JPH07106045B2 - Starter - Google Patents

Description

The present invention relates to a starter for an automobile, and more particularly to a cooling structure for a starter motor section.

[Conventional technology]

As a conventional motor cooling device, for example, Japanese Utility Model Publication No. 61-9836
A fan is provided in the motor unit as disclosed in Japanese Patent Laid-Open No. 0-228119, a part of the core is fan-shaped as disclosed in Japanese Patent Laid-Open No. 58-228119, and disclosed in Japanese Utility Model Publication No. 60-26524. As described above, there are various types such as a cooling structure in which a heat pipe is attached to a rotor.

These cooling means have an advantage of effectively cooling the heat source of the electric motor to prevent the output of the motor from decreasing. However, as for a starter for starting an automobile engine, it is necessary to apply these cooling means as described below. Not applicable due to problems.

[Problems to be Solved by the Invention]

The rated operating time of the starter is generally set to 30 seconds, and in normal use, the engine will start in a few seconds of operation.

However, if the engine does not start due to some trouble, the driver will use the starter for a long time because the engine will not start, and as a result, the motor part will generate heat and the torque will decrease, worsening the starting condition and The time may, in the worst case, range from 5 to 30 minutes before the rectifying battery has finished discharging. Moreover, the motor part of the starter is naturally air-cooled, and most of the heat from the armature of the heat source is radiated from the outer periphery of the stator via the bearing and air, so the heat dissipation is not very good, and as a result, The armature may eventually burn out due to significant heat generation. Therefore, it is necessary to protect the motor rated for a short time by cooling it so that the armature will not be burned out even under such worst use conditions.

Furthermore, the temperature of the armature also rises due to heat generation of the engine during traveling, the winding resistance of the motor increases, and the starting torque at the time of restarting decreases. For this reason, a high torque motor is required so that a start failure does not occur.

Due to the above-mentioned circumstances, it is desired to cool the heat source of the starter also in the field of the starter. But,
If the conventional motor cooling means is applied to a starter, a fan or heat pipe mechanism etc. must be incorporated inside the starter body, and the device becomes larger accordingly, so the overall size and weight of the starter can be reduced. No, it is strongly desired to reduce the size and weight of the starter due to the constraints of the engine room space. Also, the conventional motor cooling means adopts a structure in which a large number of ventilation windows are arranged in the housing. Since it is exposed to the outside for ventilation or heat dissipation, if it is applied to a starter that is easily covered with water due to water sprinkling or the like, there is a risk of rust or insulation deterioration due to flooding, which is unsuitable for application.

The present invention has been made in view of the above points, and an object thereof is to rationalize a cooling structure of a permanent magnet field type motor used for a starter, thereby reducing the size and weight of the entire starter, while enhancing a cooling function and reducing a field pole. The purpose is to reduce the magnetic resistance in the magnetic circuit and improve the output of this type of starter.

[Means for Solving the Problems]

The present invention is configured as follows to achieve the above object. The reference numerals assigned to the constituent elements are the same as those in FIG. 1 and FIG.
The reference numerals of the embodiments in the figure are cited.

That is, the present invention is an engine including a field pole 3 having a plurality of permanent magnets circumferentially arranged on the inner circumference of a cylindrical yoke 18 and an armature 2 rotating along the inner circumference of the field pole 3. In the starter for starting, a cylindrical member 19 having magnetic permeability is fitted to the inner circumference of the field pole 3, and a magnetic fluid having a high thermal conductivity is provided between the inner circumference of the cylindrical member 19 and the outer circumference of the armature 2. Alternatively, the magnetic powder 22 is attracted and held by the magnetic force of the field pole 3 to intervene, and the empty space 26 between the field poles 3 is provided on the outer periphery of the cylindrical member 19.
The heat dissipating fins 24 disposed on the armature 2,
A communication pipe 35 is connected to one end of the starter housing 1 for accommodating the pinion 6 with the one-way clutch 7 on the side opposite to the pinion side, which communicates with an air moving passage outside the starter for generating a negative pressure or a positive pressure when the engine is rotating. Free space due to the presence of the pipe 35, the pinion 6 secured in the starter housing 1, and the open space 30 for gear engagement on the engine side
It is characterized in that the cooling air that takes away the heat of the radiation fins 24 flows through the 26.

[Action]

According to the above configuration, the magnetic fluid or the magnetic powder having a higher magnetic permeability than that of the air so as to fill the space between the field pole 3 and the armature 2 (hereinafter, magnetic fluid and magnetic powder are collectively referred to as magnetic A magnetic circuit formed by the field pole 3 because the magnetic filler 22 is held by the magnetic force of the permanent magnet as the field pole 3 without scattering even when the armature 2 rotates. The magnetic resistance of is reduced and the effective magnetic flux linked to the armature coil is increased. This magnetic filler is
Due to the characteristics of fluid or powder, even if it contacts the surface of a rotating body like an armature, almost no frictional resistance is generated between the rotating body and the magnetic fluid or magnetic powder, and the rotation loss of the armature (machine It does not become a heat source due to friction.

By the way, in a permanent magnet field motor type starter in which a permanent magnet is used for the field pole (stator) 3, a heat source during driving is mainly in the armature 2. In the present invention, since the magnetic filler 22 having good thermal conductivity is interposed between the outer circumference of the armature 2 which generates heat and the inner circumference of the field pole 3 through the cylindrical member 19 having magnetic permeability, The heat of the child 2 is taken away through the magnetic filler 22 when the armature rotates, and the taken heat is further transferred to the stator member such as the field pole 3 through the cylindrical member 19 and dissipated to the outside. At the same time, the heat is dissipated into the empty space 26 between the field poles 3 through the radiation fins 24 arranged on the outer periphery of the cylindrical member 19. In this space 26, the communication pipe 35 (a pipe communicating with the external air moving passage in the negative pressure or positive pressure state) and the meshing space 30 of the pinion 6 and the engine-side gear cooperate with each other to externally operate the engine during starting and during engine operation. Since the air from the air flows, the heat of the radiation fins 24 and the field pole 3 are generated by this air circulation.
The heat transferred to the armature 2 is efficiently removed to enhance the cooling effect of the armature 2. Particularly, in the present invention, the heat radiation effect by the heat radiation fins 24 and the flow of air flowing therethrough reduces the load of heat radiation from the field poles 3 and suppresses the temperature rise of the permanent magnets serving as the field poles, thereby increasing the residual magnetic flux density. It becomes possible to use a magnet.

Therefore, the output of the motor can be improved by each of these actions (reducing the magnetic resistance of the motor magnetic circuit, cooling the armature, and suppressing the temperature rise of the field pole).

Further, in the cooling structure of the present invention, the magnetic filler 22 is interposed in the existing space (gap) 21 formed between the outer circumference of the armature 2 and the inner circumference of the field pole 3, and moreover, the installation location of the heat radiation fin 24 and the fin. The air passages that take away the heat of 24 can also be set by using the empty space 26 between the existing field poles.
The installation space 26 does not increase the outer diameter of the starter housing, but rationalizes the cooling structure to achieve high output and reduce the size and weight of the motor.

〔Example〕

 An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a partially cutaway sectional view showing a starter according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view of a motor portion thereof in a direction perpendicular to an axial direction.

As shown in these figures, a plurality of field poles 3 of permanent magnets are arranged in the circumferential direction of the yoke 18 in a cylindrical yoke 18 forming a part of the housing 1 of the starter. An armature 2 that rotates along the inner circumference of the motor 3 is provided inside, and the armature 2, field pole 3, commutator 10, brushes 14, 15 and the like constitute a motor unit 4.

A pinion 6 with a one-way clutch 7 is fitted on the output shaft 5 of the armature 2. The pinion 6 rotates in the drive direction together with the output shaft 5 via the one-way clutch 7, while it can rotate in the opposite drive direction relative to the output shaft 5 and can reciprocate (slide) in the axial direction. It is in a state.

An electromagnetic solenoid 8, which is a component of the magnetic switch unit, is mounted on the upper portion of the housing 1. When the electromagnetic solenoid 8 is activated, the pinion 6 moves via a shift lever 9 so as to mesh with an engine-side gear (not shown). To do.

An armature core 16 and a commutator 10 which are press-fitted to the output shaft 5 are arranged on the anti-pinion side of the armature 2, and a coil 20 is wound around the armature core 16.

The (−) brush 14 supported by the brush holder plate 13 is slidably contacted with the outer periphery of the commutator 10, and the (+) brush 15 is also slidably contacted via the brush holder plate 13 in the same manner. , 14 is brush cover 11
It is fixed with a screw. The field pole 3 is fixed to the yoke 18, and a metallic cylindrical member 19 is inserted in the inner peripheral side of the field magnetic pole 3 so as to be in close contact with the field magnetic pole 3, and the cylindrical member 19 is pressure-fixed from the inner peripheral side. , Are fitted so as to surround the inner circumference of the field pole 3.

In such an arrangement, the outer periphery of the armature 2 and the cylindrical member
A magnetic fluid 22 having a higher thermal conductivity than that of air in the space 21 between the inner circumference of 19 and that of being easily magnetized and having a magnetic permeability higher than that of air 22
Intervenes. Instead of this magnetic fluid, magnetic powder may be interposed. The magnetic fluid (or magnetic powder) 22 has a characteristic that it is attracted by the magnet and does not easily scatter, and is attracted and held by the magnetic force of the magnetized permanent magnet (field pole) 3.

The magnetic fluid 22 of the present embodiment is a viscous fluid such as oil mixed with magnetic powder, and its specifications are that the specific gravity is 1.02 to 1.3 and the viscosity is 5
0-300cps / 20 ℃, the strength of magnetization is 2000 Gauss / 8K Oerstedt. Also, the thermal conductivity is about 5-10Kcal / mh ℃
The thermal conductivity of air is much higher than 0.02 Kcal / mh ℃.

An empty space between the field poles 3 is provided on the outer peripheral surface of the cylindrical member 19.
The radiating fins 24 are fixedly arranged using 26, and the space 26 between the field poles 3 serves as an air passage. That is,
The brush cover 11 provided on the side of the commutator 10 of the housing 1 is provided with a ventilation hole 32, the rear cap 33 at one end of the housing 1 covering the brush cover 11 is provided with a ventilation hole 34, and the ventilation hole 34 is connected to the tube (communication pipe). ) 35 to connect to the negative pressure side of the engine (in this embodiment, the intake passage of the engine), the communication pipe 35 and the open space 30 for gear engagement provided at the other end of the housing 1 allow communication. Air can flow through the air passages 26 through the pores 32 and the ventilation holes 34. The air passage 26, the ventilation hole 32, the ventilation port 34, the communication pipe 35, and the radiation fin 2
The heat radiation mechanism 23 is constituted by 4.

When performing cranking (engine starting operation), the electromagnetic solenoid 8 of the magnetic switch section is energized to shift the pinion 6 to the right side in FIG. 1 and engage with the engine side gear. It is performed by energizing the armature coil 20 of No. 4.

In this embodiment, the gap 21 between the field pole 3 and the armature 2 is
Magnetic fluid with a higher permeability than air
, The magnetic resistance of the magnetic circuit formed by the field pole 3 is reduced, and the effective magnetic flux interlinking with the armature coil 20 is increased. As described above, the magnetic fluid 22 causes almost no frictional resistance even if it comes into contact with the surface of the armature due to the characteristics of the fluid, and there is almost no armature rotation loss or frictional heat generation.

By the way, when the motor unit 4 is energized at the time of starting the internal combustion engine, the temperature of the armature 2 rapidly rises mainly by the heat generated from the brushes 14, 15, the commutator 10, and the armature coil 20. However, this heat is radiated to the outside from the fixed outer circumference of the field pole 3 and the like via the magnetic fluid 22 having a high thermal conductivity interposed between the cylindrical member 19 and the armature 2 and the cylindrical member 19. Then, the heat is dissipated to the empty space 26 between the field poles 3 through the radiation fins 24 arranged on the outer periphery of the cylindrical member 19. This space 26
Is a communication pipe 35 and a pinion 6 leading to the engine intake passage.
In cooperation with the meshing space 30 of the engine-side gear, air from the outside flows during cranking and during engine operation, so the heat of the radiation fins 24 is efficiently removed by this air circulation, and the armature 2 is cooled. Enhance the effect. That is, during cranking of the starter or during operation of the engine, the engine rotates and a piston (not shown) reciprocates, and an air suction force is generated in the intake passage of the engine due to the negative pressure of the piston operation. When the air suction force acts on the intake passage, the suction force acts on the inside of the starter housing 1 via the tube 35, and this suction force introduces external air from the meshing space 30 of the pinion / engine-side gear to the air passage 26. In this way, an air flow phenomenon occurs in the air passage 26 in the direction of the arrow in FIG. 1, and this air becomes cooling wind and is transmitted to the heat radiation fins 24 via the magnetic flow 22 and the cylindrical member 19. The heat of the armature 2 is forcibly taken away.

Particularly in this embodiment, the heat radiation effect by the heat radiation fins 24 and the flow of air flowing therethrough reduces the burden of heat radiation from the field poles 3 and suppresses the temperature rise of the permanent magnets, which are the field poles, so that the residual magnetic flux density is high. It is possible to use a magnet with a value.

Therefore, the output of the motor can be improved by each of these actions (reducing the magnetic resistance of the motor magnetic circuit, cooling the armature, and suppressing the temperature rise of the field pole).

In addition, the cooling structure of the present embodiment includes the outer circumference of the armature 2 and the field poles 3.
The magnetic filler 22 is interposed in the existing space 21 formed between the inner periphery and the inner space, and moreover, the installation location of the heat radiation fin 24 and the fin.
The air passage for removing heat of 24 can also be set by utilizing the empty space 26 between the existing field poles 3, so that the cooling structure can be rationalized and the motor can be made compact and lightweight.

Further, since the magnetic fluid 22 is held by the magnetic force of the field pole 3,
Even if the armature 2 rotates, it does not scatter. Even if the number of rotations of the armature 2 becomes high and the magnetic filler 22 is agitated on the outer circumference of the armature 2, the magnetic filler 22 is scattered along the inner circumference of the cylindrical member 19 and is attracted to the adjacent magnetic poles to be scattered and lost. There is no. In addition,
Since the magnetic fluid (or magnetic powder) 22 is a fluid or powder, even if it comes into contact with the rotating surface of the armature 2, almost no frictional resistance is generated, and the rotation loss (mechanical loss) of the armature is so great. It does not increase and does not become a heat source due to friction.

According to the present embodiment, by reducing the magnetic resistance of the magnetic circuit and efficiently radiating heat from the armature, which is a heat source, it is possible to obtain a small-sized high-output starter having excellent heat resistance. Further, since the air flow phenomenon in the air passage 26 is generated by utilizing the intake negative pressure of the engine, it is not necessary to provide a special fan or the like inside the starter. In this example,
The ventilation port 34 inside the starter is connected to the engine intake pipe by a communication pipe 35. Instead of this, the ventilation port 34 is arranged on the downstream side of the compressor of the turbocharger, and the positive pressure during engine rotation is used to utilize the air passage 26. Air flow may be generated in the. In this case, the air flow is in the opposite direction to the arrow in FIG.

In addition, the ventilation hole for flowing the air to the air passage 26 is the meshing space 30 of the existing pinion engine side gear.
Only the opening is open and the vent is not exposed to the outside, so that the same waterproof level as the conventional one can be maintained.

〔The invention's effect〕

As described above, according to the present invention, the cooling function is improved while the cooling structure of the permanent magnet field type motor used in the starter is rationalized, and thus the size and weight of the entire starter are reduced, and the magnetic field in the magnetic circuit of the field pole is increased. The output of this type of starter can be improved by reducing the resistance.

[Brief description of drawings]

FIG. 1 is a partially cutaway sectional view showing a starter according to an embodiment of the present invention, and FIG. 2 is a partially longitudinal sectional view thereof. 1 ... Housing, 2 ... Armature, 3 ... Field pole (permanent magnet), 18 ... Yoke, 19 ... Cylindrical member, 22 ... Magnetic fluid or magnetic powder, 23 ... Heat dissipation mechanism, 24 ...... Radiation fins, 26 ...... Air passage (space between field poles), 30 ......
Space for gear engagement on the pinion / engine side, 35 ... Communication pipe.

Claims (3)

[Claims] 1. A field magnet (3) comprising a plurality of permanent magnets circumferentially disposed on the inner circumference of a cylindrical yoke (18), and an armature (which rotates along the inner circumference of the field magnet (3)). 2) In the starter for starting the engine, the cylindrical member (19) having magnetic permeability is fitted to the inner circumference of the field pole (3), and the inner circumference of the cylindrical member (19) and the A magnetic fluid or magnetic powder (22) having high thermal conductivity is attracted and held by the magnetic force of the field pole (3) to the outer periphery of the armature (2), and the magnetic fluid or magnetic powder (22) is interposed between the outer periphery of the cylindrical member (19). Is provided with a radiation fin (24) arranged in an empty space (26) between the field poles (3), while the armature (2) and the one-way clutch (7) are arranged.
The starter housing (1) for accommodating the attached pinion (6) has a communication pipe (35) connected to one end of the starter housing (1) opposite to the pinion side, the communication pipe (35) communicating with an air moving passage outside the starter for generating negative pressure or positive pressure during engine rotation, Due to the presence of the communication pipe (35) and the pinion (6) secured in the starter housing (1) and the open space (30) for gear engagement on the engine side, the radiation fin (24) is provided in the empty space (26). A starter characterized in that cooling air that removes heat flows. 2. The starter according to claim 1, wherein the communication pipe (35) communicates with an engine intake passage. 3. The starter according to claim 1, wherein the communication pipe (35) communicates with a downstream side of the compressor of the turbocharger.