JPH0627924Y2 - Electromagnetic clutch - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic clutch, and more particularly, to a field core formed of a magnetic material and having an inner cylinder portion and an outer cylinder portion having a through hole at the center, and a field core. By including an electromagnetic coil fitted between the tubular portion and the outer tubular portion and a rotating shaft inserted through a bearing into the center hole of the inner tubular portion, by controlling the energization of the electromagnetic coil, The present invention relates to an electromagnetic clutch that controls the rotation of a rotating shaft.

[0002]

2. Description of the Related Art An example of a conventional electromagnetic clutch will be described with reference to FIG. A field core 100 is made of a magnetic material. The field core 100 includes an outer tubular portion 102 and an inner tubular portion 106 having a central hole 104 formed therethrough. Reference numeral 108 denotes an electromagnetic coil, which is fitted between the outer tubular portion 102 and the inner tubular portion 106 of the field core 100. A rotating shaft 110 is rotatably inserted into the center hole 104 of the inner cylindrical portion 106. Reference numeral 112 denotes a bearing, which is made of a non-magnetic material. The bearing 112 is formed in a tubular shape having substantially the same length as the inner tubular portion 106. The bearing 112 includes the outer peripheral surface of the rotating shaft 110 and the inner cylindrical portion 10.
6 is inserted between the inner peripheral surface and the inner peripheral surface to prevent wear between the both. Reference numeral 114 denotes a rotor, which is made of a magnetic material. The rotor 114 is fixed to the rotating shaft 110. Reference numeral 116 denotes a hub, which is rotatably arranged on the rotary shaft 110. Rotational force is applied to the hub 116 from the outside, and the hub 116 is always rotating freely with respect to the rotating shaft 110. Reference numeral 118 is an armature, which is made of a magnetic material. The armature 118 is fixed to the hub 116 via a return spring 120. When the electromagnetic coil 108 is energized, the magnetic circuit X shown by the broken line is closed, is attracted to the left against the biasing force of the return spring 120, and the armature 118 is attracted to the rotor 114. By this suction, the rotation of the hub 116 can be transmitted to the rotating shaft 110. On the other hand, when the energization of the electromagnetic coil 108 is stopped, the magnetic circuit X disappears and the armature 118 moves to the rotor 114.
Move away from. Due to this separation, the rotation of the rotary shaft 110 is stopped.

[0003]

However, the above-mentioned conventional electromagnetic clutch has the following problems. The bearing inserted between the inner cylinder of the field core and the rotary shaft is made of a non-magnetic material. This is because when the bearing is made of a magnetic material, magnetic attraction occurs between the rotating shaft and the bearing, which increases rotation resistance and wear between the two, and thus prevents these problems. However, if the bearing is made of a non-magnetic material, the leakage magnetic flux increases and the magnetic attraction between the rotor and the armature decreases. As a result, there is a problem that the torque of the electromagnetic clutch becomes small. Therefore, it has been proposed to reduce the thickness of the bearing and reduce the leakage magnetic flux.However, in the conventional bearing, the inner cylinder portion is formed to have substantially the same length, and therefore, it is not necessary to form a thin wall. There is a technical problem that is difficult. Therefore, an object of the present invention is to provide an electromagnetic clutch having a bearing that can be made thin while being made of a non-magnetic material.

[0004]

In order to solve the above problems, the present invention has the following configuration. That is, a field core formed of a magnetic material and having an inner cylinder portion and an outer cylinder portion having a through hole in the center, and an electromagnetic coil fitted between the inner cylinder portion and the outer cylinder portion of the field core. And a rotating shaft rotatably inserted through a bearing made of a non-magnetic material into the center hole of the inner cylindrical portion, and the rotating shaft is controlled by controlling energization to the electromagnetic coil. In the electromagnetic clutch controlling the rotation of the bearing, the bearing is formed in a tubular shape having a length less than 1/2 of the length of the inner tubular portion, is inserted into one end of the inner tubular portion, and A first bearing portion having a flange for restricting movement in the longitudinal direction, and a tubular shape having a length less than 1/2 of the length of the inner tubular portion. It is inserted into the other end of the, and a flange is formed at one end to regulate the movement in the length direction. Characterized in that it consists of a second bearing portion.

[0005]

[Operation] The operation will be described. The bearing is formed in a tubular shape having a length less than 1/2 of the length of the inner tubular portion, and the first bearing portion inserted into one end of the inner tubular portion and the length of the inner tubular portion. Of the first bearing portion and the second bearing portion, since the first bearing portion and the second bearing portion are formed in a tubular shape having a length less than ½ of the second bearing portion and are inserted into the other end portion of the inner tubular portion. The length is short. Therefore, it is possible to reduce the thickness of the cylindrical portion. Since the flange is formed even when the first bearing portion and the second bearing portion are inserted into the inner cylindrical portion, movement in the length direction can be regulated.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings. In FIG. 1, 12 is a field core, which is made of a magnetic material such as iron. The field core 12 includes an inner cylindrical portion 16 having a central hole 14 formed therethrough and a bottomed outer cylindrical portion 18 formed on the outer periphery of the inner cylindrical portion 16. The inner tubular portion 16 is press-fitted and fixed in a through hole provided in the bottom portion 20 of the outer tubular portion 18. The field core 12 is provided with a locking portion 22 that locks a member (not shown) when the electromagnetic clutch 10 of the embodiment is attached and prevents the electromagnetic clutch 10 from rotating. Reference numeral 24 is an electromagnetic coil, which is fitted between the inner tubular portion 16 and the outer tubular portion 18 of the field core 12. Reference numeral 26 denotes a rotor shaft, which is an example of a rotating shaft, and is made of a magnetic material. The rotor shaft 26 is rotatably inserted into the center hole 14 of the inner tubular portion 16. The rotor shaft 2
A shaft (not shown) is inserted into and coupled to the rotor shaft 26 so as not to rotate therein, so as to rotate integrally with the rotor shaft 26. A rotor 28 is made of a magnetic material. The rotor 28 is fixed to the outer circumference of the rotor shaft 26.

Reference numeral 30 is a first bearing portion, which constitutes a bearing. The first bearing portion 30 will be described in detail with reference to FIG. 2 (cross-sectional view) and FIG. 3 (front view). The first bearing portion 30 is formed of a non-magnetic material (for example, copper-based oilless metal, synthetic resin, oil-containing synthetic resin).
The length of the first bearing portion 30 is 1/2 of the length of the inner tubular portion 16.
Is less than the length. The first bearing portion 30 is formed in a tubular shape, and is inserted (or press-fitted) into the left end portion of the inner tubular portion 16 of the field core 12. The left end portion is engaged with the left end surface of the inner tubular portion 16 and has a length. A flange 32a for restricting the movement in the direction (left and right direction in FIG. 1) is formed. In the present embodiment, the length A excluding the flange 32a of the first bearing portion 30 is formed to be 5 mm or less.
The thickness B excluding a is formed to be 0.25 mm or less.

Referring again to FIG. 1, reference numeral 34 denotes a second bearing portion, which constitutes a bearing together with the first bearing portion 30. The second bearing portion 34, like the first bearing portion 30, is a non-magnetic material (for example, copper-based oilless metal, synthetic resin, oil-containing synthetic resin).
Is formed by. The length of the second bearing portion 34 is also less than 1/2 of the length of the inner tubular portion 16. Second bearing part 3
4 is also formed in a tubular shape, and the inner tubular portion 16 of the field core 12 is
Is inserted (or press-fitted) into the right end of the inner cylindrical portion 16 and the right end is formed with a flange 32b for engaging with the right end surface of the inner cylindrical portion 16 and restricting movement in the length direction (the left-right direction in FIG. 1). There is. In the present embodiment, the length of the second bearing portion 34 excluding the flange 32b (corresponding to the length A in FIG. 2) is 5
The thickness (corresponding to length B in FIG. 2) excluding the flange 32b is 0.25 mm or less.

The first bearing portion 30 and the second bearing portion 34 of this embodiment are formed to have a length of 5 mm or less excluding the flanges 32a and 32b.
It is possible to form the thickness excluding 32b to be as thin as 0.25 mm or less. First bearing 3
By disposing the zero bearing and the second bearing portion 34 on both end sides of the inner tubular portion 16, the inner peripheral surface of the central portion of the inner tubular portion 16 and the rotor shaft 26 are disposed.
Since it does not contact the outer peripheral surface of the rotor shaft 26, it is possible to prevent wear of the rotor shaft 26. A hub 36 is rotatably arranged on the outer peripheral surface of the rotor shaft 26. Rotational force is applied to the gear portion on the outer periphery of the hub 36 from the outside (not shown), and the hub 36 is rotated by the rotating shaft 1.
It always rotates freely with respect to 10. Reference numeral 38 denotes an armature, which is made of a magnetic material. The armature 38 is fixed to the hub 36 via a return spring 40. A gap 42 is formed between the left end surface of the armature 38 and the right end surface of the rotor 28. The return spring 40 constantly urges the armature 38 to the right and normally has a gap 42 formed therein. Reference numeral 44 is a snap ring that determines the position of each member on the rotor shaft 26.

Subsequently, the electromagnetic clutch 1 having the above structure
The operation of 0 will be described. When the electromagnetic coil 24 is energized in the normal state shown in FIG. 1, that is, when the electromagnetic coil 24 is not energized, the magnetic circuit C shown by the broken line connects the field core 12, the rotor shaft 26, the rotor 28, and the armature 38. Closed in. Then, the armature 38 is attracted to the left against the biasing force of the return spring 40, and the rotor 28
Is adsorbed on. By this adsorption, the rotation of the hub 36 is transmitted to the rotor shaft 26 and a shaft (not shown) connected to the rotor shaft 26 via the armature 38 and the rotor 28, and both are rotated. On the other hand, when the power supply to the electromagnetic coil 24 is stopped, the magnetic circuit C disappears, the armature 38 separates from the rotor 28, and the gap 42 is formed again. As a result, the rotation of the rotor shaft 26 and the shaft (not shown) connected to the rotor shaft 26 is stopped.

Next, the first bearing portion 3 will be described with reference to FIGS.
Another example of 0 will be described. The first bearing portion 30 can also be used as the second bearing portion 34. The first bearing portion 30 shown in FIG. 4 (cross-sectional view) and FIG. 5 (front view) is provided with an engaging portion 50 for preventing rotation with respect to the field core. The engaging portion 50 engages with the engaged portion formed on the field core to prevent rotation. Also in this first bearing portion 30, the length A excluding the flange 32a is formed to be 5 mm or less, and the flange 3
The thickness B excluding 2a is 0.25 mm or less. Although various preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and many modifications can be made without departing from the spirit of the invention. .

[0012]

[Effect of the Invention] When the electromagnetic clutch according to the present invention is used,
The bearing is formed in a tubular shape having a length less than 1/2 of the length of the inner tubular portion, and the first bearing portion inserted into one end of the inner tubular portion and the length of the inner tubular portion. Of the first bearing portion and the second bearing portion, since the first bearing portion and the second bearing portion are formed in a tubular shape having a length less than ½ of the second bearing portion and are inserted into the other end portion of the inner tubular portion. The length is short. Therefore, it is possible to reduce the thickness of the portion formed in the tubular shape, so that the leakage magnetic flux in the bearing can be reduced and the torque of the electromagnetic clutch can be improved. Particularly, by providing the first bearing portion and / or the second bearing portion with the engaging portion, the rotation of the first bearing portion and / or the second bearing portion with respect to the field core can be prevented. Exerts a remarkable effect.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view showing an embodiment of an electromagnetic clutch according to the present invention.

FIG. 2 is a sectional view of a first bearing portion used for the electromagnetic clutch.

3 is a front view of the first bearing portion of FIG. 2. FIG.

FIG. 4 is a cross-sectional view showing another example of the first bearing portion.

5 is a front view of the first bearing portion of FIG. 4. FIG.

FIG. 6 is a partially cutaway side view showing an example of a conventional electromagnetic clutch.

[Explanation of symbols]

 10 Electromagnetic clutch. 12 field core 14 center hole 16 inner cylinder part 18 outer cylinder part 24 electromagnetic coil 26 rotor shaft 30 first bearing parts 32a, 32b flange 34 second bearing part 50 engagement part

Claims (5)

[Scope of utility model registration request] 1. A field core formed of a magnetic material and having an inner cylinder part and an outer cylinder part having a through hole at the center, and a field core fitted between the inner cylinder part and the outer cylinder part of the field core. And a rotary shaft that is rotatably inserted through a bearing formed of a non-magnetic material into the center hole of the inner cylindrical portion, and controls the energization of the electromagnetic coil. In the electromagnetic clutch that controls the rotation of the rotating shaft, the bearing is formed in a tubular shape having a length less than 1/2 of the length of the inner tubular portion, and is inserted into one end of the inner tubular portion. ,
A first bearing portion having a flange for restricting movement in the length direction at one end portion, and a tubular shape having a length less than 1/2 of the length of the inner tubular portion, An electromagnetic clutch comprising: a second bearing portion which is inserted into the other end portion of the tubular portion and has a flange formed at one end portion for restricting movement in the length direction. 2. The first bearing portion and / or the second bearing portion is provided with an engagement portion for preventing rotation with respect to the field core. Electromagnetic clutch. 3. The electromagnetic clutch according to claim 1, wherein the first bearing portion and / or the second bearing portion is made of synthetic resin. 4. The electromagnetic clutch according to claim 1, wherein the first bearing portion and / or the second bearing portion is made of an oil-containing synthetic resin. 5. The electromagnetic clutch according to claim 1, wherein the first bearing portion and / or the second bearing portion is made of a copper-based oilless metal.