U.S. patent application number 13/710292 was filed with the patent office on 2013-11-28 for shock absorber for vehicle.
This patent application is currently assigned to Hyundai Motor Company. The applicant listed for this patent is HYUNDAI MOTOR COMPANY. Invention is credited to Sung Bae Jang, Bo Min Kim, Jae San Kim, Jong Min Kim, Dae Sik Ko.
Application Number | 20130313792 13/710292 |
Document ID | / |
Family ID | 49546972 |
Filed Date | 2013-11-28 |
United States Patent
Application |
20130313792 |
Kind Code |
A1 |
Kim; Bo Min ; et
al. |
November 28, 2013 |
SHOCK ABSORBER FOR VEHICLE
Abstract
A shock absorber apparatus for a vehicle may include a piston
installed within a cylinder to be moved along a lengthwise
direction of the cylinder and separating the cylinder into an upper
chamber and a lower chamber, a piston rod installed to pass through
the cylinder and connected to the piston, wherein the piston rod
has an oil flow space therein, and a valve mechanism installed on
the piston rod and operated to be opened and closed to selectively
connect the upper chamber of the cylinder and the oil flow space of
the piston rod.
Inventors: |
Kim; Bo Min; (Seoul, KR)
; Jang; Sung Bae; (Suwon-si, KR) ; Kim; Jong
Min; (Seoul, KR) ; Kim; Jae San; (Yongin-si,
KR) ; Ko; Dae Sik; (Hwaseong-si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HYUNDAI MOTOR COMPANY |
Seoul |
|
KR |
|
|
Assignee: |
Hyundai Motor Company
Seoul
KR
|
Family ID: |
49546972 |
Appl. No.: |
13/710292 |
Filed: |
December 10, 2012 |
Current U.S.
Class: |
280/6.157 ;
188/269; 188/313 |
Current CPC
Class: |
B60G 13/08 20130101;
F16F 9/063 20130101; B60G 2500/30 20130101; B60G 2202/24 20130101;
F16F 9/46 20130101; B60G 17/08 20130101 |
Class at
Publication: |
280/6.157 ;
188/313; 188/269 |
International
Class: |
B60G 17/08 20060101
B60G017/08; F16F 9/06 20060101 F16F009/06 |
Foreign Application Data
Date |
Code |
Application Number |
May 22, 2012 |
KR |
10-2012-0054144 |
Claims
1. (canceled)
2. The shock absorber apparatus of claim 3, wherein the cylinder is
a monotube-type cylinder.
3. A shock absorber apparatus for a vehicle, further comprising: a
piston installed within a cylinder to be moved along a lengthwise
direction of the cylinder and separating the cylinder into an upper
chamber and a lower chamber; a piston rod installed to pass through
the cylinder and connected to the piston, wherein the piston rod
has an oil flow space therein; a valve mechanism installed on the
piston rod and operated to be opened and closed to selectively
connect the upper chamber of the cylinder and the oil flow space of
the piston rod; a support chamber formed under the lower chamber of
the cylinder by a partition wall and fluid-connected to the lower
chamber through an oil passage formed to the partition wall; a
high-pressure gas chamber formed within the support chamber and
partitioned from the support chamber by a diaphragm; and a pipe
member passing through the piston and installed to fluid-connect
the oil flow space of the piston rod and the support chamber.
4. The shock absorber apparatus of claim 3, further comprising: an
oil pump for generating a hydraulic pressure; an accumulator
storing an oil and installed to be connected to the oil pump via a
connecting pipe line; a solenoid valve including a spool
selectively slid in accordance with a controller; a supply pipe
line connecting the oil pump and the solenoid valve; a first return
pipe line and a second return pipe line connecting the accumulator
and the solenoid valve; and a first valve pipe line connecting the
upper chamber of the cylinder and the solenoid valve and a second
valve pipe line connecting the lower chamber of the cylinder and
the solenoid valve, wherein the first valve pipe line or the second
valve pipe line is selectively connected to the oil pump or the
accumulator by the movement of the spool.
5. The shock absorber apparatus of claim 3, wherein the valve
mechanism includes: a pressure-type relief valve installed on the
piston rod and operated to open a first rod passage formed to the
piston rod to fluid-connect the upper chamber of the cylinder and
the oil flow space of the piston rod when a bump occurs while a
height of the vehicle is raised in a situation where a hydraulic
pressure is supplied to the lower chamber of the cylinder; and a
pressure-type check valve installed on the piston rod and operated
to open a second rod passage to connect the upper chamber of the
cylinder and the oil flow space of the piston rod when a rebound
occurs while a height of the vehicle is lowered in a situation
where a hydraulic pressure is supplied to the upper chamber of the
cylinder.
6. The shock absorber apparatus of claim 5, wherein the
pressure-type relief valve includes: a relief valve housing
connected to the piston rod to protrude toward the upper chamber,
and having a relief valve passage fluid-connected to the upper
chamber; a relief valve member located within the relief valve
housing to open and close the first rod passage; and a relief valve
spring installed such that one end thereof is supported by the
relief valve housing and an opposite end thereof is supported by
the relief valve member and configured to provide a resilient force
to the relief valve member such that the relief valve member is
elastically biased to close the first rod passage.
7. The shock absorber apparatus of claim 5, wherein the
pressure-type check valve includes: a check valve housing connected
to the piston rod to protrude toward the upper chamber, and having
a check valve passage fluid-connected to the upper chamber; a check
valve member located within the oil flow space of the piston rod to
open and close the second rod passage; and a check valve spring
installed such that one end thereof is supported by the check valve
housing and an opposite end thereof is supported by the check valve
member and configured to provide a resilient force to the check
valve member such that the check valve member is elastically biased
to close the second rod passage.
8. The shock absorber apparatus of claim 6, wherein a resilient
force of the relief valve spring applied to the relief valve member
in a situation where the relief valve member closes the first rod
passage is larger than an oil pressure applied from the oil flow
space to the relief valve member in a situation where a hydraulic
pressure is not supplied to the cylinder and an oil pressure
applied from the oil flow space to the relief valve member when a
height of the vehicle is raised in a situation where a hydraulic
pressure is supplied to the lower chamber of the cylinder, and is
smaller than an oil pressure applied from the oil flow space to the
relief valve member when a bump occurs while a height of the
vehicle is raised in a situation where a hydraulic pressure is
supplied to the lower chamber of the cylinder.
9. The shock absorber apparatus of claim 7, wherein a resilient
force of the check valve spring applied to the check valve member
in a situation where the check valve member closes the second rod
passage is larger than an oil pressure applied to the check valve
member within the check valve housing in a situation where a
hydraulic pressure is not supplied to the cylinder and an oil
pressure applied to the check valve member within the check valve
housing when a height of the vehicle is lowered in a situation
where a hydraulic pressure is supplied to the upper chamber of the
cylinder, and is smaller than an oil pressure applied to the check
valve member within the check valve housing when a rebound occurs
while a height of the vehicle is lowered in a situation where a
hydraulic pressure is supplied to the upper chamber of the
cylinder.
10. The shock absorber apparatus of claim 3, wherein an orifice is
installed in the piston.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority to Korean Patent
Application No. 10-2012-0054144 filed May 22, 2012 the entire
contents of which is incorporated herein for all purposes by this
reference.
BACKGROUND OF. THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a shock absorber for a
vehicle, and more particularly, to a monotube-type shock absorber
for a vehicle which can adjust a height of the vehicle.
[0004] 2. Description of Related Art
[0005] A shock absorber configuring a suspension of a vehicle is an
apparatus installed between an axle and a body of the vehicle to
absorb vibrations and impacts received by the axle from a road
surface while the vehicle is driven and improve riding quality, and
serves to provide driving stability and comfortable ride.
[0006] Manual shock absorbers widely used conventionally have been
developed with only improvement of riding quality and adjustment
stability being focused, and accordingly, it is impossible to
stably control vehicle postures varying during a travel of the
vehicle.
[0007] In order to supplement this shortcoming, vehicle height
controlled shock absorbers have been developed, and the vehicle
height controlled shock absorbers generate damping forces by using
hydraulic pressures. Further, the vehicle height controlled shock
absorbers additionally function to not only absorb vibrations to
improve riding quality and adjustment stability and but also always
maintain a height of a vehicle varying during a travel of the
vehicle constantly and stably.
[0008] FIG. 1 illustrates a shock absorber according to the related
art which can adjust a height of a vehicle, and the shock absorber
includes a twin tube-type cylinder 1 having an inner tube 1a and an
outer tube 1b, a piston 2 installed within the inner tube 1a to
reciprocally move along a lengthwise direction of the inner tube
1a, a piston rod one end of which is connected to the piston 2 and
an opposite end of which passes through the cylinder 1, an oil pump
4 for generating a hydraulic pressure, and a reserve tank 5 for
storing an oil.
[0009] Further, a spring valve 6 for connecting the outer tube 1b
and the inner tube 1a is installed on a bottom surface of the inner
tube 1a, a damping force valve 7 is installed in the piston 2, an
leveling valve 9 is installed at an end of an oil passage 8
connecting the inner tube 1a and the reserve tank 5. In addition, a
valve hole (not shown) through which an oil can flow is formed in
the leveling valve 9, and a piston hole 2a connecting the inner 1a
and an interior space of the piston 3 is formed in the piston
2.
[0010] An oil is filled in a space between the inner tube 1a and
the outer tube 1b, an inner space of the inner tube 1a, and an
inner space of the piston rod 2.
[0011] The state of FIG. 1A is an initial state where neither a
bump nor a rebound situation occurs, in which state the spring
valve 6 is opened and the leveling valve 9 is closed. Then, the oil
in the inner tube 1a absorbs impacts and vibrations while smoothly
flowing through the piston hole 2a, and valve holes formed in the
spring valve 6, the damping force valve 7, and the leveling valve
9.
[0012] The state of FIG. 1B is a state where a height of the
vehicle is raised, in which state, accordingly, the oil in the
reserve tank 5 is introduced into interior spaces of the inner tube
1a and the piston rod 3 through an operation of the oil pump 4.
Then, the spring valve 6 is closed and the leveling valve 9 is
opened, so that the above-described height raised state is
maintained by the rebound side shock absorber during a straight
travel of the vehicle and by the outer turn wheel side shock
absorber during a turn of the vehicle
[0013] The state of FIG. 1C is a state where a height of the
vehicle is lowered, in which state the oil in the inner tube 1a is
withdrawn into the reserve tank 5 and accordingly, the piston 2 is
lowered. Then, the spring valve 6 is opened and the leveling valve
9 is closed, in which case the bump side shock absorber and the
inner turn wheel side shock absorber maintains a state where a
height of the vehicle is lowered during a straight travel of the
vehicle.
[0014] However, the shock absorber according to the related art is
a twin tube-type shock absorber including a cylinder 1 having an
inner tube 1a and an outer tube 1b, but the twin tube-type shock
absorber needs to be small-sized. In particular, since a sufficient
installing space needs to be secured, the twin tube-type shock
absorber is disadvantageous in the layout of the vehicle.
[0015] In addition, according to the twin tube-type shock absorber
according to the related art, a separate valve (spring valve) needs
to be installed to interrupt a passage between the inner tube 1a
and the outer tube 1b, which makes the structure of the shock
absorber complex and increases manufacturing costs.
[0016] The items described as the related art are just to help
understanding of the background of the present invention, and shall
not be construed to admit that they belong to the related art well
known to those skilled in the art to which the present invention
pertains.
[0017] The information disclosed in this Background of the
Invention section is only for enhancement of understanding of the
general background of the invention and should not be taken as an
acknowledgement or any form of suggestion that this information
forms the prior art already known to a person skilled in the
art.
BRIEF SUMMARY
[0018] Various aspects of the present invention are directed to
providing a shock absorber for a vehicle which can adjust a height
of the vehicle by using a monotube-type cylinder, which is
advantageous in a layout of the vehicle according to reduction of
weight due to reduction of size, reduction of manufacturing costs,
and securing installing space, in particular, which can eliminate
an unnecessary valve component.
[0019] In an aspect of the present invention, a shock absorber
apparatus for a vehicle, may include a piston installed within a
cylinder to be moved along a lengthwise direction of the cylinder
and separating the cylinder into an upper chamber and a lower
chamber, a piston rod installed to pass through the cylinder and
connected to the piston, wherein the piston rod may have an oil
flow space therein, and a valve mechanism installed on the piston
rod and operated to be opened and closed to selectively connect the
upper chamber of the cylinder and the oil flow space of the piston
rod.
[0020] The cylinder is a monotube-type cylinder.
[0021] The shock absorber apparatus may further include a support
chamber formed under the lower chamber of the cylinder by a
partition wall and fluid-connected to the lower chamber through an
oil passage formed to the partition wall, a high-pressure gas
chamber formed within the support chamber and partitioned from the
support chamber by a diaphragm, and a pipe member passing through
the piston and installed to fluid-connect the oil flow space of the
piston rod and the support chamber.
[0022] The shock absorber apparatus may further include an oil pump
for generating a hydraulic pressure, an accumulator storing an oil
and installed to be connected to the oil pump via a connecting pipe
line, a solenoid valve including a spool selectively slid in
accordance with a controller, a supply pipe line connecting the oil
pump and the solenoid valve, a first return pipe line and a second
return pipe line connecting the accumulator and the solenoid valve,
and a first valve pipe line connecting the upper chamber of the
cylinder and the solenoid valve and a second valve pipe line
connecting the lower chamber of the cylinder and the solenoid
valve, wherein the first valve pipe line or the second valve pipe
line is selectively connected to the oil pump or the accumulator by
the movement of the spool.
[0023] The valve mechanism may include a pressure-type relief valve
installed on the piston rod and operated to open a first rod
passage formed to the piston rod to fluid-connect the upper chamber
of the cylinder and the oil flow space of the piston rod when a
bump occurs while a height of the vehicle is raised in a situation
where a hydraulic pressure is supplied to the lower chamber of the
cylinder, and a pressure-type check valve installed on the piston
rod and operated to open a second rod passage to connect the upper
chamber of the cylinder and the oil flow space of the piston rod
when a rebound occurs while a height of the vehicle is lowered in a
situation where a hydraulic pressure is supplied to the upper
chamber of the cylinder.
[0024] The pressure-type relief valve may include a relief valve
housing connected to the piston rod to protrude toward the upper
chamber, and having a relief valve passage fluid-connected to the
upper chamber, a relief valve member located within the relief
valve housing to open and close the first rod passage, and a relief
valve spring installed such that one end thereof is supported by
the relief valve housing and an opposite end thereof is supported
by the relief valve member and configured to provide a resilient
force to the relief valve member such that the relief valve member
is elastically biased to close the first rod passage.
[0025] The pressure-type check valve may include a check valve
housing connected to the piston rod to protrude toward the upper
chamber, and having a check valve passage fluid-connected to the
upper chamber, a check valve member located within the oil flow
space of the piston rod to open and close the second rod passage,
and a check valve spring installed such that one end thereof is
supported by the check valve housing and an opposite end thereof is
supported by the check valve member and configured to provide a
resilient force to the check valve member such that the check valve
member is elastically biased to close the second rod passage.
[0026] A resilient force of the relief valve spring applied to the
relief valve member in a situation where the relief valve member
closes the first rod passage is larger than an oil pressure applied
from the oil flow space to the relief valve member in a situation
where a hydraulic pressure is not supplied to the cylinder and an
oil pressure applied from the oil flow space to the relief valve
member when a height of the vehicle is raised in a situation where
a hydraulic pressure is supplied to the lower chamber of the
cylinder, and is smaller than an oil pressure applied from the oil
flow space to the relief valve member when a bump occurs while a
height of the vehicle is raised in a situation where a hydraulic
pressure is supplied to the lower chamber of the cylinder.
[0027] A resilient force of the check valve spring applied to the
check valve member in a situation where the check valve member
closes the second rod passage is larger than an oil pressure
applied to the check valve member within the check valve housing in
a situation where a hydraulic pressure is not supplied to the
cylinder and an oil pressure applied to the check valve member
within the check valve housing when a height of the vehicle is
lowered in a situation where a hydraulic pressure is supplied to
the upper chamber of the cylinder, and is smaller than an oil
pressure applied to the check valve member within the check valve
housing when a rebound occurs while a height of the vehicle is
lowered in a situation where a hydraulic pressure is supplied to
the upper chamber of the cylinder.
[0028] The shock absorber apparatus of claim 1, wherein an orifice
is installed in the piston.
[0029] It is understood that the term "vehicle" or "vehicular" or
other similar term as used herein is inclusive of motor vehicles in
general such as passenger automobiles including sports utility
vehicles (SUV), buses, trucks, various commercial vehicles,
watercraft including a variety of boats and ships, aircraft, and
the like, and includes hybrid vehicles, electric vehicles, plug-in
hybrid electric vehicles, hydrogen-powered vehicles and other
alternative fuel vehicles (e.g. fuels derived from resources other
than petroleum). As referred to herein, a hybrid vehicle is a
vehicle that has two or more sources of power, for example both
gasoline-powered and electric-powered vehicles.
[0030] The methods and apparatuses of the present invention have
other features and advantages which will be apparent from or are
set forth in more detail in the accompanying drawings, which are
incorporated herein, and the following Detailed Description, which
together serve to explain certain principles of the present
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 is a view of a twin tube-type shock absorber
according to the related art.
[0032] FIG. 2 is a view of a monotube shock absorber capable of
adjusting a height of a vehicle according to an exemplary
embodiment of the present invention, wherein a piston rod is
contracted during a normal situation where a height of the vehicle
is neither raised nor lowered.
[0033] FIG. 3 is an enlarged view of a portion of FIG. 2 to which a
valve mechanism is mounted.
[0034] FIG. 4 is a view of a state where the piston rod is expanded
in a normal situation where a height of the vehicle is neither
raised nor lowered.
[0035] FIG. 5 is a view of a state where a height of the vehicle is
raised.
[0036] FIG. 6 is a view of a state where a bump occurs while a
height of the vehicle is raised.
[0037] FIG. 7 is an enlarged view of a portion of FIG. 6 to which a
valve mechanism is mounted.
[0038] FIG. 8 is a view of a state where a height of the vehicle is
lowered.
[0039] FIG. 9 is a view of a state where a rebound occurs while a
height of the vehicle is lowered.
[0040] FIG. 10 is an enlarged view of a portion of FIG. 9 to which
a valve mechanism is mounted.
[0041] It should be understood that the appended drawings are not
necessarily to scale, presenting a somewhat simplified
representation of various features illustrative of the basic
principles of the invention. The specific design features of the
present invention as disclosed herein, including, for example,
specific dimensions, orientations, locations, and shapes will be
determined in part by the particular intended application and use
environment.
[0042] In the figures, reference numbers refer to the same or
equivalent parts of the present invention throughout the several
figures of the drawing.
DETAILED DESCRIPTION
[0043] Reference will now be made in detail to various embodiments
of the present invention(s), examples of which are illustrated in
the accompanying drawings and described below. While the
invention(s) will be described in conjunction with exemplary
embodiments, it will be understood that the present description is
not intended to limit the invention(s) to those exemplary
embodiments. On the contrary, the invention(s) is/are intended to
cover not only the exemplary embodiments, but also various
alternatives, modifications, equivalents and other embodiments,
which may be included within the spirit and scope of the invention
as defined by the appended claims.
[0044] Hereinafter, a shock absorber for a vehicle to an exemplary
embodiment of the present invention will be described with
reference to the accompanying drawings.
[0045] As shown in FIGS. 2 and 3, the shock absorber according to
an exemplary embodiment of the present invention includes a
monotube-type cylinder 11, a piston 12 installed within the
cylinder 11 to move along a lengthwise direction of the cylinder 11
and having an orifice 12a passing through upper and lower surfaces
thereof, a piston rod 13 installed to pass through the cylinder 11
so as to be connected to the piston 12 and having an oil flow space
13a, a valve mechanism 14 installed in the piston rod 13 and
operated to be opened and closed to selectively connect an upper
chamber 11a of the cylinder 11 and the oil flow space 13a of the
piston rod 13 according to a pressure change of the piston rod 13,
a support chamber 16 partitioned from the lower chamber 11b of the
cylinder 11 by a partition wall 15 and formed to be connected to
the lower chamber 11b through an oil passage 15a, a high-pressure
gas chamber 18 formed in the support chamber 16 to be partitioned
from the support chamber 16 by means of a diaphragm 17, and a pipe
member 19 installed to connect the oil flow space 13a of the piston
rod 13 and the high-pressure gas chamber 18.
[0046] The shock absorber according to an exemplary embodiment of
the present invention further includes an oil pump 21 operated
under the control of a controller to generate a hydraulic pressure,
an accumulator 23 storing an oil and installed to be connected to
the oil pump 21 via a connecting pipe line 22, a supply pipe line
25 connecting the oil pump 21 and the solenoid valve 24, a first
return pipe line 26 and a second return pipe line 27 connecting the
accumulator 23 and the solenoid valve 24, a first valve pipe line
28 connecting the upper chamber 11a of the cylinder 11 and the
solenoid valve 24 and a second valve pipe line 29 connecting the
lower chamber 11b of the cylinder 11 and the solenoid valve 24.
[0047] Here, the solenoid valve 24 includes a solenoid valve spring
31 for endowing movement of a spool 24a with a resilient force, and
a check valve 32 is installed in the supply pipe line 25 to prevent
an oil from reversely flowing from the solenoid valve 24 to the oil
pump 21.
[0048] Meanwhile, the valve mechanism 14 includes: a pressure-type
relief valve 50 installed in a first rod passage 13b passing
through the piston rod 13 and operated to be opened to connect the
upper chamber 11a of the cylinder 11 and the oil flow space 13a of
the piston rod 13 only when a bump occurs while a height of the
vehicle is raised in a situation where a hydraulic pressure is
supplied to the lower chamber 11b of the cylinder, and a
pressure-type check valve 60 installed in a second rod passage 13c
passing through the piston rod 13 and operated to be opened to
connect the upper chamber 11a of the cylinder 11 and the oil flow
space 13a of the piston rod 13 only when a rebound occurs while a
height of the vehicle is lowered in a situation where a hydraulic
pressure is supplied to the upper chamber 11a of the cylinder
11.
[0049] The pressure-type relief valve 50 includes a relief valve
housing 51 connected to the first rod passage 13b, fixedly
installed in the piston rod 13 to protrude toward the upper chamber
11a, and having a relief valve passage 51a connected to the upper
chamber 11a, a relief valve member 52 located within the relief
valve housing 51 to open and close the first rod passage 13b, and a
relief valve spring 53 installed such that one end thereof is
supported by the relief valve housing 51 and an opposite end
thereof is supported by the relief valve member 52 and configured
to provide a resilient force to the relief valve member 52 for the
relief valve member 52 to close the first rod passage 13b.
[0050] Here, a resilient force of the relief valve spring 53
applied to the relief valve member 52 in a situation where the
relief valve member 52 closes the first rod passage 13b is larger
than an oil pressure applied from the oil flow space 13a to the
relief valve member 52 in a situation where a hydraulic pressure is
not supplied to the cylinder 11 and an oil pressure applied from
the oil flow space 13a to the relief valve member 52 when a height
of the vehicle is raised in a situation where a hydraulic pressure
is supplied to the lower chamber 11b of the cylinder 11, and is
smaller than an oil pressure applied from the oil flow space 13a to
the relief valve member 52 when a bump occurs while a height of the
vehicle is raised in a situation where a hydraulic pressure is
supplied to the lower chamber 11b of the cylinder 11.
[0051] The pressure-type check valve 60 includes a check valve
housing 61 connected to the second rod passage 13c, fixedly
installed in the piston rod 13 to protrude toward the upper chamber
11a, and having a check valve passage 61a connected to the upper
chamber 11a, a check valve member 62 located within the oil flow
space 13a of the piston rod 13 to open and close the second rod
passage 13c, and a check valve spring 63 installed such that one
end thereof is supported by the check valve housing 61 and an
opposite end thereof is supported by the check valve member 62 and
configured to provide a resilient force to the check valve member
62 for the check valve member 62 to close the second rod passage
13c.
[0052] Here, a resilient force of the check valve spring 63 applied
to the check valve member 62 in a situation where the check valve
member 62 closes the second rod passage 13c is larger than an oil
pressure applied to the check valve member 62 within the check
valve housing 61 in a situation where a hydraulic pressure is not
supplied to the cylinder 11 and an oil pressure applied to the
check valve member 62 within the check valve housing 61 when a
height of the vehicle is lowered in a situation where a hydraulic
pressure is supplied to the upper chamber of the cylinder 11, and
is smaller than an oil pressure applied to the check valve member
62 within the check valve housing 61 when a rebound occurs while a
height of the vehicle is lowered in a situation where a hydraulic
pressure is supplied to the upper chamber 11a of the cylinder
11.
[0053] Hereinafter, an operation of the shock absorber according to
an exemplary embodiment of the present invention will be
described.
[0054] FIGS. 2 and 4 illustrate a normal state where a height of
the vehicle is neither raised nor lowered, and FIG. 2 illustrates a
state where the piston rod is contracted and FIG. 4 illustrates a
state where the piston rod is expanded.
[0055] At this time, since the oil pump 21 is not operated and the
spool 24a of the solenoid valve 24 blocks the first and second
valve pipe lines 28 and 29, an oil is not supplied to the cylinder
11 and the pressure-type relief valve 50 and the pressure-type
check valve 60 keep blocking the first and second rod passages 13b
and 13c, respectively.
[0056] When the piston rod 13 is contracted as in FIG. 2, as a
volume of the lower chamber 11b is reduced, the oil in the oil flow
space 13a flows into the support chamber 16 through a pipe member
19 and the oil in the lower chamber 11b flows into the support
chamber 16 through an oil passage 15a of the partition 15 at the
same time. Accordingly, a pressure in the support chamber 16
increases and a pressure in the high-pressure gas chamber 18 also
increases at the same time as the diaphragm 17 is contracted.
[0057] Then, when the piston rod 13 is expanded as in FIG. 4, a
volume of the lower chamber 11b increases. While the contracted
diaphragm 17 is expanded by the pressure in the high-pressure gas
chamber 18 to pressure the oil in the support chamber 16.
Accordingly, the oil in the support chamber 16 flows into the oil
flow space 13a of the piston rod 13 through the pipe member 19 and
flows into the lower chamber 11b through the oil passage 15a of the
partition wall 15 at the same time.
[0058] At this time, a force pushing the piston 12 upward in the
lower chamber 11b and a force pushing the piston rod 13 upward in
the oil flow space 13a are added, and accordingly, the piston rod
13 is moved upward promptly.
[0059] Thus, in a normal situation where a height of the vehicle is
neither raised nor lowered, the shock absorber according to an
exemplary embodiment of the present invention can absorb
vibrations, thereby improving riding quality and adjustment
stability.
[0060] FIG. 5 illustrates a state where a height of the vehicle is
raised, and a rebound side shock absorber during a straight travel
of the vehicle and an outer turn wheel side shock absorber during a
turn of the vehicle correspond thereto.
[0061] Then, the oil pump 21 is operated and the spool 24a of the
solenoid valve 24 is lowered while overcoming a force of the
solenoid valve spring 31, and accordingly, the supply pipe line 25
and the second valve pipe line 29 are connected to each other and
the first return pipe line 26 and the first valve pipe line 28 are
connected to each other.
[0062] As illustrated in FIG. 3, the pressure-type relief valve 50
and the pressure-type check valve 60 keep blocking the first and
second rod passages 13b and 13c, respectively.
[0063] The oil is introduced into the lower chamber 11b of the
cylinder 11 through the supply pipe line 25 and the second valve
pipe line 29 due to an operation of the oil pump 21, and some of
the oil introduced into the lower chamber 11b pushes a lower
portion of the piston 12 to move the piston 12 upward and the
remaining oil is introduced into the support chamber 16 through the
oil passage 15a and then flows into the oil flow space 13a of the
piston rod 13 through the pipe member 19 again.
[0064] Thus, a force pushing the piston 12 upward within the lower
chamber 11b of the cylinder 11 and a force pushing the piston rod
13 upward within the oil flow space 13a are added to promptly move
the piston 12 upward. As a result, the shock absorber according to
an exemplary embodiment of the present invention always maintains a
height of the vehicle variously changing during a travel of the
vehicle constantly and stably.
[0065] FIG. 6 illustrates a state where a bump occurs while a
height of the vehicle is raised, and then the piston 12 is
lowered.
[0066] As a bump occurs while a height of the vehicle is raised, if
the piston 12 is lowered, the oil pressure in the oil flow space
13a primarily increases while the height of the vehicle is raised
as in FIG. 5 and as the pressure in the support chamber 16 is
increased by the piston 12 lowered when a bump occurs as in FIG. 6
the oil pressure in the oil flow space 13a secondarily increases
additionally.
[0067] Thus, while the pressure-type check valve 60 installed in
the piston rod 13 keeps closing the second rod passage 13c, the
pressure-type relief valve 50 is moved to the inner side of the
relief valve housing 51 while the relief valve member 52 overcomes
a force of the relief valve spring 53. Accordingly, the fluid flow
space 13a of the cylinder rod 13 is connected to the upper chamber
112a of the cylinder 11 through the first rod passage 13b and the
relief valve passage 51a, and the oil in the fluid flow space 13a
returns to the accumulator 23 through the upper chamber 11a via the
first valve pipe line 28 and the first return pipe line 28.
[0068] That is, the shock absorber according to an exemplary
embodiment of the present invention improves riding quality,
improves adjustment stability, always maintains a height of the
vehicle constantly and stably, and improves durability as the
pressure-type relief valve 50 installed in the piston rod 13 does
not perform an opening operation against the high pressure
generated by an operation of the oil pump 21 and performs an
opening operation only in a situation where an additional pressure
is generated within the oil flow space 13a when a bump occurs while
a height of the vehicle is raised.
[0069] FIG. 8 illustrates a state where a height of the vehicle is
lowered, and a bump side shock absorber during a straight travel of
the vehicle and an inner turn wheel side shock absorber during a
turn of the vehicle correspond thereto.
[0070] At this time, the oil pump 21 is operated and the spool 24a
of the solenoid valve 24 is raised. Accordingly, the supply pipe
line 25 and the first valve pipe line 28 are connected to each
other, and the second return pipe line 27 and the second valve pipe
line 29 are connected to each other.
[0071] As illustrated in FIG. 3, the pressure-type relief valve 50
and the pressure-type check valve 60 keep blocking the first and
second rod passages 13b and 13c, respectively.
[0072] If the oil is introduced into the upper chamber 11a of the
cylinder 11 through the supply pipe line 25 and the first valve
pipe line 28 due to an operation of the oil pump 21, the piston 12
is lowered by the oil pressure in the upper chamber 11a. At this
time, the oil in the lower chamber 11b of the cylinder 11 returns
to the accumulator 23 through the second valve pipe line 29 and the
second return pipe line 27.
[0073] Thus, the shock absorber according to an exemplary
embodiment of the present invention always maintains a height of
the vehicle variously changing when a height of the vehicle is
lowered, constantly and stably.
[0074] FIG. 9 illustrates a state where a rebound occurs while a
height of the vehicle is lowered, and then the piston 12 is
raised.
[0075] As a rebound occurs while a height of the vehicle is
lowered, if the piston 12 is raised, the oil pressure in the upper
chamber 11a primarily increases while the height of the vehicle is
lowered as in FIG. 8 and as the pressure in the upper chamber 11a
is increased by the piston 12 raised when a rebound occurs as in
FIG. 9, the oil pressure in the upper chamber 11a secondarily
increases additionally.
[0076] Thus, while the pressure-type relief valve 50 installed in
the piston rod 13 continuously closes the first rod passage 13b as
in FIG. 10, the check valve member 62 of the pressure-type check
valve 60 overcomes a force of the check valve spring 63 due to the
additional pressure of the oil generated in the upper chamber 11a
to flow into the oil flow space 13a. Accordingly, the upper chamber
11a of the cylinder 11 is connected to the fluid flow space 13a of
the cylinder rod 13 through the check valve passage 61a and the
second rod passage 13c.
[0077] As described above, if the upper chamber 11a of the cylinder
11 and the fluid flow space 13a of the cylinder rod 13 are
connected to each other, the oil introduced into the upper chamber
11a flows into the fluid flow space 13a through the first valve
pipe line 28, the oil having flowed into the fluid flow space 13a
flows into the support chamber 16 through the pipe member 19 and
then flows into the lower chamber 11b of the cylinder, and the oil
in the lower chamber 11b returns to the accumulator 23 through the
second valve pipe line 29 and the second return pipe line 27.
[0078] Thus, the shock absorber according to an exemplary
embodiment of the present invention improves riding quality,
improves adjustment stability, always maintains a height of the
vehicle constantly and stably, and improves durability as the
pressure-type check valve 60 installed in the piston rod 13 does
not perform an opening operation against the high pressure
generated by an operation of the oil pump 21 and performs an
opening operation only in a situation where an additional pressure
is generated within the upper chamber 11a of the cylinder 11 when a
rebound occurs while a height of the vehicle is lowered.
[0079] As described above, the shock absorber according to an
exemplary embodiment of the present invention improves riding
quality, improves adjustment stability, and always maintains a
height of the vehicle constantly and stably by using the
monotube-type cylinder 11 when a height of the vehicle is adjusted,
which is advantageous in a layout of the vehicle according to
reduction of weight due to reduction of size, reduction of
manufacturing costs, and securing an installation space.
[0080] While the twin tube-type shock absorber using an inner tube
and an outer tube employs a separate valve member for interrupting
a passage between an inner tube and an outer tube, the shock
absorber according to an exemplary embodiment of the present
invention eliminates an necessary valve member with a construction
using the monotube-type cylinder 11, thereby reducing the number of
parts, reducing weight, and reducing manufacturing costs.
[0081] As described above, the shock absorber according to an
exemplary embodiment of the present invention improves riding
quality, improves adjustment stability, and always maintains a
height of the vehicle constantly and stably by using the
monotube-type cylinder when a height of the vehicle is adjusted,
which is advantageous in a layout of the vehicle according to
reduction of weight due to reduction of size, reduction of
manufacturing costs, and securing an installation space.
[0082] While the invention will be described in conjunction with an
exemplary embodiment, it will be understood that present
description is not intended to limit the invention to those
exemplary embodiments. On the contrary, the invention is intended
to cover not only the exemplary embodiments, but also various
alternatives, modifications, equivalents and other embodiments,
which may be included within the spirit and scope of the invention
as defined by the appended claims.
[0083] For convenience in explanation and accurate definition in
the appended claims, the terms "upper", "lower", "inner" and
"outer" are used to describe features of the exemplary embodiments
with reference to the positions of such features as displayed in
the figures.
[0084] The foregoing descriptions of specific exemplary embodiments
of the present invention have been presented for purposes of
illustration and description. They are not intended to be
exhaustive or to limit the invention to the precise forms
disclosed, and obviously many modifications and variations are
possible in light of the above teachings. The exemplary embodiments
were chosen and described in order to explain certain principles of
the invention and their practical application, to thereby enable
others skilled in the art to make and utilize various exemplary
embodiments of the present invention, as well as various
alternatives and modifications thereof. It is intended that the
scope of the invention be defined by the Claims appended hereto and
their equivalents.
* * * * *