FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&d
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10, rule 13)
“ON-VEHICLE TRANSFORMER AND OIL FLOW
RELAY”
MITSUBISHI ELECTRIC CORPORATION, a Of 7-3,
Marunouchi 2-chome, Chiyoda-ku, Tokyo 1008310
The following specification particularly describes the invention and the manner in
which it is to be performed.

DESCRIPTION
TITLE OF INVENTION
On-Vehicle Transformer and Oil Flow Relay

TECHNICAL FIELD
[0001] The present invention relates to an on-vehicle transformer and an oil flow
relay.

BACKGROUND ART
[0002] Japanese Patent Laying-Open No. 2004-363253 (PTL 1) is a prior art
10 document that discloses a configuration of an on-vehicle transformer. The onvehicle
transformer described in PTL 1 includes a pipe, a transformer body and a
plurality of coolers. The pipe forms a circulation path for refrigerant. The
transformer body is arranged at some midpoint in a path of the pipe to house
refrigerant together with a winding. The plurality of coolers are arranged in a
distributed manner at some midpoint in the path of the pipe to cool the refrigerant
by heat exchange with the air. The plurality of coolers are arranged in a
distributed manner under a vehicle floor which is a passage for traveling wind.
CITATION LIST

PATENT LITERATURE
[0003] PTL 1: Japanese Patent Laying-Open No. 2004-363253
SUMMARY OF INVENTION
TECHNICAL PROBLEM
[0004] In the on-vehicle transformer, when an insulating oil is used as the
refrigerant, an oil flow relay is placed in a connection pipe through which the
insulating oil flows. In order to prevent insufficient cooling of the transformer
body, the oil flow relay operates when a flow rate of the insulating oil becomes
equal to or less than a threshold value.
[0005] Furthermore, in the on-vehicle transformer, an insulating oil having small
environmental load and high dependence of viscosity on temperature may be used
in some cases. The insulating oil having high dependence of viscosity on
temperature increases in viscosity and decreases in fluidity as the temperature
becomes lower. Therefore, when the above-described insulating oil is used, the
oil flow relay may erroneously detect an abnormality of the on-vehicle
transformer at low temperature.
[0006] In order to reduce or prevent erroneous detection by the oil flow relay, the
conventional on-vehicle transformer is provided with a thermometer to perform
control using a value measured by the thermometer.
[0007] The present invention has been made in view of the above-described
problem, and an object of the present invention is to provide an on-vehicle
transformer and an oil flow relay that can reduce or prevent erroneous detection
by the oil flow relay at low temperature, without providing a thermometer.
SOLUTION TO PROBLEM
[0008] An on-vehicle transformer based on the present invention includes: a
transformer body; a tank; an insulating oil; a cooler; a connection pipe; a pump;
and an oil flow relay. The tank houses the transformer body. The insulating oil
is filled into the tank to cool the transformer body. The cooler cools the
insulating oil. The connection pipe connects the tank to the cooler. The pump
is placed in the connection pipe to circulate the insulating oil between the tank and
the cooler. The oil flow relay is placed on a discharge portion side of the pump
in the connection pipe. The oil flow relay includes: a blade member; a movable
contactor; and a fixed contact. The blade member is arranged in the connection
pipe and supported so as to be rotatable about a central axis orthogonal to the
connection pipe. The movable contactor has a movable contact and rotates about
the central axis with rotation of the blade member. The fixed contact is located
on a rotation path of the movable contact. The oil flow relay is configured such
that an operating flow rate in the oil flow relay becomes smaller as a temperature
of the insulating oil becomes lower, the operating flow rate being a flow rate of
the insulating oil flowing through the connection pipe when the movable contact
and the fixed contact come into contact with each other.
ADVANTAGEOUS EFFECTS OF INVENTION

[0009] According to the present invention, the oil flow relay is configured such
that the operating flow rate of the oil flow relay becomes smaller as the
temperature of the insulating oil flowing through the oil flow relay becomes lower,
and thus, it is possible to reduce or prevent erroneous detection by the oil flow
relay at low temperature, without providing 5 a thermometer.

BRIEF DESCRIPTION OF DRAWINGS
[0010] Fig. 1 is a system diagram showing a configuration of an on-vehicle
transformer according to a first embodiment of the present invention.
Fig. 2 is a perspective view showing a state of an oil flow relay placed in
the on-vehicle transformer according to the first embodiment of the present
invention at high temperature and in a pump stop state.
Fig. 3 is a perspective view showing a state of the oil flow relay placed in
the on-vehicle transformer according to the first embodiment of the present
invention at high temperature and in a pump operation state.
Fig. 4 is a schematic view when an internal structure of the oil flow relay
according to the first embodiment of the present invention is viewed from a
central axis direction.
Fig. 5 is a perspective view showing a shape of a blade member of the oil
flow relay according to the first embodiment of the present invention at high
temperature.
Fig. 6 is a perspective view showing a state of the oil flow relay placed in
the on-vehicle transformer according to the first embodiment of the present
invention at low temperature and in the pump stop state.
Fig. 7 is a graph showing transition of each of a flow rate of an insulating
oil in a connection pipe and an operating flow rate of the oil flow relay with
respect to a temperature of the insulating oil flowing through the connection pipe.
Fig. 8 is a schematic view showing a compressive stress generated
between a shaft portion and a bearing portion at high temperature in an oil flow
relay according to a second embodiment of the present invention, when viewed
from the central axis direction.
Fig. 9 is a schematic view showing a compressive stress generated
between the shaft portion and the bearing portion at low temperature in the oil
flow relay according to the second embodiment of the present invention, when
viewed from the central axis direction.
Fig. 10 shows a movable contactor and a fixed contact at 5 high temperature,
when a flow rate of an insulating oil flowing through a connection pipe is equal to
an operating flow rate, in an oil flow relay according to a third embodiment of the
present invention.
Fig. 11 shows the movable contactor and the fixed contact at low
temperature, when the flow rate of the insulating oil flowing through the
connection pipe is equal to the operating flow rate at high temperature shown in
Fig. 10, in the oil flow relay according to the third embodiment of the present
invention.
Fig. 12 is a perspective view showing a state in which the flow rate of the
insulating oil flowing through the connection pipe is equal to an operating flow
rate at low temperature in the oil flow relay according to the third embodiment of
the present invention.

DESCRIPTION OF EMBODIMENTS
[0011] An on-vehicle transformer and an oil flow relay according to each
20 embodiment of the present invention will be described hereinafter with reference
to the drawings. In the description of the embodiments below, the same or
corresponding portions in the drawings are denoted by the same reference
characters and description thereof will not be repeated.
[0012] First Embodiment
Fig. 1 is a system diagram showing a configuration of an on-vehicle
transformer according to a first embodiment of the present invention. Fig. 2 is a
perspective view showing a state of an oil flow relay placed in the on-vehicle
transformer according to the first embodiment of the present invention at high
temperature and in a pump stop state. Fig. 3 is a perspective view showing a
state of the oil flow relay placed in the on-vehicle transformer according to the
first embodiment of the present invention at high temperature and in a pump
operation state. Fig. 4 is a schematic view when an internal structure of the oil
flow relay according to the first embodiment of the present invention is viewed
from a central axis direction. Fig. 5 is a perspective view showing a shape of a
blade member of the oil flow relay according to the first 5 embodiment of the
present invention at high temperature. Fig. 6 is a perspective view showing a
state of the oil flow relay placed in the on-vehicle transformer according to the
first embodiment of the present invention at low temperature and in the pump stop
state.
[0013] In the description of the embodiments below, "at high temperature" refers
to the time when a temperature of an insulating oil flowing through the oil flow
relay is relatively high, and "at low temperature" refers to the time when the
temperature of the insulating oil flowing through the oil flow relay is relatively
low.
[0014] As shown in Fig. 1, an on-vehicle transformer 100 according to the first
embodiment of the present invention includes a transformer body 1, a tank 110, an
insulating oil 120, a cooler 130, a connection pipe 140, a pump 150, and an oil
flow relay 160.
[0015] On-vehicle transformer 100 according to the present embodiment is
mounted on, for example, a railway vehicle. The operation of on-vehicle
transformer 100 mounted on a railway vehicle stops at a higher frequency than a
power transformer. Therefore, in on-vehicle transformer 100, it is important to
reduce or prevent erroneous detection by the oil flow relay at the start of operation,
i.e., at low temperature.
[0016] When on-vehicle transformer 100 is mounted on a railway vehicle,
transformer body 1 converts a high voltage current supplied from an overhead
wire into a low voltage current and supplies the current to a motor, an airconditioning
facility or the like used in the railway vehicle. Transformer body 1
is housed in tank 110.
[0017] Insulating oil 120 is filled into tank 110 to cool transformer body 1.
Since on-vehicle transformer 100 may be mounted on a railway vehicle, insulating
oil 120 is preferably a flame-resistant insulating oil from a safety point of view.
Examples of insulating oil 120 include an ester oil that is a vegetable oil, a
silicone oil and the like. The number of users who select the ester oil as
insulating oil 120 is on the increase. The ester oil has higher 5 dependence of
viscosity on temperature than that of the silicone oil.
[0018] Insulating oil 120 having high dependence of viscosity on temperature,
such as the ester oil, has a remarkable tendency of decreasing in viscosity as the
temperature becomes higher, and increasing in viscosity as the temperature
becomes lower. Therefore, in connection pipe 140, insulating oil 120 having
high dependence of viscosity on temperature, such as the ester oil, decreases in
viscosity and increases in fluidity as the temperature becomes higher, and
increases in viscosity and decreases in fluidity as the temperature becomes lower.
[0019] Cooler 130 cools insulating oil 120. Examples of cooler 130 include an
air-cooled type cooler and the like, although not particularly limited.
[0020] Connection pipe 140 connects tank 110 to cooler 130. Connection pipe
140 is composed of a first connection pipe for conveying insulating oil 120 from
cooler 130 to tank 110, and a second connection pipe for conveying insulating oil
120 from tank 110 to cooler 130.
[0021] Pump 150 is placed in connection pipe 140 to circulate insulating oil 120
between tank 110 and cooler 130. In the present embodiment, pump 150 is
placed in the second connection pipe.
[0022] Insulating oil 120 having an increased temperature as a result of cooling of
transformer body 1 housed in tank 110 is conveyed from tank 110 through the
second connection pipe of connection pipe 140 to cooler 130, where insulating oil
120 is cooled. Cooled insulating oil 120 is conveyed from cooler 130 through
the first connection pipe of connection pipe 140 to tank 110, where insulating oil
120 cools transformer body 1 again.
[0023] Oil flow relay 160 is placed on the discharge portion side of pump 150 in
connection pipe 140. In the present embodiment, oil flow relay 160 is placed in
the second connection pipe of connection pipe 140. Oil flow relay 160 is
provided between pump 150 and cooler 130.
[0024] As shown in Figs. 2 to 4, oil flow relay 160 according to the first
embodiment of the present invention includes a blade member 162, a movable
contactor 164 and a 5 fixed contact 166.
[0025] As shown in Figs. 2 and 3, blade member 162 is arranged in the pipe in
which insulating oil 120 flows, and is supported so as to be rotatable about a
central axis C orthogonal to the pipe. In on-vehicle transformer 100 according to
the first embodiment, blade member 162 is arranged in connection pipe 140 and
supported so as to be rotatable about central axis C orthogonal to connection pipe
140. Although Fig. 2 shows a direction of a flow of insulating oil 120 by an
arrow, insulating oil 120 is not flowing in the state shown in Fig. 2.
[0026] Blade member 162 includes a plate-shaped portion extending from central
axis C in a radial direction, and a main surface of the plate-shaped portion has a
substantially rectangular outer shape. A radially outward edge portion of the
plate-shaped portion is curved radially outward in the shape of an arc.
[0027] As shown in Fig. 3, when a flow rate of insulating oil 120 becomes equal
to or more than a predetermined rate, blade member 162 rotates about abovedescribed
central axis C, and thus, the plate-shaped portion of blade member 162
in a pump operation state becomes substantially horizontal along a direction of
extension of the pipe in which oil flow relay 160 is placed, i.e., connection pipe
140.
[0028] As shown in Fig. 4, inside oil flow relay 160, movable contactor 164 has a
movable contact 164c and rotates about above-described central axis C with
rotation of blade member 162. A hollow portion 168 is formed in oil flow relay
160 such that movable contactor 164 can rotate.
[0029] Fixed contact 166 is located on a rotation path of movable contact 164c.
In Fig. 4, a position of movable contactor 164 at high temperature and during
operation of pump 150 is indicated by a solid line, and each of a position of
movable contactor 164 when movable contact 164c and fixed contact 166 come
into contact with each other and a position of movable contactor 164 when pump
150 is not operating is indicated by a dotted line.
[0030] As shown in Fig. 5, in the present embodiment, blade member 162
includes a first plate-shaped portion 162a and a second plate-shaped portion 162b
as the plate-shaped portion. In the present embodiment, 5 first plate-shaped
portion 162a and second plate-shaped portion 162b have substantially the same
shape at high temperature. However, first plate-shaped portion 162a and second
plate-shaped portion 162b may have different shapes.
[0031] First plate-shaped portion 162a extends from above-described central axis
C in a radial direction of above-described central axis C. At high temperature, a
main surface of first plate-shaped portion 162a has a substantially rectangular
outer shape. A radially outward edge portion of first plate-shaped portion 162a
is curved radially outward.
[0032] Second plate-shaped portion 162b extends from above-described central
axis C in the above-described radial direction and is joined to the downstream side
of first plate-shaped portion 162a in the direction of the flow of insulating oil 120.
That is, second plate-shaped portion 162b extends from above-described central
axis C in the above-described radial direction and is joined to a side of first plateshaped
portion 162a opposite to the pump 150 side.
[0033] At high temperature, a main surface of second plate-shaped portion 162b
has a substantially rectangular outer shape. A radially outward edge portion of
second plate-shaped portion 162b is curved radially outward.
[0034] Blade member 162 further has a shaft portion 162c extending on abovedescribed
central axis C. Blade member 162 may be formed by joining shaft
portion 162c to each of first plate-shaped portion 162a and second plate-shaped
portion 162b. In addition, shaft portion 162c and one of first plate-shaped
portion 162a and second plate-shaped portion 162b may be formed as an
integrated member.
[0035] Blade member 162 is supported by a bearing portion 163 that is in sliding
contact with shaft portion 162c. In the present embodiment, bearing portion 163
has a cylindrical shape. However, the shape of bearing portion 163 is not
particularly limited as long as bearing portion 163 has a shape of being in sliding
contact with shaft portion 162c. In addition, as shown in Fig. 2, bearing portion
163 is exposed to the outside of oil flow relay 160. However, bearing portion
163 may be housed in oil 5 flow relay 160.
[0036] First plate-shaped portion 162a is made of a material having a thermal
expansion coefficient higher than that of second plate-shaped portion 162b.
Although each of first plate-shaped portion 162a and second plate-shaped portion
162b is made of a metal material or a resin material, the present invention is not
limited thereto. When first plate-shaped portion 162a and second plate-shaped
portion 162b are made of metal materials having different thermal expansion
coefficients, a so-called bimetal is formed.
[0037] Since first plate-shaped portion 162a is made of a material having a
thermal expansion coefficient higher than that of second plate-shaped portion
162b, first plate-shaped portion 162a contracts more greatly than second plateshaped
portion 162b at low temperature as shown in Fig. 6, and thus, blade
member 162 is curved to protrude to the second plate-shaped portion 162b side.
Therefore, as the temperature becomes lower, blade member 162 is more likely to
receive the rotational force from flowing insulating oil 120. Thus, when the flow
rate is small due to an increase in viscosity of insulating oil 120 at low
temperature, the rotational force of blade member 162 can be supplemented.
[0038] With the above-described configuration, oil flow relay 160 according to
the present embodiment is configured such that an operating flow rate of oil flow
relay 160 becomes smaller as the temperature of insulating oil 120 becomes lower,
the operating flow rate being a flow rate of insulating oil 120 flowing through the
above-described pipe when movable contact 164c and fixed contact 166 come into
contact with each other. That is, oil flow relay 160 in on-vehicle transformer 100
according to the present embodiment is configured such that the operating flow
rate of oil flow relay 160 becomes smaller as the temperature of insulating oil 120
becomes lower, the operating flow rate being a flow rate of insulating oil 120

flowing through connection pipe 140 when movable contact 164c and fixed
contact 166 come into contact with each other.
[0039] Specifically, as the temperature becomes lower, blade member 162 is
curved and is more likely to receive the rotational force from flowing insulating
oil 120, and thus, the rotational force of blade member 162 obtained from
insulating oil 120 having a decreased flow rate due to an increase in viscosity can
be supplemented and the flow rate of insulating oil 120 flowing through
connection pipe 140 when movable contact 164c and fixed contact 166 come into
contact with each other can be reduced. That is, the operating flow rate of oil
flow relay 160 can be made smaller as the temperature of insulating oil 120
becomes lower.
[0040] Now, description will be given of an experiment example performed to
check a correlation between the operating flow rate of oil flow relay 160
according to the present embodiment and the temperature of the insulating oil.
[0041] Fig. 7 is a graph showing transition of each of the flow rate of the
insulating oil in the connection pipe and the operating flow rate of the oil flow
relay with respect to the temperature of the insulating oil flowing through the
connection pipe. In Fig. 7, the horizontal axis represents the temperature (C) of
the insulating oil, and the vertical axis represents each flow rate (L/min). During
the experiment, the operation condition of pump 150 is kept constant and pump
150 operates normally.
[0042] As shown in Fig. 7, the operating flow rate of oil flow relay 160 became
smaller as the temperature of insulating oil 120 became lower. It could be
confirmed from the result of the experiment that, in on-vehicle transformer 100
according to the present embodiment, when pump 150 operates normally and the
temperature of insulating oil 120 is equal to or higher than 20C, the flow rate of
insulating oil 120 in connection pipe 140 does not fall below the operating flow
rate of oil flow relay 160, and thus, erroneous detection of an abnormality of onvehicle
transformer 100 by oil flow relay 160 can be reduced or prevented.
[0043] As described above, on-vehicle transformer 100 and oil flow relay 160
according to the present embodiment are configured such that the operating flow
rate of oil flow relay 160 becomes smaller as the temperature of insulating oil 120
becomes lower. Therefore, on-vehicle transformer 100 and oil flow relay 160
according to the present embodiment can reduce or prevent erroneous detection by
the oil flow relay at low temperature, without providing a thermometer. This can
eliminate the need for providing placement space for a thermometer, which can
lead to a reduction in size of on-vehicle transformer 100.
[0044] Furthermore, a railway vehicle on which on-vehicle transformer 100
according to the present embodiment having reduced size and mass is mounted
can travel faster and can travel with a larger number of cargo and passengers.
[0045] In the present embodiment, first plate-shaped portion 162a is made of a
material having a thermal expansion coefficient higher than that of second plateshaped
portion 162b. Therefore, when the temperature of insulating oil 120
decreases, blade member 162 can be deformed to receive the greater rotational
force from the flow of insulating oil 120. Thus, the operating flow rate of oil
flow relay 160 can be made smaller as the temperature of insulating oil 120
becomes lower.
[0046] Second Embodiment
An on-vehicle transformer and an oil flow relay according to a second
embodiment of the present invention will be described below. The on-vehicle
transformer and the oil flow relay according to the second embodiment of the
present invention are different from on-vehicle transformer 100 and oil flow relay
160 according to the first embodiment of the present invention mainly in terms of
the feature for making the operating flow rate smaller as the temperature of the
insulating oil becomes lower. Therefore, description of the features similar to
those of on-vehicle transformer 100 and oil flow relay 160 according to the first
embodiment of the present invention will not be repeated.
[0047] Fig. 8 is a schematic view showing a compressive stress generated
between the shaft portion and the bearing portion at high temperature in the oil
flow relay according to the second embodiment of the present invention, when
viewed from the central axis direction. Fig. 9 is a schematic view showing a
compressive stress generated between the shaft portion and the bearing portion at
low temperature in the oil flow relay according to the second embodiment of the
present invention, when viewed from the central axis direction.
[0048] In the on-vehicle transformer and the oil flow relay 5 according to the
second embodiment of the present invention, the plate-shaped portions of blade
member 162 are formed as an integrated member.
[0049] In the on-vehicle transformer and the oil flow relay according to the
second embodiment of the present invention, shaft portion 162c is made of a
material having a thermal expansion coefficient higher than that of bearing portion
163. Although each of shaft portion 162c and bearing portion 163 is made of a
metal material or a resin material, the material of each of shaft portion 162c and
bearing portion 163 is not limited thereto.
[0050] In the present embodiment, shaft portion 162c is made of a material having
15 a thermal expansion coefficient higher than that of bearing portion 163.
Therefore, shaft portion 162c contracts more greatly than bearing portion 163 at
low temperature.
[0051] As a result, the compressive stress generated between shaft portion 162c
and bearing portion 163 at low temperature shown in Fig. 9 is smaller than the
compressive stress generated between shaft portion 162c and bearing portion 163
at high temperature shown in Fig. 8. Therefore, the rotational force necessary for
rotation of blade member 162 is reduced as the temperature becomes lower.
[0052] With the above-described configuration, the rotational force necessary for
rotation of blade member 162 can be reduced as the temperature becomes lower.
Therefore, even when the rotational force of blade member 162 obtained from
insulating oil 120 having a decreased flow rate due to an increase in viscosity is
reduced, blade member 162 can rotate. As a result, the flow rate of insulating oil
120 flowing through connection pipe 140 when movable contact 164c and fixed
contact 166 come into contact with each other can be reduced. That is, the
operating flow rate of the oil flow relay can be made smaller as the temperature of
insulating oil 120 becomes lower.
[0053] In the present embodiment, shaft portion 162c is made of a material having
a thermal expansion coefficient higher than that of bearing portion 163.
Therefore, when the temperature of insulating oil 120 decreases, the rotational
force necessary for rotation of blade member 162 can be reduced. 5 Thus, the
operating flow rate of the oil flow relay can be made smaller as the temperature of
insulating oil 120 becomes lower.
[0054] Third Embodiment
An on-vehicle transformer and an oil flow relay according to a third
embodiment of the present invention will be described below. The on-vehicle
transformer and the oil flow relay according to the third embodiment of the
present invention are different from on-vehicle transformer 100 and oil flow relay
160 according to the first embodiment of the present invention mainly in terms of
the feature for making the operating flow rate smaller as the temperature of the
insulating oil becomes lower. Therefore, description of the features similar to
those of on-vehicle transformer 100 and oil flow relay 160 according to the first
embodiment of the present invention will not be repeated.
[0055] Fig. 10 shows the movable contactor and the fixed contact at high
temperature, when the flow rate of the insulating oil flowing through the
connection pipe is equal to an operating flow rate, in the oil flow relay according
to the third embodiment of the present invention. Fig. 11 shows the movable
contactor and the fixed contact at low temperature, when the flow rate of the
insulating oil flowing through the connection pipe is equal to the operating flow
rate at high temperature shown in Fig. 10, in the oil flow relay according to the
third embodiment of the present invention. Fig. 12 is a perspective view
showing a state in which the flow rate of the insulating oil flowing through the
connection pipe is equal to an operating flow rate at low temperature in the oil
flow relay according to the third embodiment of the present invention.
[0056] In the on-vehicle transformer and the oil flow relay according to the third
embodiment of the present invention, the plate-shaped portions of blade member
162 are formed as an integrated member.
[0057] As shown in Figs. 10 and 11, in the on-vehicle transformer and the oil flow
relay according to the third embodiment, movable contactor 164 includes a first
piece 164a and a second piece 164b.
[0058] First piece 164a extends in the radial direction of above-5 described central
axis C. One end of first piece 164a is directly or indirectly connected to shaft
portion 162c of blade member 162. The other end of first piece 164a is
connected to movable contact 164c.
[0059] Second piece 164b extends in the above-described radial direction and is
joined to a rear side of first piece 164a in a rotation direction of movable contactor
164 when the flow rate of insulating oil 120 increases. One end of second piece
164b is directly or indirectly connected to shaft portion 162c of blade member 162.
The other end of second piece 164b is connected to movable contact 164c.
Second piece 164b is joined to first piece 164a over the entire surface of first
piece 164a in the radial direction.
[0060] In the on-vehicle transformer and the oil flow relay according to the third
embodiment of the present invention, first piece 164a is made of a material having
a thermal expansion coefficient higher than that of second piece 164b. Although
each of first piece 164a and second piece 164b is made of a metal material or a
resin material, the material of each of first piece 164a and second piece 164b is
not limited thereto.
[0061] In the present embodiment, first piece 164a is made of a material having a
thermal expansion coefficient higher than that of second piece 164b. Therefore,
first piece 164a contracts more greatly than second piece 164b at low temperature.
[0062] As a result, as shown in Fig. 11, movable contactor 164 is curved to
protrude to the second piece 164b side at low temperature. Therefore, movable
contact 164c moves forward in the rotation direction of movable contactor 164
when the flow rate of insulating oil 120 increases. As a result, the flow rate of
insulating oil 120 flowing through connection pipe 140 when movable contact
164c and fixed contact 166 come into contact with each other can be made smaller
as the temperature becomes lower. That is, the operating flow rate of the oil
flow relay can be made smaller as the temperature of insulating oil 120 becomes
lower.
[0063] Therefore, as shown in Fig. 12, a rotation angle of blade member 162 in
the state in which the flow rate of insulating oil 120 flowing 5 through connection
pipe 140 is equal to the operating flow rate at low temperature can be made
smaller.
[0064] In the present embodiment, first piece 164a of movable contactor 164 is
made of a material having a thermal expansion coefficient higher than that of
second piece 164b. Therefore, the flow rate of insulating oil 120 flowing
through connection pipe 140 when movable contact 164c and fixed contact 166
come into contact with each other can be reduced. That is, the operating flow
rate of the oil flow relay can be made smaller as the temperature of insulating oil
120 becomes lower.
[0065] In the description of the embodiments above, features that can be
combined may be combined with each other.
[0066] It should be understood that the embodiments disclosed herein are given
by way of illustration in all respects, not by way of limitation. It is therefore
intended that the scope of the present invention is defined by the claims, not only
by the embodiments described above, and encompasses all modifications and
variations equivalent in meaning and scope to the claims.
REFERENCE SIGNS LIST
[0067] 1 transformer body; 100 on-vehicle transformer; 110 tank; 120 insulating
oil; 130 cooler; 140 connection pipe; 150 pump; 160 oil flow relay; 162 blade
member; 162a first plate-shaped portion; 162b second plate-shaped portion; 162c
shaft portion; 163 bearing portion; 164 movable contactor; 164a first piece; 164b
second piece; 164c movable contact; 166 fixed contact; 168 hollow portion; C
central axis.

CLAIMS
1. An on-vehicle transformer comprising:
a transformer body;
a tank to house the 5 transformer body;
an insulating oil filled into the tank to cool the transformer body;
a cooler to cool the insulating oil;
a connection pipe to connect the tank to the cooler;
a pump placed in the connection pipe to circulate the insulating oil
between the tank and the cooler; and
an oil flow relay placed on a discharge portion side of the pump in the
connection pipe,the oil flow relay including:
a blade member arranged in the connection pipe and supported so
as to be rotatable about a central axis orthogonal to the connection pipe;
a movable contactor having a movable contact and rotating about
the central axis with rotation of the blade member; and
a fixed contact located on a rotation path of the movable contact,
wherein the oil flow relay is configured such that an operating flow rate in the oil
flow relay becomes smaller as a temperature of the insulating oil becomes lower,
the operating flow rate being a flow rate of the insulating oil flowing through the
connection pipe when the movable contact and the fixed contact come into contact
with each other.

2. The on-vehicle transformer according to claim 1, wherein
the blade member includes:
a first plate-shaped portion extending from the central axis in a radial
direction of the central axis; and a second plate-shaped portion extending from the central axis in the radial direction and joined to a side of the first plate-shaped portion opposite to a pump side, and the first plate-shaped portion is made of a material having a thermal
expansion coefficient higher than that of the second plate-shaped portion.

3. The on-vehicle transformer according to claim 1, wherein
the blade member has a shaft portion extending on the central axis and is
supported by a bearing portion that is in sliding contact with the shaft portion, and
the shaft portion is made of a material having a thermal expansion
coefficient higher than that of the bearing portion.

4. The on-vehicle transformer according to claim 1, wherein
the blade member has a shaft portion extending on the central axis,
the movable contactor includes:
a first piece extending in a radial direction of the central axis; and
a second piece extending in the radial direction and joined to a rear side of
the first piece in a rotation direction of the movable contactor when the flow rate
of the insulating oil increases, and the first piece is made of a material having a thermal expansion coefficient higher than that of the second piece.

5. An oil flow relay comprising:
a blade member arranged in a pipe in which an insulating oil flows, and
supported so as to be rotatable about a central axis orthogonal to the pipe;
a movable contactor having a movable contact and rotating about the
central axis with rotation of the blade member; and a fixed contact located on a rotation path of the movable contact, wherein the oil flow relay is configured such that an operating flow rate becomes smaller as a temperature of the insulating oil becomes lower, the operating flow rate being a flow rate of the insulating oil flowing through the pipe when the
movable contact and the fixed contact come into contact with each other.

6. The oil flow relay according to claim , wherein
the blade member includes:
a first plate-shaped portion extending from the central 5 axis in a radial
direction of the central axis; and a second plate-shaped portion extending from the central axis in the radial direction and joined to a downstream side of the first plate-shaped portion in a flow direction of the insulating oil, and the first plate-shaped portion is made of a material having a thermal expansion coefficient higher than that of the second plate-shaped portion.

7. The oil flow relay according to claim wherein
the blade member has a shaft portion extending on the central axis and is
supported by a bearing portion that is in sliding contact with the shaft portion, and
the shaft portion is made of a material having a thermal expansion
coefficient higher than that of the bearing portion.

8. The oil flow relay according to claim , wherein
the blade member has a shaft portion extending on the central axis,
the movable contactor includes:
a first piece extending in a radial direction of the central axis; and
a second piece extending in the radial direction and joined to a rear side of
the first piece in a rotation direction of the movable contactor when the flow rate
of the insulating oil increases, and the first piece is made of a material having a thermal expansion coefficient higher than that of the second piece.