U.S. patent application number 10/922268 was filed with the patent office on 2005-04-07 for operator's seat supporting device for service vehicle.
This patent application is currently assigned to KOMATSU LTD.. Invention is credited to Tamaru, Masatake, Tsuji, Hideki.
Application Number | 20050073184 10/922268 |
Document ID | / |
Family ID | 34385919 |
Filed Date | 2005-04-07 |
United States Patent
Application |
20050073184 |
Kind Code |
A1 |
Tsuji, Hideki ; et
al. |
April 7, 2005 |
Operator's seat supporting device for service vehicle
Abstract
An operator's seat (6) is mounted via a posture adjusting
mechanism (40) on a supporting plate (3) supported by at least two
damper cylinders (50, 30) at a place where an operator's seat is
installed, and at least one of the damper cylinders (50, 30) is
used as a damper cylinder (50) for reducing vibrations by making
use of a magnetic rheological fluid.
Inventors: |
Tsuji, Hideki;
(Hiratsuka-shi, JP) ; Tamaru, Masatake; (Osaka,
JP) |
Correspondence
Address: |
FRISHAUF, HOLTZ, GOODMAN & CHICK, PC
767 THIRD AVENUE
25TH FLOOR
NEW YORK
NY
10017-2023
US
|
Assignee: |
KOMATSU LTD.
Tokyo
JP
|
Family ID: |
34385919 |
Appl. No.: |
10/922268 |
Filed: |
August 19, 2004 |
Current U.S.
Class: |
297/284.1 |
Current CPC
Class: |
B60N 2/508 20130101;
B60N 2/505 20130101; B60N 2/544 20130101; B60N 2/522 20130101; B60N
2/509 20130101; B60N 2/502 20130101; B60N 2/527 20130101; B60N
2/501 20130101 |
Class at
Publication: |
297/284.1 |
International
Class: |
A47C 003/025 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 22, 2003 |
JP |
2003-299132 |
Claims
What is claimed is:
1. An operator's seat supporting device for a service vehicle,
wherein at least biaxially supported by damper cylinders each are
arranged along an axial line parallel to a vertical line passing
through a shoulder of an operator sitting on a seat, and the
operator's seat supporting device includes a posture adjusting
mechanism provided by the sections supported by the damper
cylinders and the seat.
2. An operator's seat supporting device for a service vehicle,
wherein an operator's seat is mounted via a posture adjusting
mechanism on a supporting plate supported by at least two damper
cylinders at a place where an operator's seat is installed, and at
least one of the damper cylinders reduces vibrations by making use
of a magnetic rheological fluid.
3. The operator's seat supporting device for a service vehicle
according to claim 2, wherein, in the damper cylinder for reducing
vibrations by making use of the magnetic rheological fluid, a
buffering cylinder and a control cylinder for controlling
vibrations with the magnetic rheological fluid are monolithically
formed.
4. The operator's seat supporting device for a service vehicle
according to claim 2, wherein the damper cylinder has a biaxial
slide supporting structure, and a coil spring is provided in the
inner side or in the outer side from a shaft body having
dual-shafts.
5. The operator's seat supporting device for a service vehicle
according to claim 3, wherein the damper cylinder has a biaxial
slide supporting structure, and a coil spring is provided in the
inner side or in the outer side from a shaft body having
dual-shafts.
6. The operator's seat supporting device for a service vehicle
according to claim 2, wherein an operator's seat rotating mechanism
is provided on the supporting plate supported by the damper
cylinders.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an operator's seat
supporting device for a service vehicle having a variable damping
mechanism provided mainly in an operator's cabin of a construction
machinery and capable of improving the availability.
[0003] 2. Description of Related Art
[0004] The conventional type of supporting device for an operator's
seat provided in an operator's cabin of a construction machine such
as a hydraulic shovel or a bulldozer receives a larger shock
delivered to the seat on which the operator sits as compared to
that delivered to an operator's seat in a general industrial
vehicle, and there have been proposed various measures for a
suspension structure for reducing the shock.
[0005] As a suspension structure for an operator's seat in this
type of service vehicle, there has been known one, for instance, as
shown in FIG. 9A and FIG. 9B. In this suspension structure, an
X-shaped link 102 with the link members crossing each other in the
longitudinal direction and linked to each other with a pin 103 at a
crossing point on a base member 101 are provided with a
prespecified space in both right and left sides thereof, and a link
110 with the height adjustable is provided between the right and
left X-shaped links 102, 102.
[0006] In the X-shaped link 102, a base edge of one link member
102a is pivotably connected to the base member 101 with the other
edge connected to a seat mounting base frame 104 with a pin 105,
and a lower edge of another link member 102b can move on the base
member 101 with the upper edge connected to the seat mounting base
frame 104 with a pin 106, and the cushioning capability is provided
by a suspension cylinder 107.
[0007] The height-adjustable link 110 is rolled in the state in
which a roller 111 provided at a lower edge thereof is engaged with
a guide rail 108 provided on the base member 101 with an upper edge
thereof linked to an edge of a coil spring 112 on the seat mounting
base frame 104 so that the tension is energized in the erecting
direction, and further an adjustment knob 113 capable of adjusting
the weight and height by displacing the link 110 in the vertical
direction by means of adjusting tension of the spring 112 is
provided therein. In the figures, the reference numeral 115
indicates a seat, and the reference numeral 116 indicates a
suspension cover.
[0008] Reference 1 (Japanese Patent Laid-Open Publication No. HEI
9-209406) discloses a suspension structure in which a forward
section thereof is supported with a rubber spring system which
elastically deforms little in the vertical direction, and a rear
section thereof is supported by a coil damper unit system which
elastically deforms largely in the vertical direction. In addition,
a suspension mechanism for an operating seat using the X-shaped
link is disclosed, for instance, in Reference 2 (Japanese Patent
Laid-Open Publication No. HEI 11-280117).
[0009] However, with the supporting means for an operator's seat
employing the X-shaped link 102 as used in the conventional
technology, the link 102 occupies a space under the seat 115, which
narrows a space under the operator's feet.
[0010] Further there is another disadvantage that a damper is
provided externally, which disables effective utilization of the
space.
[0011] In addition, the X-shaped link is generally made from flat
steel bars, so that the rigidity in the lateral direction is
disadvantageously low, and as the joint section includes a pin, and
therefore there is another disadvantage that it is difficult to
insure strength against load.
[0012] As the mechanism for adjusting a body weight is integrated
with that for adjusting the height, it is difficult to achieve the
complete balance between an operator's body type and the operator's
body weight.
[0013] Namely, when an operator is a person not having the standard
body type such as a relatively heavy person having the low seating
height or a person having the relatively high seating height
against the body weight, if a seat height is adjusted to the
operator's posture, the buffering function is disadvantageously
lost, which is another problem.
[0014] In the suspension seat structure as disclosed in the cited
reference 1, as dampers having different structures respectively
are provided in the front of and at the back of the seat, and the
dampers are required to be adjusted discretely, and in addition the
damper provided at the back of the seat is attached to an outer
side of a backrest of the seat, so that, when an inclination of the
backrest is changed, the buffering effect also varies, which is
disadvantageous from a view point of structure and not preferable
because of its complicated structure.
[0015] The suspension device in the operator's seat device
disclosed in the cited reference 2 also has the problems as
described above.
SUMMARY OF THE INVENTION
[0016] An object of the present invention is to provide an
operator's seat supporting device for a service vehicle with a
compact suspension mechanism with improved functions and capable of
ensuring operator's comfortable posture during the operation.
[0017] In an operator's seat supporting device for a service
vehicle according to an aspect of the present invention, at least
biaxially supported by damper cylinders each are arranged along an
axial line parallel to a vertical line passing through a shoulder
of an operator sitting on a seat, and the operator's seat
supporting device includes a posture adjusting mechanism provided
by the sections supported by the damper cylinders and the seat.
[0018] In an operator's seat supporting device for a service
vehicle according to another aspect of the present invention, an
operator's seat is mounted via a posture adjusting mechanism on a
supporting plate supported by at least two damper cylinders at a
place where an operator's seat is installed, and at least one of
the damper cylinders reduces vibrations by making use of a magnetic
rheological fluid.
[0019] Preferably, with the above operator's seat supporting device
for a service vehicle, in the damper cylinder for reducing
vibrations by making use of the magnetic rheological fluid, a
buffering cylinder and a control cylinder for controlling
vibrations with the magnetic rheological fluid may be
monolithically formed.
[0020] Preferably, with the operator's seat supporting device for a
service vehicle, the damper cylinder may have a biaxial slide
supporting structure, and a coil spring may be provided in the
inner side or in the outer side from a shaft body having
dual-shafts.
[0021] Preferably, with the operator's seat supporting device for a
service vehicle, an operator's seat rotating mechanism may be
provided on the supporting plate supported by the damper
cylinders.
[0022] With the configuration as described above, an area occupied
by a seat supporting section on a floor surface can be reduced,
whereby a wide space can be provided under an operator's feet to
secure that the operator can take a comfortable posture during the
operation.
[0023] Further there is also provided the advantage that a floor
surface of the operator's cabin can easily be cleaned.
[0024] With the configuration as described above, in addition to
the advantages described above, there is provided the advantage
that the height adjustment of the seat can be carried out
independently from adjustment of a body weight of an operator
sitting thereon with the optimal height provided to secure that the
operator can take a more comfortable posture during the operation.
Further by making use of a magnetic rheological fluid, a vibration
damping force can variably be set according to change of the
magnetic field, and a damping force can previously be set according
to an operator's body weight, which advantageously improves the
buffering effect against a shock by an external force.
[0025] When the configuration as described above is employed, the
structure is compact, so that a space required for installation
thereof can be reduced, so that the occupied space under operator's
feet can be minimized to secure that the operator can take a
comfortable posture during the operation.
[0026] With the configuration described above, a damper cylinder
functioning as a supporting body has a biaxial slide structure, so
that only a further small space is required, and a load is shared
by a plurality of damper cylinders, so that the stable supporting
force can be obtained without causing any saccadic movement.
[0027] Further with the configuration described above, a rotating
mechanism is provided on a supporting plate supported by the damper
cylinder, so that a rotating movement can be carried out without
spoiling the buffering function of the seat.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 is a front elevational view showing a first
embodiment of an operator's seat supporting device for a service
vehicle according to the present invention;
[0029] FIG. 2 is a side elevational view of FIG. 1;
[0030] FIG. 3 is a longitudinal cross-sectional view showing a
damping function control mount;
[0031] FIG. 4 is a cross-sectional view showing the primary portion
of the damping function control mount cylinder;
[0032] FIG. 5 is a longitudinal cross-sectional view showing a
supporting damper;
[0033] FIG. 6 is a cross-sectional view showing a second embodiment
of a damping function control mount cylinder;
[0034] FIG. 7 is a cross-sectional view showing the primary portion
of the damping function control mount cylinder according to the
second embodiment;
[0035] FIG. 8 is a cross-sectional view showing a third embodiment
of a damping function control mount cylinder;
[0036] FIG. 9A is a side elevational view showing an embodiment of
a supporting structure for an operator's seat based on the
conventional technology; and
[0037] FIG. 9B is a view showing the operator's seat based on the
conventional technology viewed from the front side.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT(S)
[0038] Embodiments of an operator's seat supporting device for a
service vehicle according to the present invention is described
below with reference to the related drawings.
First Embodiment
[0039] FIG. 1 is a front elevational view showing a first
embodiment of the operator's seat supporting device for a service
vehicle according to the present invention; FIG. 2 is a side
elevational view of FIG. 1; FIG. 3 is a longitudinal
cross-sectional view showing a damping function control mount; FIG.
4 is a cross-sectional view showing the primary portion of the
damping function control mount cylinder; and FIG. 5 is a
longitudinal cross-sectional view showing a supporting damper.
[0040] An operator's seat supporting device 1 according to this
embodiment includes two damper cylinders 50, 30 erecting from and
provided on a floor surface 2 of an operator's cabin with a
prespecified space; a posture adjusting section 40 provided on a
movable supporting plate 5 disposed via a rotating mechanism 4 on a
supporting plate 3 supported by these damper cylinders 50, 30; and
an operator's seat 6 mounted via this posture adjusting section
40.
[0041] Of the damper cylinders 50, 30, one is a damping function
control mount 50 (described simply as a damper cylinder 50
hereinafter) having a magnetic rheological fluid control function,
and the other is a damper cylinder 30 for supporting (supporting
damper).
[0042] The damper cylinder 50 having a magnetic rheological fluid
control function includes, as shown in the cross-sectional view in
FIG. 3, a buffering cylinder 53 externally and coaxially engaging a
fixed member 51 having a mounting base 52 against the floor surface
2 (corresponding to the biaxial slide support structure according
to the present invention), a coil spring 59 for restoring a damper
provided inside the fixed member 51, and a control cylinder 60 for
a magnetic Theological fluid associated with the buffering cylinder
53 and capable of controlling operations of the buffering cylinder
53, and a mounting base plate 58' for mounting the supporting plate
3 thereon is provided on a top of the buffering cylinder 53.
[0043] The buffering cylinder 53 is a tubular cylinder including a
movable member 54 provided outside and the fixed member 51 provided
inside and coaxially engaged therewith.
[0044] The movable member 54 is so connected that a male screw 54b
formed on an external peripheral surface of an upper end of the
cylinder member 54a is screwed to a female screw 54d formed on an
internal peripheral surface of a drooping spherical base section
54c. Further, a female screw 54e is formed on an inner peripheral
surface of a lower end of the cylinder member 54a, to which a cover
member 54f with a male screw formed is screwed.
[0045] An internal capacity of the cylinder is controlled to a
prespecified value by the cylinder member 54a, the base section 54c
and the cover member 54f.
[0046] The buffering cylinder 53 is slidably assembled with the
fixed member 51 with a circular projection 55 functioning as a
piston integrally provided at an intermediate section of the fixed
member 51, and a seal ring 55b is engaged in a groove section 55a
formed on an outer peripheral surface of the circular projection 55
and contacts an internal surface of the movable member 54 (cylinder
member 54a) with a first chamber 56a and a second chamber 56b
defined vertically.
[0047] Incidentally, the internal peripheral surface of the
cylinder member 54a located at an upper edge section of the first
chamber 56a is projected in a ring-shaped manner, and a seal ring
56c is fitted to a groove formed at the tip end thereof. Further,
the screwing portion of the cover member 54f located at a lower
edge section of the second chamber 56b is formed cylindrical, and
seal rings 56d and 56e are fitted to grooves formed on upper and
lower sides of the internal peripheral surface thereof. With the
use of the seal rings 56c, 56d and 55b, the sealability of the
first chamber 56a and the second chamber 56b is secured.
Additionally, the seal ring 56e inhibits the dust entering from the
outside.
[0048] The control cylinder 60 includes a cylindrical main body 61,
an upper cover member 63 and a lower cover member 63' that cover
holes 62 opening at the upper and lower part of the cylindrical
main body 61.
[0049] An insert body 64 is provided inside the cylindrical main
body 61 on the center line of the cylindrical main body 61, the
upper and lower edges of the insert body 64 is joined and fixed to
the cylindrical main body 61 as well as to the lower cover member
63'.
[0050] The insert body 64 includes a clearance forming section 64a
made of a magnetic material such as electromagnetic soft iron, and
a shaft 64b made of a non-magnetic material such as stainless, the
shaft 64b press-fitted to the upper and lower edges of the
clearance forming section 64a.
[0051] On the other hand, as shown in FIG. 4, a bobbin 61a made of
a non-magnetic material is embedded on an inner peripheral surface
of the cylindrical main body 61 corresponding to the position of
the clearance forming section 64a. A coil 61b with a lead wire
being winded is provided around the bobbin 61a, the end of the lead
wire being connected to a controller provided at the outside of the
damper cylinder 50. The bobbin 61a and the coil 61b function as an
electromagnetic control section that controls the viscosity of the
magnetic rheological fluid flowing through the cylinder.
[0052] Two connecting holes 65 are formed at the upper and lower
parts of a lateral surface of the cylindrical main body 61 to
communicate the inside and the outside thereof, and the connecting
holes 65 are respectively connected to two connecting holes 54g
penetrating the inside and the outside of the cylinder member 54a
via a cylindrical connecting member 66. It is to be noted that the
one of connecting holes 54g is connected to the first chamber 56a
while the other one is connected to the second chamber 56b.
[0053] Further a buffering chamber 67 is provided below the upper
cover member 63, so that expansion of the magnetic rheological
fluid to be sealed therein due to temperature change can be
accommodated.
[0054] When the insert body 64 is installed in the cylindrical main
body 61, as shown in FIG. 4, the interior of the cylindrical main
body 61 is divided into the upper side chamber 62a and the lower
side chamber 62b by interposing the clearance forming section 64a,
thereby forming a space S between the inner surface of the
cylindrical main body 61 and the outer surface of the clearance
forming section 64a. The space S functions as a restrictor for
adjusting the fluid flow rate flowing between the upper side
chamber 62a and the lower side chamber 62b.
[0055] A magnetic rheological fluid (such as, for instance, iron
carbonyl particles suspended in mineral oil as a carrier) is filled
in each of the control cylinder 60 and the buffering cylinder 53
each having the configuration as described above.
[0056] In contrast to the damper cylinder 50 as described above,
the damper cylinder 30 for supporting includes, as shown in FIG. 5,
a fixed member 31 having a column-like form with a mounting base 32
attached at a lower edge thereof, a tubular movable member 34
engaged with this fixed member 31 and having a base plate for
mounting the supporting plate 3 thereon; and a coil spring 37
provided concentrically with the lower edge supported by a top
surface of a bottom edge member 31a of the fixed member 31 and also
the upper edge thereof contacting an internal bottom surface of a
mounting cap member 35 of the movable member 34.
[0057] The fixed member 31 has the structure in which the bottom
edge member 31a which is a tubular body having prespecified
dimension and closes the lower edge section of the fixed member 31
is attached, and the mounting base 32 is monolithically attached to
this bottom edge member 31a with the upper edge section opened.
[0058] A circular member 34a is monolithically attached to an upper
edge section of the movable member 34, and the cap member 35 is
screwed into an upper edge section of this circular member 34a to
close the upper section. Monolithically attached to a top surface
of this cap member 35 is a mounting base plate 38 for supporting
the supporting plate 3.
[0059] Bearings 36, 36' are monolithically attached to an internal
peripheral surface of the circular member 34a of the movable member
34 and a portion 34b thereof with the internal peripheral section
of the lower edge section having a smaller diameter respectively so
that the fixed member 31 can be slid in the vertical direction
without losing the concentric positional relation thereto.
[0060] As shown in FIGS. 1 and 2, the damper cylinders 50, 30
having the configuration as described above respectively are
provided in the erecting state on a floor surface of the operator's
cabin so that the center line is substantially aligned to a
vertical plane (vertical line C) passing through a shoulder Q' of
an operator Q when the operator Q sits on the seat 6 with the
normal posture with the mounting bases 52, 32 attached to the
damper cylinders 50, 30 respectively. These two damper cylinders
50, 30 support the supporting plate 3 having a dimension slightly
larger than the width of a seat plate section 6a of the seat 6.
[0061] With the configuration as described above, the operator Q
sitting on the seat 6 is supported by the damper cylinders 50, 30
at a position on a line passing through a gravity center or a
position close to the gravity center of the operator Q, so that,
although the operator Q is supported by two damper cylinders,
vibrations in the longitudinal direction and those in the lateral
direction do not occur, and the seat 6 is securely supported with
the simple supporting structure.
[0062] A swivel ring (rotating mechanism 4) is provided with the
shaft center positioned at a central position of a line connecting
centers supported by the damper cylinders 50, 30 on the supporting
plate 3, and the movable supporting plate 5 is attached thereto
with a supporting member 4b attached to the swivel ring so that the
swivel ring can freely swivel.
[0063] Slide mechanisms 41 each for adjusting an operator's
position in the longitudinal direction as a posture adjusting
section 40 and a height adjusting mechanism 42 are provided on the
movable supporting plate 5, and the seat 6 is attached thereto via
the height adjusting mechanism 42.
[0064] The slide mechanisms 41 each extending in the longitudinal
direction are arranged with a prespecified space in the lateral
direction, and a mounting base member 7 of the seat 6 is supported
by the movable member. The slide mechanism 41 has a known
structure, and a movable member can intermittently move in the
longitudinal direction thereon along a rail so that a position of
the operator Q in the longitudinal direction can be adjusted.
[0065] The height adjusting mechanism 42 having a known structure
is provided on the mounting base member 7, and a seat plate section
6a of the seat 6 is attached with a known means to a seat mounting
frame body above this height adjusting mechanism 42. The height
adjusting mechanism 42 employed in the present invention can adjust
a position in the vertical direction with cross links. It is to be
noted that also the height adjusting mechanism 42 not employing the
cross links may be used in the present invention.
[0066] The reference numerals 8 and 8' each indicate a console in
which an operating lever or other operating sections of machines
and equipments are accommodated, and this console 8 is
monolithically attached with a bracket to the mounting base member
7, and can move in the vertical direction and swivel together with
the operator's seat 6 to allow for operations without requiring an
operator to change the positional relation therewith. The reference
numeral 6b in the figure indicates a backrest.
[0067] The operator's seat supporting device 1 according to this
embodiment is installed in an operator's cabin (not shown) of a
service vehicle, and supports the operator's seat 6 as described
above.
[0068] The operator's seat supporting device 1 having the
configuration as described above according to this embodiment can
set an operator's position in the longitudinal direction with the
slide mechanisms 41 and the operator's height with the height
adjusting mechanism 42 respectively, when the operator adjusts the
operating posture.
[0069] The two damper cylinders 50, 30 are balanced with the
energizing forces of the coil springs 59, 37 respectively in the
normal state to support the operator's seat 6.
[0070] Vibrations due to a shock or any other load from the outside
during the operation are damped by the two damper cylinders 50, 30
supporting the seat 6, and one damper cylinder 50 has a function
for controlling attenuation with an electromagnetic control section
with a magnetic rheological fluid included therein, and with the
configuration as described above, a signal from a sensor for
detecting vibrations previously installed in an operator's cabin or
on a machine frame is received by the controller, and a current is
flown at a required rate to the coil 61b of the control cylinder 60
according to an output signal generated by comparing the received
signal to preset data, so that the vibrations are quickly damped by
controlling the pressure difference generated between the first
chamber 56a and the second chamber 56b in the buffering cylinder 53
from the control cylinder 60, thus the vibration-controlling
function being provided.
[0071] The other damper cylinder 30 has the function for dampening
a shock by following the vibration controlling and buffering
function of the damper cylinder 50 with a cushioning function with
the coil spring 37 with the movable member 34 against the fixed
member 31 provided therein. Therefore, even when a large shock is
applied thereto, vibrations can quickly be absorbed and
dampened.
[0072] As for the vibration controlling action by the damper
cylinder 50, when vibrations are delivered from a vehicle's body,
the movable member 54 displaces against the fixed member 51 in the
axis line direction. When the movable member 54, for example, moves
in the downward direction of the vertical direction against the
energizing force by the coil spring 59,the cylinder member 54a of
the movable member 54 acts to push down the magnetic Theological
fluid in the first chamber 56a.
[0073] As shown in FIG. 4, the magnetic Theological fluid in the
first chamber 56a is pushed out into an upper side chamber 62a of
the control cylinder 60 through the connecting hole 54g, the
connecting member 66 and the connecting hole 65 by pushing down
action of the magnetic rheological fluid. In this step, a reduced
pressure state is generated in the second chamber 56b of the
buffering cylinder 53, so that the magnetic Theological fluid is
fed from a lower side chamber 62b of the control cylinder 60
through the connecting hole 65, the connecting member 66 and the
connecting hole 54g into the second chamber 56b.
[0074] When the magnetic Theological fluid in the first chamber 56a
is moved into the upper side chamber 62a of the control cylinder 60
in association with the downward movement of the movable member 54
in the buffering cylinder 53, the pressure of the second chamber
56b is reduced, so that the pressure of the lower side chamber 62b
of the control cylinder 60 communicating the second chamber 56b
through the connecting hole 65, the connecting member 66 and the
though hole 54g is also reduced.
[0075] Therefore, the upper side chamber 62a of the control
cylinder 60 enters the pressurized state, while the lower side
chamber 62b enters the reduced pressure state, so that the magnetic
rheological fluid filled in the upper side chamber 62a flows toward
the lower side chamber 62b due to the pressure difference.
[0076] In this step, a flow rate of the magnetic rheological fluid
is restricted at the space S between the outer surface of the
clearance forming section 64a and the inner surface of the
cylindrical main body 61, the space S separating the upper side
chamber 62a from the lower side chamber 62b.
[0077] A vibration signal indicating vibrations of the fluid
passing through the space S is sent from the sensor (not shown) to
the controller, and the coil 61b is energized at a prespecified
current rate based on preset data so that the magnetic field
corresponding to the current is generated between the clearance
forming section 64a made of a magnetic material and the cylindrical
main body 61 with the flowing magnetic Theological fluid
magnetized, thereby the magnetic rheological fluid being magnetized
to change the viscosity. In other words, fluidity of the magnetic
Theological fluid changes in proportion to intensity of the
magnetic field.
[0078] When the movable member 54 moves in the upward direction,
the magnetic Theological fluid flows between the control cylinder
60 and the buffering cylinder 53 in the direction reverse to that
in the operating sequence described above with the flow state
controlled.
[0079] By changing the flow state of the magnetic rheological fluid
as described above to change the flow resistance of the magnetic
rheological fluid in flowing, the movement speed in the vertical
direction of the buffering cylinder 53 is controlled to dampen a
shock loaded thereto.
[0080] In a case of an operator's seat in an operator's cabin
provided in a bulldozer, when a large shock such as that
experienced in running over a large rock or a projection, for
instance, when a vehicle moves backward is loaded thereto, for
dampening the vibrations caused by the shock, with the use of the
above-described electromagnetic control section in the control
cylinder 60, by raising a rate of a current loaded from the
controller to a level higher than that in the normal state to raise
the intensity of a magnetic field generated between the cylindrical
main body 61 and the clearance forming section 64a proportionately,
the apparent viscosity of the magnetic rheological fluid flowing
through the space S is made larger with the flow resistance at
space S raised, so that the flow velocity of the movable member 54
is reduced.
[0081] In other words, the cushioning function of buffering a
sudden and heavy shock with a soft buffering action provided by a
soft spring action and also suppressing vibrations occurring after
the shock is loaded by giving a damping force with the control
cylinder 60 is achieved in the present invention as described
above.
[0082] Against the small and successive shocks experienced when
driving on an irregular ground surface, by sending a control signal
in the direction for lowering the intensity of a magnetic field
from the controller to the coil 61b in response to a detection
signal from the sensor to lower the magnetic flux density to the
magnetic rheological fluid in the control cylinder 60 with the
electromagnetic control section, the flow resistance is reduced
with the fluidity of the magnetic rheological fluid raised contrary
to the case described above, so that a movement rate of the movable
member 54 in the axial direction in the buffering cylinder 53 is
reduced, and therefore soft and smooth action for dampening
vibrations is provided.
[0083] In contrast to the damper cylinder 50 having the functions
as described above, the other damper cylinder 30 has a supporting
function with a simple structure including the coil spring 37 for
buffering therein, and performs the supporting function in
association with actions of the damper cylinder 50 as a damper
cylinder supporting the whole seat 6 leaving a main portion of the
vibration-controlling function for dampening vibration to the
damper cylinder 50.
[0084] With the configuration, the seat 6 is smoothly buffered
against vibrations with the two damper cylinders 50, 30, thus
comfortable and smooth operations being insured to an operator.
[0085] As described above, the operator's seat supporting device 1
according to this embodiment has the configuration in which
vibrations are dampened with a vibration buffering device
completely different and independent from the seat height adjusting
mechanism 42, so that adjustment in response to an operator's body
weight is not required, and the efficient buffering function can be
provided in the optimal state only by carrying out positional
adjustment according to the operator's body type, thereby the
operator performing required operations in the comfortable state.
Further a wide space can be secured under an operator's feet, so
that the problem of narrow space under the operator's feet as
experienced in the supporting device based on the conventional
technology can be eliminated, whereby there is provided the
advantage that an operator can perform various operations in a
relaxed and comfortable posture.
Second Embodiment
[0086] Next, referring to FIG. 6, a second embodiment of the
present invention is described below.
[0087] In the present embodiment, it is only different from the
operator's seat supporting device I according to the first
embodiment that the structure of the damper cylinder 50 (damping
function control mount cylinder) is modified. In the following, the
description of the components have been described already or that
of the same components as the above-described components will be
omitted or simplified.
[0088] The damper cylinder 10 according to the second embodiment
having a magnetic Theological fluid control function includes, as
shown in the cross-sectional view in FIG. 6, a buffering cylinder
13 externally and coaxially engaging a fixed member 11 having a
mounting base 12 against the floor surface 2 (corresponding to the
biaxial slide support structure according to the present
invention), a coil spring 19 for restoring a damper provided inside
the fixed member 11, and a control cylinder 20 for a magnetic
rheological fluid associated with the buffering cylinder 13 and
capable of controlling operations of the buffering cylinder 13, and
a mounting base plate 18' for mounting the supporting plate 3
thereon is provided on a top of the buffering cylinder 13.
[0089] The buffering cylinder 13 is a tubular cylinder including a
movable member 14 provided outside and the fixed member 11 provided
inside and coaxially engaged therewith. The movable member 14 has a
thick circular member 14b connected to and integrated with an upper
edge section of the cylinder member 14a and also has a circular
head member 14c screwed into a lower edge section thereof, and
controls an internal capacity of the cylinder to a prespecified
value with an internal lower edge of the circular member 14b fixed
to an upper edge section of the cylinder member 14a and an internal
upper edge of the head member 14c.
[0090] The buffering cylinder 13 is slidably assembled with the
fixed member 11 with a circular projection 15 functioning as a
piston integrally provided at an intermediate section of the fixed
member 11, and a seal ring 15b is engaged in a groove section 15a
formed on an outer peripheral surface of the circular projection 15
and contacts an internal surface of the movable member 14 (cylinder
member 14a) with a first chamber 16a and a second chamber 16b
defined in front and at the back thereof. A seal ring 16d is
engaged in each of the first chamber 16a and the second chamber 16b
to restrict the fluid from leaking from the inside of the
cylinder.
[0091] Bearing bushes 17 guided by the fixed member 11 are provided
in the circular member 14b and the head member 14c each connected
to the movable member 14 respectively, and with the bearing bushes
17 the movable member 14 can slide up and down being aligned with
the center line and also accommodate a load applied to the
supporting plate 3 in the stable state. Therefore the two bearing
bushes 17, 17 should preferably be arranged with a space between
the two within a reasonable range. A seal member 17' is provided in
the engaging state at an outer side from the engaging position of
the bearing bush 17 so that the chambers 16a and 16b are
water-tight against the outside. A cap member 18 is screwed into
the circular member 14b at a top section of the buffering cylinder
13 having the configuration as described above, and a mounting base
plate 18' for mounting the supporting plate 3 thereon is attached
to this cap member 18.
[0092] The control cylinder 20 has a hole 22 with a prespecified
internal diameter penetrating through a main body 21 with
prespecified dimensions in the vertical direction and also has an
upper cover member 23 and a bottom cover member 23' provided to
close two edge sections of this penetrating hole 22. A supporting
member consisting of a coil section 25 and a sleeve 24a is provided
between the upper cover member 23 and the bottom cover member 23',
and the supporting member is so arranged that the coil section 25
is located at an intermediate position of the supporting member
supported by the sleeve 24a made from a non-magnetic material with
the upper and bottom sections engaged with the supporting
member.
[0093] A slight clearance "a" is formed between an internal
peripheral surface of the main body 21 and an external peripheral
surface of a bobbin 25a of the coil section 25. A lead wire 27
extending over a controller not shown enabling electric control is
connected to a coil 25b of the coil section 25, and the coil 25b is
attached to the bobbin 25a made of magnetic material as the core of
a wire-wound section of the coil section 25 with the small
clearance "a" defined and maintained between the bobbins 25a and an
internal peripheral surface of the cylinder member 26 to form an
electromagnetic control section causing a flow resistance of the
magnetic Theological fluid. The main body 21 is made from an
electromagnetic soft iron for example so that a magnetic field is
strongly formed only in the range of the bobbin 25a.
[0094] In the main body 21, connecting holes 28a and 28b
communicating to the first chamber 16a and the second chamber 16b
inside the cylinder member 14a of the buffering cylinder 13 are
provided with appropriate spaces from the cylinder member 26
respectively so that the magnetic rheological fluid can flow from
the control cylinder 20 to the buffering cylinder 13. Further a
buffering chamber 29 with gas such as the air included therein is
provided at the top of the control cylinder 20 so that expansion of
the magnetic rheological fluid due to temperature change can be
accommodated. A magnetic rheological fluid (such as, for instance,
iron carbonyl particles suspended in mineral oil as a carrier) is
filled in each of the control cylinder 20 and the buffering
cylinder 13 each having the configuration as described above.
[0095] As shown in FIG. 7, the electromagnetic control section
causing a flow resistance in the magnetic rheological fluid in the
control cylinder 20 includes a cylinder member of the control
cylinder 20 and the coil section 25 provided therein, and also
includes a known controller not shown and connected with the lead
wire 27 to the coil section 25. The coil section 25 is energized
via the controller through the lead wire 27.
[0096] The electromagnetic control section controls a signal from a
sensor for detecting vibration provided, for instance, in an
operator's cabin not shown, and changes intensity of a magnetic
flux generated between the bobbin 25a and the main body 21 by
flowing a prespecified rate of electric current to the coil section
25 according to an output signal therefrom, so that the
electromagnetic control section can increase or reduce the flow
resistance by changing the apparent viscosity (fluidity) of the
magnetic rheological fluid within the magnetic field when the
magnetic Theological fluid flows through the narrow clearance "a"
formed between the bobbin 25a and an internal wall of the main body
21 to control the vibration-controlling function.
[0097] Even when such damper cylinder 10 according to the second
embodiment is applied to the operator's seat supporting device 1,
the same advantages as that of the first embodiment can be
obtained.
Third Embodiment
[0098] Next, FIG. 8 is a cross-sectional view showing a third
embodiment of a damping function control mount cylinder.
[0099] Basic configuration of the damping function control mount
cylinder (described simply as a damper cylinder 10A hereinafter) is
the same as that in the embodiment described above, but the
combinatorial structure is different from that in the embodiment
described above. Therefore the basic actions and effects are the
same as those described in the respective embodiments described
above. It is to be noted that the same reference numerals are
assigned to the same components as those in the embodiment
described above and detailed description is omitted herefrom.
Therefore description is made only to components having different
functions respectively.
[0100] The damper cylinder 10A according to this embodiment has a
control cylinder 20A incorporated in and at a central position of
the buffering cylinder 13A.
[0101] Further a coil spring 19A for restoration is provided
between a mounting base 12A provided outside the buffering cylinder
13A and attached to a lower edge of the fixed member 11A and a
mounting base plate 18a provided at an upper edge of the movable
member 14A.
[0102] The buffering cylinder 13A includes the fixed member 11A
having the mounting base 12A and the movable member 14A sliding in
the axis line direction in the inner side therefrom, which are
combined with each other.
[0103] The fixed member 11A constituting the buffering cylinder 13A
has the mounting base 12A in the lower section, and in the upper
section, a head member 11b is screwed into and fixed to an upper
edge section of the cylinder member 11a which is a main body of the
fixed member 11A.
[0104] Further a lower section member 11c is fixed to a lower edge
section of the cylinder member 11a, and a circular projection 15A
of the movable member 14A is slidably provided between an upper
edge of the lower section member 11c and a lower edge of the head
member 11b, so that the first chamber 16a is separated from the
second chamber 16b by the circular projection 15A.
[0105] The movable member 14A is a tubular body slidably and
coaxially engaged in the fixed member 11A, in which an upper edge
section thereof protrudes by an appropriate length from an upper
edge of the fixed member 11A, and at the top, the mounting base
plate 18a monolithically formed with a screwed cap 18A for
supporting the supporting plate 3 is attached thereto, while a
screw mounted cover 14e is provided at the lower edge section to
function as a piston and a rod.
[0106] The circular projection 15A is provided on an external
peripheral surface of the intermediate section of this movable
member 14A, and a seal ring 15b is engaged in a groove section 15a
formed on the external peripheral surface and contacts an internal
peripheral surface of the cylinder member 11a of the fixed member
11A to define a third chamber 16f and a fourth chamber 16g in the
cylinder.
[0107] The control cylinder 20A is coaxially provided and engaged
in the movable member 14A.
[0108] At a center of this control cylinder 20A, a supporting
member consisting of a coil section 25 and the sleeve 24a is
provided with a lower edge thereof engaged in and supported by a
shaft supporting hole 14f provided on a top surface of the screw
mounted cover 14e and also with an upper edge thereof engaged in a
shaft hole 14f' provided at a center of a bottom surface of a
supporting piece 14h engaged in the movable member 14A, and further
a cylinder member 26A made from electromagnetic soft iron is
concentrically provided outside the supporting member with both
edges thereof held by the screw mounted cover 14e and the
supporting piece 14h. The coil section 25 is provided at the
intermediate position with the upper and lower sections thereof
supported by a non-magnetic sleeve 24a with a slight clearance left
with an internal peripheral surface of the cylinder member 26A made
from electromagnetic soft iron.
[0109] A bobbin 25a made of a magnetic material are provided at the
wire-winded section of the coil section 25 so as to be the core of
the wire-winded section, and a narrow clearance "a" is formed
between the bobbin 25a and an internal peripheral surface of the
cylinder member 26A. The lead wire 27 leading to a controller (not
shown) through inside of the supporting member is connected to the
coil 25b of the coil section 25, and a required current is fed
through the lead wire 27 under control by the controller.
[0110] An internal peripheral surface of the circular projection
15B protruding inward from an internal peripheral section of the
movable member 14A slidably contacts an external peripheral surface
of the cylinder member 26A of the control cylinder 20A via a seal
ring 15d engaged in a groove section 15c provided on the peripheral
surface so as to be slidable, and the third chamber 16f and the
fourth chamber 16g partitioned in the vertical direction by the
circular projection 15B is formed between the cylinder member 26A
and an internal peripheral surface of the movable member 14A.
[0111] A connecting hole 14j communicating to the first chamber 16a
and the third chamber 16f and a connecting hole 14k communicating
to the second chamber 16b and the fourth chamber 14g are provided
above and under internal and external circular projections 15A, 15B
of the movable member 14A, and further a connecting hole 26a
communicating to the third chamber 16f and the upper side chamber
22a inside the control cylinder 20A and a connecting hole 26b
communicating to the fourth chamber 16g and the lower side chamber
22b of the control cylinder 20A are provided in the cylinder member
26A respectively.
[0112] The chambers described above are filled with a magnetic
rheological fluid. Further seal rings are provided at an upper edge
section of an internal peripheral surface of the head member 11b
positioned on the fixed member 11A and at a lower edge section of
an internal peripheral surface of the lower section member 11c
respectively to keep inside of the cylinder water-tight.
[0113] The damper cylinder 10A having the configuration as
described above is arranged like in the embodiment described above
and is used to excite the coil section 25 of the control cylinder
20A under control by the controller, and the functions are the same
as those described in the embodiment above.
[0114] As for the flowing state of the magnetic rheological fluid,
when the movable member 14A is pushed down, the circular
projections 15A, 15B move downward, so that, in the buffering
cylinder 13A, the fluid in the second chamber 16b is pressurized
and flows through the connecting hole 14k into the fourth chamber
16g, and is further fed from this fourth chamber 16g through the
connecting hole 26b into the lower side chamber 22b of the control
cylinder 20A. In contrast, the first chamber 16a and the third
chamber 16f in the buffering cylinder 13A enter the reduced
pressure state, so that the fluid in the upper side chamber 22a of
the control cylinder 20A passing through the connecting hole 14j
flows from the third chamber 16f into the first chamber 16a due to
a pressure difference.
[0115] In the control cylinder 20A, the magnetic rheological fluid
flows from the lower side chamber 22b through the clearance "a"
into the upper side chamber 22a due to a pressure difference
between the lower side chamber 22b and the upper side chamber
22a.
[0116] With the configuration, movement velocity of the buffering
cylinder 13A is controlled by controlling a signal from a detection
sensor (not shown), which is provided in the machine side against
the magnetic rheological fluid and detects vibrations of the
magnetic rheological fluid passing through the clearance "a", with
the controller based on data to feed a current at a required rate
through the lead wire 27 to the coil section 25 and generate a
magnetic field corresponding to the current value around the bobbin
25a for the purpose to change fluidity of the magnetic Theological
fluid to control the flow resistance.
[0117] The descriptions above assume the configuration in which two
units of damper cylinders are employed to support an operator's
seat, but the present invention is not limited to this
configuration, and for instance, another additional damper cylinder
for supporting may be provided in the front side or in the rear
side, if necessary. With the configuration, even when a large load
is applied to the front side or the rear side of the operator's
seat, the load can be accommodated and dampened.
* * * * *