Patent Grant
9284717
1. Technical Field
The present invention relates to a swivel control apparatus for controlling a swivel motion of an electrical swivel mechanism such as a construction machine and a method of controlling the swivel.
2. Description of Related Art
In a construction machine such as a shovel, an electrical swivel mechanism where a motor is used as a power source for a swivel mechanism for swiveling an upper-part swivel body may be used. The upper-part swivel body of the shovel is provided with a cabin including an operator's room. A boom is supported by an upper-part swivel body so as to be rotatable. Therefore, a boom and an operation element such as an arm connected to a leading end of the boom and a bucket connected to the leading end of the boom swivel together with the upper-part swivel body. A cabin including an operator's room is provided in the upper-part swivel body. An operator operating a shovel in the operator's room swivels together with the boom and the arm when the upper-part swivel body swivels. In order to bring the operation element such as the end attachment provided to the leading end of the arm to a position where the operation is performed, the upper-part swivel body is caused to swivel to make the end attachment swivel along with the boom. A shovel having a swivel control apparatus is proposed. According to the shovel, an electric swivel motor for driving the upper-part swivel body is controlled by the swivel control apparatus in conformance to an operation amount of an operation lever.
According to an embodiment of the present invention, there is provided a swivel control apparatus for swiveling a swivel body that supports an attachment including a boom, an arm, and an end attachment by a motor, wherein a swivel drive command to the motor is generated according to a posture of the attachment.
In a control of the above swivel control apparatus, a speed command sent to an electric swivel motor is determined by an operation amount of an operation lever operated by an operator. Said differently, when an operator wish to rapidly move an operation element, the operator makes the operation amount of the operation lever great. With this, a swivel speed command in response to the operation amount of the operation lever is generated, and the electric swivel motor is driven by this swivel speed command. If the operation amount of the operation lever is great, the electric swivel motor suddenly accelerates to thereby increase a revolution speed. Therefore, the upper-part swivel body suddenly accelerates and the swivel speed becomes high.
As described, the swivel speed command is generated based only on the operation amount of the operation lever regardless of the position of the operation element such as a boom, an arm, and a bucket (an end attachment). Therefore, in cases where the boom and the arm are opened and the bucket is positioned far from the swivel center of the upper-part swivel body and where the boom and the arm are folded and the bucket is positioned near from the swivel center of the upper-part swivel body, the swivel speed of the upper-part swivel body is controlled in response to only the operation amount of the operation lever.
Because an operator operates an operation lever inside the cabin of the upper-part swivel body, the operator swivels along with the upper-part swivel body. Then, the operator feels the swivel speed of the upper-part swivel body or the operation element while seeing the boom, the arm, and the bucket. Inventors of the present invention or the like researched a swivel speed actually perceived by the operator. As a result, the operator feels the perceived swivel speed higher than the actual swivel speed in a case where the boom and the arm are opened and the bucket is positioned apart from the swivel center of the upper-part swivel body (in a leading end range).
The range where an operation of the bucket is performed is positioned between the above leading end range and a proximity range. The leading end range and the proximity range are called an actual operation range. In a case where the bucket is in the actual operation range, in order to rapidly perform the operation and enhance working efficiency, the swivel speed of the bucket (i.e., the swivel speed of the upper-part swivel body) is made faster. However, if the swivel speed of the upper-part swivel body is made fast, the operator feels that the swivel speed is too fast. Then, comfortable operational feeling is lost.
Therefore, a development of a technique of variably controlling the swivel speed of the upper-part swivel body based on the position of the end attachment such as the bucket is desired.
Next, embodiments of the present invention are described with reference to figures.
An upper-part swivel body 3 is installed in the lower-part travel body 3 through a swivel mechanism 2. A boom 4 is attached to the upper-part swivel body 3. An arm 5 is attached to a leading end of the boom 4, and a bucket 6 is attached to the leading end of the arm 5. A boom 4, the boom 5, and the bucket 6 included in an attachment are hydraulically driven by a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9, respectively. The upper-part swivel body 3 has a cabin 10 and a power source such as an engine.
An engine 11 as a mechanical drive part and a motor generator 12 as an assist drive part are both connected to two input shafts of a transmission 13. A main pump 14 and a pilot pump 15 are connected to an output shaft of the transmission 13 as hydraulic pumps. A control valve 17 is connected to the main pump 14 through a high-pressure hydraulic line 16.
The control valve 17 is a control unit that controls a hydraulic system of the hybrid shovel. Hydraulic motors 1A (for the right) and 1B (for the left) for the lower-part travel body 1, the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 are connected to the control valve 17 via the high-pressure hydraulic line 16.
An electric power storage system 120 includes a capacitor as an electrical power storage system 120 and is connected to the motor generator 12 through an inverter 18. An electric swivel motor 21 as an operation element is connected to the electrical power storage system 120 through the invertor 20. A resolver 22, a mechanical brake 23, and a swivel transmission 24 are connected to a rotation shaft 21A of the electric swivel motor 21. An operation unit 26 is connected to the pilot pump 15 through a pilot line 25. A load driving system is comprised of the electronic swivel motor 21, the inverter 20, the resolver 22, the mechanical brake 23, and the swivel transmission 24.
The operation unit 26 includes a lever 26A, a lever 26B and a pedal 26C. The lever 26A, the lever 26B and the pedal 26C are connected to the control valve 17 and a pressure sensor 29 through hydraulic lines 27 and 28. The pressure sensor 29 is connected to the controller 30, which controls a drive of an electric system.
Within this embodiment, a boom angle sensor 7B for detecting the angle of the boom 4 is attached to a support shaft of the boom 4. An arm angle sensor 8A for detecting the angle of the arm 5 is attached to a support shaft of the arm 5. The boom angle sensor 7B and the arm angle sensor 8A supply a detected boom angle θB and a detected arm angle θA to the controller 30. Further, a hydraulic pressure sensor 7P for detecting the hydraulic pressure on a bottom side of the boom cylinder 7 is attached to the hydraulic cylinder 7. The hydraulic pressure sensor 7P supplies the detected hydraulic pressure Pb to the controller 30.
The buck-boost converter 100 switches over between the boosting operation and the bucking operation so as to converge a DC bus voltage value within a predetermined range depending on running states of the motor generator 12 and the electric swivel motor 21. The DC bus 110 is arranged among the inverter 18A, an inverter 20, and the buck-boost converter 100 to exchange electric power among the capacitor 19, the motor generator 12, and the swivel motor 21.
Referring back to
The controller 30 converts a signal supplied from the pressure sensor 29 to a speed command and controls a drive of the electric swivel motor 21. The signal supplied from the pressure sensor 29 corresponds to a signal indicative of an operation amount of operating the operation unit 26 for swiveling the swivel mechanism 2.
The controller 30 switches over the control of driving the motor generator 12 between a motor (assisting) operation and a generator operation, and simultaneously controls charge or discharge of the capacitor 19 by driving the buck-boost converter 100 as the buck-boost converting unit. The controller 30 controls a switch of the buck-boost converter 100 between an boosting operation and a bucking operation based on a charging state of the capacitor 19, the running state (the motor (assisting) operation or the generation operation) of the motor generator 12, and a running state (a power running operation or a regenerating operation) of the electric swivel motor 21, and performs a charge or discharge control in the capacitor 19 by switching the buck-boost converter 100.
The control of the switch between the boosting operation and the bucking operation in the buck-boost converter 100 is performed based on the DC bus voltage value detected by the DC bus voltage detecting unit 111, the capacitor voltage value detected by the capacitor voltage detecting unit 112, and the capacitor current value detected by the capacitor current detecting unit 113.
In the above described structure, the electric power generated by the motor generator 12 being the assist motor is supplied to the DC bus 110 of the electrical power storage system 120 through the inverter 18A and supplied to the capacitor 19 through the buck-boost converter 100. The regenerative electrical power generated by the electric swivel motor 21 is supplied to the DC bus 110 of the electrical power storage system 120 through the inverter 20 and supplied to the capacitor 19 through the buck-boost converter 100.
The revolution speed (the angular speed ω) of the electric swivel motor 21 is detected by the resolver 22. The angle (the boom angle θB) of the boom 4 is detected by the boom angle sensor 7B such as a rotary encoder provided in the support shaft of the boom 4. The angle (the arm angle θA) of the arm 5 is detected by the arm angle sensor 8A such as a rotary encoder provided in the support shaft of the arm 5. A swivel control part 40 provided in the controller 30 generates a speed command given to the electric swivel motor 21 based on the boom angle θB, the arm angle θA, the hydraulic pressure Pb of the boom cylinder 7 on the bottom side, and the angular speed ω of the electric swivel motor 21. Within the embodiment, the swivel control part 40 is assembled in the controller 30. However, the swivel control part 40 may be a swivel driving unit provided separate from the controller 30.
In the above hybrid shovel having the above described structure, an operation range where the bucket 6 as the end attachment is attached to the leading end of the arm 5 is described below.
The bucket 6 performs an excavation operation and a loading operation. In a state where the boom 4 and the arm 5 are maximally opened (the maximum reach), the operation is scarcely performed. Ordinarily, the operation is performed in a range equal to about 80% or less of the maximum reach of the bucket 6. Meanwhile, in a state where the boom 4 and the arm 5 are completely closed, the operation is scarcely performed. Ordinarily, the operation is performed in a range equal to about 40% or greater of the maximum reach of the bucket 6. Said differently, the ordinary operation is performed in a state where the bucket 6 is positioned between 40% and 80% of the maximum reach. Therefore, the actual operation range is defined as the range between 40% and 80% of the maximum reach. The range exceeding 80% of the maximum reach is referred to as a leading end operation range, and the range less than 40% of the maximum reach is referred to as a proximity operation range.
In the leading end operation range, the driver feels an acceleration and a deceleration of a swivel motion greater than those of an actual swivel motion. For example, in a case where an operator performs the swivel motion by operating the operation lever while the bucket 6 is in a leading end operation range, the operator actually feels the swivel acceleration higher than a swivel acceleration intended by the operator. Therefore, the operator may possibly feel uncomfortable feeling or unpleasant feeling. Therefore, in the leading end operation range, the uncomfortable feeling of the operator is less to make the operator feel comfortableness when the acceleration and the deceleration of the bucket 6 (the upper-part swivel body 3) are not too great.
In a situation where the bucket 6 is positioned above the operator, it is difficult for the operator to directly see the bucket 6. Therefore, when the bucket 6 is positioned above the operator (the upper part operation range), the operation without excessively accelerating or decelerating the bucket 6 (the upper-part swivel body 3) makes the operator comfortable. Especially, it is desirable to reduce the acceleration and the deceleration in the situation where the bucket 6 is positioned outside the field of view. Further, when the bucket 6 is positioned below the ground, the bucket is hard to be seen by the operator. Therefore, when the bucket 6 is positioned below the ground (the lower part operation range), the operation without excessively accelerating or decelerating the bucket 6 (the upper-part swivel body 3) makes the operator comfortable.
As a result, when the bucket is positioned in the leading end operation range, the upper part operation range, and the lower part operation range, a comfortable operation for the operator can be implemented by a swivel acceleration and deceleration smaller than usual. On the other hand, when the bucket is positioned in the proximity operation range, a comfortable operation for the operator can be substantialized by a swivel acceleration greater than usual.
In consideration of the above description, the swivel control part 40 of the above embodiment can substantialize a comfortable operability by variably controlling, the swivel acceleration and deceleration depending on the operation ranges where the end attachment (the bucket, the lift magnet, or the like) is positioned. Specifically, within this embodiment, the comfortable operability for the operator is substantialized by considering the leading end operation range, the proximity operation range, the upper part operation range, and the lower part operation range, and making the acceleration and the deceleration in the actual range less than the acceleration and the deceleration in the leading end operation range and the proximity operation range. Further, the comfortable operability for the operator is substantialized by making the acceleration and deceleration in the proximity operation range greater than the acceleration and deceleration in the actual operation range.
Referring to
Next, a swivel acceleration control of this embodiment is described. The deceleration control at a time of decelerating the swivel motion is similar to an acceleration control at a time of accelerating the swivel motion. Here, only the acceleration control at the time of accelerating the swivel motion is described.
The swivel acceleration control of this embodiment is performed by the swivel control part 40 of the controller 30.
Meanwhile, the swivel control part 40 includes a speed command calculating part 50 as a first swivel drive command generating portion. The speed command calculating part 50 generates a first speed command V1 (a first swivel drive command) from a lever operation amount of the swivel operation lever and outputs the generated first speed command V1 to the switch part 48.
The switch part 48 for switching over the drive signal compares the second speed command supplied from the speed command calculating part 46 with the first speed command V1 supplied from the speed command calculating part 50 and determines which of the first speed command V1 and the second speed command V2 is smaller. In this case, the speed command value has a positive or negative sign depending on a swivel direction. Therefore, absolute values of the first speed command V1 and the second speed command V2 are used to compare the first speed command V1 with the second speed command V2. In a case where the second speed command V2 is smaller than the first speed command V1, the second speed command V2 is selected and output to a torque command generating part 52. In a case where the second speed command V2 is equal to or greater than the first speed command V1, the switch part 48 selects the first speed command V1 and outputs it to the torque command generating part 52.
The torque command generating part 52 generates the torque command from the supplied first and second speed commands V1 and V2, and outputs the generated torque command. The torque command output from the torque command generating part 52 is supplied to an inverter 20 that controls the drive of the electric swivel motor 21. The inverter 20 drives the electric swivel motor 21 based on the supplied torque command. Therefore, the swivel acceleration of the upper-part swivel body 3 that is driven by the electric swivel motor 21 is determined by the torque command output from the torque command generating part 52.
As described above, the acceleration is determined based on the posture of the attachment. Therefore, regardless of whether the swivel motion is a single operation or a complex operation that is performed along with an operation of the attachment, a stable swivel motion can be substantialized.
An example of a swivel control performed by the swivel control part 40 is further described.
In addition to the boom angle θB and the arm angle θA, a hydraulic pressure Pb of the boom cylinder 7 on the bottom side and a present revolution speed (an angular speed ω) of the electric swivel motor 21 are supplied to the swivel control part 40. The boom angle θB and the arm angle θA represent the posture of the boom 4 and the arm 5 whether the boom 4 and the arm 5 are opened so as to extend or closed so as to fold.
The hydraulic pressure of the boom cylinder on the bottom side how much a load is applied to the attachment. When a great amount of earth and sand are loaded (during heavy work) in the bucket, the earth and sand may be easily spilled out when the swivel motion is a sudden acceleration or deceleration. Therefore, the hydraulic pressure Pb of the boom cylinder 7 on the bottom side is input into an acceleration map 42a and the deceleration map 42b. With this, the acceleration and the deceleration of the swivel motion are adjusted in consideration of the load applied to the attachment.
The present revolution speed (an angular speed ω) of the electric swivel motor 21 may be used as a trigger for changing the swivel acceleration as described below.
The acceleration map 42a illustrates a relationship between the postures of the boom 4 and the arm 5 and the acceleration to be output. When the boom angle θB and the arm angle θA are input into the acceleration and deceleration determining part 42 as information of the posture, the acceleration and deceleration determining part 42 outputs the acceleration suitable for the boom 4 and the arm 5 with reference to the acceleration map 42a.
For example, when the position of the bucket 6 is determined to be within the actual operation range based on the postures of the boom 4 and the arm 5, which are determined by the boom angle θB and the arm angle θA, the acceleration map 42a indicative of the acceleration in the actual operation range is referred to. The acceleration obtained from the acceleration map 42a is output from the acceleration and deceleration determining part 42. The height of the acceleration illustrated in (b) of
According to the graph illustrated in (b) of
For example, when the position of the bucket 6 is determined to be within the leading end operation range based on the postures of the boom 4 and the arm 5, which are determined by the boom angle θB and the arm angle θA, the acceleration map 42a indicative of the acceleration in the leading end operation range is referred to. The acceleration obtained from the acceleration map 42a is output from the acceleration and deceleration determining part 42. The height of the acceleration illustrated in (b) of
According to the graph illustrated in (b) of
The acceleration G4 illustrated in (b) of
There is a case where the bucket 6 enters into a different operation range during the swivel motion. In this case, it is possible to determine that the bucket 6 enters a different range from the postures of the boom 4 and the arm 5. If it is determined that the bucket 6 transits to the different range, the acceleration map 42a to be referred to is change to that in the operation range before the transition to the operation range after the transition.
For example, in a case where the bucket 6 transits from the actual operation range to the leading end operation range during the swivel motion, the referred acceleration map is switched from the acceleration map illustrated in (b) of
A change of the acceleration provided with smoothing by the smoothing part 44 is indicated by a solid line in (b) of
In the smoothing at a part A of (a) of
In the above example, the accelerations in the leading end operation range and the proximity operation range are variably controlled. By preparing the acceleration maps corresponding to the upper part operation range and the lower part operation range, even in a case where the bucket 6 (the end attachment) is in the upper part operation range or the lower part operation range, in a manner similar to the leading end operation range or the proximity operation range, the acceleration can be variably changed to provide comfortable operability. Whether the bucket 6 is in the upper part operation range or the lower part operation range can be determined from the boom angle θB and the arm angle θA. Even when the position of the attachment is changed through multiple operation ranges, if the swivel acceleration smoothly changes, it is not always necessary to perform the smoothing. Thus, the smoothing part 44 may be provided when necessary.
Further, within the above described embodiment, the acceleration is obtained from the acceleration map, the speed command is obtained by converting the acceleration to a speed, and the speed command is converted to the torque command. A torque map indicative of a relationship between the postures of the boom and the arm in each operation range and a torque command value may be prepared. Instead of the acceleration map 42a and the deceleration map 42b, the torque map may be used to directly obtain a torque command value.
The acceleration torque determined by referring to the acceleration torque map 43a is output from the torque determining part 43, is subjected to smoothing by the smoothing part 44, and is output to the switch part 48. The acceleration and deceleration determining part 41 compares a present speed (an angular speed ω) with the first speed command V1 output from the speed command calculating part 50 to determine whether the swivel motion is accelerating or decelerating. The determined result is sent to the torque determining part 43. The torque determining part 43 refers to the acceleration map 43a based on the determined result of whether the swivel motion is accelerating or decelerating. If the swivel motion is accelerating, the acceleration torque map 43a is referred to, and if the swivel motion is decelerating, the deceleration torque map 43b is referred to. The second torque command T2 (a second swivel drive command) output from the smoothing part 44 is supplied to the switch part 48. In the swivel control part 40 illustrated in
On the other hand, the swivel control part 40 includes a speed command calculating part 50 and a torque command generating part 51 as a first swivel drive command generating portion. The speed command calculating part 50 generates a first speed command V1 (a first swivel drive command) from a lever operation amount of the swivel operation lever and outputs the generated first speed command V1 to the torque command generating part 51. The torque command generating part 51 generates a first torque command (a first swivel drive command) based on the first speed command V1 supplied from the speed command calculating part 50 and a present speed of the upper-part swivel body 3, and outputs the first torque command to the switch part 48.
The switch part 48 for switching over the drive signal compares the second torque command T2 supplied from the torque determining part 43 through the smoothing part 44 with the first torque command T1 supplied from the torque command generating part 51 and determines which of the second torque command T2 and the first torque command T1 is smaller. In a case where the second torque command T2 is smaller than the first torque command T1, the second torque command T2 is selected and output to an inverter 20. In a case where the second torque command T2 is equal to or greater than the first torque command T1, the first torque command T1 is selected and output to the inverter 20. The inverter 20 drives the electric swivel motor 21 based on the supplied torque command. Therefore, the swivel acceleration of the upper-part swivel body 3 that is driven by the electric swivel motor 21 is determined by the torque command output from the switch part 48. As described above, the torque command is determined based on the posture of the attachment. Therefore, regardless of whether the swivel motion is the single operation or the complex operation that is performed along with the operation of the attachment, the stable swivel motion can be substantialized.
Next, a second embodiment of the present invention is described.
Within the second embodiment described below, the swivel speed of the end attachment (the upper-part swivel body 3) is controlled by correcting the swivel speed command based on the swivel radius R of the end attachment.
Referring to
In consideration of a case where the shovel is horizontally positioned, a distance L1 from the swivel center Ctb of the upper-part swivel body 3 to the rotational center Cbm in the horizontal direction is a known value. A distance L2 from the rotational center Cbm of the boom 4 to the rotational center Cam of the arm 5 in the horizontal direction can be obtained as Lb×cos θB using the length Lb of the boom 4 and the boom angle θB. A distance L3 from the rotational center Cam of the arm 5 to the rotational center Cbt of the bucket 6 in the horizontal direction can be obtained as La×cos(θA−(θB−θC)) using the length La of the arm 5, the arm angle θA, and a bent angle θC of the boom 4.
The swivel radius R is obtained by adding the distance L2=Lb×cos θB and the distance L3=La×cos(θA−(θB−θC)) to the distance L1 as R=L1+Lb×cos θB+La×cos(θA−(θB−θC)). The distance L1, the boom length Lb, the arm length La, and the boom bent angle θC are known values. The swivel radius R can be obtained by substituting the boom angle θA detected by the boom angle sensor 7B and the arm angle θB detected by the arm angle sensor 8A with those detected by the boom angle sensor 7B and the arm angle sensor 8A.
The above swivel radius R is changed by the postures of the boom 4 and the arm 5. Said differently, the swivel radius R is changed by the boom angle θB being a tilt angle of the boom 4 and the boom angle θA being a tilt angle of the arm 5. As the boom angle θB becomes smaller, the swivel radius R becomes greater. As the arm angle θA becomes smaller, the swivel radius R becomes greater. When the boom angle θB and the arm angle θA is the minimum, the swivel radius R becomes the maximum. Said differently, when both of the boom angle θB and the arm angle θA are the minimum, the end attachment (the bucket 6) is positioned at the farthest position from the swivel center Ctb of the upper-part swivel body 3. On the contrary, when both of the boom angle θB and the arm angle θA are the maximum, the end attachment (the bucket 6) is positioned at the closest position from the swivel center Ctb of the upper-part swivel body 3. As described, the swivel radius R can be used as a parameter indicative of the position of the end attachment (the bucket 6).
Within this embodiment, the speed command value is corrected based on the swivel radius R. Therefore, in a manner similar to the first embodiment, the swivel speed or the swivel acceleration are variably controlled to thereby provide a comfortable operability.
The speed command generating part 60 includes a map as illustrated in
On the other hand, the boom angle θB and the arm angle θA are input into the swivel radius calculating part 64. The swivel radius calculating part 64 calculates the swivel radius R of the end attachment from the boom angle θB and the arm angle θA, and outputs the calculated swivel radius R to the above speed command correcting part 62.
The speed command correcting part 62 corrects the swivel speed command V1 generated by the speed command generating part 60 based on the swivel radius R to generate the swivel speed command TV2, and outputs the generated swivel speed command TV2 to the electric swivel motor 21. Specifically, the speed command correcting part 62 multiplies the swivel speed command TV1 by the speed command ratio VR to correct the swivel speed command TV1 to be the swivel speed command TV2 (TV2=TV1×VR).
The speed command ratio VR is a predetermined ratio equal to or less than 1.0. As illustrated in
As describe above, the swivel speed command TV2 corrected by multiplying the swivel speed command TV1, which is generated from the lever operation amount, by the speed command ratio RV is supplied to the electric swivel motor 21. With this, the swivel speed of the electric swivel motor 21 (i.e., the swivel speed of the upper-part swivel body 3 and the end attachment) is controlled by the swivel speed command TV2. Therefore, as the swivel radius R of the end attachment (the bucket 6) becomes greater, the swivel speed of the upper-part swivel body 3 is controlled to be smaller than the swivel speed controlled by the swivel speed command TV1.
After the swivel speed reaches the maximum speed corresponding to the lever operation amount, the swivel speed is maintained at the maximum speed while the lever operation amount is maintained as illustrated in
As described above, within this embodiment, the swivel speed is variably controlled to provide a comfortable operability by correcting the swivel speed command TV1, which is an example of the swivel drive command, based on the swivel radius R to thereby variably control the swivel speed command TV1.
In the above embodiment, a so-called parallel-type hybrid shovel, in which the engine 11 and the motor generator 12 are connected to the main pump 14 being the hydraulic pump to thereby drive the main pump 14, is applied to the present invention. However, the embodiment is applicable also to a so-called series-type hybrid shovel, in which the motor generator 12 is driven by the engine 11, electric power generated by the motor generator 12 is accumulated in the electric power storage system 120, and a pump motor 400 is driven by only the stored electric power to drive the main pump 14, as illustrated in
Further, the present invention is not limited to the hybrid shovel and is applicable to an electric shovel as illustrated in
The present invention is not limited to the above embodiments where the above shovel specifically disclosed, as an example. Various modified examples and altered examples are to be provided without departing from the scope of the present invention.
It should be understood that the invention is not limited to the above-described embodiment, but may be modified into various forms on the basis of the spirit of the invention. Additionally, the modifications are included in the scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-289430 | Dec 2011 | JP | national |
This application is a continuation application of and is claiming benefit under 35 U.S.C. 120 and 365(c) of PCT International Patent Application No. PCT/JP2012/083721 filed on Dec. 26, 2012 and designating the U.S., which claims priority to Japanese Patent Application No. 2011-289430 filed on Dec. 28, 2011. The entire content of the foregoing applications are incorporated herein by reference
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| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2012/083721 | Dec 2012 | US |
| Child | 14305192 | US |
