BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fuel supply device which is used to supply fuel to
an injector of an internal combustion engine (hereafter referred to as "engine"), and more
particularly to a fuel supply device which is disposed in a fuel tank of a vehicle such as a
two-wheeled vehicle equipped with a small displacement engine.
2. Description of the Related Art
Fuel supply devices in which a fuel pump, fuel pressure regulator, filter and so on
are incorporated integrally and disposed inside a fuel tank are known as systems for
supplying fuel to an engine mounted in a four-wheeled vehicle or the like. A circumferential
flow type turbine pump, for example, is employed as the fuel pump which constitutes this
fuel supply device.
A turbine pump has a comparatively large and complicated structure comprising a
pump portion, a motor portion and so on, and furthermore, since the turbine pump itself has
no self-priming ability, it is disposed inside the fuel tank. Accordingly, these conventional
fuel supply devices are suited to being stored in comparatively large fuel tanks such as the
fuel tanks of four-wheeled vehicles and the like.
However, in small displacement engines such as engines mounted in two-wheeled
vehicles and the like of around 50cc-250cc per cylinder, the fuel tank is comparatively small
and there are restrictions as to shape and the like thereof. It is therefore difficult to store a
fuel supply device such as that described above in the fuel tank.
Furthermore, in two-wheeled vehicles and the like, the engine, fuel tank and so on
are disposed in comparatively proximal regions, and hence it must be ensured that the fuel
supply system is as little affected as possible by radiation heat from the engine, and further,
in order to avoid damage and the like if the vehicle overturns or such, the system must be
simplified as far as possible by reducing the number of parts, or it must be ensured that
there is no exposure to the outside.
SUMMARY OF THE INVENTION
The present invention has been designed in consideration of the aforementioned
points, and it is an object thereof to provide a fuel supply device in which size has been
reduced, structure has been simplified, and functional reliability has been improved, and
particularly one which is suited to a vehicle such as a two-wheeled vehicle which is equipped
with a small displacement engine.
The fuel supply device of the present invention is disposed inside a fuel tank and
supplies fuel toward the injector of an internal combustion engine, and comprises: a positive
displacement plunger pump consisting of a pump main body which demarcates a suction
port and a discharge port, a plunger which performs suction and pressure feeding of fuel by
means of a linearly reciprocating motion within the pump main body, and an electromagnetic
coil for driving the plunger; and a fuel pressure regulator consisting of a regulator main body
which demarcates an influx channel connected to the discharge port and a supply channel
for supplying fuel toward the injector, and an adjustment valve disposed between the influx
channel and the supply channel for adjusting the fuel pressure, wherein the pump main
body and the regulator main body are integrally coupled.
According to this constitution, the plunger pump itself, which is capable of pressure
feeding fuel by means of the reciprocating motion of the plunger, is formed in a
comparatively small size, and this small size plunger pump and the fuel pressure regulator
are formed integrally (modularized). As a result, a fuel supply device with an overall small
(compact) size, and which is therefore convenient from the point of view of handling, is
provided, this device being particularly suited to installation in a small size fuel tank of a
two-wheeled vehicle or the like.
In the aforementioned constitution, a constitution may be employed in which the
direction of reciprocating motion of the plunger and the direction of extension of the supply
channel are formed so as to be substantially parallel.
According to this constitution, the plunger and the supply channel are formed so as
to be substantially parallel, or in other words, the longitudinal direction of the pump main
body and the longitudinal direction of the regulator main body are formed so as to be
substantially parallel. Hence, the two bodies are integrated, enabling further size reduction
(compacting). In particular, by forming the outer profile of the device into a quadratic prism
or substantially cylindrical shape, for example, a profile form which is compact and therefore
convenient to handle can be achieved.
In the above constitution, a constitution may be employed in which the regulator
main body has a mounting flange portion formed on the upper side of the direction of
extension for mounting the device onto the fuel tank, and the pump main body has the
suction port which is formed on the lower side of the direction of reciprocating motion, and a
filter which is attached around the suction port.
According to this constitution, the filter is disposed on the lower side, the pump main
body and regulator main body are disposed in an intermediate position, and the mounting
flange portion is disposed on the upper side. Consequently, the device can be easily
installed inside a fuel tank simply by fixing the mounting flange portion to the upper wall of
the fuel tank, for example. The device can also be dealt with as a modular item which
includes a filter.
In the above constitution, a constitution may be employed in which a pulsation
damper which is connected to the supply channel so as to absorb fuel pulsations is provided
in the regulator main body.
According to this constitution, fuel pulsations or pressure fluctuations (pulsations)
generated during fuel injection can be efficiently absorbed and dampened. Furthermore, by
providing the pulsation damper in the regulator main body, the components are integrated,
and thus the size of the device is reduced.
In the above constitution, a constitution may be employed in which the pump main
body and the regulator main body have a first connecting portion and a second connection
portion which are formed so as to be freely attachable and detachable in a direction which is
substantially perpendicular to the direction of reciprocating motion and the direction of
extension, whereby the first connecting portion doubles as an electrical connector for
connecting the electrical wiring provided in the regulator main body and the electrical wiring
of the electromagnetic coil, and the second connecting portion doubles as a linking channel
to link the discharge port and the influx channel.
According to this constitution, the plunger pump and the fuel pressure regulator
become freely attachable and detachable by means of the first connecting portion and
second connecting portion, and thus assembly is ameliorated and the two members can
each be formed from a different material; for example, the plunger pump being formed from
a metallic material or the like and the fuel pressure regulator being formed from a resinous
material or the like. Moreover, since the first connecting portion and second connecting
portion double as an electrical connector and a fuel channel respectively, the structure of the
device is simplified in comparison with a case in which these connecting portions are formed
as separate entities.
In the above constitution, a constitution may be employed in which the pump main
body and the regulator main body are coupled so as to be freely attachable and detachable
by means of a snap-fit connection.
According to this constitution, the two bodies can be connected by means of a simple
one-touch operation. As a result, special connecting components such as fastening screws
become unnecessary and the structure of the device is simplified, the size is reduced, and
the weight is reduced.
In the above constitution, a constitution may be employed in which the pump main
body has adjusting means which are capable of adjusting the spacing between the first
connecting portion and second connecting portion.
According to this constitution, when the pitches of the first connecting portion and
the second connecting portion differ on the plunger pump side and the fuel pressure
regulator side, this misalignment can be adjusted by the adjusting means, thereby
ameliorating the assembly of the two bodies.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a schematic diagram of a fuel supply system showing the state of the fuel
supply device in accordance with the present invention when installed in a fuel tank;
Fig. 2 is a side view of the fuel supply device in accordance with the present
invention;
Fig. 3 is a top view of the fuel supply device in accordance with the present
invention;
Fig. 4 is a longitudinal cross sectional view of the fuel supply device in accordance
with the present invention;
Fig. 5 is a longitudinal cross sectional view showing one part of the fuel pressure
regulator;
Fig. 6 is an exploded view showing an exploded state of the plunger pump and the
fuel pressure regulator prior to coupling;
Fig. 7 is a partial enlarged perspective view showing snap-fit coupling; and
Fig. 8 is a longitudinal cross sectional view showing another embodiment of the
position of attachment of a pulsation damper.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiments of the present invention will be described below with reference to the
attached drawings.
Figs. 1 through 7 show one embodiment of the fuel supply device in accordance with
the present invention. This fuel supply device 10 in accordance with the present invention
constitutes one part of a fuel supply system for supplying fuel toward an electromagnetic
valve driven injector in an engine in which fuel is injected by means of electronic control.
Here, as is illustrated in Fig. 1, the fuel supply device 10 is disposed inside a fuel tank 1 of a
two-wheeled vehicle so as to supply fuel through a supply pipe 5 toward an injector 4 which
is attached to a suction port 3 of an engine 2.
As is illustrated in Figs. 2 and 3, the fuel supply device 10 has a positive displacement
plunger pump 20 and an inlet control-type fuel pressure regulator 50 for adjusting the
pressure of the fuel on the upstream side of the injector 4, which are integrally coupled and
modularized without the use of connecting piping or the like. The dimensions of the outer
profile of this module are as follows: the height H is approximately 80mm-100mm; the outer
diameter D is approximately 70mm-80mm at the attachment flange portion where the
diameter is the largest; and the width W of the main body part is approximately 40mm-60mm.
By integrating (modularizing) the device in such a compact fashion, a profile with an
overall small size, and which is therefore convenient from the point of view of handling, is
formed.
The plunger pump 20 is an electromagnetically driven positive displacement pump,
and as is illustrated in Fig. 4, comprises: a cylinder 21; a plunger 22 which is inserted so as
to slide within the cylinder 21, thereby performing a linearly reciprocating motion; an upper
side core 23 and a lower side core 24 which are fitted around the periphery of the cylinder
21; an electromagnetic coil 26 wound onto a bobbin 25 which is fitted around the periphery
of the upper side core 23 and the lower side core 24; an exterior case 27 formed from a
resinous material or the like for covering the periphery of the electromagnetic coil 26; a
bracket 28 and a latching plate 29 which are mounted around the exterior case 27 as is
illustrated in Figs. 6 and 7; and a wave washer 30 which serves as adjusting means,
disposed between the bobbin 25 and latching plate 29, and so on.
An end face wall 23a is formed on the upper end portion of the upper side core 23,
and a through hole 23a' is formed in the center of this end face wall 23a, connecting to the
outside. Further, a coil spring 31 is disposed between the end face wall 23a and the plunger
22.
A channel member 32, which is formed with a channel 32a which has a suction port
32a' on its lower end, is fitted onto the lower end portion of the lower side core 24. The
channel member 32 supports a check valve 33 for opening and closing the channel 32a in a
state in which this check valve 33 is urged in the closing direction by a spring 34. A coil
spring 35 is disposed between the top end surface of the channel member 32 and the
plunger 22.
A coupling member 36 which serves as a second linking portion, and which is formed
with a channel 36a having a discharge port 36a' on its tip end, is linked to the side face
portion of the lower side core 24, extending in a direction which is perpendicular to the
direction of reciprocating motion L1 of the plunger 22. The coupling member 36 supports a
check valve 37 for opening and closing the channel 36a in a state in which this check valve
37 is urged in the closing direction by a spring 38.
Further, a filter 40 is attached to the lower end portion of the lower side core 24 (in
other words, around the suction port 32a'). The filter 40 is formed by a filter main body 41,
a fitting tube portion 42 for connecting the filter main body 41 to the lower side core 24, and
a protruding piece 43 which protrudes outward in a diametrical direction from the periphery
of the fitting tube portion 42.
A female-type electrical connector 39 which serves as a first linking portion, protrudes
in a direction perpendicular to the direction of reciprocating motion L1 of the plunger 22,
and has a linking hole 39a, is formed on the upper side face of the exterior case 27. The
electrical connector 39 supports a terminal 26a serving as the electrical wiring of the
electromagnetic coil 26 in a state in which this terminal 26a is exposed within the linking
hole 39a.
As is illustrated in Figs. 6 and 7, the bracket 28 forms an inverse U shape, and has
two engaging pieces 28a which extend from one side face thereof toward the direction H1
which is perpendicular to the direction of reciprocating motion L1. A substantially
rectangular latching hole 28a' is formed in each of the latching pieces 28a. Further, the
bracket 28 is linked to the latching plate 29 via a latching claw 28c.
In other words, the pump main body, which is directly connected to the fuel pressure
regulator 50, is formed by the exterior case 27 which forms the electrical connector 39, the
channel member 32 and the lower side core 24 which demarcate the suction port 32a', the
coupling member 36 which demarcates the discharge port 36a', the bracket 28, and so on.
As concerns an explanation of the operation of the plunger pump 20, first, when the
plunger 22 moves upward in the direction of reciprocating motion L1 due to the power
supply to the electromagnetic coil 26, the check valve 33 opens in resistance to the urging
force of the spring 34 due to pressure difference. Then, fuel is sucked up from the suction
port 32a and flows into a space S1.
Then, when the power supply to the electromagnetic coil 26 is cut, the plunger 22
stops and the check valve 33 closes. Simultaneously, the plunger 22 moves downward in
the direction of reciprocating motion L1 due to the urging force of the coil springs 31 and 35,
thereby compressing the fuel in the space S1. When the fuel is compressed beyond a
predetermined pressure, the check valve 37 opens in resistance to the urging force of the
spring 38, and the compressed fuel is discharged from the discharge port 36a'. Then, the
urging forces of the coil springs 31 and 35 balance, whereupon the plunger 22 stops.
Note that the above describes a basic operation in which the plunger 22 performs
one reciprocal motion; however, during normal operations, the plunger 22 performs
continuous reciprocal motions, whereby fuel is continuously suctioned and pressure fed in
prescribed volumes according to these movement strokes.
The fuel pressure regulator 50 is an inlet control type regulator for adjusting the
pressure of fuel (fuel pressure) upstream of the injector 4 and, as is illustrated in Fig. 4,
comprises: a regulator main body 53, in which a horizontal tube portion 51 which
demarcates an influx channel 51a and a vertical tube portion 52 which demarcates a supply
channel 52a, and so on, are molded using a resinous material; a mounting flange portion 54
which is formed integrally with the upper end portion of the regulator main body 53; an
adjustment valve 55 disposed between the influx channel 51a and the supply channel 52a
for opening and dosing both of these channels and thereby adjusting the fuel pressure; and
a support bracket 56 which is formed integrally with the regulator main body 53 as
illustrated in Fig. 6, and so on.
As is illustrated in Fig. 4, the influx channel 51a is formed in the horizontal tube
portion 51, and the coupling member 36 of the plunger pump 20 is fitted into the opening of
the influx channel 51a, thereby functioning as the second connecting portion. Further, the
horizontal tube portion 51 supports a check valve 57 for opening and closing the influx
channel 51a in a state in which this check valve 57 is driven to the closing direction by a
spring 58. The check valve 57 and the spring 58 constitute one part of the adjustment valve
55.
Further, an inserting hole 65 for inserting the protruding piece 43 of the filter 40 is
formed on the lower side of the horizontal tube portion 51.
As is illustrated in Fig. 4, a diaphragm 59 which constitutes one part of the
adjustment valve 55 is disposed in the space in which the horizontally extending influx
channel 51a and the vertically extending supply channel 52a intersect. The diaphragm 59 is
formed from a diaphragm main body 59a, a spring 59b, and a cover cap 59c with a through
hole 59c'. One part of the diaphragm main body 59a abuts against a needle 57a of the
check valve 57, whereby the check valve 57 is caused to open in resistance to the urging
force of the spring 58.
In other words, the adjustment valve 55 which adjusts the pressure of the fuel in the
supply channel 52a and the influx channel 51a is constituted by the check valve (needle 57a)
57, spring 58, and diaphragm 59. To explain the operation of the adjustment valve 55,
when the pressure inside the supply channel 52a or the diaphragm chamber 55a reaches or
exceeds a predetermined pressure, the check valve 57 closes the influx channel 51a by
means of the urging force of the spring 58.
In this state, when the fuel pressure inside the supply channel 52a reaches or falls
below a predetermined pressure, the diaphragm 59 is activated by the urging force of the
spring 59b to push down the needle 57a and open the check valve 57.
As a result, the fuel on the upstream side of the influx channel 51a flows into the
diaphragm chamber 55a and is led to the supply channel 52a. Then, when the pressure of
the fuel inside the supply channel 52a reaches or exceeds a predetermined pressure, the
diaphragm 59 is activated by this pressure to close the check valve 57.
A connecting portion 60 for connecting the connector of the supply pipe 5 is formed
at the top end portion of the supply channel 52a, and a connector 61 for making an
electrical connection and having a terminal 61a exposed in its interior space is formed to the
side of the connecting portion 60. Further, a male-type electrical connector 62 is formed on
the lower side of the mounting flange portion 54 so as to protrude in the horizontal
direction.
The electrical connector 62 has a female-type terminal 62a which is connected from
the terminal 61a via electrical wiring 61b buried inside the regulator main body 51. The
terminal 26a is connected to the female-type terminal 62a by fitting the electrical connector
62 into the electrical connector 39 of the plunger pump 20.
As is illustrated in Fig. 5, a channel 63 and a damper chamber 64 which are linked
to the supply chamber 52a are formed in the regulator main body 53. Further, a pulsation
damper 70 for absorbing and thereby dampening fuel pulsations (pressure fluctuations) is
housed in the damper chamber 64. The pulsation damper 70 is a hollow body which is
capable of altering its form through elasticity. A latticed framework of supports 71 is
provided in the interior of the pulsation damper 70, and a rubber shape-altering film 72 is
mounted over the exterior of the supports 71.
Accordingly, when a pulsation (pressure fluctuation) occurs in the fuel inside the
supply channel 52a, the pressure inside the damper chamber 64 also fluctuates, whereby the
volume occupied (demarcated) by the shape-altering film 72 increases or decreases in
accordance with the pressure of this fluctuation. Thus, pulsations generated in the fuel are
efficiently absorbed and dampened.
Here, the direction of extension L2 of the supply channel 52a and the direction of
extension L3 of the damper chamber 64 (pulsation damper 70) are formed so as to be
substantially parallel, and hence the two can be placed close to each other and integrated,
thereby contributing to the narrowing and size reduction of the device.
As is illustrated in Figs. 6 and 7, two support brackets 56 are formed extending
from the regulator main body 53 in the horizontal direction H1 and facing each other.
Flexible pieces 56a which are demarcated by inverted "C"-shaped helical grooves are also
formed, and latching claws 56a' are formed facing inward on the tip end portions of these
flexible pieces 56a.
Further, the width of the inner walls W1 of the two support brackets 56 is formed
so as to be substantially equal to the width of the outer walls W2 of the two engaging pieces
28a formed on the bracket 28. Thus, when the engaging pieces 28a are inserted inside the
support brackets 56, the flexible pieces 56a are pushed so as to bend outward, and when
the latching claws 56a' enter the latching holes 28b, a secure snap-fit connection is made
between the two bodies.
In other words, by means of a simple one-touch operation, namely, pushing in the
engaging pieces 28a of the plunger pump 20, the two bodies can be connected, and hence
special connecting components such as fastening screws become unnecessary, and the
structure of the device is simplified, reduced in size, and reduced in weight. Moreover, the
two bodies can also be separated by means of a simple operation of opening the flexible
parts 56a outward so that the latching claws 56a' are separated from the latching holes 28b.
As is illustrated in Fig. 6, the assembly of the plunger pump 20 and the fuel
pressure regulator 50 begins with the attachment of the filter 40 to the plunger pump 20.
Next, the two bodies are brought into proximity in the horizontal direction H1 which
is perpendicular to the direction of reciprocating motion L1 and the direction of extension L2.
Then the female-type electrical connector 39 and male-type electrical connector 62, which
serve as the first connecting portion, are caused to engage, and the male-type coupling
member 36 and the female-type horizontal tube portion 51, which serve as the second
connecting portion, are also caused to engage.
At this time, the protruding part 43 is assembled by insertion into the inserting hole
65. Furthermore, the flexible pieces 56a (latching claws 56a') of the support brackets 56 are
caused to latch with the latching holes 28b of the engaging pieces 28a to conclude the snap-fit
connection.
In this case, if the spacing (pitch) between the electrical connector 39 and the
coupling member 36, and the spacing (pitch) between the electrical connector 62 and the
horizontal tube portion 51 do not match, and especially if the pitch of the former is larger,
the amount of shape alteration of the wave washer 30 (which serves as the adjustment
means) can be appropriately adjusted such that the pitch is aligned, whereby assembly can
be performed with ease.
Furthermore, when the two bodies are in an assembled state, the protruding piece
43 of the filter 40 is in a state of insertion inside the inserting hole 65, and therefore even if
the coupling force of the fitting tube portion 42 were to weaken, the filter 40 could be
prevented from falling off the plunger pump 20. As a result, special fastening components
such as fastening screws are not used, and the fuel supply device 10 can be dealt with as a
modular item with the filter 40 built-in.
Moreover, when the plunger pump 20 and the fuel pressure regulator 50 are
coupled together, the direction of reciprocating motion L1 of the plunger 22 and the
direction of extension L2 of the supply channel 52a are formed so as to be substantially
parallel. More specifically, the plunger pump 20 itself forms a profile elongated in the
direction of reciprocating motion L1 of the plunger 22, and the regulator main body 53 itself
of the fuel pressure regulator 50 is formed lengthwise in the direction of extension L2 of the
supply channel 52a, and thus both directions L1 and L2 become substantially parallel. As a
result, the constituent components can be integrated in the central portion, thus enabling
the formation of a narrow profile, which in turn enables reductions in the width and size of
the fuel supply device 10.
Furthermore, by placing the plunger pump 20 vertically, disposing the suction port
32a' and filter 40 at the lower end portion thereof, providing the discharge port 36a' on the
side face near the lower end portion thereof, forming the influx channel 51a which connects
to the discharge port 36a' horizontally, and disposing the adjustment valve 55 in the region
of intersection between the influx channel 51a and the supply channel 52a, the fuel suction
and pressure feeding functions and the pressure adjusting function can be securely
maintained while the length (height) H of the device can be kept as low as possible and the
fuel supply device 10 can be finished as a compact (small size) modular item.
As for the connecting portions which connect the plunger pump 20 and the fuel
pressure regulator 50, the first connecting portion doubles as the electrical connectors 39
and 62, which connect the electrical wiring, and the second connecting portion doubles as a
linking channel linking the discharge port 36a' and the influx channel 51a, and hence the
structure of the device is simplified when compared with a case in which connecting portions
are provided as separate entities. Moreover, a snap-fit coupling is employed as a connecting
portion, and hence the two bodies can be coupled more securely when compared with a
case in which the first and second connecting portions alone are coupled.
Fig. 8 shows another embodiment in which the position of attachment of the
pulsation damper 70 has been altered. Note that identical structures from the
aforementioned embodiment have been assigned identical notations and explanations
thereof have been omitted.
In this embodiment, as is illustrated in Fig. 8, the channel 63 which leads into the
damper chamber 64 is formed upstream, rather than downstream of the adjustment valve
55, or in other words, so as to connect with the influx channel 51a.
Consequently, when a pulsation (pressure fluctuation) occurs in the fuel inside the
influx channel 51a, the pressure inside the damper chamber 64 also fluctuates, whereby the
volume occupied (demarcated) by the shape-altering film 72 increases or decreases in
accordance with the pressure of this fluctuation. As a result, pulsations generated in the fuel
can be absorbed and dampened more efficiently than in the case shown in Fig. 5.
In the aforementioned embodiments, a case was described in which the fuel supply
device 10 of the present invention is disposed inside the fuel tank 1 of a two-wheeled
vehicle. However, the present invention is not limited to this case, and may be satisfactorily
applied to other vehicles such as three-wheeled or four-wheeled carts, lawnmowers,
multipurpose engines such as power generators, or any vehicles which are equipped with a
small displacement engine and a comparatively small fuel tank, for example marine vessels
such as leisure boats, snowmobiles and so on.
As described above, according to the fuel supply device of the present invention, a
plunger pump equipped with a plunger for suctioning and pressure feeding fuel by means of
a linealy reciprocating motion, and a fuel pressure regulator which is linked to the discharge
port of this plunger pump, and which adjusts the pressure at the time when fuel is supplied
toward the injector, are integrally coupled to form a module. As a result, a fuel supply
device with an overall small (compact) size, and one which is particularly suited to being
disposed in a small fuel tank of a two-wheeled vehicle or the like, can be provided.
In particular, by forming the direction of reciprocating motion of the plunger and
the direction of extension of the supply channel of the fuel pressure regulator so as to be
substantially parallel, the two bodies can be effectively integrated so that the size of the
entire device can be further reduced (compacted).
Furthermore, by disposing the filter on the lower side of the device, the pump main
body and regulator main body in an intermediate position, and the mounting flange portion
on the upper side of the device, the device can be easily disposed inside a fuel tank simply
by, for example, fixing the mounting flange portion to the wall of the fuel tank.
Furthermore, the device can be dealt with as a modular item with a filter included.
Moreover, by making the pump main body of the plunger pump and the regulator
main body of the fuel pressure regulator connectable using the first connecting portion and
the second connecting portion, and by having the first connecting portion and the second
connecting portion function respectively as an electrical connection and a linking channel,
assembly is ameliorated and secured, and the structure of the device is simplified in
comparison with a case in which entities that function merely as connecting portions are
provided separately. Also, by employing a snap-fit connection, the two bodies can be
securely connected with a simple one-touch operation, and since special connecting
components such as fastening screws are unnecessary, the structure can be simplified,
reduced in size and reduced in weight.
Furthermore, by employing adjusting means capable of adjusting the spacing
between the first connecting portion and the second connecting portion, the two bodies can
be easily assembled even if pitch misalignment occurs.