WO2022049956A1

WO2022049956A1 - Rotating electric machine for internal combustion engine

Info

Publication number: WO2022049956A1
Application number: PCT/JP2021/028531
Authority: WO
Inventors: 誠一水谷; 優太小寺; 知也大原
Original assignee: 株式会社デンソートリム
Priority date: 2020-09-03
Filing date: 2021-08-02
Publication date: 2022-03-10
Also published as: JPWO2022049956A1; CN116171520A; JP7074945B1

Abstract

The present invention comprises: a Hall sensor that is disposed between adjacent coils of a plurality of coils to face a magnet and detects the magnetic flux of the magnet; and a sensor case that holds a substrate of this Hall sensor. The sensor case is disposed on an engine cover side of a stator, and the sensor case is fixed to a base portion of the stator and also to the engine cover. The Hall sensor is held in the sensor case together with the substrate, and the sensor case is directly fixed to the engine cover. Therefore, heat of the Hall sensor can be released to the outside air from the engine cover through the sensor case, thereby improving the heat resistance of the Hall sensor.

Description

Rotating electric machine for internal combustion engine

Cross-reference of related applications

This application is based on Patent Application No. 2020-148482 filed in Japan on September 3, 2020, and the contents of the basic application are incorporated by reference as a whole.

The description in this specification relates to a rotary electric machine that can be used as a generator or a starter for a two-wheeled vehicle.

Patent Document 1 and Patent Document 2 disclose that a three-phase brushless motor is used as a rotary electric machine that can be used as a generator or a starter for a two-wheeled vehicle. In the techniques of Patent Document 1 and Patent Document 2, the rotational position of the rotor is detected from the magnetic flux change of the magnet provided in the rotor, and the reference position signal for ignition control of the internal combustion engine is detected.

Japanese Unexamined Patent Publication No. 2016-11917 Japanese Unexamined Patent Publication No. 2014-152662

In the rotary electric machine described in Patent Document 1, the case of the hall sensor is fixed to the stator and also tightened to the engine block side for the hall sensor that detects the position of the rotor of the start generator for two wheels. This improves the positioning accuracy.

By the way, since the Hall sensor is an electronic component, there is a limit to the heat resistant temperature. Generally, in the case of a scooter, the mounting portion of the starting generator is outside the engine, and the structure is such that the outside air constantly flows in and is cooled. Therefore, the heat resistance of the Hall sensor is not a big problem. On the other hand, there is also a structure in which the engine structure is different and the starting generator is arranged inside the engine. In this case, the starting generator will be sealed in a high temperature environment and in engine oil. Therefore, when the sensor is fixed to the engine block side, the temperature becomes high and exceeds or approaches the heat resistant temperature. In addition, there is a problem that the life of the resin that protects the sensor and the attached substrate is shortened due to the high temperature in the environment where the engine oil is scattered.

In the rotary electric machine described in Patent Document 1, the temperature rises by assembling the case of the hall sensor to the engine block, which causes a problem in heat resistance. In particular, when the rotary electric machine is arranged inside the engine, it is used in a higher temperature environment, and the problem of heat resistance becomes more remarkable.

The rotary electric machine described in Patent Document 2 is a type in which a starting generator is arranged inside the engine, and the stator is fixed to the engine cover. The Hall sensor is arranged on the stator, and the electric wire of the Hall sensor is taken out from the engine cover together with the power line of the coil. The Hall sensor disclosed in Patent Document 2 is also used in a high temperature engine internal environment, and has a problem of heat resistance.

The subject of this disclosure is to improve the heat resistance of the hall sensor used in a high temperature environment on the premise that the rotary electric machine to be the starting generator is arranged inside the engine.

The first of the present disclosure is a rotor that rotates integrally with the crankshaft, a plurality of magnets arranged in the circumferential direction on the rotor, a base portion attached to the engine cover, and a plurality of portions extending radially outward from the base portion. It is a rotary electric machine for an internal combustion engine including a teeth portion and a coil arranged in the teeth portion, and a stator having a radially outer end portion of the teeth portion facing a magnet. The first aspect of the present disclosure stipulates the premise that the rotary electric machine is arranged inside the engine by assembling the rotor to the crankshaft and the stator to the engine cover.

The first of the present disclosure is provided with a sensor case which is arranged between adjacent coils of a plurality of coils so as to face the magnet and holds a hall sensor for detecting the magnetic flux of the magnet and a substrate of the hall sensor. The case is arranged on the engine cover side of the stator, and the sensor case is fixed to the base portion of the stator and also to the engine cover.

The first of the present disclosure is that the Hall sensor is held in the sensor case together with its substrate, and the sensor case is directly fixed to the engine cover, so that the heat of the Hall sensor is transferred to the engine cover via the substrate and the sensor case. do. Since the engine cover is in contact with the outside air, heat can be released to the outside air from the engine cover, and the heat resistance of the hall sensor can be improved.

The second of the present disclosure is that the rotary electric machine for an internal combustion engine is a three-phase starting generator, and the Hall sensor has three sensors for detecting the rotation positions of the U phase, the V phase, and the W phase, and a reference position of the crankshaft. There are four sensors in total, one sensor for detecting the above, and each Hall sensor is arranged between adjacent coil portions.

In the second aspect of the present disclosure, since the sensor case is fixed to the stator, the positional relationship between the Hall sensor and the U-phase, V-phase, and W-phase of the coil portion is accurately determined. In addition, since the sensor case is also fixed to the engine cover, the stator fixed to the engine cover can be positioned via the sensor case. for that reason. In the second aspect of the present disclosure, the rotation position of the rotor can be detected accurately, and the reference position for ignition control can be detected accurately.

The third of the present disclosure has a plurality of Hall sensors, at least one of which is arranged on the engine cover side from the intermediate position of the axial length of the teeth portion. Therefore, the distance between the hall sensor and the engine cover becomes relatively short, and heat is smoothly dissipated from the hall sensor to the engine cover.

The fourth aspect of this disclosure is the structure of the sensor case. The sensor case includes the hall sensor, the sensor body that holds the hall sensor board, the stator fixing part that is located inward in the radial direction of the sensor body, and the engine cover that is located in the radial direction of the sensor body. Provided with a fixed portion.

In the fourth aspect of the present disclosure, the sensor main body portion can be arranged so as to correspond to the tooth portion and the coil of the stator, and the stator fixing portion can be arranged so as to correspond to the base portion of the stator. On top of that, since the engine cover fixing portion is located radially outside, the sensor case can be compactly stored inside the engine cover.

The fifth of the present disclosure is a fixed structure of the stator and the sensor case. A fixing bolt hole is formed in the stator fixing portion of the sensor case, and a sensor case bolt through hole is also formed in the base portion of the stator. The stator and the sensor case are fixed by screwing the stator bolts into the fixing portion bolt holes of the stator fixing portion of the sensor case through the sensor case bolt through holes of the stator. In the fifth aspect of the present disclosure, the sensor case is fixed to the stator by using a base portion for fixing the stator to the engine cover.

The sixth of the present disclosure is a fixed structure of the sensor case and the engine cover. A positioning hole is formed in the engine cover fixing portion, and the sensor case is fixed to the engine cover by a positioning screw. The positioning screw includes a positioning cylinder portion corresponding to the positioning hole of the engine cover fixing portion, a bolt portion formed on one end side of the positioning cylinder portion and screwed with the screw portion of the engine cover, and the positioning cylinder portion. It has a wrench head formed on the end side. Moreover, the diameter of the positioning cylinder portion is larger than the diameter of the bolt portion.

In the sixth aspect of the present disclosure, the sensor case and the engine cover are fixed at accurate positions by the positioning hole of the engine cover fixing portion and the cylindrical portion of the positioning screw. In addition, since the diameter of the positioning cylinder portion is larger than the diameter of the bolt portion, the heat of the sensor case easily escapes to the engine cover through the cylinder portion and the wrench head.

The seventh of the present disclosure is to position the stator fixing part and the engine cover fixing part in the substantially central part of the sensor main body part to improve the balance of the sensor case at the time of fixing.

The eighth of the present disclosure is the placement position of the sensor case. The sensor case is arranged above the intermediate position of the engine cover including the intermediate position in the vertical direction. Splashes of engine oil are scattered inside the engine cover, and this engine oil is relatively abundant in the lower part. Therefore, if the sensor case is arranged above, the possibility that the high temperature engine oil directly scatters on the hall sensor can be reduced.

The ninth of the present disclosure is also the placement position of the sensor case. The sensor case is arranged below the intermediate position of the engine cover including the intermediate position in the vertical direction. In a situation where the engine is stopped after rotating the engine at high speed for a long time, the hot air inside the engine flows upward. If the sensor case is located in the upper part in such a state, it is easily affected by the heat of the high temperature air, but if it is arranged in the lower part, it is less likely to be affected by the high temperature air.

The tenth of the present disclosure has a gap between the hall sensor and the coil. As a result, the Hall sensor has a structure that does not come into direct contact with the coil, and the heat of the coil can be prevented from being directly transferred to the Hall sensor.

The eleventh of this disclosure is that the engine cover is ribbed. That is, the engine cover has a cylindrical portion provided in the central portion corresponding to the crankshaft, a bolt through hole provided in the peripheral portion, and a rib extending from the cylindrical portion toward the bolt through hole. There is. Then, the sensor case is fixed on the rib or on the line of the rib in the engine cover. This makes it possible to improve the seismic resistance of the sensor case.

In the twelfth aspect of the present disclosure, the sensor case is fixed to the engine cover on the rib or on the line of the rib at a position where the distance to the bolt through hole is shorter than the distance to the cylindrical portion. The earthquake resistance of the sensor case can be further improved.

In the thirteenth aspect of the present disclosure, the sensor case includes a sensor main body made of a resin material that holds the hall sensor and the substrate, and a metal heat dissipation plate portion that is arranged on the engine cover side of the sensor main body. Since a metal heat sink is formed on the sensor case and the heat sink is arranged on the engine cover side, the heat transfer efficiency from the hall sensor to the engine cover side can be improved. As a result, the heat resistance of the Hall sensor can be further improved.

In the fourteenth aspect of the present disclosure, the sensor case has a sensor main body made of a resin material that holds the hall sensor and the substrate, a metal heat sink arranged on the engine cover side of the sensor main body, and the heat sink. It is equipped with a metal cooling plate portion that extends from the portion to the hall sensor side. By adding a metal cooling plate portion extending from the heat sink portion to the hall sensor side with respect to the thirteenth of the present disclosure, the heat of the hall sensor is transferred to the heat sink portion via the cooling plate portion. This makes it possible to further improve the heat resistance performance of the Hall sensor.

Fifteenth of the present disclosure, the sensor case includes a sensor main body portion that holds the hall sensor and the substrate, and an engine cover fixing portion that fixes the sensor case to the engine cover. Further, the sensor case is fixed to the engine cover by a positioning screw. The positioning screw has a bolt portion that sandwiches the engine cover fixing portion and the heat sink portion of the sensor case and is screwed with the screw portion of the engine cover. Since the heat sink of the sensor case is screwed to the engine cover, the metal heat sink comes into direct contact with the engine cover. As a result, heat is smoothly transferred from the sensor case to the engine cover.

Also in the 16th of the present disclosure, the sensor case is fixed to the engine cover by the positioning screw. The positioning screw has a bolt portion that sandwiches only the heat sink portion of the sensor case and is screwed with the screw portion of the engine cover. Since the engine cover fixing part of the sensor case is made of a resin material, the dimensional accuracy may be inferior if warpage occurs due to the influence of heat. On the other hand, the metal heat sink is less affected by warpage, and the position can be easily adjusted when it is fixed to the engine cover with the positioning screw.

Furthermore, the engine cover fixing part made of resin material may cause creep deformation when screwed with the positioning screw, but the metal heat dissipation plate part may not cause creep deformation. In addition, since it is screwed to the engine cover only through the metal heat sink portion, heat transfer from the sensor case to the engine cover is made smoother.

In the 17th aspect of the present disclosure, the portion of the engine cover facing the heat sink portion has a shape corresponding to the heat sink portion. The heat radiating plate portion has a structure in contact with a portion of the engine cover facing the radiating plate portion. Since the sensor case is arranged so as to straddle a plurality of tooth portions, it has a predetermined length in the circumferential direction. In the 17th aspect of the present disclosure, since the heat radiating plate portion is in contact with the engine cover over a predetermined length in the circumferential direction, heat transfer from the sensor case to the engine cover is further smoothed.

In the eighteenth aspect of the present disclosure, an adhesive layer is interposed between the heat sink portion and the portion of the engine cover facing the heat sink portion. Even if there is a gap between the heat sink and the engine cover, the gap can be filled with the adhesive layer. Therefore, heat is smoothly transferred from the sensor case to the engine cover.

FIG. 1 is a perspective view showing a state in which a rotary electric machine is combined with a crankshaft and an engine cover. FIG. 2 is a perspective view showing a rotor, a stator, and a sensor case. FIG. 3 is a front view showing the stator and the sensor case. FIG. 4 is a perspective view showing the stator and the sensor case. FIG. 5 is a perspective view showing the engine cover and the sensor case. FIG. 6 is a cross-sectional perspective view showing the engine cover, the stator, and the sensor case. FIG. 7 is a cross-sectional perspective view showing the engine cover, the stator, and the sensor case. FIG. 8 is a cross-sectional perspective view showing the engine cover and the sensor case. FIG. 9 is a perspective view showing the heat sink portion. FIG. 10 is a perspective view showing a sensor case to which a heat sink portion is assembled. FIG. 11 is a perspective sectional view showing an assembled state of the sensor case shown in FIG. 10 and the engine cover. FIG. 12 is a cross-sectional view showing a part of a sensor case including a heat radiating plate portion and a cooling plate portion. FIG. 13 is a perspective view showing a heat sink portion and a cooling plate portion. FIG. 14 is a perspective view showing another example of the heat sink portion and the cooling plate portion. FIG. 15 is a perspective view showing another example of the sensor case to which the heat sink portion is assembled. FIG. 16 is a perspective sectional view showing an assembled state of the sensor case shown in FIG. 15 and the engine cover. FIG. 17 is a perspective view showing another example of the engine cover. FIG. 18 is a perspective sectional view showing another example of the assembled state of the sensor case and the engine cover.

Hereinafter, an example of the present disclosure will be described with reference to the figure. FIG. 1 is a perspective view showing a state in which the rotary electric machine 1 is combined with the crankshaft 100 and the engine cover 200. Reference numeral 101 denotes a web, which rotates a crankshaft 100 by receiving a movement of a piston (not shown) reciprocating in a cylinder (not shown) via a connecting rod (not shown). The crankshaft 100 is made of an iron material having a diameter of about 20 mm, and is rotationally supported by a cylinder block (not shown).

The engine cover 200 covers the opening of the cylinder block and is bolted to the cylinder block by the bolt through hole 201. The engine cover 200 is made of die-cast aluminum or an aluminum alloy, and has a wall thickness of about 4 mm. Since the engine cover 200 is continuous with the opening of the cylinder block, the internal environment is the same as that of the cylinder block.

The rotor 300 of the rotary electric machine 1 is fixed to the crankshaft 100 at the base 301 (shown in FIG. 2). Therefore, the rotor 300 rotates integrally with the crankshaft 100. The rotor 300 is made of an iron material and includes a disk portion 302 extending radially outward from the base portion 301, and a cylindrical portion 303 formed in the radial outer portion of the disk portion 302. As shown in FIG. 2, 12 permanent magnets 304 are arranged side by side in the circumferential direction inside the cylindrical portion 303. The thickness of the permanent magnet is about 4 to 5 mm. The number of permanent magnets 304 is not limited to 12, but can be appropriately set to 20 or 24 depending on the required performance.

As shown in FIG. 2, a stator 400 is arranged inside the rotor 300. The stator 400 is configured by laminating a plurality of magnetic steel plates. The stator 400 integrally forms a base portion 401 attached to the engine cover 200, and a plurality of tooth portions 402 (shown in FIG. 6) extending radially outward from the base portion 401. The outer diameter of the stator 400 is about 110 to 130 mm. Therefore, the inner diameter of the rotor 300 is such that a minute gap is formed between the outer diameter of the stator 400 and the permanent magnet 304.

The base portion 401 is formed with three stator bolt through holes 403 for fixing the stator 400 to the engine cover 200. Further, the base portion 401 is also formed with one sensor case bolt through hole 410 (shown in FIG. 6) for fixing the sensor case 500, which will be described later, to the stator 400.

The tooth portion 402 is electrically insulated by an insulator made of an insulating resin such as polyamide, and a coil 404 made of a copper wire or an aluminum wire is wound on the insulator. FIG. 3 is a front view showing the stator 400 and the sensor case 500 with the rotor 300 removed from FIG. FIG. 4 is a perspective view showing the stator 400 and the sensor case 500 from the direction opposite to that of FIG.

As shown in FIG. 3, a gap 405 is formed between adjacent coils 404, and the gap 405 widens toward the outside in the radial direction. Further, as shown in FIG. 4, the sensor case 500 includes a sensor main body 501 and first to fourth hole sensors 502 to 505 extending between the sensor main body 501 and the adjacent coil 404. The sensor main body 501 holds the first to fourth hole sensors 502 to 505 and the substrate 521 (shown in FIG. 6). The first to fourth hole sensors 502 to 505 are arranged so as not to come into contact with the coil 404 in the gap 405 between the adjacent coils 404. Each Hall sensor 502 to 504 has a size of about 2 mm × about 3 mm. The hall sensors 502 to 505 are covered with the sensor case 500 (sensor main body 501). The sensor main body 501 is made of a resin material such as polyamide, and the substrate 521 is enclosed therein with a potting material 520.

The second to

fourth Hall sensors

503, 504, and 505 detect the position where the N pole and the S pole alternate with each other facing the permanent magnet 304 in which the N pole and the S pole are alternately magnetized. The detection positions of the second to

fourth hole sensors

503, 504, and 505 correspond to the energization timings of the V phase, the W phase, and the U phase. According to these detection positions, when the rotary electric machine 1 is used as a motor as a starter, the supply of voltage to the coil 404 corresponding to the U phase, the V phase, and the W phase is controlled. Even when the rotary electric machine 1 is used as a generator, it is used as a timing signal for controlling the current from the coil 404 corresponding to the U phase, the V phase, and the W phase.

The first hole sensor 502 detects a reference position for ignition control. The first hole sensor 502 is arranged at a position different from that of the

other hall sensors

503, 504, and 505 in the axial direction of the crankshaft 100. At the arrangement position of the first hole sensor 502, there is no inversion from the N pole to the S pole at the reference position, and the N poles are continuous with the three permanent magnets 304. By detecting the continuity of these three N poles, the reference position can be detected. Since the rotor 300 rotates integrally with the crankshaft 100, the reference position indicates the position of the crankshaft 100 in the rotation direction. The ignition timing of a spark plug (not shown) arranged in the cylinder of the engine is controlled by utilizing the fact that the crankshaft 100 is in the reference position and the switching of the magnetic poles of other Hall sensors.

Although the first hole sensor 502 extends to an intermediate position in the axial direction, the first to fourth hole sensors 502 to 505 are set to have a short axial length. As a result, all the first to fourth Hall sensors 502 to 505 are arranged at positions relatively close to the sensor main body portion 501. In other words, at least one Hall sensor is arranged on the engine cover 200 side from the intermediate position of the axial length Lx of the teeth portion 402. In this embodiment, all the Hall sensors 502-505 are arranged on the engine cover 200 side from the intermediate position of the axial length of the teeth portion 402. As a result, the heat of the first to fourth hole sensors 502 to 505 can easily escape to the sensor main body 501.

A substrate 521 (shown in FIGS. 6 to 8) to which a power line, a signal line, and a ground line from the hall sensors 502 to 505 are connected is arranged in the sensor main body 501. The substrate 521 is embedded and fixed in the sensor main body 501 by a potting material 520 together with a power supply line, a signal line, and a ground wire. As the potting material 520, an epoxy resin or the like is used.

As shown in FIG. 3, in the sensor case 500, a stator fixing portion 506 is formed inward in the radial direction of the sensor main body portion 501. The stator fixing portion 506 is formed with a fixing portion bolt hole 507 at a position corresponding to the sensor case bolt through hole 410 provided in the base portion 401 of the stator 400. Further, an engine cover fixing portion 508 is formed on the outer side in the radial direction of the sensor main body portion 501. The engine cover fixing portion 508 is formed with a positioning hole 509 having a diameter larger than that of the fixing portion bolt hole 507.

In this example, both the stator fixing portion 506 and the engine cover fixing portion 508 are formed on the substantially center line of the sensor case. That is, it is located at the center of the sensor main body 501 extending in the circumferential direction of the stator 400. Therefore, the sensor case 500 in a state where the bolt 512 and the positioning screw 515 are tightened and fixed is held in a well-balanced manner.

FIG. 5 is a perspective view showing a connected state between the engine cover 200 and the sensor case 500. FIG. 5 shows the state of FIG. 1 with the crankshaft 100, the rotor 300, and the stator 400 removed. However, FIG. 5 shows a base portion 401 (a part of the base portion 401) to which the sensor case 500 is fixed in the stator 400. As shown in FIG. 5, the sensor case 500 is attached to the engine cover 200 by inserting the positioning screw 515 into the positioning hole 509 of the engine cover fixing portion 508. Note that FIG. 5 shows the wrench head 510 of the positioning screw 515, and a hexagonal groove 511 is generated at the center of the wrench head 510. In FIG. 5, only a part of the base portion 401 of the stator 400 is shown. In the sensor case 500, the bolt 512 is screwed into the fixing portion bolt hole 507 of the stator fixing portion 506. As a result, the stator 400 and the stator fixing portion 506 are coupled.

Reference numeral 220 is a rib formed on the engine cover 200, and the rib 220 improves the strength of the engine cover 200. In this example, the bolt through holes 201 of the engine cover 200 are formed at seven locations apart from each other in the circumferential direction. The engine cover 200 is formed around a position facing the crankshaft 100. Therefore, the rib 220 includes a radial portion 220a that extends radially from the central cylindrical portion 205 toward the bolt through holes 201 at seven locations. Further, the rib 220 includes a circular portion 220b formed concentrically with the cylindrical portion 205 and orthogonal to the radial portion 220a.

The sensor case 500 is arranged on the radial portion 220a of the rib 220 extending toward the bolt through hole 201a located on the right side of FIG. 5 in the bolt through hole 201. The screw portion 210 is also located on the line of the radial portion 220a (FIG. 6 is shown). Therefore, the sensor case 500 is located in a portion of the engine cover 200 having excellent seismic strength, and the vibration of the sensor case 500 can be suppressed. In particular, the screw portion 210 is formed in the engine cover 200 at a position close to the bolt through hole 201a, not the cylindrical portion 205. The sensor case 500 is fixed on the rib 220 or on the line of the rib 220. The sensor case 500 is fixed to the engine cover 200 by the screw portion 210 and the bolt portion 514 at a position where the distance L1 to the bolt through hole 201 is shorter than the distance L2 to the cylindrical portion 205. Therefore, the vibration suppressing effect of this embodiment is higher.

FIG. 6 is a cross-sectional perspective view illustrating an assembled state of the engine cover 200, the sensor case 500, and the stator 400. As described above, the base portion 401 and the teeth portion 402 of the stator 400 are configured by laminating a large number of magnetic steel plates. The base portion 401 is formed with a stator bolt through hole 403 for attaching the stator 400 to the engine cover 200. Further, the base portion 401 is formed with a sensor case bolt through hole 410 for fixing the sensor case 500 to the stator 400. The above-mentioned insulator is indicated by reference numeral 420.

A female screw is formed in the fixing portion bolt hole 507 formed in the stator fixing portion 506 of the sensor case 500. The bolt 512 inserted in the sensor case bolt through hole 410 is screwed with the female screw of the fixing portion bolt hole 507. The bolt 512 has a diameter of about 6 mm.

The positioning screw 515 that fixes the sensor case 500 to the engine cover 200 is formed with a positioning cylindrical portion 513 corresponding to the positioning hole 509. The positioning cylindrical portion 513 is also referred to as a cylindrical portion 513. A bolt portion 514 is provided on one end side of the cylindrical portion 513, and the bolt portion 514 is screwed with the screw portion 210 of the engine cover 200. The bolt portion 514 also has a diameter of about 6 mm. Further, the inner diameter of the positioning hole 509 and the outer diameter of the cylindrical portion 513 are both set to about 10 mm. The sensor case 500 and the engine cover 200 are aligned by fitting the positioning hole 509 and the cylindrical portion 513.

In particular, after tightening the positioning screw 515, the axial force of the positioning screw 515 is applied to the positioning hole 509, so that the positioning hole 509 has a structure that is not easily deformed. Further, as shown in FIG. 5, the positioning hole 509 is located in the vicinity of the

hall sensors

503 and 504. Therefore, the sensor main body 501 and the engine side can be directly positioned via the engine cover 200, and in that sense, the position detection accuracy is improved. On the other hand, a comparative example in which the sensor case 500 is not provided with the positioning hole 509 and the sensor case 500 is fixed to the stator 400 can be considered. In this comparative example, the position detection accuracy may not meet the predetermined required level due to the influence of the molding distortion of the sensor case 500 and the like.

Further, the above-mentioned wrench head 510 is formed on the other end side of the cylindrical portion 513. The above-mentioned potting material 520 is sealed in the sensor main body 501 of the sensor case 500 to protect the substrate 521.

As shown in FIG. 6, the portion of the engine cover 200 facing the base portion 401 of the stator 400 is a cylindrical portion 205 having the same shape as the base portion 401. The tip of the crankshaft 100 is arranged inside the base portion 401 of the stator 400 and the cylindrical portion 205.

FIG. 7 is a cross-sectional perspective view showing an assembled state of the engine cover 200, the stator 400, and the sensor case 500 as in FIG. However, it shows a cross section different from that of FIG. A cover bolt hole 206 is formed in the cylindrical portion 205 of the engine cover 200. The cover bolt hole 206 coincides with the stator bolt through hole 403 of the stator 400, and the stator 400 is fixed to the engine cover 200 by the stator bolt 430.

FIG. 8 is a cross-sectional perspective view showing an assembled state of the engine cover 200 and the sensor case 500 with the stator 400 removed from FIG. The third hole sensor 504 and the fourth hole sensor 505 arranged between the adjacent coils 404 appear.

Next, the procedure for assembling the stator 400 and the sensor case 500 to the engine cover 200 will be described. First, as shown in FIG. 4, the first to fourth Hall sensors 502 to 505 are positioned at predetermined axial positions between the predetermined coils 404. In this state, the sensor case 500 is assembled to the stator 400. At the time of this assembly, the first to fourth hole sensors 502 to 505 do not directly touch the coil 404, but form a gap between the first and fourth hole sensors 502 to 504. In that state, as shown in FIG. 3, the sensor case bolt through hole 410 of the stator 400 and the fixing portion bolt hole 507 of the sensor case 500 coincide with each other within a certain tolerance. In the matched state, as shown in FIGS. 6 and 7, the bolt 512 passes through the sensor case bolt through hole 410 and is screwed into the fixed portion bolt hole of the sensor case 500. As a result, the stator 400 and the sensor case 500 are fixed.

With the stator 400 and the sensor case 500 assembled, the positioning hole 509 of the sensor case 500 and the screw portion 210 of the engine cover 200 are aligned. In this state, the positioning screw 515 is tightened. At this time, the cylindrical portion 513 of the positioning screw 515 fits into the positioning hole 509 of the sensor case 500. As a result, the relative positional relationship between the sensor case 500 and the engine cover 200 is determined. As a result, the relative positional relationship between the stator 400 fixed to the sensor case 500 and the engine cover 200 is also determined.

After that, the stator bolt 430 is screwed into the cover bolt hole 206 of the engine cover 200. Here, the stator bolt through hole 403 of the stator 400 has a large tolerance. As a result, even when the relative positional relationship between the stator 400 and the engine cover 200 is determined by the sensor case 500, the stator bolt 430 can be tightened and fixed without any problem. More specifically, the tolerance of the stator bolt through hole 403 is twice the tolerance of the positioning screw 515 of the sensor case 500.

Next, the thermal states of the first to fourth hole sensors 502 to 505 in the usage environment will be described. As shown in FIG. 1, since the engine cover 200 covers the opening of the cylinder block of the engine, it is in the same thermal environment as the cylinder block. At high temperatures, the temperature rises to about 150 degrees Celsius (same below). Further, due to the heat generated by the coil 404, the temperature of the coil 404 portion may exceed 150 degrees and rise to 180 to 200 degrees. Since the Hall sensor is an electronic component, in the worst case, it may exceed the heat resistant temperature.

On the other hand, since the first to fourth hole sensors 502 to 505 of the present disclosure have a gap between them and the coil 404, the heat of the coil 404 is not directly transferred. Moreover, since the sensor case 500 is fixed to the engine cover 200, the first to fourth hole sensors 502 to 505 are also arranged on the engine cover 200 side. Since the engine cover 200 is exposed to the outside air, it is lower than the temperature of the cylinder block, and is about 100 degrees even at a high temperature. Therefore, the temperature rise is the smallest in the cylinder block that becomes hot. By arranging the first to fourth hole sensors 502 to 505 at a position close to the engine cover 200, the possibility of exceeding the heat resistant temperature can be reduced.

Then, the sensor case 500 of the present disclosure is directly fixed to the engine cover 200 by the positioning screw 515. Therefore, the heat of the first to fourth hole sensors 502 to 505 can be released to the engine cover 200. That is, the heat of each Hall sensor is transferred to the substrate 521 via the power supply line, signal line, and ground line. Next, heat is transferred from the potting material 520 to the engine cover fixing portion 508. Next, the heat is transferred to the engine cover 200 via the positioning screw 515 via the engine cover fixing portion 508. In this disclosure, a path is provided for heat to conduct directly to the engine cover 200. As a result, the temperature of the sensor case 500 can be suppressed to 120 to 130 degrees even when the temperature of the coil 404 is as high as 180 to 200 degrees. In particular, in the present disclosure, since the distance from the first to fourth hole sensors 502 to 505 to the sensor main body 501 is relatively short, the structure is such that heat can easily escape. This makes it possible to increase the heat resistance of the first to fourth hole sensors 502 to 505.

Next, the placement position of the sensor case 500 in consideration of the influence of temperature will be described. The inside of the cylinder block is filled with mist of air and engine oil. Therefore, the setting of the arrangement position of the sensor case 500 also differs depending on the design selection according to the usage environment, which of the air and the engine oil should be given more importance to the heat effect.

In a usage environment where the thermal effect of engine oil is important, it is desirable to arrange the sensor case 500 above the intermediate position of the engine cover 200 including the intermediate position in the vertical direction. This is because the splashes of engine oil are scattered in the engine cover 200, and this engine oil is relatively abundant in the lower part. Therefore, if the sensor case 500 is arranged above, the possibility that the high temperature engine oil directly scatters on the hall sensors 502 to 505 can be reduced. In particular, in the present disclosure, since the sensor case 500 is arranged on the engine cover 200 side, the rotor 300 and the stator 400 are interposed between the sensor case 500 and the cylinder block. Therefore, since the engine oil is inherently difficult to scatter, if the sensor case 500 is arranged above, the thermal influence of the engine oil can be minimized.

On the contrary, in the usage environment where the air temperature is important, the sensor case 500 is arranged below the intermediate position of the engine cover 200 including the intermediate position in the vertical direction. In a situation where the engine is stopped after the engine has been rotated at high speed for a long time, the temperature inside the engine rises sharply. Since the high-temperature air flows upward, if the sensor case 500 is located in the upper portion in such a state, it is likely to receive the heat of the high-temperature air. On the other hand, if the sensor case 500 is arranged below, it is less likely to be affected by high temperature air. In particular, as described above, the sensor case 500 of the present disclosure is originally arranged at a position that is not easily affected by engine oil. Therefore, the influence of high temperature air becomes remarkable, and the lower arrangement is well-balanced.

As described above, in the present disclosure, since the sensor case 500 is arranged on the engine cover 200 side, the heat of the sensor case 500 is radiated to the engine cover 200 side. In order to further promote this heat dissipation, a heat sink portion 550 (shown in FIG. 9) may be arranged in the sensor case 500. As shown in FIG. 10, the heat sink portion 550 has a heat sink main body portion 551 corresponding to the sensor main body portion 501 and a heat sink engine cover fixing portion 552 corresponding to the engine cover fixing portion 508. The heat sink engine cover fixing portion 552 is formed with a positioning hole 509 having the same shape as the engine cover fixing portion 508.

The heat sink portion 550 is made of a metal material such as iron, aluminum, and copper, and has a structure that dissipates heat from the hall sensors 502 to 505 to the engine cover 200. FIG. 11 shows a state in which the sensor case 500 including the heat sink portion 550 is fixed to the engine cover 200. The cylindrical portion 513 of the positioning screw 515 is located in the positioning hole 509 provided in the engine cover fixing portion 508 and the heat sink engine cover fixing portion 552 of the sensor case 500. The heat sink engine cover fixing portion 552 of the heat sink portion 550 is screwed to the screw portion 210 of the engine cover 200 with the bolt portion 514 of the positioning screw 515. Further, the heat sink main body portion 551 of the heat sink portion 550 is in contact with the rib 202 of the engine cover 200. The heat sink portion 550 having good thermal conductivity is arranged on the engine cover 200 side so as to be in direct contact with the engine cover 200. Therefore, the heat transfer from the Hall sensors 502 to 505 to the engine cover 200 is made smoother.

FIG. 12 is an example in which a cooling plate portion 553 extending from the heat sink portion 550 toward the hall sensors 502 to 505 is added. The cooling plate portion 553 is made of the same metal material as the heat sink portion 550. The metal cooling plate portion 555 extends from the heat sink portion 550 to the Hall sensors 502 to 505. The metal cooling plate portion 555 provides a heat transfer path between the heat sink portion 550 and the Hall sensors 502 to 505. As shown in FIG. 13, the cooling plate portion 553 and the heat sink portion 550 may be fixed by welding, brazing, or soldering. Further, as shown in FIG. 14, it may be integrally molded. In the example of FIG. 14, the cooling plate portion 553 is bent and molded from the heat sink main body portion 551.

As shown in FIG. 12, in the sensor case 500, the substrate 521, the sensor elements 522 of the Hall sensors 502 to 505, and the lead wire 523 are both enclosed and fixed by a potting material 520. As described above, three lead wires 523 are arranged for each sensor element 522, that is, a power supply line, a ground wire, and a signal line. Further, the lead wire 523 is soldered to the substrate 521.

The potting material 520 also encloses and fixes the cooling plate portion 553. Moreover, the potting material 520 is also in contact with the heat radiating plate main body 551 of the heat radiating plate 550. Therefore, the heat sink portion 550 is adhesively fixed to the sensor case 500 by the potting material 520.

In the examples of FIGS. 10 and 11, the sensor case 500 is screwed to the engine cover 200 with two members, an engine cover fixing portion 508 and a heat sink engine cover fixing portion 552. That is, in the examples of FIGS. 10 and 11, the positioning screw 515 has a bolt portion 514 that sandwiches the engine cover fixing portion 508 and the heat sink portion 550 of the sensor case 500 and is screwed with the screw portion 210 of the engine cover 200. .. In the example of FIG. 16, the positioning screw 515 has a bolt portion 514 that sandwiches only the heat sink portion 550 of the sensor case 500 and is screwed with the screw portion 210 of the engine cover 200. As shown in FIGS. 15 and 16, the engine cover fixing portion 508 may be abolished. The engine cover fixing portion 508 made of a resin material may be warped due to heat, and in that case, the dimensional accuracy may be inferior. On the other hand, if the heat sink made of a metal material is fixed to the engine cover 200 only by the engine cover fixing portion 552, there is no risk of warping. Further, since the heat radiating plate portion 550 is adhesively fixed to the sensor main body portion 501 by the potting material 520, the dimensions can be adjusted at the time of the adhesive fixing.

At the same time, if the engine cover fixing portion 508 made of resin material receives the axial force of the positioning screw 515 for a long period of time, the risk of creep deformation cannot be ignored. On the other hand, there is no risk of creep deformation in the heat sink engine cover fixing portion 552 made of metal material. In addition, the heat sink engine cover fixing portion 552 made of a metal material smoothly conducts heat. Therefore, the heat from the Hall sensors 502 to 505 can be better released to the engine cover 200 side.

In the example of FIG. 16, the heat sink portion 550 is in full contact with the engine cover 200. This is because, as shown in FIG. 17, a heat radiating portion 220C having a shape corresponding to the heat radiating plate portion 550 is formed in a portion of the engine cover 200 corresponding to the sensor case 500. The portion of the engine cover 200 facing the heat sink portion 550 (heat sink portion 220c) has a shape corresponding to the heat sink portion 550. The heat radiating plate portion 550 is in contact with a portion (heat radiating portion 220c) of the engine cover 200 facing the heat radiating plate portion 550. The heat radiating plate portion 550 is in full contact with the radiating portion 220C of the engine cover 200. With this structure, the heat from the Hall sensors 502 to 505 is better released to the engine cover 200 side.

However, in the examples of FIGS. 16 and 17, even if the heat sink portion 550 is in full contact with the heat sink portion 220C of the engine cover 200, the tolerance, the surface roughness of the engine cover 200 and the heat sink portion 550, etc. are actually observed. Due to the influence of, a non-contact part is partially generated. Therefore, an adhesive layer made of a resin such as epoxy may be interposed between the heat radiating plate portion 550 and the radiating portion 220C of the engine cover 200. By filling the gap with the adhesive layer, the heat from the Hall sensors 502 to 505 can be released to the engine cover 200 side more smoothly.

The adhesive layer is not limited to the example in which the heat radiating portion 220C is formed on the engine cover 200. Moreover, the present invention is not limited to the example in which the heat sink portion 550 is formed on the sensor case 500. FIG. 18 is an example in which the sensor case 500 is not provided with the heat sink portion 550 as in FIG. 6, but the adhesive layer 560 is interposed between the sensor case 500 and the engine cover 200. More specifically, the adhesive layer 560 is interposed between the potting material 520 of the sensor case 500 and the engine cover 200. The heat from the Hall sensors 502 to 505 is released to the engine cover 200 side via the potting material 520 and the adhesive layer 560.

In the example of FIG. 18, the sensor case 500 is not placed on the rib 220 either. Placing the sensor case 500 on the rib is desirable for increasing strength and heat transfer, but it is not always an essential requirement. In particular, if the adhesive layer 560 is interposed as in the example of FIG. 18, even if the distance between the sensor case 500 and the engine cover 200 is widened, the heat transfer property to the engine cover 200 can be maintained. Is possible.

The above example is a desirable example of the present disclosure, but the present disclosure is not limited to the above example. The material and size of each part can be changed as appropriate. In the illustrated example, the engine cover fixing portion 508 of the sensor case 500 is located substantially in the center of the sensor main body portion 501. The stator fixing portion 506 and the engine cover fixing portion 508 are located at substantially the center of the sensor main body portion 501 in the circumferential direction. Depending on the relationship with the engine cover 200, the engine cover fixing portion 508 may be outside the radial direction of the sensor main body portion 501. Therefore, the position of the engine cover fixing portion 508 in the circumferential direction can be appropriately changed. Similarly, the position of the stator fixing portion 506 can also be changed in the circumferential direction.

Also, in the above example, a method using four hall sensors is described, but the number of hall sensors may differ. As an example, the second, third, and

fourth Hall sensors

503, 504, and 505 obtain signals that serve as a reference for the timing of energization of the U, V, W phases, and each coil. Since these sensors measure the magnetic flux of one rotor, a signal reflecting the positional deviation in each angular direction on the time axis is output. Therefore, it is possible to estimate another signal from the signal of any one of the hall sensors.

Further, although the first hall sensor 502 outputs an ignition reference signal, it is also conceivable that the ignition reference signal may be obtained from a source other than the hall sensor. For example, it is also possible to use a crank angle signal from a crank angle sensor. The crank angle sensor outputs a pulsed crank angle signal capable of detecting a predetermined crank angle by using a detection disk that rotates with the rotation of the crank shaft. The crank angle sensor is configured to generate an output signal having a continuous pass pulse portion and a non-passing pulse portion during one rotation of the crankshaft 100.

Therefore, the number of Hall sensors may be at least one. As described above, the number of hall sensors is appropriately changed depending on the method on the control circuit side in which the output of the hall sensors is input. When there is one hose sensor, it is preferable to arrange the one hall sensor on the side closer to the engine cover 200 in order to dissipate heat.

Claims

A rotor having a base attached to the crankshaft, a disk portion extending radially outward from this base, and a cylindrical portion formed in the radial outer portion of the disk portion, and rotating integrally with the crankshaft.
A plurality of magnets arranged in the circumferential direction in the cylindrical portion of the rotor,
It is provided with a base portion attached to an engine cover, a plurality of teeth portions extending radially outward from the base portion, and a plurality of coils arranged in the teeth portion, and the radial outer end portion of the teeth portion is the magnet. With the stator facing the
A hole sensor that is arranged between adjacent coils of the plurality of coils so as to face the magnet and detects the magnetic flux of the magnet and a sensor case that holds the substrate of the hall sensor are provided.
The sensor case is arranged on the engine cover side of the stator, and the sensor case is arranged.
A rotary electric machine for an internal combustion engine, wherein the sensor case is fixed to the base portion of the stator and also to the engine cover.
The rotary electric machine for an internal combustion engine is a three-phase starting generator.
The Hall sensor is a total of four Hall sensors, including three Hall sensors that detect the rotational positions of the U phase, V phase, and W phase, and one Hall sensor that detects the reference position of the crankshaft.
The rotary electric machine for an internal combustion engine according to claim 1, wherein each Hall sensor is arranged between the adjacent coils.
The teeth portion has a predetermined length in the axial direction of the crankshaft, and has a predetermined length.
The rotation for an internal combustion engine according to claim 1 or 2, wherein a plurality of Hall sensors exist, and at least one of them is arranged on the engine cover side from an intermediate position of the axial length of the teeth portion. Electric.
The sensor case includes a sensor main body that holds the hall sensor and the substrate, a stator fixing portion that is located inward in the radial direction of the sensor main body, and an engine cover that is located in the radial direction of the sensor main body. The rotary electric machine for an internal combustion engine according to any one of claims 1 to 3, further comprising a fixed portion.
A fixing bolt hole is formed in the stator fixing portion, a sensor case bolt through hole is formed in the base portion of the stator, and a stator bolt is passed through the sensor case bolt through hole of the base portion. The rotary electric machine for an internal combustion engine according to claim 4, wherein the stator and the sensor case are fixed by screwing into the bolt hole of the fixing portion of the stator fixing portion.
A positioning hole is formed in the engine cover fixing portion.
The sensor case is fixed to the engine cover by a positioning screw.
The positioning screw includes a positioning cylinder portion corresponding to the positioning hole of the engine cover fixing portion, a bolt portion formed on one end side of the positioning cylinder portion and screwed with the screw portion of the engine cover, and the positioning cylinder. Has a wrench head formed on the other end side of the portion
The rotary electric machine for an internal combustion engine according to claim 4 or 5, wherein the diameter of the positioning cylinder portion is larger than the diameter of the bolt portion.
The rotation for an internal combustion engine according to any one of claims 4 to 6, wherein the stator fixing portion and the engine cover fixing portion are located at a substantially central portion of the sensor main body portion in the circumferential direction of the stator. Electric.
The rotary electric machine for an internal combustion engine according to any one of claims 1 to 6, wherein the sensor case is arranged above the intermediate position of the engine cover including the intermediate position in the vertical direction.
The rotary electric machine for an internal combustion engine according to any one of claims 1 to 6, wherein the sensor case is arranged below the intermediate position including the intermediate position in the vertical direction of the engine cover.
The rotary electric machine for an internal combustion engine according to any one of claims 1 to 8, wherein a gap is formed between the hall sensor and the coil, and the hall sensor does not come into direct contact with the coil.
The engine cover has a cylindrical portion provided in a central portion corresponding to the crankshaft, a bolt through hole provided in a peripheral portion, and a rib extending from the cylindrical portion toward the bolt through hole. death,
The rotary electric machine for an internal combustion engine according to any one of claims 1 to 10, wherein the sensor case is fixed on the rib or the wire of the rib in the engine cover.
The sensor case is characterized in that it is fixed to the engine cover at a position on the rib or on the line of the rib where the distance to the bolt through hole is shorter than the distance to the cylindrical portion. 11. The rotary electric machine for an internal combustion engine according to 11.
The sensor case is characterized by including a sensor main body made of a resin material that holds the Hall sensor and the substrate, and a metal heat dissipation plate portion that is arranged on the engine cover side of the sensor main body. The rotary electric machine for an internal combustion engine according to any one of claims 1 to 12.
The sensor case is composed of a sensor main body made of a resin material that holds the Hall sensor and the substrate, a metal heat sink portion arranged on the engine cover side of the sensor main body, and the heat sink portion. The rotary electric machine for an internal combustion engine according to any one of claims 1 to 12, further comprising a metal cooling plate portion extending toward the Hall sensor side.
The sensor case includes a sensor main body portion that holds the hall sensor and the substrate, and an engine cover fixing portion that fixes the sensor case to the engine cover.
The sensor case is fixed to the engine cover by a positioning screw.
The internal combustion engine according to claim 13 or 14, wherein the positioning screw has a bolt portion that sandwiches the engine cover fixing portion and the heat radiation plate portion of the sensor case and is screwed with the screw portion of the engine cover. Rotating electric machine for engine.
The sensor case is fixed to the engine cover by a positioning screw.
The rotary electric machine for an internal combustion engine according to claim 13 or 14, wherein the positioning screw has a bolt portion that sandwiches only the heat sink portion of the sensor case and is screwed with the screw portion of the engine cover.
The portion of the engine cover facing the heat sink portion has a shape corresponding to the heat sink portion.
The rotary electric machine for an internal combustion engine according to any one of claims 13 to 16, wherein the heat sink portion is in contact with a portion of the engine cover facing the heat sink portion.
The rotary electric machine for an internal combustion engine according to any one of claims 13 to 17, wherein an adhesive layer is interposed between the heat radiating plate portion and a portion of the engine cover facing the heat radiating plate portion.