JP6988401B2 - Generator cooling structure - Google Patents

Description

The present invention relates to a cooling structure of a generator.

Vehicles such as motorcycles are equipped with a generator that uses the power of the engine to generate electricity. This type of generator has a rotor (rotor) that rotates by transmitting a force from a rotating shaft such as a crank shaft, and a stator (stator) that is arranged so as to face the rotor.

The generator generates heat during operation, and if the temperature becomes excessively high, the power generation efficiency will decrease. However, in a motorcycle or the like in which the space around the engine or the generator is limited, sufficient heat dissipation and cooling performance may not be obtained only by the air flow flowing around the generator. In particular, when using a generator with a large amount of power generation or when trying to reduce the size and weight of the generator while maintaining the amount of power generation, it is required to enhance the cooling performance of the generator.

For example, in the cooling structure of a generator described in Patent Document 1, a hollow portion is provided in a mounting boss portion of a generator connected to a rotating shaft such as a crank shaft, and a hollow portion is connected to a rotor on the side portion of the generator. An oil passage is provided to communicate with the stator to the gap. Oil is supplied to the hollow portion from the oil supply source on the crankcase side, and the oil guided from the hollow portion to the oil passage passes through the gap between the rotor and the stator to cool the generator.

Japanese Unexamined Patent Publication No. 63-234856

The cooling structure of the generator in Patent Document 1 is provided with a dedicated oil passage for guiding the oil to the generator in the cover covering the generator. Therefore, the formation of the oil passage causes an increase in the size and weight of the cover. Further, since it is necessary to provide an oil passage according to the shape of the cover, the shape of the oil passage tends to be complicated and the manufacturing man-hours increase. Further, depending on the injection location of the oil, a large amount of oil is required to satisfy the required cooling performance, which may have an adverse effect such as an insufficient amount of oil in the engine lubrication system and a decrease in oil pressure. Further, by injecting oil into the rotating rotor, the drag resistance due to the oil viscosity increases, and there is a possibility that the mechanical operation loss increases.

The present invention has been made in view of the above points, and an object of the present invention is to provide a cooling structure for a generator capable of performing efficient cooling with a simple configuration.

The present invention includes a rotor provided in a generator room covered with a generator cover, fixed to a crank shaft and rotating together with the crank shaft, and a stator fixed with a core facing a permanent magnet provided in the rotor. In the cooling structure that cools the generator, the crank case that supports the crank shaft is provided with an oil injection port that injects oil toward the generator cover, and inside the generator cover , facing the oil injection port. An oil guide groove is provided to guide the oil to the generator by changing the direction of the oil injected from the oil injection port, and the oil guide groove is a rectangular bottomed groove having a bottom surface and a wall portion surrounding the bottom surface. It is characterized in that the side facing the oil injection port is opened to expose the bottom surface, and a portion other than the open portion is surrounded by a wall portion .

According to the present invention, the generator can be efficiently cooled by a simple configuration including an oil injection port provided in the crankcase and an oil guide groove provided inside the generator cover.

It is a left side view of the engine which concerns on this embodiment. It is a front view of the engine which concerns on this embodiment. It is a left side view of a crankcase. It is a right side view of a generator cover. It is a perspective view which shows a part of the inside of a generator cover. It is sectional drawing which follows the VI-VI line of FIG. It is sectional drawing which shows the deformation example of the oil guide groove. It is sectional drawing which shows the deformation example of the oil guide groove.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the front-rear, left-right, and up-down directions refer to the front-back, left-right, and up-down directions of the vehicle (motorcycle) equipped with the engine of the present embodiment. The left-right direction is the width direction of the engine. The object to which the engine provided with the cooling structure of the generator according to the present invention is mounted is not limited to the motorcycle, and the present invention may be applied to the engine of a four-wheeled vehicle, a ship, or the like.

1 and 2 show the appearance of the engine 10 of the present embodiment. The engine 10 is an engine for a motorcycle, and is configured by attaching a cylinder block 12, a cylinder head 13, and a cylinder head cover 14 to an upper portion of a crankcase 11. Further, an oil pan 15 is provided at the lower part of the crankcase 11.

The crankcase 11 is divided into upper and lower parts, and has an upper case 11a constituting an upper half portion and a lower case 11b constituting a lower half portion. By combining the upper case 11a and the lower case 11b, a space for accommodating the crankshaft 16 (the position in FIG. 3 when viewed from the side of the engine and the axial cross section in FIG. 6) and the like are accommodated in the crankcase 11. Is formed. The crank shaft 16 extends to the left and right, and the crank shaft 16 is arranged substantially at the center of the mating surface of the upper case 11a and the lower case 11b in a side view (see FIG. 3). As shown in FIG. 6, the crankcase 11 is formed with a bearing portion 50 that rotatably supports the crankshaft 16. In the following description, the direction orthogonal to the axis (center) of the crank shaft 16 is the radial direction, and the rotation direction about the axis of the crank shaft 16 is the circumferential direction.

The upper front side of the upper case 11a is open, and the cylinder block 12 is attached so as to close the opening. A piston (not shown) that moves back and forth in the cylinder (not shown) is arranged in the cylinder block 12. The piston is connected to the crank shaft 16 via a connecting rod (not shown), and the forward / backward movement of the piston is transmitted via the connecting rod to rotate the crank shaft 16.

The lower case 11b is opened downward, and an oil pan 15 is attached so as to close this opening. It has a lubrication structure in which oil is stored in the oil pan 15 and oil is supplied from the oil pan 15 to each part of the engine 10. The lubrication structure will be briefly described because the existing configuration can be used for the configuration other than the cooling of the generator 30, which will be described later.

As shown in FIGS. 1 and 2, an oil filter 17 for filtering oil and an oil cooler 18 for cooling oil are attached to the front surface of the lower case 11b. The oil in the oil pan 15 is sucked by an oil pump (not shown), relatively large foreign matter is removed by a strainer (not shown), and sent to an oil filter 17 to remove fine foreign matter. The oil that has passed through the oil filter 17 is cooled by the oil cooler 18 and sent to the main gallery 51 (partially shown in FIG. 6).

Oil is supplied from the main gallery 51 to each part of the engine 10. As shown in FIG. 6, the crankcase 11 is formed with an oil passage 52 extending in the radial direction from the main gallery 51 toward the bearing portion 50. The oil that has lubricated the bearing portion 50 through the oil passage 52 is collected in the oil pan 15 through a predetermined path. A plurality of oil passages extend from the main gallery 51 in addition to the oil passage 52, and oil is supplied to a plurality of locations other than the bearing portion 50. For example, oil is supplied from the main gallery 51 to the bearing portion of the balancer shaft arranged in the crankcase 11.

As shown in FIG. 2, a clutch cover 19 is attached to the right side surface of the crankcase 11. A clutch chamber (not shown) for accommodating a clutch mechanism (not shown) is formed between the crankcase 11 and the clutch cover 19. The rotation of the crankshaft 16 is transmitted to a speed change mechanism (not shown) in the transmission chamber of the crankcase 11 via the clutch mechanism, and is taken out as a driving force for driving the drive wheels (rear wheels) of the motorcycle.

As shown in FIG. 6, on the left side surface of the crankcase 11, an outer peripheral wall 11d projects to the left from the side wall 11c in which the bearing portion 50 and the oil passage 52 are formed. As shown in FIG. 3, the outer wall 11d is formed over the upper case 11a and the lower case 11b so as to surround the crank shaft 16 (bearing portion 50), and the end faces of the outer wall 11d are aligned to the left. The surface is 11e.

A generator cover 20 is attached to the left side of the crankcase 11 so as to close the opening surrounded by the outer wall 11d. The generator cover 20 has a lid portion 20a facing the side wall 11c of the crankcase 11 and an outer peripheral wall 20b protruding to the right from the peripheral edge of the lid portion 20a. The outer wall 20b has a shape continuous with the outer wall 11d of the crankcase 11 in the left-right direction, and the end surface of the outer wall 20b is a mating surface 20c facing to the right (see FIG. 4).

When the mating surface 11e and the mating surface 20c are brought into contact with each other and the generator cover 20 is fastened and fixed to the crankcase 11, a generator chamber 21 (see FIG. 6) surrounded by the crankcase 11 and the generator cover 20 is formed. As shown in FIG. 3, the side wall 11c of the crankcase 11 is formed with a penetrating portion 11f that communicates the lowermost portion of the generator chamber 21 with the inside of the crankcase 11, and the oil that has entered the generator chamber 21 is formed. Can be returned to the inside of the crankcase 11 from the penetrating portion 11f.

As shown in FIG. 6, one end of the crank shaft 16 projects into the generator chamber 21, and the generator 30 that generates power by the rotation of the crank shaft 16 is housed in the generator chamber 21. The generator 30 of the present embodiment is an outer rotor type generator in which a permanent magnet located on the outer diameter side of the core (coil) rotates to generate an electromotive force, and is a bottomed cylindrical rotor as a rotor. It has 31 and has a stator 36 located inside the rotor 31 as a stator.

The rotor 31 has a bottom portion 32 facing the side wall 11c side (right side) of the crankcase 11, and an outer cylinder 33 and an inner cylinder 34 having a concentric cylindrical shape protruding left from the bottom portion 32. The inner peripheral surface of the outer cylinder 33 and the outer peripheral surface of the inner cylinder 34 are cylindrical surfaces that are radially opposed to each other and extend in the circumferential direction. A permanent magnet 35 is attached along the inner peripheral surface of the outer cylinder 33. In the permanent magnet 35, N poles and S poles are alternately arranged in the circumferential direction. For example, a plurality of magnets may be arranged in the circumferential direction by alternating the directions of the magnetic poles to form the permanent magnet 35, or the magnetizing states of the annular magnets continuous in the circumferential direction may be partially different to form the permanent magnet 35. May be configured. One end of the crank shaft 16 protruding into the generator chamber 21 is inserted into the center of the inner cylinder 34 in a press-fitted state, and when the engine is driven and the crank shaft 16 rotates, the rotor 31 rotates together with the crank shaft 16. do.

The stator 36 has a plurality of cores 38 that radiate from the annular base 37 surrounding the inner cylinder 34 of the rotor 31 toward the outer diameter side (see FIG. 3). As shown in FIG. 6, each core 38 is a coil in which a conducting wire is wound around a core portion 38a made of a magnetic metal to form a conducting wire portion 38b. The stator 36 is fixed to the generator cover 20. When the generator cover 20 is attached to the crankcase 11, as shown in FIGS. 3 and 6, a predetermined gap is provided in the radial direction with respect to the inner peripheral surface of the permanent magnet 35, and the outer circumference of each core 38 of the stator 36 is formed. The parts face each other.

When the rotor 31 rotates with the rotation of the crank shaft 16, the N pole and the S pole of the permanent magnet 35 alternately pass outside the core 38 of the stator 36, so that the magnetic flux density passing through the core 38 changes, and electromagnetic induction is performed. Causes a current to be generated in the core 38. The generator 30 generates alternating current, which is converted to direct current by a rectifier (not shown) and controlled by a voltage adjustment circuit (not shown) to a certain level or less. The electric power thus obtained by using the generator 30 is supplied to the electrical system of the motorcycle equipped with the engine 10.

In the generator room 21, two starter idle gears 40 and a starter motor 41 are arranged above the rear part of the generator 30 (see FIG. 3). The starter motor 41 applies a rotational force to the crank shaft 16 when the engine 10 is started, and the driving force is transmitted from the starter motor 41 to the starter one-way clutch (not shown) via the starter idle gear 40. The starter one-way clutch is a clutch mechanism capable of transmitting a rotational force to the crankshaft 16 in only one direction.

The generator cover 20 has a first cover portion 22 that covers the generator 30, and a second cover portion 23 that covers the starter idle gear 40 and the starter motor 41.

The first cover portion 22 is formed in a substantially circular shape in a side view, and the outer cylinder portion 20b covers the outer diameter side of the outer cylinder 33 of the rotor 31 and the lid portion 20a covers the left side of the rotor 31 and the stator 36. It constitutes a part. An oil injection port 24 (see FIG. 4) penetrating the lid portion 20a is provided near the upper end of the first cover portion 22, and an oil cap 25 (see FIG. 1) is attached to the oil injection port 24. Oil can be injected into the engine 10 from the oil inlet 24 by removing the oil cap 25. A cylindrical mounting portion 26 projecting inward from the lid portion 20a from the lid portion 20a is formed substantially in the center of the first cover portion 22 (see FIGS. 4 to 6). The base portion 37 of the stator 36 is fitted to the mounting portion 26, and the mounting portion 26 and the base portion 37 are fixed with bolts (not shown) or the like.

The second cover portion 23 has a substantially triangular shape in a side view protruding upward from the first cover portion 22. Inside the second cover portion 23, two bearing portions 27 are formed so as to project from the lid portion 20a into the generator chamber 21 and support the shaft of each starter idle gear 40 (see FIG. 4).

In this embodiment, oil is injected into the generator 30 in the generator room 21 with a simple structure to cool the generator, and the details thereof will be described below.

As shown in FIG. 6, on the side wall 11c of the crankcase 11, an oil injection port 53 extending in the left-right direction and opening into the generator chamber 21 is provided in the middle of the oil passage 52 from the main gallery 51 to the bearing portion 50. It is formed. As shown in FIG. 3, the oil injection port 53 is formed in the lower case 11b of the crankcase 11 and is located in front of and below the center of the crankshaft 16.

The oil injection port 53 is, for example, a circular cross-sectional hole having a diameter of about 1 mm, and has an extremely small cross-sectional area as compared with the oil passage 52. Therefore, a part of the oil pumped from the main gallery 51 to the oil passage 52 is vigorously injected into the generator chamber 21 through the oil injection port 53.

When viewed from the side as shown in FIG. 3, the oil injection port 53 includes the inner wall surfaces of the outer peripheral walls 11d and 20b of the crankcase 11 and the generator cover 20 (first cover portion 22), and the outermost periphery of the generator 30. It is located between the outer peripheral surface of the rotor 31 which is a portion. Therefore, as shown by the arrow line A1 in FIG. 6, the oil injected from the oil injection port 53 passes near the inner wall surface of the outer wall 11d and travels to the left in the generator chamber 21 to the outer wall 20b. It passes between the inner wall surface and the outer peripheral surface of the rotor 31.

As shown in FIG. 6, an oil guide groove 55 is formed inside the generator cover 20 at a position facing the oil injection port 53. The oil guide groove 55 is a bottomed groove that is formed at the boundary between the lid portion 20a and the outer peripheral wall 20b in the first cover portion 22 and extends in the radial direction, and is substantially rectangular in side view (see FIG. 4). More specifically, the oil guide groove 55 is composed of a bottom surface 55a and a wall portion 55b surrounding the bottom surface 55a, and the right side surface facing the oil injection port 53 is opened to expose the bottom surface 55a and the right side surface. The parts other than the above are surrounded by the wall portion 55b (see FIG. 5).

As shown in FIGS. 5 and 6, the bottom surface 55a becomes shallower from the outer diameter side near the outer wall 20b toward the inner diameter side where the center of the crank shaft 16 is located (the amount of protrusion to the right increases). ). The length of the oil guide groove 55 in the radial direction is larger than the diameter of the oil injection port 53, and the one located on the extension of the oil injection port 53 in the left-right direction is the outside of the oil guide groove 55 having a large depth. It is on the diameter side (see FIG. 6). As shown in FIG. 6, the position B1 of the end portion on the inner diameter side of the bottom surface 55a in the radial direction is located on the inner diameter side of the position B2 on the outer peripheral surface of the rotor 31. More specifically, in the radial direction, the position B1 of the end portion on the inner diameter side of the bottom surface 55a is substantially the same as the boundary between the inner peripheral surface of the rotor 31 and the permanent magnet 35. Then, there is a gap between the rotor 31 (permanent magnet 35) and the stator 36 (core 38) at a position where the bottom surface 55a is virtually extended from the position B1 of the inner diameter side end portion to the inner diameter side.

The oil injected into the generator chamber 21 from the oil injection port 53 (arrow line A1 in FIG. 6) passes between the outer wall 20b and the rotor 31 and reaches the oil guide groove 55. The oil hits a portion of the bottom surface 55a of the oil guide groove 55 on the outer diameter side (position close to the outer peripheral wall 20b) having a large depth. Then, as shown by the arrow line A2 in FIG. 6, the traveling direction of the oil is changed by the oil guide groove 55, and the oil heads toward the generator 30 along the inclined shape of the bottom surface 55a. The wall portion 55b of the oil guide groove 55 suppresses the scattering of oil to the surroundings when the oil hits the bottom surface 55a vigorously from the oil injection port 53, and efficiently in the direction along the arrow A2. It works to direct the oil.

In this way, the oil injected from the oil injection port 53 and whose traveling direction is changed by the oil guide groove 55 is located near the gap between the permanent magnet 35 inside the rotor 31 and the core 38 of the stator 36 in the generator 30. To reach. As shown in FIG. 6, since the left end portion of the core 38 protrudes to the left rather than the left end portion of the permanent magnet 35, the outer peripheral surface of the core 38 is positioned in the traveling direction of the oil from the oil guide groove 55. And you can definitely receive the oil.

The oil that has entered the gap between the permanent magnet 35 and the core 38 is transferred in the circumferential direction along the inner peripheral surface of the permanent magnet 35 by the rotation of the rotor 31, and the oil adhering to the inner peripheral surface of the permanent magnet 35 causes the stator 36. The outer peripheral portion of the core 38 is cooled. In the generator 30, the core 38 tends to generate heat, and the outer peripheral portion of the core 38 is the portion where cooling is most required. Therefore, efficient cooling can be performed by guiding the cooling oil toward the outer peripheral portion of the core 38 by the oil guide groove 55. On the other hand, since the calorific value of the central portion of the stator 36 where the base portion 37 is located is small, the need to supply cooling oil is low.

The oil that has entered between the permanent magnets 35 and the core 38 and contributed to cooling is discharged from the end of the rotor 31 to the outside of the generator 30 by the centrifugal force of the rotating rotor 31. More specifically, since the oil guide groove 55 is located on the diagonally left side of the generator 30 (the lid portion 20a side of the generator cover 20), oil is injected to the left end side of the generator 30. Since the gap between the inner peripheral surface of the permanent magnet 35 and the outer peripheral portion of the core 38 is narrow, it is necessary for cooling without passing wasteful oil to the inner side of the generator 30 (to the right where the bottom 32 of the rotor 31 is located). A moderate amount of oil can be distributed in the gap. Then, the oil that has taken heat from the core 38 and the like is discharged from the gap by the centrifugal force of the rotor 31. The discharged oil travels along the inner surface of the generator cover 20 or naturally falls, moves downward in the generator chamber 21, and passes through the penetration portion 11f (FIG. 3) formed in the crankcase 11. It is collected in the oil pan 15.

With the above cooling structure, cooling oil can be efficiently supplied to the generator 30 by a configuration that can be easily and inexpensively obtained. Since the generator cover 20 is only provided with an oil guide groove 55 having a simple shape exposed on the inner surface, the configuration of the generator cover 20 is simplified as compared with the case where a complicated oil passage is provided in the cover wall portion. It can be made smaller and lighter. Further, when the generator cover 20 is manufactured, the oil guide groove 55 has a shape that does not interfere with the die cutting of the molding die, so that the manufacturing cost and the manufacturing man-hours can be reduced. The crankcase 11 also has a simple configuration in which a short oil injection port 53 having a small diameter is formed in the middle of the oil passage 52 from the main gallery 51 to the bearing portion 50, and the crankcase 11 is enlarged and the internal structure is complicated. Can be avoided. Therefore, the number of parts does not increase with respect to the cooling of the generator 30, and the processing man-hours required for manufacturing the generator cover 20 and the crankcase 11 do not need to be increased.

Further, since the oil injected from the oil injection port 53 is received by the oil guide groove 55 and the direction is changed, the internal space of the generator chamber 21 functions as an oil passage between the crank case 11 and the generator cover 20. , Does not require its own oil passage. Therefore, when the generator cover 20 is attached to the crankcase 11, it is not necessary to connect the cooling oil passage of the generator 30, and the assembly man-hours can be reduced. When the generator cover 20 is attached to the crankcase 11, the mutual positions of the oil injection port 53 and the oil guide groove 55 are automatically determined, so that time-consuming position adjustment is not required.

Further, the oil injection port 53 for injecting oil into the generator room 21 is provided in the middle of the oil passage 52 from the main gallery 51 to the bearing portion 50, instead of directly branching from the main gallery 51. As a result, it is possible to suppress a decrease in hydraulic pressure and a fluctuation in hydraulic pressure of the main gallery 51 when injecting cooling oil from the oil injection port 53 to the generator 30 side. Further, since the oil injection port 53 is provided on the upstream side of the bearing portion 50, the conditions such as the hydraulic pressure sent from the oil injection port 53 to the oil guide groove 55 are stable, and the excellent cooling performance for the generator 30 is achieved. Can be obtained.

The oil injection port 53 and the oil guide groove 55 are arranged forward and downward with respect to the center of the crank shaft 16. As shown in FIGS. 1 and 2, the oil filter 17 and the oil cooler 18 are provided forward and downward with respect to the center of the crank shaft 16, and the oil injection port 53 and the oil guide groove 55 are provided in the front-rear direction and the vertical direction. It is located close to the oil filter 17 and the oil cooler 18. That is, the oil paths from the oil filter 17 to the oil injection port 43 and the oil guide groove 55 are centrally arranged in the region from the lower part to the front of the crank shaft 16, and the generator cooling system can be configured in a space-saving manner. can. Further, since the oil path from the oil filter 17 to the oil injection port 43 and the oil guide groove 55 is short, pressure loss when sending oil is small, and the load on the oil pump can be suppressed.

The oil injection position of the oil guide groove 55 is optimized so as to efficiently cool the generator 30 with a small amount of oil. The main heat generating source of the generator 30 is the core 38 (particularly the outer peripheral portion), but instead of simply injecting oil only toward the core 38, the permanent magnet 35 and the core provided on the inner circumference of the rotating rotor 31 are provided. The oil guide groove 55 is configured so that the gap of 38 is the target of oil injection. When oil is injected from the oil guide groove 55, the oil easily enters the gap between the permanent magnet 35 and the core 38, and the oil that has entered the gap is transferred to a wide range in the circumferential direction by the rotation of the rotor 31. In other words, the rotating rotor 31 is used as part of the cooling structure of the generator 30. As a result, the oil can be distributed not only to the specific position in the circumferential direction in which the oil guide groove 55 is provided but also to the outer peripheral portion of the core 38 in the entire circumferential direction. Then, since a high cooling effect of the core 38 can be obtained over the entire circumference of the generator 30 with a small amount of oil, oil is applied to the rotating portion (bottom 32 of the rotor 31, inner cylinder 34, etc.) where cooling is less necessary. It is possible to reduce adhesion and suppress drag resistance and stirring resistance due to oil viscosity. That is, it is possible to reduce the mechanical operation loss during the operation of the generator 30.

Further, when the amount of oil used for cooling the generator 30 is small, the load on the oil pump is reduced, and the amount of oil for lubrication of each part of the engine 10 and fluctuations in oil pressure are suppressed. As a result, it is possible to prevent an adverse effect on the lubrication performance while cooling the generator 30 by using the lubricating oil.

In the generator 30, no changes such as providing a cooling oil passage in the rotor 31 and the stator 36 have been made, and a generator having a general configuration can be used, so that the number of parts increases and the manufacturing cost increases. Does not lead to an increase in.

The amount of oil supplied to the generator 30 and the momentum of oil injection can be changed by setting the inner diameter and the cross-sectional shape of the oil injection port 53. Further, the state of oil injection from the oil injection port 53 is also affected by the oil pressure of the oil traveling from the main gallery 51 to the oil passage 52, the performance of the oil pump, and the like. Therefore, the oil injection port 53 is designed so as to obtain the optimum cooling performance for the generator 30 in consideration of these factors comprehensively.

7 and 8 show a modified example of the oil guide groove provided in the generator cover 20. Although the oil injection port 53 is not shown in FIGS. 7 and 8, it is assumed that the oil injection port 53 is located on the right extension of the arrow line A1 as in FIG.

The bottom surface 60a of the oil guide groove 60 shown in FIG. 7 increases in distance from the oil injection port 53 from the outer diameter side near the outer peripheral wall 20b of the generator cover 20 toward the inner diameter side where the center of the crank shaft 16 is located. A surface that inclines in the direction (to the left).

The oil guide groove 60 further has an introduction guide surface 60c located on the outer diameter side and a discharge guide surface 60d located on the inner diameter side as the inner surface of the wall portion 60b surrounding the bottom surface 60a. The introduction guide surface 60c and the discharge guide surface 60d are surfaces extending in the left-right direction, respectively. The introduction guide surface 60c is formed in the vicinity of the oil introduction portion that is injected from the oil injection port 53 and reaches the oil guide groove 60 along the arrow line A1, and guides the oil to the bottom surface 60a. The oil that hits the bottom surface 60a near the introduction guide surface 60c changes the traveling direction and advances toward the inner diameter side along the inclination of the bottom surface 60a, and further hits the discharge guide surface 60d and changes the traveling direction to the right (arrow line in FIG. 7). A3). A gap between the rotor 31 (permanent magnet 35) and the stator 36 (core 38) is located to the right of the discharge guide surface 60d, and the oil whose traveling direction has been changed in two stages by the oil guide groove 60 is near the gap. Is sprayed on. Then, the generator 30 can be efficiently cooled centering on the outer peripheral portion of the core 38 having a large calorific value.

The oil guide groove 65 shown in FIG. 8 has a structure in which the central portion in the radial direction of the oil guide groove 60 of FIG. 7 is omitted. The introduction guide surface 65c and the discharge guide surface 65d in the oil guide groove 65 have substantially the same shape and function as the introduction guide surface 60c and the discharge guide surface 65d of the oil guide groove 60, respectively. The bottom surface 65a is formed only on the outer diameter side portion close to the introduction guide surface 65c and the inner diameter side portion close to the discharge guide surface 65d, and the generator cover located at a position deeper than the bottom surface 65a in the central portion in the radial direction. The inner surface of 20 (cover portion 20a) is exposed. Correspondingly, the vertical wall 65b does not exist in the central portion in the radial direction.

Since the momentum of the oil injected from the oil injection port 53 is strong, even in the form of the oil guide groove 65, the traveling direction of the oil is changed to two stages as shown by the arrow A3, and the generator 30 needs to be cooled. Oil can be reliably guided to the part.

In the configurations shown in FIGS. 7 and 8, the traveling direction of the oil from the oil guide groove 60 and the oil guide groove 65 toward the generator 30 is the direction along the gap between the permanent magnet 35 and the core 38. It becomes easier for oil to infiltrate.

On the other hand, in the configuration shown in FIG. 6, the oil guide groove 55 injects oil in a direction (arrow line A2) inclined with respect to the direction along the gap between the permanent magnet 35 and the core 38. Therefore, even if there is some accuracy error between the oil guide groove 55 and the generator 30, it is easy to apply oil to the vicinity of the gap between the permanent magnet 35 and the core 38. In particular, the left end of the core 38 protrudes to the left of the left end of the permanent magnet 35, making it easier to receive the oil traveling along the arrow A2, so that the inner diameter of the core 38 is not cooled. Wasteful oil that flows to the side is unlikely to occur.

As described above, according to the cooling structure of the generator according to the present embodiment, the oil injection port 53 formed in the crank case 11 and the oil guide groove 55 (60, 65) formed inside the generator cover 20. ), The generator 30 can be efficiently cooled.

The present invention is not limited to the above embodiment, and can be modified in various ways. In the above embodiment, the size, shape, and the like shown in the accompanying drawings are not limited to this, and can be appropriately changed within the range in which the effects of the present invention are exhibited. In addition, it can be appropriately modified and implemented as long as it does not deviate from the scope of the object of the present invention.

For example, in the above embodiment, the oil guide grooves 55, 60, 65 are integrally formed with the generator cover 20, but the oil guide grooves 55, 60, 65 are members different from the generator cover 20. It is also possible to attach it to the generator cover 20 after forming the above.

The generator 30 of the above embodiment is an outer rotor type in which the rotating rotor 31 is located on the outer diameter side and the non-rotating stator 36 is located on the inner diameter side. Unlike this, the present invention can also be applied as a cooling structure for an inner rotor type generator in which the rotor is arranged on the inner diameter side and the stator is arranged on the outer diameter side.

As described above, the present invention has an effect that the generator can be efficiently cooled with a simple configuration, and is particularly useful for an engine or the like equipped with a small and lightweight generator having a large amount of power generation.

10: Engine 11: Crankcase 12: Cylinder block 13: Cylinder head 14: Cylinder head cover 15: Oil pan 16: Crank shaft 17: Oil filter 18: Oil cooler 19: Clutch cover 20: Generator cover 21: Generator room 22 : 1st cover part (outer cylinder part)
23: 2nd cover part 26: Mounting part 27: Bearing part 30: Generator 31: Rotor 33: Outer cylinder 34: Inner cylinder 35: Permanent magnet 36: Stator 37: Base 38: Core 50: Bearing part 51: Main gallery 52: Oil passage 53: Oil injection port 55: Oil guide groove 55a: Bottom surface 55b: Wall 60: Oil guide groove 60a: Bottom surface 60b: Wall 60c: Introduction guide surface 60d: Discharge guide surface 65: Oil guide groove 65a: Bottom surface 65b: Wall 65c: Introduction guide surface 65d: Discharge guide surface

Claims (7)

In the generator room covered with the generator cover, a generator having a rotor fixed to the crank shaft and rotating together with the crank shaft and a stator fixed with the core facing the permanent magnet provided in the rotor is installed. Prepare,
The crankcase that supports the crankshaft is provided with an oil injection port that injects oil toward the generator cover.
An oil guide groove is provided inside the generator cover, which is located facing the oil injection port and guides the oil to the generator by changing the direction of the oil injected from the oil injection port .
The oil guide groove is a rectangular bottomed groove having a bottom surface and a wall portion surrounding the bottom surface, and the side facing the oil injection port is opened to expose the bottom surface, and a portion other than the opened portion is described. The cooling structure of the generator, which is characterized by being surrounded by a wall. The rotor has a bottomed cylindrical shape whose central portion is fixed to the crank shaft, the permanent magnet is arranged on the inner circumference of the cylindrical portion of the rotor, and the core of the stator is located inside the cylindrical portion. ,
The generator cover has an outer cylinder portion that surrounds the rotor.
The oil guide groove is provided on the outer peripheral portion of the outer cylinder portion of the generator cover, and extends in the radial direction about the center of the crank shaft in a side view.
The cooling structure for a generator according to claim 1, wherein one end of the oil guide groove is located closer to the center of the crank shaft than the outer periphery of the generator in the radial direction. The length of the oil guide groove in the radial direction is larger than the diameter of the oil injection port.
The oil guide groove has the largest depth to the bottom surface at a position facing the oil injection port, and is characterized in that the depth to the bottom surface decreases toward the center of the crank shaft in the radial direction. The cooling structure for the generator according to claim 2. The oil guide groove is
A bottom surface in which the distance from the oil injection port increases toward the center of the crank shaft in the radial direction.
A discharge guide surface provided at one end in the radial direction and protruding from the bottom surface toward between the permanent magnet and the core.
2. The cooling structure for a generator according to claim 2. The generator according to any one of claims 2 to 4, wherein the oil injection port is located between the outer cylinder portion of the generator cover and the generator in a side view. Cooling structure. The cooling structure for a generator according to any one of claims 1 to 5, wherein the oil guide groove is located in front of and below the center of the crank shaft. The cooling of the generator according to any one of claims 1 to 6, wherein the oil injection port is provided in an oil passage connecting the main gallery and the bearing portion supporting the crank shaft. structure.

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