JP5606363B2 - Electromagnetic switch for engine start, starter, and engine start method - Google Patents

Description

  The present invention relates to an engine start electromagnetic switch used for a starter for starting an engine, a starter, and an engine start method.

  The conventional starter rotates the lever by the electromagnetic force of the electromagnetic switch to push out the pinion gear, and the pinion gear is brought into contact with the ring gear of the engine to be engaged. The electromagnetic switch used here converts electromagnetic energy into mechanical linear motion by attracting the plunger toward the core by energizing the exciting coil (see, for example, Patent Document 1).

  Further, it is known that the suction force with respect to the stroke that is the movable range of the plunger of the electromagnetic switch appears as a characteristic that the suction force increases as it approaches the suction position side (for example, FIG. (See FIG. 4 of Patent Document 2).

  Furthermore, in order to improve the attractive force characteristics of the electromagnetic switch, an electromagnetic switch that keeps the attractive force constant has also been proposed (see, for example, Patent Document 3 and Patent Document 4 in FIG. 3). In an electromagnetic switch as shown in Patent Document 4, the attractive force does not depend on the stroke, and the attractive force is adjusted by current control.

JP 2004-190500 A JP 2010-177459 A JP-A-8-330131 Japanese Patent Laid-Open No. 10-61811

  However, the conventional devices as shown in Patent Documents 1 and 2 have a problem that the responsiveness is poor because the suction force at the beginning of movement is the lowest. In addition to this, in the conventional devices as shown in Patent Documents 1 and 2, when the plunger is accelerated and the pinion gear and the ring gear come into contact with each other due to the characteristic that the suction force increases as it approaches the suction position side. There is a problem that the impact sound becomes relatively large due to the increased suction force.

  Moreover, in the conventional apparatus as shown in said patent document 4, in order to solve said subject, the current control means which controls the electric current which flows into an exciting coil is used. For this reason, there existed a subject that manufacturing cost increased.

  The present invention has been made to solve the above-described problems. An electromagnetic switch for starting an engine that can improve the responsiveness and reduce the impact sound while suppressing the manufacturing cost, An object is to obtain a starter and an engine starting method.

An electromagnetic switch for starting an engine according to the present invention includes a core, a plunger disposed coaxially with the core, and provided so as to be displaceable with respect to the core. An attraction coil, which is provided in a starter, wherein the attraction force is characterized by an attraction position where the plunger is attracted to the core and an axial direction of the core from the attraction position. in stroke shall be the movable range of the plunger between an initial position is a position spaced, characteristic of the suction force is decreased toward the suction side from the initial position side of the stroke minimum The point reaches the point and rises from the minimum point toward the suction position.

  According to the engine start electromagnetic switch of the present invention, since the attractive force characteristic is reduced from the initial position side of the stroke toward the suction position side, the current control means is not required, thereby reducing the manufacturing cost. Responsiveness can be improved by suppressing the acceleration of the plunger and the impact sound can be reduced by generating a relatively large suction force at the initial position of the stroke.

It is a block diagram which shows the starter by Embodiment 1 of this invention. It is sectional drawing which expands and shows the solenoid of FIG. It is a schematic diagram in case a columnar core enters into the internal space of the cylindrical protrusion part of FIG. It is a graph which shows the BH curve of a magnetic body. It is explanatory drawing for demonstrating the flow of the magnetic flux in an initial position. It is explanatory drawing for demonstrating the flow of the magnetic flux at the time of attraction force fall. It is explanatory drawing for demonstrating the flow of the magnetic flux in the adsorption position vicinity. It is a graph which shows the change of the attractive force with respect to the stroke of the solenoid of FIG. It is sectional drawing which shows an example of the structure of the core and plunger of a solenoid by Embodiment 2 of this invention. It is sectional drawing which shows an example of the structure of the core and plunger of a solenoid by Embodiment 3 of this invention. It is sectional drawing which shows an example of the structure of the core and plunger of a solenoid by Embodiment 4 of this invention. It is sectional drawing which shows an example of the structure of the core and plunger of a solenoid by Embodiment 5 of this invention. It is sectional drawing which shows an example of the structure of the core and plunger of a solenoid by Embodiment 6 of this invention. It is sectional drawing which shows an example of the structure of the core and plunger of a solenoid by Embodiment 7 of this invention. It is sectional drawing which shows an example of the structure of the core and plunger of a solenoid by Embodiment 8 of this invention. It is sectional drawing which shows an example of the structure of the core and plunger of a solenoid by Embodiment 9 of this invention.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
1 is a block diagram showing a starter according to Embodiment 1 of the present invention.
The starter 1 includes a pinion gear 2, a starter motor 3, a lever 4, and an electromagnetic switch (an engine starting electromagnetic switch) 5. The operation of the starter 1 is controlled by a starter control device or an engine control device (both not shown).

  The pinion gear 2 can be displaced toward and away from the ring gear 6 provided on the crankshaft of the engine. The pinion gear 2 is rotated by the driving force of the starter motor 3. Further, the pinion gear 2 is connected to one end of the lever 4. Further, the pinion gear 2 is displaced in the direction of approaching / separating from the ring gear 6 as the lever 4 rotates. Furthermore, the pinion gear 2 meshes with the ring gear 6 when it approaches the ring gear 6 and contacts the ring gear 6 (when it reaches the contact position).

  The lever 4 is rotated by receiving an external force from the electromagnetic switch 5. Here, the engine is cranked when the pinion gear 2 is rotated by the driving force of the starter motor 3 while the pinion gear 2 is engaged with the ring gear 6.

  FIG. 2 is a cross-sectional view showing the electromagnetic switch 5 of FIG. In FIG. 2, the electromagnetic switch 5 includes a cylindrical excitation coil 11, a yoke 12, a cylindrical guide member 13, a core 14, a columnar plunger 15, and a spring 16. The exciting coil 11 generates a magnetic field when a current flows. The yoke 12 is made of a magnetic material. The yoke 12 is configured to cover the outer shape of the exciting coil 11 in order to form a magnetic path.

  The guide member 13 is made of a nonmagnetic material. Further, the guide member 13 is disposed inside the exciting coil 11 so as to overlap the entire inner peripheral surface of the exciting coil 11 in the radial direction. Further, the guide member 13 is fixed to the yoke 12. The guide member 13 guides the displacement of the plunger 15. The core 14 is made of a magnetic material. The core 14 is disposed inside the excitation coil 11 and the guide member 13 and is fixed to the yoke 12.

  The plunger 15 is made of a magnetic material. The plunger 15 is disposed inside the guide member 13 and coaxially with the core 14. Furthermore, the plunger 15 is provided so as to be displaceable in a direction in which the plunger 15 approaches and separates from the core 14. When the exciting coil 11 is energized, the plunger 15 is attracted to the core 14 and is attracted to the core 14. Here, the stroke that is the movable range of the plunger 15 is between the suction position where the plunger 15 is attracted to the core 14 and the initial position that is spaced from the suction position in the axial direction of the core 14. It has become.

  The shape of the spring 16 is a spiral. The spring 16 is disposed so as to surround the side surface of the core 14 and is attached to the yoke 12. Further, the spring 16 applies a spring force toward the anti-core 14 side to the plunger 15. That is, the spring 16 urges the plunger 15 toward the initial position.

  Furthermore, a protrusion 15 a that protrudes in a cylindrical shape toward the core 14 is provided (for example, by cutting) on the outer peripheral portion of the end portion of the plunger 15 on the core 14 side. The inner peripheral surface of the projecting portion 15 a is disposed so as to face the outer peripheral surface of the core 14 with a gap when the plunger 15 is attracted to the core 14. That is, the core 14 and the plunger 15 are configured such that when the plunger 15 is adsorbed to the core 14, the core 14 enters the internal space (cavity) of the protruding portion 15 a.

  Here, the diameter of the core 14 is such that the permeance of the gap between the end surface of the core 14 on the plunger 15 side and the attracted surface of the plunger 15 (the inner surface of the protruding portion 15a) is larger than the permeance of the protruding portion 15a. The diameter is large (for example, 20 mm).

  Both the radial thickness and the member of the protruding portion 15a are set so that magnetic saturation occurs during the operation of the plunger 15 (for example, the radial thickness of 2 mm and the material S15C). In addition, since magnetic saturation occurs with an increase in magnetic flux density, it is not determined by any one of dimensions and members. Moreover, although the diameter is described about each dimension of the protrusion part 15a and the core 14, the protrusion part 15a does not necessarily need to be cylindrical shape, and the core 14 does not necessarily need to be columnar.

  Next, the principle of lowering the attractive force due to magnetic saturation will be described, and the operation of the electromagnetic switch 5 of the first embodiment will be described. First, the suction force is expressed as follows.

  Here, P is permeance, μ is magnetic permeability, S is magnetic path cross-sectional area, l is magnetic path length, F is attractive force, U is magnetomotive force, and x is stroke.

  FIG. 3 is a schematic view when the columnar core 14 enters the internal space of the cylindrical protrusion 15a of FIG. If the permeance of the protrusion 15a is sufficiently large, the suction force can be expressed by the following equation from the permeance of the gap between the inner peripheral surface of the protrusion 15a and the outer peripheral surface of the core 14.

Where μ ₀ is the vacuum permeability, D is the diameter of the core 14, and δ is the gap distance.
In the above formula, there is no term related to the stroke. For this reason, when magnetic saturation does not generate | occur | produce in the protrusion part 15a, it becomes a solenoid by which attraction force is kept constant like patent document 3, 4, for example. On the other hand, in the first embodiment, magnetic saturation occurs in the internal space of the protrusion 15a. FIG. 4 shows a BH curve of the magnetic material. Since the magnetic flux density B and the magnetic permeability μ are represented by the relationship B = μH, they coincide with the slope of the curve. H is the strength of the magnetic field. As shown in FIG. 4, when the magnetic flux density increases and approaches magnetic saturation, the slope becomes μ1, and the permeance of the magnetic path decreases, so the attractive force decreases. The above is the outline of the decrease in attractive force due to magnetic saturation.

  Next, the operation of the electromagnetic switch 5 according to Embodiment 1 will be described. FIG. 5 is an explanatory diagram for explaining the flow of magnetic flux at the initial position. FIG. 6 is an explanatory diagram for explaining the flow of magnetic flux when the attractive force is reduced. FIG. 7 is an explanatory diagram for explaining the flow of magnetic flux in the vicinity of the attracting position. FIG. 8 is a graph showing a change in attractive force with respect to the stroke of the electromagnetic switch 5 in FIG.

  As shown in FIG. 5, at the initial position, the magnetic flux generated by the exciting coil 11 flows into the protruding portion 15 a from the end surface or outer peripheral surface (side surface) of the core 14 on the plunger 15 side. Here, since the magnetic flux density of the protrusion part 15a is low, the attraction | suction force obtained becomes large. As shown in FIG. 6, as the displacement of the plunger 15 progresses, the magnetic flux flows from the outer peripheral surface of the core 14 to the protruding portion 15a, and the magnetic flux density of the protruding portion 15a increases to cause magnetic saturation. For this reason, the suction force decreases.

  Thereafter, when the displacement of the plunger 15 proceeds, as shown in FIG. 7, the permeance of the gap between the end surface of the core 14 and the back surface of the plunger 15 becomes larger than the permeance of the projecting portion 15a that is magnetically saturated, Magnetic flux begins to flow between the end surface of the core 14 and the back surface of the plunger 15 that have not flowed until now, and the attractive force increases. Therefore, as shown in FIG. 8, the suction force characteristic decreases from the initial position side of the stroke toward the suction position side, reaches a minimum point on the initial position side of the stroke contact position, and reaches the minimum point. It can be set as the characteristic which raises toward the adsorption | suction position side.

  According to the first embodiment as described above, since the attractive force characteristic is reduced from the initial position side of the stroke toward the suction position side, the current control means is unnecessary, and thus the manufacturing cost is reduced. Responsiveness can be improved by generating a relatively large suction force at the initial position of the stroke. At the same time, the impact sound can be reduced by suppressing the acceleration of the plunger 15.

  Further, since the characteristic reaches a minimum value on the initial position side with respect to the contact position, the suction force when the pinion gear 2 contacts the ring gear 6 and the speed of the plunger 15 can be reduced. Impact sound at the time of contact can be suppressed.

  Here, in the conventional devices as shown in Patent Documents 1 and 2, in order to improve the meshing properties of the pinion gear 2 and the ring gear 6, it is necessary to strongly attract the plunger in the axial direction, and the suction force is increased over the entire stroke. It was necessary to strengthen. On the other hand, in the first embodiment, the suction force is increased near the suction position near the suction position after the minimum stroke value, so that the plunger 15 is held with a strong suction force. Can do. As a result, the meshability of the pinion gear 2 and the ring gear 6 can be improved.

  In general starters, the resistance of the electromagnetic coil increases when the engine room is hot, compared to when the engine room is cold, and the attractive force of the electromagnetic coil decreases. May become stable. In particular, in the engine start / restart system, since the starter is used frequently, it is necessary to suppress such unstable operation of the starter. On the other hand, in the first embodiment, since the suction force at the initial position is the highest in the stroke, instability of the operation of the starter 1 can be suppressed without current control.

Embodiment 2. FIG.
FIG. 9 is a sectional view showing an example of the structure of the solenoid core 24 and plunger 25 according to the second embodiment of the present invention. In FIG. 9, the shape of the core 24 of Embodiment 2 is cylindrical. A columnar insertion portion 25a is provided at the distal end portion (left end in FIG. 9) of the plunger 25 of the second embodiment.

  The outer diameter of the insertion portion 25a is smaller than the inner diameter of the core 24 and the outer diameter of the base end portion of the plunger 25 (the right end in FIG. 9). Further, the axial length of the insertion portion 25 a is a dimension that can be inserted into the internal space of the core 24. Thereby, when the plunger 25 is adsorbed to the core 24, the insertion portion 25 a of the plunger 25 is inserted into the internal space of the core 24.

  Other configurations in the second embodiment are the same as those in the first embodiment, and even if an insertion portion 25a that can be inserted into the core 24 is provided in the plunger 25, the formed magnetic path does not change. Even with the configuration of 2, the same effect as in the first embodiment can be obtained.

Embodiment 3 FIG.
FIG. 10 is a sectional view showing an example of the structure of the solenoid core 34 and plunger 35 according to the third embodiment of the present invention. In the third embodiment, as shown in FIG. 10, an annular notch 35 b is formed at the base end portion of the cylindrical protrusion 35 a in the plunger 35.

  The other configuration in the third embodiment is the same as that in the first embodiment, and the magnetic path passing through the gap does not change, so that the same effect as in the first embodiment can be obtained. Moreover, since the magnetic flux density of the protrusion part 35a can be adjusted according to the shape of the notch part 35b, the minimum value of the attractive force with respect to the stroke can be arbitrarily set.

Embodiment 4 FIG.
FIG. 11 is a sectional view showing an example of the structure of the solenoid core 44 and plunger 45 according to the fourth embodiment of the present invention. In the fourth embodiment, as shown in FIG. 11, the inner peripheral surface of the cylindrical projecting portion 45a tapers from the base end side (right side in FIG. 11) toward the tip end side (left side in FIG. 11). It is inclined to.

  The other configuration in the fourth embodiment is the same as that in the first embodiment, and the magnetic path passing through the gap does not change, so that the same effect as in the first embodiment can be obtained. Moreover, since the magnetic flux density of the protrusion 45a can be adjusted according to the inclined state of the inner peripheral surface of the protrusion 45a, the minimum value of the attractive force with respect to the stroke can be arbitrarily set.

Embodiment 5 FIG.
FIG. 12 is a sectional view showing an example of the structure of the solenoid core 54 and plunger 55 according to the fifth embodiment of the present invention. In the fifth embodiment, as shown in FIG. 12, a step is provided on the outer peripheral surface (side surface) of the core 54. Other configurations in the fifth embodiment are the same as those in the first embodiment, and the magnetic path passing through the gap does not change. Therefore, the same effect as in the first embodiment can be obtained. Further, since the magnetic flux density of the protrusion 55a can be adjusted according to the shape of the step, the minimum value of the attractive force with respect to the stroke can be arbitrarily set.

Embodiment 6 FIG.
FIG. 13 is a cross-sectional view showing an example of the structure of the solenoid core 64 and the plunger 65 according to the sixth embodiment of the present invention. In the sixth embodiment, as shown in FIG. 13, the outer peripheral surface of the core 64 is inclined so as to taper from the plunger 65 side toward the counter plunger 65 side. Other configurations in the sixth embodiment are the same as those in the first embodiment, and the magnetic path passing through the gap does not change. Therefore, the same effect as in the first embodiment can be obtained. Moreover, since the magnetic flux density of the protrusion 65a can be adjusted according to the inclined state of the outer peripheral surface of the core 64, the minimum value of the attractive force with respect to the stroke can be arbitrarily set.

Embodiment 7 FIG.
FIG. 14 is a sectional view showing an example of the structure of the solenoid core 74 and plunger 75 according to the seventh embodiment of the present invention. In the seventh embodiment, as shown in FIG. 14, a step is formed on the inner peripheral surface of the cylindrical core 74 so that the inner diameter changes between the distal end side and the proximal end side.

  Other configurations in the seventh embodiment are the same as those in the second embodiment, and the magnetic path passing through the gap does not change. Therefore, the same effects as in the first and second embodiments can be obtained. In addition, since the magnetic flux density at the tip of the core 74 can be adjusted according to the shape of the step on the inner peripheral surface of the core 74, the minimum value of the attractive force with respect to the stroke can be set arbitrarily.

Embodiment 8 FIG.
FIG. 15 is a sectional view showing an example of the structure of the solenoid core 84 and plunger 85 according to the eighth embodiment of the present invention. In the eighth embodiment, as shown in FIG. 15, the inner peripheral surface of the cylindrical core 84 is inclined so as to taper from the proximal end side to the distal end side.

  Other configurations in the eighth embodiment are the same as those in the second embodiment, and the magnetic path passing through the gap does not change, so that the same effect as in the first and second embodiments can be obtained. Further, since the magnetic flux density at the tip of the core 84 can be adjusted according to the inclined state of the inner peripheral surface of the core 84, the minimum value of the attractive force with respect to the stroke can be arbitrarily set.

Embodiment 9 FIG.
FIG. 16 is a sectional view showing an example of the structure of the solenoid core 94 and plunger 95 according to the ninth embodiment of the present invention. In the ninth embodiment, as shown in FIG. 16, a cylindrical protruding portion 94 a that protrudes toward the plunger 95 is provided on the outer peripheral portion of the end surface of the core 94 on the plunger 95 side. An annular groove 95 a is formed on the end surface of the plunger 95 on the core 94 side. That is, the core 94 and the plunger 95 are configured such that the protruding portion 94a enters the internal space of the groove 95a when the plunger 95 is attracted to the core 94.

  Other configurations in the ninth embodiment are the same as those in the second embodiment, and the magnetic path passing through the gap does not change, so that the same effect as in the first and second embodiments can be obtained. Further, since the magnetic flux density of the protrusion 94a can be adjusted according to the shapes of the core 94 and the plunger 95, the minimum value of the attractive force with respect to the stroke can be arbitrarily set.

  1 starter, 2 pinion gear, 3 starter motor, 4 lever, 5 electromagnetic switch, 6 ring gear, 11 excitation coil, 12 yoke, 13 guide member, 14 core, 15 plunger, 15a protrusion, 16 spring, 24 core, 25 Plunger, 25a Insertion, 34 Core, 35 Plunger, 35a Protrusion, 35b Notch, 44 Core, 45 Plunger, 45a Protrusion, 54 Core, 55 Plunger, 55a Protrusion, 64 Core, 65 Plunger, 65a Protrusion , 74 core, 75 plunger, 84 core, 85 plunger, 94 core, 94a protrusion, 95 plunger, 95a groove.

Claims (9)

The core,
A plunger disposed coaxially with the core and provided displaceable with respect to the core;
An electromagnetic coil for starting an engine provided in a starter, comprising an excitation coil that generates an attractive force by energization and attracts the plunger toward the core,
The characteristics of the suction force, position and suction position is where the plunger is attracted to the core, movable of said plunger between an initial position is a position spaced in the axial direction of the core from the suction position in stroke shall be the range, the characteristics of the suction force is reached minimum point from the initial position side of the stroke decreases toward the suction side, rising toward from the minimum point to the suction side An electromagnetic switch for starting the engine, characterized by The characteristic of the attraction force is a characteristic that reaches the minimum point on the initial position side with respect to the contact position where the pinion gear of the starter contacts the ring gear in the stroke. The electromagnetic switch for starting the engine as described. 3. The engine start electromagnetic switch according to claim 2, wherein one of the plunger and the core has a protruding portion that protrudes in the axial direction toward the other side. The electromagnetic switch for engine start according to claim 3, wherein the plunger and the core are configured so that magnetic saturation occurs in the protrusion during displacement of the plunger. The core is configured such that a permeance of a gap between the core and the protrusion at the suction position is larger in an axial direction of the core than in a radial direction of the core. Electromagnetic switch for starting the engine. The core has a cylindrical shape,
The electromagnetic switch for engine start according to claim 2, wherein the plunger has an insertion portion that is inserted into the internal space of the core when adsorbed to the core. The engine starter according to claim 6, wherein the plunger and the core are configured so that magnetic saturation occurs at an end of the plunger on the initial position side of the plunger during displacement of the plunger. Electromagnetic switch. An electromagnetic switch for starting the engine according to any one of claims 1 to 7,
A pinion gear provided to be displaceable with respect to a ring gear provided on the crankshaft of the engine, and for transmitting a rotational driving force to the ring gear;
A lever connecting the plunger of the engine start electromagnetic switch and the pinion gear;
A starter comprising: a starter motor that applies a rotational driving force to the crankshaft via the pinion gear and the ring gear. An engine starting method using the starter according to claim 8,
Meshing the pinion gear with the ring gear by energizing the coil to displace the plunger toward the core and moving the pinion gear toward the ring gear;
Driving the starter motor and applying a rotational driving force to the crankshaft via the pinion gear and the ring gear.

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