JP2008128315A - Suspension unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact and lightweight suspension unit which can reduce resonance frequency and decrease a resonance peak and acceleration in a high-frequency band. <P>SOLUTION: The suspension unit includes a lower frame 2 and an upper frame 4 which is mounted on the lower frame 2 so as to be freely vertically movable by means of a link mechanism. The suspension unit includes further metal springs 14, 46 and a magnetic spring unit 54 for supporting elastically the upper frame 4 with respect to the lower frame 2, and a magnetic damper 70 which is mounted on the upper frame 4 so as to damp vertical movement of the upper frame 4. The magnetic damper 70 is operated by utilization of electromagnetic induction of copper as a dynamic vibration absorber which gets the vertical movement of the upper frame 4 damped by horizontal movement of a copper plate 70c by means of the link mechanism. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a suspension unit having a metal spring and a magnetic spring unit. More specifically, the present invention relates to a metal spring having a positive spring constant and a magnetic spring unit having a negative spring constant. This relates to a suspension unit.

  In recent years, various vehicle technologies, including automobile technology, have made rapid progress, and not only motor performance but also safety and comfort have been demanded. Recently, as permanent magnets with high coercive force and high residual magnetic flux density are put into practical use, research on magnetic control systems such as magnetic levitation, magnetic bearings, dampers using magnetic fluid has been actively conducted, The present applicant has also proposed various suspension units using a magnetic spring.

  However, in a suspension unit that exhibits a spring constant of approximately zero in a predetermined region by combining a metal spring having a positive spring constant and a magnetic spring unit having a negative spring constant, an extremely large unit is obtained when an attempt is made to increase the stroke. Was the current situation.

  Accordingly, the applicant of the present application has proposed a suspension unit that can ensure a large stroke and achieve downsizing by making the operation amount of the magnetic spring unit smaller than the operation amount of the suspension unit (for example, patents). Reference 1).

JP 2004-353770 A

  In the case of a working machine, a suspension like a general vehicle cannot be introduced due to the mechanism. That is, there is no space in the bottom space, and a sufficient stroke for vibration isolation cannot be secured. Therefore, the spring constant cannot be reduced, and vibration isolation around the resonance point is difficult. On the other hand, if the spring constant is set small by vibration isolation around the resonance point, the possibility of bottoming out due to impact vibration increases. Further, there is a problem that the vibration isolation performance fluctuates and deteriorates even when the weight is shifted due to a change in the driving posture of the operator.

  Furthermore, friction dampers and oil dampers of damping mechanisms used in general seat suspensions induce an increase in resonance frequency, which makes it difficult to reduce acceleration in the high frequency band and also causes mechanical deterioration. Cheap. In addition, the air suspension leads to an increase in size and weight.

  The present invention has been made in view of such problems of the prior art, and provides a lightweight and compact suspension unit that can lower the resonance frequency and reduce the acceleration in the resonance peak and high frequency band. The purpose is to provide.

  In order to achieve the above object, the invention according to claim 1 of the present invention includes a lower frame and an upper frame attached to the lower frame via a first link mechanism so as to be movable up and down. The suspension unit further includes a metal spring and a magnetic spring unit that elastically support the upper frame with respect to the lower frame, and a magnetic damper that is attached to the upper frame and attenuates the vertical movement of the upper frame. It is characterized by that.

  According to a second aspect of the present invention, the magnetic spring is slidably disposed with a magnet pair facing different magnetic poles at a predetermined interval and a predetermined clearance between the magnetic poles of the magnet pair. The copper plate is slid by the vertical movement of the upper frame to attenuate the vertical movement of the upper frame.

  Further, the invention according to claim 3 is characterized in that the upper frame has a front connecting shaft connected to the first link mechanism, and the front connecting shaft and the copper plate are connected via the second link mechanism. And the copper plate is slid in the front-rear direction via the second link mechanism by the vertical movement of the upper frame.

  According to a fourth aspect of the present invention, the front connecting shaft is formed in a hollow shape, and the metal spring includes a first torsion bar that is loosely inserted into the front connecting shaft. One end of the torsion bar is connected to a part of the first link mechanism, and the other end of the first torsion bar is connected to a rotation driving means via a third link mechanism, and the rotation driving means By adjusting the load applied to the upper frame by twisting the other end of the first torsion bar via a third link mechanism, one end of the first torsion bar is twisted with respect to the other end. The upper frame is elastically supported.

  According to a fifth aspect of the present invention, the lower frame has a hollow rear connecting shaft connected to the first link mechanism, and the metal spring is loosely inserted into the rear connecting shaft. Having a torsion bar, one end of the second torsion bar is connected to the lower frame, and the other end of the second torsion bar is connected to another part of the first link mechanism. The upper frame is elastically supported by twisting the other end of the torsion bar with respect to the one end.

  According to a sixth aspect of the present invention, the metal spring has a positive spring constant, while the magnetic spring unit has a negative spring constant in a predetermined region. The spring constant of the metal spring and the magnetic spring The spring constant obtained by superimposing the spring constant of the unit is substantially 0 in the predetermined region.

  According to the present invention, a magnetic damper that is attached to the upper frame and attenuates the vertical movement of the upper frame is provided, and a suspension with two degrees of freedom is realized by using this magnetic damper as a dynamic vibration absorber, and the resonance frequency is reduced. Resonance peaks and high-frequency gain can be reduced, and bottoming due to low-frequency impact vibration can be absorbed.

  In addition, since the magnetic damper is used and the torsion bar is used as the metal spring, a lightweight suspension unit having a simple configuration can be provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 and 2 show a seat of a working machine (for example, a forklift) provided with the suspension unit S according to the present invention, and show a state in which a seat cushion and a seat back are removed. 3 to 7 show the suspension unit S with the seat frame F removed, and FIGS. 8 and 9 show the suspension unit S with the magnetic damper mounting plate (described later) removed. .

  As shown in FIGS. 1 to 9, the suspension unit S includes a lower frame 2 attached to the vehicle body floor, and an upper frame 4 attached to the lower frame 2 via a link mechanism so as to be movable up and down. The seat frame F is joined to the upper frame 4, and the seat cushion and the seat back are attached to the seat frame F.

  The lower frame 2 includes front and rear frames 2a and 2b and a pair of left and right side frames 2c, and is formed in a substantially rectangular shape. Similarly, the upper frame 4 is also composed of front and rear frames 4a and 4b and a pair of left and right side frames 4c, and is formed in a substantially rectangular shape.

  The lower frame 2 and the upper frame 4 are connected to each other by two parallel links 6, 8. The upper frame 4 is connected to the lower frame 2 by a parallel link including a front link 6 and a rear link 8. It can be moved up and down. That is, the lower end of the front link 6 is pivotally attached in the vicinity of the front end of the side frame 2c, and the upper end of the front link 6 is a hollow front connection shaft 10 whose both ends are pivotally attached to the left and right side frames 4c. It is joined to one end. The lower end of the rear link 8 is joined to one end of a hollow rear connecting shaft 12 pivoted at both ends to the left and right side frames 2c, and the upper end of the rear link 8 is pivoted near the rear end of the side frame 4c. It is worn.

  In addition, a torsion bar 14 having both ends of a rectangular cross section is loosely inserted into the front connecting shaft 10, and one end (the left end as viewed from the seat occupant) of the torsion bar 14 is connected to the L-shaped lever 16. Has been. The L-shaped lever 16 includes a cylindrical base portion 16a and a plate-like lever 16b that are rotatably attached to the front frame 4a via a bracket 17, and the cylindrical base portion 16a has an opening (not shown) having a rectangular cross section. And one end of the torsion bar 14 is fitted into the opening. The plate lever 16 b is pivotally attached to one end of the link 18, and the other end of the link 18 is pivotally attached to one end of the link 20. The other end of the link 20 is fixed to one end of a load adjusting rotary shaft 22, and the other end of the rotary shaft 22 is pivotally attached to a bracket 24 whose section is screwed to the front frame 4 a. Has been.

  Further, one end of a pair of nut mounting levers 26 extending in parallel is fixed to the load adjusting rotary shaft 22, and a nut 28 having a rectangular parallelepiped shape is attached to the other end of the nut mounting lever 26 as a mounting shaft (not shown). ) Is attached through. The nut 28 is screwed with a male screw formed on the operation shaft 30, and the operation shaft 30 is connected to an electric motor 34 as a rotation driving means via a reduction gear unit 32. The attachment portion of the electric motor 34 is attached to a U-shaped bracket 36, and the U-shaped bracket 36 is attached to a bracket 38 joined to the front frame 4a.

  A load adjustment scale plate 40 is further attached to the front frame 4a. A long hole 40a formed in the load scale plate 40 has a tip of a pointer 42 fixed to the load adjustment rotary shaft 22. Is loosely inserted so that it can move along the long hole 40a.

  The other end of the torsion bar 14 whose one end is connected to the L-shaped lever 16 is connected to one end of the link 44, and the other end of the link 44 is connected to the front link 6 via a pin 45 (see FIG. 13). The upper frame 4 is elastically supported with respect to the lower frame 2 by being pivotally attached to the intermediate portion.

  Similarly, a torsion bar 46 having both ends of a rectangular cross section is loosely inserted in the rear connecting shaft 12, and one end of the torsion bar 46 (the right end as viewed from the seat occupant) is fixed to the side frame 2c. . The other end of the torsion bar 46 is connected to one end of the link 48, and the other end of the link 48 is pivotally attached to the intermediate portion of the rear link 8 via a pin 50.

  The front and rear frames 2a and 2b constituting the lower frame 2 are joined to the front end and the rear end of the support member 52, respectively, and the upper frame 4 is connected to the lower frame 2 on the support member 52. On the other hand, a fixed magnet unit 56 of a magnetic spring unit 54 that is elastically supported is attached.

  More specifically, the magnetic spring unit 54 includes a fixed magnet unit 56 and a movable magnet unit 58. As shown in FIG. 10, the fixed magnet unit 56 is opposed to the same magnetic pole at a predetermined interval. The upper and lower permanent magnets arranged on the same side are joined to each other so that different magnetic poles are directed in the same direction (inward or outward). On the other hand, the movable magnet unit 58 has a permanent magnet inserted into the internal space of the fixed magnet unit 56, the permanent magnet has a magnetic pole formed in the vertical direction, and the upper magnetic pole is the upper magnet pair of the fixed magnet unit 56. While the same magnetic pole as 56a faces, the lower magnetic pole is set so that the same magnetic pole faces the lower magnet pair 56b of the fixed magnet unit 56. As shown in FIG. 10B, a predetermined clearance is provided between the fixed magnet unit 56 and the movable magnet unit 58.

  The fixed magnet unit 56 is attached to the inner surface of the side wall of the metal frame 59, and the metal frame 59 is attached to the support member 52. Further, as shown in FIG. 2, FIG. 8 or FIG. 9, the front end and the rear end of the support member 60 are joined to the front and rear frames 4a, 4b constituting the upper frame 4, respectively. Both ends of the support shaft 62 of the movable magnet unit 56 are attached to the support member 60 via brackets 64 and 66.

  A magnetic damper mounting plate 68 is attached to the front frame 4a of the upper frame 4, one side frame (the right side frame as viewed from the seat occupant) 4c, and the support member 60, and this magnetic damper mounting plate. The structure of the magnetic damper 70 attached to 68 will be described with reference to FIGS.

  The magnetic damper 70 has a front magnet pair 70a and a rear magnet pair 70b facing different magnetic poles at a predetermined interval, and the front and rear permanent magnets arranged on the same side (upper or lower) are different. The magnetic poles are joined together so as to face in the same direction (upward or downward). A copper plate 70c is slidably disposed in the front-rear direction with a predetermined clearance between the magnetic poles of the front magnet pair 70a and between the magnetic poles of the rear magnet pair 70b. The front magnet pair 70a and the rear magnet pair 70b and the copper plate 70c are held by a frame 70d. FIG. 16 schematically illustrates the configuration of the front magnet pair 70a, the rear magnet pair 70b, and the copper plate 70c excluding the frame body 70d.

  One end of a connecting member 72 is fixed to the rear end portion of the copper plate 70c, and one end of a long link 74 is pivotally attached to the other end of the connecting member 72. Further, the other end of the long link 74 is pivotally attached to one end of an L-shaped link 78 whose intermediate portion is pivotally attached to the magnetic damper mounting plate 70 via a bracket 76. The end is pivotally attached to one end of the short link 80. Further, the other end of the short link 80 is pivotally attached to the other end of the lever 82 having one end fixed to the front connecting shaft 10.

  A belt holding member 84 is attached to the rear portion of the lower frame 2, and both ends of the stroke regulating belt 86 wound around the rear frame 4 b of the upper frame 4 are held on the lower frame 2 by the belt holding member 84. Has been. Further, cushion members 88 such as rubber are attached to the upper and lower side frames 2c and 4c located on the left side as viewed from the seat occupant in a state of facing each other.

The operation of the suspension unit S according to the present invention having the above configuration will be described below.
When a person sits on the seat cushion attached to the seat cushion frame F, the upper frame 4 descends according to the load (the weight of the seated person). When the upper frame 4 is lowered, the front torsion bar 14 and the rear torsion bar 46 are respectively twisted, and a lifting force for the upper frame 4 is generated according to the lowering amount of the upper frame 4. On the other hand, the magnetic spring unit 54 exhibits a negative spring constant until a load of a predetermined value or more is applied to the upper frame 4 and the upper frame 4 is lowered by a predetermined value (for example, 25 mm) or more. When it further falls below the value, it shows a positive spring constant, and a lifting force is gradually generated according to the descending amount of the upper frame 4.

  FIG. 17 shows a spring characteristic in which the positive spring constant of the metal spring and the negative spring constant of the magnetic spring unit 54 are superimposed. As can be seen from the graph of FIG. 17, there is a region where the load is constant regardless of the displacement (region where the spring constant is approximately 0), and in the present invention, the equilibrium point with the load mass is approximately at the center of this region. Is set.

Here, load (weight) adjustment performed by driving the electric motor 34 will be described.
The operating shaft 30 is connected to the electric motor 34 via the reduction gear unit 32. Since the male screw formed on the operating shaft 30 and the female screw formed on the nut 28 are screwed together, the electric motor 34 is driven. By rotating the operating shaft 30, the nut 28 moves back and forth. As a result, the nut mounting lever 26 to which the nut 28 is mounted swings, so that the load adjusting rotary shaft 22 rotates and the link 20 fixed to the end of the load adjusting rotary shaft 22 swings. Move. When the link 20 swings, the L-shaped lever 16 rotates via the link 18, so that the end of the front torsion bar 14 (the left end as viewed from the seat occupant) is twisted and depends on the twisting direction. To adjust the load.

  This load adjustment can be performed while observing the scale of the load scale plate 40 pointed to by the pointer 42, and can be adjusted, for example, in a load range of 50 to 130 kg.

Next, the operation of the magnetic damper 70 will be described with reference to FIG.
FIG. 18B shows the standard position after load adjustment, and FIG. 18A shows the state where the upper frame 4 is raised to the top dead center (for example, 20 mm above the standard position). ) Shows a state where the upper frame 4 is lowered to the bottom dead center (for example, 20 mm below the standard position). In FIG. 18, hatched circles indicate the rotation center of the front link 6, and the front connecting shaft 10 to which the lever 82 is fixed rotates around the rotation center of the front link 6.

  When the upper frame 4 rises from the standard position shown in FIG. 18 (b) to the top dead center shown in FIG. 18 (a), the front connecting shaft 10 rises rearward and rotates around the center of rotation of the front link 6. And the lever 82 swings in this direction. As a result, the L-shaped link 78 rotates in the clockwise direction via the short link 80, so that the copper plate 70c constituting the magnetic damper 70 slides backward via the long link 74 and the connecting member 72. .

  On the other hand, when the upper frame 4 is lowered from the standard position shown in FIG. 18 (b) to the bottom dead center shown in FIG. 18 (c), the front link shaft 10 is lowered forward and the front link 6 is rotated. It rotates clockwise around the center and the lever 82 swings in this direction. As a result, the L-shaped link 78 rotates counterclockwise via the short link 80, so that the copper plate 70 c of the magnetic damper 70 slides forward via the long link 74 and the connecting member 72.

  FIG. 19 shows the relationship between the vertical stroke amount of the upper frame 4 and the longitudinal stroke amount of the copper plate 70c. The upward stroke amount of the upper frame 4 is set to the positive stroke amount of the copper plate 70c. The amount is just taken.

  As can be seen from the graph of FIG. 19, the stroke amount of the copper plate 70 c changes to a substantially linear shape in accordance with the stroke amount of the upper frame 4.

  Since the front magnet pair 70a and the rear magnet pair 70b are disposed above and below the copper plate 70c with a predetermined clearance, the copper plate 70c moves in the front-rear direction in the magnetic field. Therefore, the magnetic lines of force inside the copper plate 70c change, and an eddy current is generated in a direction that prevents the change of the magnetic lines of force. As a result, an attractive force is generated when the copper plate 70c moves away from the front magnet pair 70a and the rear magnet pair 70b, while a repulsive force (repulsive force) is generated when the copper plate 70c moves in the approaching direction. That is, the magnetic damper 70 is a damping mechanism that uses electromagnetic induction of copper, and acts as a dynamic vibration absorber that attenuates the vertical movement of the upper frame 4 by moving the copper plate 70c back and forth (horizontal) via the link mechanism. It plays a role of mitigation.

  FIG. 20 shows the result of measuring the vibration transmissibility of the suspension unit S according to the present invention and the conventional suspension unit using the metal spring and the oil damper, and the weight of the subject was 85 kg.

  As is clear from FIG. 20, the suspension unit S according to the present invention has a low vibration transmission rate at the resonance point, and has good vibration characteristics at the resonance point and absorbability of impact force, compared to the conventional suspension unit. In addition, the vibration characteristics in the high frequency region are also good.

  When an impact force is input and the lower frame 2 approaches the upper frame 4 abnormally, the two cushion members 88 facing each other come into contact with each other and absorb the impact (with bottom). Further, when the lower frame 2 is abnormally separated from the upper frame 4, tension is applied to the stroke regulating belt 86 and the stroke of the upper frame 4 with respect to the lower frame 2 is restricted.

  The above embodiment has been described by taking the seat suspension as an example. However, the present invention is not limited to the seat suspension, and the present invention is not limited to the seat suspension. Is possible.

  The suspension unit according to the present invention can reduce the resonance frequency, reduce the resonance peak and acceleration in a high frequency band, and is a lightweight and compact configuration. It is useful as a suspension for trucks and the like.

It is a perspective view of a seat provided with a suspension unit concerning the present invention in the state where a seat cushion and a seat back were removed. It is a disassembled perspective view of the sheet | seat of FIG. FIG. 2 is a perspective view of the suspension unit shown in FIG. 1. FIG. 4 is another perspective view of the suspension unit of FIG. 3. FIG. 4 is a plan view of the suspension unit of FIG. 3. FIG. 4 is a front view of the suspension unit of FIG. 3. FIG. 4 is a side view of the suspension unit of FIG. 3. FIG. 4 is a perspective view of the suspension unit of FIG. 3 with a magnetic damper mounting plate removed. It is a top view of the suspension unit of FIG. FIG. 4 is a schematic perspective view of a magnetic spring unit provided in the suspension unit of FIG. 3. FIG. 4 is a side view when a magnetic damper is attached to an upper frame provided in the suspension unit of FIG. 3. FIG. 12 is a bottom view of the upper frame of FIG. 11. It is a perspective view when the upper frame of FIG. 11 is seen from the bottom. FIG. 12 is a perspective view of the magnetic damper shown in FIG. 11. It is a side view of the magnetic damper of FIG. It is a side view which shows schematic structure of the magnetic damper of FIG. It is a graph which shows the spring characteristic which superimposed the spring constant of a metal spring, and the spring constant of a magnetic spring unit. It is a side view which shows the effect | action of a magnetic damper. It is a graph which shows the relationship between the stroke amount of the up-down direction of an upper frame, and the stroke amount of the front-back direction of the copper plate which comprises a magnetic damper. It is a graph which shows the vibration transmissibility of the conventional suspension unit which uses the suspension unit concerning this invention, a metal spring, and an oil damper.

Explanation of symbols

2 lower frame, 2a front frame, 2b rear frame,
2c side frame, 4 upper frame, 4a front frame,
4b rear frame, 4c side frame, 6 front link, 8 rear link,
10 front connecting shaft, 12 rear connecting shaft, 14 torsion bar,
16 L-shaped lever, 16a Cylindrical base, 16b Plate-shaped lever,
17 bracket, 18 link, 20 link, 22 load adjusting rotary shaft,
24 bracket, 26 nut mounting lever, 30 operating shaft,
32 reduction gear unit, 34 electric motor, 36 U-shaped bracket,
38 bracket, 40 load scale plate, 40a long hole, 42 pointer,
44 links, 45 pins, 46 torsion bars, 48 links,
50 pins, 52 support members, 54 magnetic spring units,
56 fixed magnet unit, 56a upper magnet pair, 56b lower magnet pair,
58 movable magnet unit, 59 frame, 60 support member, 62 support shaft,
64 bracket, 66 bracket, 68 magnetic damper mounting plate,
70 magnetic damper, 70a front magnet pair, 70b rear magnet pair, 70c copper plate,
70d frame, 72 connecting member, 74 long link, 76 bracket,
78 L-shaped link, 80 short link, 82 lever, 84 belt holding member,
86 Stroke regulating belt, 88 Cushion material, F Seat frame,
S Suspension unit.

Claims (6)

A suspension unit comprising a lower frame and an upper frame attached to the lower frame via a first link mechanism so as to be movable up and down,
A suspension unit further comprising: a metal spring and a magnetic spring unit that elastically support the upper frame with respect to the lower frame; and a magnetic damper that is attached to the upper frame and attenuates the vertical movement of the upper frame. .   The magnetic spring is composed of a magnet pair opposed to different magnetic poles at a predetermined interval, and a copper plate slidably disposed with a predetermined clearance between the magnetic poles of the magnet pair. The suspension unit according to claim 1, wherein the copper plate is slid by vertical movement to attenuate the vertical movement of the upper frame.   The upper frame has a front connecting shaft connected to the first link mechanism, the front connecting shaft and the copper plate are connected via a second link mechanism, and the upper frame is moved vertically. The suspension unit according to claim 2, wherein the copper plate is slid in the front-rear direction via the second link mechanism.   The front connecting shaft is formed in a hollow shape, and the metal spring has a first torsion bar loosely inserted into the front connecting shaft, and one end of the first torsion bar is connected to the first link mechanism. And the other end of the first torsion bar is connected to a rotation driving means via a third link mechanism, and the first driving mechanism is connected to the first torsion bar via the third link mechanism. While adjusting the load applied to the upper frame by twisting the other end of the torsion bar, the upper frame is elastically supported by twisting one end of the first torsion bar with respect to the other end. The suspension unit according to claim 2, wherein   The lower frame has a hollow rear connecting shaft connected to the first link mechanism, and the metal spring has a second torsion bar loosely inserted into the rear connecting shaft, and the second torsion One end of the bar is connected to the lower frame, the other end of the second torsion bar is connected to another part of the first link mechanism, and the other end of the second torsion bar is connected to the one end. The suspension unit according to claim 4, wherein the upper frame is elastically supported by being twisted.   While the metal spring has a positive spring constant, the magnetic spring unit has a negative spring constant in a predetermined region, and a spring constant obtained by superimposing the spring constant of the metal spring and the spring constant of the magnetic spring unit is The suspension unit according to any one of claims 1 to 5, wherein substantially 0 is indicated in a predetermined region.

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