame and a spring having a negative characteristic in a predetermined displacement range. Consists of
The suspension according to any one of claims 1 to 5, wherein the suspension has a region in which a spring constant is substantially zero near the neutral position of the upper frame by superimposing the characteristics of the springs.
The suspension according to any one of claims 1 to 6, wherein the suspension is used as a vehicle seat suspension in which the lower frame is fixed to a vehicle body side and a seat is supported by the upper frame.