Patent Application
20240077014
The present invention relates to an electric outboard motor.
An outboard engine is known as a propulsion apparatus of a ship. The outboard engine is attached to a stern plate (transom board) of a hull, and a screw which is a propellant is provided in a lower region submerged in outside water such as seawater or fresh water. In recent years, an electric outboard motor that employs an electric motor as a drive source which drives a screw has been developed (for example, refer to patent document 1 (Japanese Unexamined Patent Application, First Publication No. 2010-228528)).
The electric outboard motor described in patent document 1 includes a screw that is submerged in outboard water and generates a propulsion force and an electric motor that drives the screw, and the electric motor is accommodated in an outboard motor case. The outboard motor case is attached to a stern plate of a hull together with an internal support structure body. A lower region of the outboard motor case is submerged in outside water (seawater or fresh water) together with the screw at the time of operation of the ship.
Further, the electric outboard motor described in patent document 1 includes a motor cooling portion for cooling a heat generation portion of an electric motor in the outboard motor case. The motor cooling portion includes a water jacket that surrounds the heat generation portion of the electric motor and cools the heat generation portion by causing a cooling liquid to flow through the water jacket.
The water jacket is connected to a circulation passage through which the cooling liquid flows. A pump device for circulating the cooling liquid and a heat exchange device that performs heat exchange between the cooling liquid and the outside water are provided in the circulation passage. In the heat exchange device, a heat exchange pipe through which the cooling liquid that has cooled the heat generation portion flows is arranged in a container, and the outside water is introduced into a space portion that surrounds the heat exchange pipe in the container. The outside water is introduced into the container by a pump for pumping up and is discharged to the outside of the outboard motor after absorbing heat of the cooling liquid in the heat exchange pipe.
The electric outboard motor described in patent document 1 includes the heat exchange device that pumps the outside water into the container and performs heat exchange between the cooling liquid and the outside water in order to cool the heat generation portion of the electric motor. However, the heat exchange device requires a dedicated pump and a plurality of piping in order to pump the outside water into the container, which is likely to cause the whole outboard motor to become large.
Further, an operation sound of the screw that rotates at the time of operation of the ship is easily transmitted via an inner space of the outboard motor case to an upper region of the case. Therefore, as a measure against the noise, it is conceivable that a dedicated sound insulation structure is provided inside the outboard motor case, but the dedicated sound insulation structure is likely to cause the structure of the electric outboard motor to be complicated.
Accordingly, the present invention is intended to provide an electric outboard motor capable of efficiently cooling a cooling liquid by outside water without providing an extensive heat exchange device and capable of preventing an operation sound of a screw from being transmitted to an upper portion of an outboard motor case.
An electric outboard motor according to an aspect of the present invention includes: a screw (for example, a screw 10 of an embodiment) that is submerged in outside water and generates a propulsion force; an electric motor (for example, an electric motor 11 of the embodiment) that drives the screw; an outboard motor case (for example, an outboard motor case 12 of the embodiment) that accommodates the electric motor; and a cooling portion (for example, a cooling liquid supply port 23 of the embodiment) that cools a heat generation portion (for example, a heat generation portion 11b of the embodiment) at an inside or an outside of the outboard motor case by a cooling liquid, wherein at least a lower region (for example, a gear case portion 12L of the embodiment) of the outboard motor case that is submerged in the outside water is constituted of a multiple case structure body (for example, a multiple case structure body of the embodiment) that includes an outer case (for example, an outer case 20o of the embodiment) and an inner case (for example, an inner case 20i of the embodiment), and in the multiple case structure body of the lower region, at least part of a space portion that is surrounded by the outer case and the inner case is a cooling liquid passage (for example, a cooling liquid passage 24 of the embodiment) through which the cooling liquid supplied to the cooling portion flows.
In the configuration described above, when the cooling liquid flows into the multiple case structure body (cooling liquid passage) of the lower region, the heat of the cooling liquid is exchanged with the outside water through the outer case. Thereby, the heat of the cooling liquid is released to the outside water, and the cooling liquid is cooled. The cooled cooling liquid is supplied to the cooling portion and cools the heat generation portion.
Further, since the lower region of the outboard motor case that is submerged in the outside water is constituted of the multiple case structure body, and the cooling liquid flows between the outer case and the inner case, an operation sound of the screw is not easily transmitted to an inner space of the inner case of the lower region. Therefore, it is possible to prevent the operation sound of the screw from being transmitted to an upper side of the outboard motor case through the inner space of the outboard motor case.
The outer case may have an inner surface that is in contact with the cooling liquid in the cooling liquid passage and may be a heat exchange portion that performs heat exchange between the outside water and the cooling liquid in the cooling liquid passage.
In this case, the inner surface of the outer case is in contact with the cooling liquid in the cooling liquid passage. Therefore, the heat of the cooling liquid in the cooling liquid passage is efficiently exchanged with the outside water through the outer case which is the heat exchange portion.
The space portion of the multiple case structure body may be partitioned by a partition wall (for example, a longitudinal partition plate 22 of the embodiment), and the cooling liquid passage may be formed.
In this case, even though the structure is simple, it is possible to efficiently cause the cooling liquid to flow to the inside of the multiple case structure body.
The cooling liquid passage may be constituted of part of the space portion partitioned by the partition wall.
In this case, since the cooling liquid passage is constituted of part of the space portion partitioned by the partition wall, a portion in the cooling liquid passage at which the cooling liquid accumulates is not easily formed. Accordingly, when the present configuration is employed, the circulation of the cooling liquid is improved, and it becomes possible to further efficiently cool the heat generation portion.
A piping that forms the cooling liquid passage may be arranged in the space portion of the multiple case structure body.
In this case, since the cooling liquid passage arranged in the space portion is formed of the piping, the cooling liquid flows smoothly in the cooling liquid passage. Accordingly, when the present configuration is employed, the circulation of the cooling liquid is improved, and it becomes possible to further efficiently cool the heat generation portion. Further, when the present configuration that uses the piping is employed, it is possible to easily form a cooling liquid passage in which the cooling liquid does not easily accumulate.
In the outboard motor case, the lower region and a motor accommodation portion (for example, a motor case portion 12U of the embodiment) that continues to the lower region may be constituted of the multiple case structure body.
In this case, a wall of the motor accommodation portion of the outboard motor case can also be utilized as part of a flow passage through which the cooling liquid flows. Further, it is possible to prevent an operation sound of the electric motor or the like in the motor accommodation portion from leaking to the outside by the multiple case structure body.
A cooling liquid supply port (for example, a cooling liquid supply port 23 of the embodiment) that supplies the cooling liquid which has flowed through the multiple case structure body of the lower region to the heat generation portion of the electric motor may be provided on a wall of the inner case of the motor accommodation portion.
In this case, only by providing the cooling liquid supply port on the wall of the inner case of a motor accommodation room at a position that faces the heat generation portion of the electric motor, the cooling liquid can be stably supplied to the heat generation portion from an appropriate position that faces the heat generation portion. Accordingly, when the present configuration is employed, it is possible to easily manufacture a structure for efficiently cooling the electric motor (heat generation portion).
A cooling liquid storage portion (for example, a cooling liquid storage portion of the embodiment) that stores the cooling liquid which has cooled the electric motor and a pump device (for example, a pump device 30 of the embodiment) that supplies the cooling liquid stored in the cooling liquid storage portion to the multiple case structure body of the lower region may be arranged in the motor accommodation portion.
In this case, even though the structure is simple, the cooling liquid which has cooled the heat generation portion of the electric motor in the motor accommodation portion can be supplied to the multiple case structure body (the cooling liquid passage) of the lower region by the pump device. Further, since the motor accommodation portion is constituted of the multiple case structure body, it is possible to prevent the operation sound of the pump device from leaking to the outside of the outboard motor case.
A power transmission mechanism (for example, a power transmission mechanism 13 of the embodiment) that transmits a drive force of the electric motor to the screw may be accommodated inside the inner case of the lower region.
In this case, it is possible to prevent an operation sound of the power transmission mechanism from leaking to the outside of the outboard motor case by the multiple case structure body of the lower region and the cooling liquid that flows therein. Accordingly, when the present configuration is employed, it is also possible to change a gear of the power transmission mechanism from an expensive helical gear to an inexpensive straight gear.
The cooling liquid in the cooling liquid passage may flow from a rearward side in a propulsion direction of the lower region of the outboard motor case through a forward side toward the cooling portion.
In this case, the cooling liquid finally flows through the forward side of the lower region of the outboard motor case where the outside water hits at the time of navigation of the ship. Therefore, the cooling liquid that is efficiently cooled at the forward side of the lower region can be supplied to the cooling portion. Accordingly, when the present configuration is employed, the cooling performance with respect to the heat generation portion can be further enhanced.
The electric outboard motor according to an aspect of the present invention has a structure in which at least the lower region of the outboard motor case is constituted of the multiple case structure body, at least part of the space portion between the outer case and the inner case of the lower region is the cooling liquid passage, and the outer case of the lower region is submerged in the outside water. Accordingly, by employing the present configuration, it is possible to efficiently cool the cooling liquid by outside water without providing an extensive heat exchange device, and it is possible to prevent an operation sound of the screw from being transmitted to an upper portion of the outboard motor case.
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In an appropriate position of the drawing, an arrow FR that indicates a propulsion direction of an electric outboard motor is shown. The flow of a cooling liquid 50 is represented by an arrow in the drawing. The flow of the cooling liquid 50 that flows from a front side to a rear side of a paper plane in the drawing is represented by a symbol that schematically indicates an arrow rear, and the flow of the cooling liquid 50 that flows from the rear side to the front side of the paper plane in the drawing is represented by a symbol that schematically indicates an arrow front.
In the embodiments described below, common portions are denoted by the same reference numerals, and redundant descriptions are partially omitted.
The electric outboard motor 1 can be attached to a stern plate (transom board) at a rear portion of a hull (not shown). The electric outboard motor 1 includes: a screw 10 that is submerged in water (hereinafter, referred to as “outside water w”) of a sea, a river, a lake, or the like and generates a propulsion force; an electric motor 11 that rotates and drives the screw 10; and an outboard motor case 12 that accommodates a drive-related component including the electric motor 11 therein. The outboard motor case 12 is supported by a skeleton member (not shown). The skeleton member is rotatably supported by the rear portion of the hull around a swivel shaft (not shown). A main body portion of the electric outboard motor 1 including the skeleton member is operated to be rotated rightward and leftward by a steering motor (not shown). Further, the skeleton member is also rotatable in an upward-downward direction at the rear portion of the hull around a tilt shaft (not shown).
When the electric outboard motor 1 is in an attitude in which the screw 10 is submerged in the outside water w, a side that faces vertically upward is referred to as “upward”, and a side that faces vertically downward is referred to as “downward”. Further, a direction in which the electric outboard motor 1 proceeds in response to the propulsion force of the screw 10 is referred to as “forward”, and a direction opposite to the direction in which the electric outboard motor 1 proceeds is referred to as “rearward”.
The outboard motor case 12 includes a motor case portion 12U that accommodates the electric motor 11 and a gear case portion 12L that accommodates a power transmission mechanism 13. The power transmission mechanism 13 is a speed reduction mechanism including a plurality of gears, reduces the speed of the power of the electric motor 11 at a predetermined speed reduction ratio, and transmits the power to the screw 10. The motor case portion 12U is larger in capacity than the gear case portion 12L and is provided to continue to an upper section of the gear case portion 12L. The motor case portion 12U is formed such that a cross-sectional shape cut in a horizontal direction is a substantially circular shape. The gear case portion 12L is formed such that a cross-sectional shape cut in the horizontal direction is a substantially elliptical shape elongated in a forward-rearward direction. However, these shapes of the motor case portion 12U and the gear case portion 12L are merely examples, and the shapes are not limited thereto.
In the present embodiment, the gear case portion 12L constitutes a lower region of the outboard motor case 12, and the motor case portion 12U constitutes a motor accommodation portion of the outboard motor case 12.
The screw 10 is supported rotatably integrally with a screw shaft 10a that penetrates in a forward-rearward direction through a rear wall of the gear case portion 12L. The screw shaft 10a is connected to the power transmission mechanism 13 at the inside of the gear case portion 12L. The screw 10 is arranged on a rear lower end of the gear case portion 12L. The screw 10 generates a propulsion force by receiving a rotation power of the electric motor 11 and rotating in the outside water w.
The gear case portion 12L which constitutes the lower region of the outboard motor case 12 is submerged in the outside water w together with the screw 10 at the time of navigation of the ship.
A partition wall 14 partitions the motor case portion 12U and the gear case portion 12L. A through hole 15 is provided in the partition wall 14, and an input shaft 16 of the power transmission mechanism 13 is inserted through the through hole 15. A space between the through hole 15 and the input shaft 16 is sealed by a seal member 17. A space between the screw shaft 10a and an insertion hole 18 of the screw shaft 10a of the gear case portion 12L is also sealed by a seal member 19.
In the present embodiment, a control device (not shown) for controlling the electric motor 11, a battery (not shown) which is an electric power source of the electric motor 11, and the like in addition to the electric motor 11 are accommodated inside the motor case portion 12U. However, the battery and the control device may be arranged on a hull side. The control device may be arranged on the electric outboard motor 1 at the outside of the outboard motor case 12 (motor case portion 12U).
A pump device 30 for circulating the cooling liquid 50 for cooling the electric motor 11 and the input shaft 16 of the power transmission mechanism 13 are connected to an output shaft 11a of the electric motor 11. The pump device 30 is arranged within the motor case portion 12U and operates in response to a drive force of the electric motor 11. Various types of pump devices 30 can be employed such as a centrifugal type or a gear type as long as the pump device 30 is capable of sending the cooling liquid 50 suctioned from a suction portion 30i to a discharge portion 30o.
A lower side in the motor case portion 12U is a cooling liquid storage portion 35 that stores the cooling liquid 50. The cooling liquid 50 that has cooled a heat generation portion 11b of the electric motor 11 drops downward and is stored in the cooling liquid storage portion 35. The cooling liquid 50 in the cooling liquid storage portion 35 is suctioned by the pump device 30 and is discharged from the discharge portion 30o.
The heat generation portion 11b of the electric motor 11 is, for example, a motor case that covers the outside of a stator and a coil, a drive circuit of a motor, and the like. However, depending on the structure of the electric motor 11, the heat generation portion 11b may be a rotor or the coil itself.
The motor case portion 12U and the gear case portion 12L of the outboard motor case 12 are constituted of a multiple case structure body 20 having an outer case 20o and an inner case 20i. In the multiple case structure body 20, a space portion is formed between the outer case 20o and the inner case 20i, and the electric motor 11, the power transmission mechanism 13, and the like are capable of being accommodated inside the inner case 20i. The space portion surrounded by the outer case 20o and the inner case 20i is partitioned by a transverse partition plate 21 (partition wall) and a pair of longitudinal partition plates 22 (partition wall) and defines a circulation passage through which the cooling liquid 50 circulates.
The transverse partition plate 21 is formed in a substantially arc shape as shown in
As shown in
The discharge portion 30o of the pump device 30 is connected to the flow passage C1 of the motor case portion 12U. As shown in
The cooling liquid 50 that is discharged from the discharge portion 30o of the pump device 30 flows from the flow passage C1 in the motor case portion 12U to the flow passage C2 in the gear case portion 12L, and flows through the flow passages C3 and C4 in the gear case portion 12L into the flow passage C5 in the motor case portion 12U. The cooling liquid 50 that flows into the flow passage C5 in the motor case portion 12U is discharged from the plurality of cooling liquid supply ports 23 toward the heat generation portion 11b of the electric motor 11. The cooling liquid 50 that is discharged toward the heat generation portion 11b of the electric motor 11 cools the heat generation portion 11b, drops to the cooling liquid storage portion 35 at a lower position, and is stored. The cooling liquid 50 that is stored in the cooling liquid storage portion is suctioned from the suction portion 30i by the pump device 30 and is discharged again to the flow passage C1 from the discharge portion 30o of the pump device 30. In this way, the cooling liquid 50 circulates through the inside of the multiple case structure body 20.
In the present embodiment, the cooling liquid supply port 23 that is formed on the inner case 20i of the motor case portion 12U constitutes a cooling portion that cools the heat generation portion 11b by the cooling liquid.
Here, the flow passages C2, C3, and C4 in the gear case portion 12L constitute a cooling liquid passage 24 in the lower region of the outboard motor case 12. The outer case 20o of the gear case portion 12L is in direct contact with the cooling liquid (the cooling liquid in the space portion between the outer case 20o and the inner case 20i) in the cooling liquid passage 24. When the gear case portion 12L is submerged in the outside water w, the outer case 20o of the gear case portion 12L comes into direct contact with the outside water w and releases the heat of the cooling liquid 50 that flows through the cooling liquid passage 24 to the outside water w. That is, the outer case 20o of the gear case portion 12L functions as a heat exchange portion that performs heat exchange between the outside water w and the cooling liquid 50 in the cooling liquid passage 24.
Accordingly, when the cooling liquid 50 that has absorbed the heat of the heat generation portion 11b of the electric motor 11 is pumped by the pump device 30 and flows into the cooling liquid passage 24 through the flow passage C1 at the inside of the multiple case structure body 20, the cooling liquid 50 is cooled by the outside water w through the outer case 20o. Then, the cooling liquid 50 that is cooled by the cooling liquid passage 24 passes through the flow passage C5 and the cooling liquid supply port 23 and is supplied to the heat generation portion 11b of the electric motor 11. As a result, the heat of the heat generation portion 11b is absorbed by the cooling liquid 50 that is sufficiently cooled.
Further, in the present embodiment, the cooling liquid 50 that is suctioned from the cooling liquid storage portion 35 through the pump device 30 passes through the flow passages C1 and C2 that are located at a rearward side in the propulsion direction of the electric outboard motor 1 and exchanges heat with the outside water w at the cooling liquid passage 24. Then, the cooling liquid 50 that has exchanged heat with the outside water w passes through the flow passages C4 and C5 that are located at a forward side in the propulsion direction of the electric outboard motor 1 and is discharged from the cooling liquid supply port 23 to the heat generation portion 11b of the electric motor 11. That is, the cooling liquid 50 in the cooling liquid passage 24 flows from the rearward side in the propulsion direction of the gear case portion 12L (the lower region) of the outboard motor case 12 through the forward side toward the cooling liquid supply port 23 (the cooling portion). Accordingly, the cooling liquid 50 that passes through the flow passage C4 of the gear case portion 12L is efficiently cooled by the outside water w through a front surface of the outer case 20o at the time of propulsion of the electric outboard motor 1. Accordingly, the cooling liquid 50 that is sufficiently cooled is discharged from the cooling liquid supply port 23 toward the heat generation portion 11b.
As described above, in the electric outboard motor 1 of the present embodiment, the gear case portion 12L (the lower region) of the outboard motor case 12 is constituted of the multiple case structure body 20. The space portion between the outer case 20o and the inner case 20i of the gear case portion 12L is the cooling liquid passage 24, and the outer case 20o of the gear case portion 12L is the heat exchange portion between the cooling liquid 50 and the outside water w. Therefore, the heat of the cooling liquid 50 can be efficiently released to the outside water w through the outer case 20o of the multiple case structure body 20. Further, since the gear case portion 12L of the outboard motor case 12 is constituted of the multiple case structure body 20, an operation sound of the screw 10 is not easily transmitted to an upper portion of the outboard motor case 12 through the inner space of the outboard motor case 12. Specifically, since the cooling liquid 50 flows between the outer case 20o and the inner case 20i of the gear case portion 12L, it is further unlikely that the operation sound of the screw 10 is transmitted to the upper portion of the outboard motor case 12.
Accordingly, when the electric outboard motor 1 of the present embodiment is employed, it is possible to efficiently cool the cooling liquid 50 by the outside water w without providing an extensive heat exchange device, and it is possible to prevent the operation sound of the screw 10 from being transmitted to the upper portion of the outboard motor case 12.
Further, in the electric outboard motor 1 of the present embodiment, the inner surface of the outer case 20o is in contact with the cooling liquid in the cooling liquid passage 24, and the outer case 20o is the heat exchange portion that performs heat exchange between the outside water w and the cooling liquid 50 in the cooling liquid passage 24. Therefore, the heat of the cooling liquid 50 in the cooling liquid passage 24 can be efficiently exchanged with the outside water w through the outer case 20o which is the heat exchange portion.
Further, in the electric outboard motor 1 of the present embodiment, the space portion between the outer case 20o and the inner case 20i of the multiple case structure body 20 is partitioned by the transverse partition plate 21 and the longitudinal partition plate 22, and the cooling liquid passage 24 (the flow passages C1 to C5 of the cooling liquid 50) is formed. Therefore, when the present configuration is employed, even though the structure is simple, it is possible to efficiently cause the cooling liquid 50 to flow to the inside of the multiple case structure body 20.
Further, in the electric outboard motor 1 of the present embodiment, not only the gear case portion 12L of the outboard motor case 12, but also the motor case portion 12U which is the motor accommodation portion is constituted of the multiple case structure body 20 having the outer case 20o and the inner case 20i. Therefore, the wall of motor case portion 12U can also be utilized as part of the flow passage through which the cooling liquid 50 flows, and it is possible to prevent an operation sound of the electric motor 11, the pump device 30, or the like in the motor case portion 12U from leaking to the outside of the motor case portion 12U by the multiple case structure body 20.
Specifically, in the electric outboard motor 1 of the present embodiment, since almost the entire region of the motor case portion 12U including an upper wall portion is constituted of the multiple case structure body 20, it is possible to effectively prevent a variety of noises in the outboard motor case 12 from leaking to the outside.
Further, in the electric outboard motor 1 of the present embodiment, the cooling liquid supply port 23 that discharges the cooling liquid 50 that has flowed through the multiple case structure body 20 of the gear case portion 12L to the heat generation portion 11b of the electric motor 11 is provided on the wall of the inner case 20i of the motor case portion 12U. Therefore, only by providing the cooling liquid supply port 23 on the wall of the inner case 20i of the motor case portion 12U at an appropriate position, the cooling liquid can be stably injected and supplied to the heat generation portion 11b of the electric motor 11.
Accordingly, when the present configuration is employed, it is possible to easily manufacture a structure for efficiently cooling the heat generation portion of the electric motor.
Further, in the electric outboard motor 1 of the present embodiment, the cooling liquid storage portion 35 that stores the cooling liquid 50 which has cooled the electric motor 11 and the pump device 30 that supplies the cooling liquid 50 of the cooling liquid storage portion 35 to the cooling liquid passage 24 of the gear case portion 12L are arranged in the motor case portion 12U. Therefore, even though the structure is simple, the cooling liquid 50 which has cooled the heat generation portion 11b of the electric motor 11 in the motor case portion 12U can be supplied to the cooling liquid passage 24 of the gear case portion 12L by the pump device 30. Further, in the case of the present configuration, since the motor case portion 12U is constituted of the multiple case structure body 20, it is possible to prevent the operation sound of the pump device 30 from leaking to the outside of the outboard motor case 12.
Further, in the electric outboard motor 1 of the present embodiment, the power transmission mechanism 13 that transmits the drive force of the electric motor 11 to the screw 10 is accommodated inside the inner case 20i of the gear case portion 12L. Therefore, it is possible to prevent an operation sound of the power transmission mechanism 13 from leaking to the outside of the outboard motor case 12 by the multiple case structure body 20 of the gear case portion 12L and the cooling liquid that flows therein. Accordingly, when the present configuration is employed, it is possible to change a gear of the power transmission mechanism 13 from an expensive helical gear to an inexpensive straight gear and reduce the manufacturing cost.
Further, in the electric outboard motor 1 of the present embodiment, the cooling liquid 50 in the cooling liquid passage 24 flows from the rearward side in the propulsion direction of the gear case portion 12L (the lower region) of the outboard motor case 12 through the forward side toward the cooling liquid supply port 23 (the cooling portion). Therefore, the cooling liquid 50 flows through the forward side of the gear case portion 12L of the outboard motor case 12 where the outside water w hits at the time of navigation of the ship immediately before the cooling liquid 50 is directed to the cooling liquid supply port 23 (the cooling portion). Accordingly, when the present configuration is employed, the cooling liquid 50 that is efficiently cooled at a front surface side of the gear case portion 12L can be supplied to the cooling liquid supply port 23 (the cooling portion), and the cooling performance with respect to the heat generation portion 11b can be further enhanced.
Although the basic configuration of the electric outboard motor 101 of the present embodiment is almost similar to that of the first embodiment, the inside of the multiple case structure body 20 of the outboard motor case 12 is partitioned by two pairs of longitudinal partition plates 22F and 22R. A pair of longitudinal partition plates 22R on the rearward side constitute the flow passages C1 and C2 together with the inner case 20i and the outer case 20o, and a pair of longitudinal partition plates 22F on the forward side constitute the flow passages C5 and C4 together with the inner case 20i and the outer case 20o.
In the case of the present embodiment, space portions sandwiched by the longitudinal partition plate 22R on the rearward side and the longitudinal partition plate 22F on the forward side at the inside of the multiple case structure body 20 are defined as unused spaces 40L and 40R. The unused spaces 40L and 40R are not in communication with a flow passage at the inside of the multiple case structure body 20 by another partition wall. Also in the case of the present embodiment, the cooling liquid 50 in the cooling liquid passage 24 flows from the rearward side in the propulsion direction of the gear case portion 12L (the lower region) of the outboard motor case 12 through the forward side toward the cooling portion.
Since the electric outboard motor 101 of the present embodiment has a basic configuration similar to that of the first embodiment, it is possible to obtain effects almost similar to those of the first embodiment.
However, in the electric outboard motor 101 of the present embodiment, the inner portion of the multiple case structure body 20 is partitioned into a region that becomes a flow passage and a region that becomes the unused spaces 40L and 40R by the two pairs of longitudinal partition plates 22F and 22R. That is, the cooling liquid passage 24 is formed by only part of the space portion partitioned by the two pairs of longitudinal partition plates 22F and 22R. Therefore, a portion where the cooling liquid 50 is accumulated is not easily generated in the cooling liquid passage 24 in the multiple case structure body 20. Accordingly, when the present configuration is employed, the circulation of the cooling liquid 50 is improved, and it is possible to further efficiently cool the heat generation portion.
In the present embodiment, the space portions sandwiched by the longitudinal partition plate 22R on the rearward side and the longitudinal partition plate 22F on the forward side at the inside of the multiple case structure body 20 are the unused spaces 40L and 40R; however, a space portion sandwiched by the longitudinal partition plate 22R on the rearward side and the longitudinal partition plate 22F on the forward side may be used as flow passages C1, C2, C4, and C3, and a space portion sandwiched by the two longitudinal partition plates 22R on the rearward side and a space portion sandwiched by the two longitudinal partition plates 22F on the forward side may be the unused space.
The basic configuration of the electric outboard motor 201 of the present embodiment is almost similar to that of the first embodiment. Further, in the electric outboard motor 101 of the second embodiment described above, the inner portion of the multiple case structure body 20 of the outboard motor case 12 is partitioned by the two pairs of longitudinal partition plates 22F and 22R and is thereby partitioned into the cooling liquid passage 24 (the flow passages C1, C2, C3, C4, and C5) and the unused spaces 40L and 40R. However, in the electric outboard motor 201 of the present embodiment, a plurality of piping 45 that constitute the cooling liquid passage 24 is arranged in the space portion of the multiple case structure body 20. One end side of the plurality of piping 45 is connected to the discharge portion of the pump device, and the other end side is connected to the cooling liquid supply port (cooling portion).
Further, also in the case of the present embodiment, the cooling liquid in the cooling liquid passage 24 (the piping 45) flows from the rearward side in the propulsion direction of the gear case portion 12L (the lower region) of the outboard motor case 12 through the forward side toward the cooling portion.
Since the electric outboard motor 201 of the present embodiment has a basic configuration similar to that of the first embodiment, it is possible to obtain effects almost similar to those of the first embodiment.
However, in the electric outboard motor 101 of the present embodiment, since the cooling liquid passage 24 arranged in the space portion of the multiple case structure body 20 is constituted of the piping 45, the cooling liquid flows smoothly in the cooling liquid passage 24. Accordingly, when the present configuration is employed, the circulation of the cooling liquid is improved, and it becomes possible to further efficiently cool the heat generation portion.
Further, when the piping 45 is used, a shape having an inside where the cooling liquid is not easily accumulated can be easily formed. Therefore, when the configuration of the present embodiment is employed, it is possible to easily form a cooling liquid passage 24 having a high heat exchange efficiency.
Although the basic configuration of the electric outboard motor 301 of the present embodiment is almost similar to that of the first embodiment, the structure of a motor case portion 312U of an outboard motor case 312 is slightly different from that of the first embodiment.
The motor case portion 312U includes: a case main body 60 which has a substantially cylindrical shape and in which an upper portion opens; and an upper cover 61 that closes an opening 60a of the case main body 60 such that the opening 60a is capable of being opened and closed. In the motor case portion 312U, only the case main body 60 is constituted of the multiple case structure body 20, and the upper cover 61 is constituted of a cover member that does not have a flow passage therein. A flow passage almost similar to that of the first embodiment is formed on the multiple case structure body 20 of the case main body 60.
In the electric outboard motor 301 of the present embodiment, although an upper section (upper cover 61) of the motor case portion 312U is not constituted of the multiple case structure body 20, it is possible to obtain basic effects almost similar to those of the first embodiment.
In the electric outboard motor 301 of the present embodiment, since the upper section of the motor case portion 312U is constituted of the upper cover 61 that is capable of being opened and closed, at the time of maintenance of the electric motor 11, the pump device 30, or the like, the maintenance work can be easily performed by opening the upper cover 61.
Further, in the electric outboard motor 301 of the present embodiment, since the upper section (upper cover 61) of the motor case portion 312U is not constituted of the multiple case structure body 20, the flow passage volume of the motor case portion 312U is decreased, and it is possible to enhance the fluidity of the cooling liquid 50. Accordingly, when the present configuration is employed, it is possible to cause the cooling liquid 50 not to unnecessarily accumulate at the upper section of the motor case portion 312U and enhance the cooling performance of the electric motor 11, and it is possible to reduce the size of the pump device 30.
The present invention is not limited to the embodiments described above, and various design changes can be made without departing from the scope of the invention.
For example, the above embodiments are described using an example in which the outboard motor case 12, 312 is constituted of the multiple case structure body 20 having an inner outer double wall (the inner case 20i and the outer case 20o); however, part or all of the multiple case structure body 20 that constitutes the outboard motor case 12, 312 may have a triple or more wall.
Further, the above embodiments are described using an example in which the cooling liquid supply port 23 that is provided on the inner case 20i of the motor case portion 12U constitutes the cooling portion; however, the configuration of the cooling portion is not limited thereto. The cooling portion may be, for example, a water jacket or the like that causes the cooling liquid to flow around the heat generation portion 11b of the electric motor 11.
Further, the above embodiments are described using an example in which the heat generation portion 11b of the electric motor 11 is cooled by the cooling liquid 50 that is cooled by the gear case portion 12L (the lower region); however, the heat generation portion is not limited to the heat generation portion 11b of the electric motor 11. The heat generation portion may be, for example, the control device, the battery, or the like. Further, the arrangement position of the heat generation portion is not limited to the inside of the outboard motor case 12 and may be the outside of the outboard motor case 12.
Further, the number of the heat generation portion which is a cooling target may be two or more. For example, the electric motor and the control device which are heat generation portions may be arranged at different positions, a cooling portion may be provided on each of the electric motor and the control device, and the cooling liquid 50 that is cooled by the gear case portion 12L (the lower region) may be caused to flow to each cooling portion.
