JPH0314916A - Electromagnetic clutch - Google Patents

Abstract

PURPOSE:To provide sure transmission of rotational force, in an electromagnetic clutch where rotational force is transmitted through a pin, by arranging the pin and a pin hole so that the direction of the rotational force by the pin working upon the contact point between the pin and the pin hole may be a tangential one to the rotational direction of a rotor. CONSTITUTION:When an exciting coil 2 is energized, an armature 4 is sucked by a rotor 3, so that a leaf spring 6 is deflected by the force, and the armature 4 moves and comes into close contact with the rotor 3. By the close contact, a flux passing through the sucking part 9a of a pin 9 installed on the armature 4 increases, and the sucking force which exceeds the energizing force of a spring for holding the pin 9 works. When the rotor 3 rotates and a pin hole 4b on the armature 4 side coincides with a pin hole 3e on the rotor 3 side, a pin body 9b is fitted into the pin hole 3e. This clutch is constructed so that the direction of the rotational force F working upon the contact point P between the pin 9 and the pin hole 3e may be a tangential one to the rotational direction D of the rotor 3, so that the component force in the radial direction of a rotating shaft 103 does not occur at all, and the rotational force is transmitted surely.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a motor which is disposed between a driving device and a driven device, and is adapted to intermittently transmit rotation from the driving device to the driven device. The present invention relates to an electromagnetic crunch suitable for, for example, a compressor used in a vehicle air conditioner.

[Conventional technology]

Conventionally, a general dry single-plate electromagnetic clutch consists of a stator that generates magnetic force, a rotor supported by bearings to be rotated by the rotational force from the drive source, and an armature that can slide in the axial direction by the magnetic force of the stator. (Refer to Japanese Utility Model Publication No. 14998/1983).

When an electromagnetic crunch having such a structure is used, for example, attached to a compressor of a vehicle air conditioner, there is a stator attached to the compressor that generates magnetic force, and a stator that is attached to the compressor via a bearing so as to be rotatable. The compressor is constructed of a rotor that is attached to the compressor and has an armature that can be slid in the axial direction by the magnetic force of the stator, and the friction surface of the armature that is provided opposite to the friction surface of the rotor is generated by the stator. The compressor is attracted to the rotor by magnetic force, and the torque transmitted from the drive device is transmitted to the compressor, which is the driven side. In the electromagnetic clutch with the structure described above, rotational force is transmitted exclusively by the frictional force between the rotor and the armature, but this frictional force has a limit, making it difficult to generate high torque. there were.

In order to solve this problem, the applicant first developed an electromagnetic clutch configured to engage a pin attached to the armature and a pin hole provided in the rotor when transmitting rotation to a driven body (patent application). (See No. 171945, 1983).

An electromagnetic clutch using this pin has a stator having an exciting coil, a rotor that is rotated by rotational force from a drive source and has a friction surface on one side, and a friction surface opposite to the friction surface of the rotor. an armature that is movably attached to a rotating shaft in the axial direction with a predetermined gap between the armature and the rotor, and the friction surface of the armature is brought into contact with the friction surface of the rotor by the operation of the excitation coil. In the electromagnetic clutch, the armature is equipped with a pin that is biased away from the friction surface of the rotor, and the pin is attached to the friction surface of the rotor. A pin hole corresponding to the excitation coil is provided, and the pin fits into the pin hole when the excitation coil is activated.

[Problem to be solved by the invention]

However, if the clutch is operated in this way, the ninth
As shown in the figure, the rotational force F1 acting on the contact point between the pin 9 and the pin hole 3e when transmitting the rotational force via the pin 9 generates a component force F2 in the radial direction of the rotor, and therefore An eccentric load is applied in the radial direction, and the rotating shaft rotates eccentrically, generating vibration and noise, which also adversely affects the radial bearing and reduces its durability. On the other hand, since the same force as F, , F2 is applied to the pin 9 in the opposite direction, this becomes a force that tilts the pin, and in extreme cases, the pin may break and the function as a clutch may be lost.

In view of the above points, the present invention provides an electromagnetic clutch using a pin that does not apply excessive force to driven rotating members, reduces vibration and noise, and does not cause damage to the pin. This is what we are trying to provide.

[Means to solve the problem]

According to the present invention, the above problem can be solved by the fact that when the electromagnetic clutch is activated, the direction of the rotational force due to the pin is tangential to the rotational direction of the rotor when the rotational force is transmitted to the rotating shaft via the pin. It is solved by doing this. That is, the structure of the present invention as a means for solving the above problems includes a stator having an excitation coil, a rotor that is rotated by a rotational force from a drive source and has a friction surface on one side,
an armature having a friction surface opposite to the rotor friction surface and movably attached to the rotary shaft in the axial direction with a predetermined gap between the armature and the rotor; The friction surface of the armature is brought into contact with the friction surface of the rotor to transmit the rotation of the rotor to the rotating shaft, and the armature has a pin urged away from the friction surface of the rotor. Attachment, a pin hole corresponding to the pin is provided in the friction surface of the rotor, so that the pin fits into the pin hole when the excitation coil is activated, and the rotational force from the rotor is transmitted through the pin. In the electromagnetic clutch configured to be transmitted to the rotating shaft, the pin and the pin are arranged such that the direction of the rotational force of the rotor acting on the contact point between the pin and the pin hole is tangential to the rotational direction of the rotor. It is characterized by the arrangement of holes.

[For production]

In the present invention having the above structure, when the rotation from the rotor is to be transmitted to the rotating shaft, when the excitation coil is energized, the armature is attracted and moved in the axial direction and comes into close contact with the rotor. When the rotor rotates and the pin hole on the rotor side matches the position of the pin, the pin fits into this pin hole,
The armature is firmly connected to the rotor, and the rotational force from the rotor is transmitted to the rotating shaft through the pin hole, pin, and armature on the rotor side.

When transmitting this rotational force, the direction of the rotational force acting on the contact point between the pin and the pin hole is tangential to the rotational direction of the rotational shaft, so there is no component force applied in the radial direction of the rotational shaft, and the eccentricity of the rotational force is Rotation is avoided. Further, since no force is generated to tilt the pin, damage caused by this load is prevented.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

Referring to FIGS. 2 and 3, 100 is a housing of the compressor, and 103 is a rotating shaft of the compressor. Reference numeral 1 denotes a stator housing made of a magnetic material, in which an excitation coil 2 is embedded with epoxy resin 20. This excitation coil 2 is connected to an external power source via a lead wire (not shown). Further, a mounting flange 1a is joined to the stator housing l, and this mounting flange 1
The stator housing 1 is fixed to the compressor housing 100 by a circlip 101 via a.

Reference numeral 3 denotes a magnetic rotor integrally formed with a pulley 3a, which is rotatably mounted on the compressor housing 100 via a bearing 7. The outer ring 7a of the bearing 7 is fixed to the rotor 3 with a presser, and the inner ring 7b is fitted into the compressor housing 100, and is attached to the housing 100 by a circlip 102.
is fixed. The friction surface 3b of the rotor 3 has elongated holes 3c and 3a for the purpose of magnetic isolation, a hole 3e into which a pin (described later) is inserted, a flat surface 3f for guiding the pin, and a recess 3g for adjusting magnetic flux density ( Fig. 4) is provided.

An armature 4 is disposed opposite to this rotor friction surface 3b with a small gap interposed therebetween. The armature 4 is made of a magnetic material and has an annular shape, and is connected to the rotary shaft 103 of the compressor by a bolt 104 via a plurality of leaf springs 6 which are spring means fixed to the armature 4 with a plurality of rivets 5. It is fixed by a connected hub 7 and a plurality of rivets 8.

As shown in FIG. 5, the armature 4 is provided with three magnetically blocking elongated holes 4a and three round holes 4b whose centers are substantially the same as the center line of the elongated holes 4a along the circumferential direction. A pin 9 is fitted into this round hole 4b. The pin 9 has an attraction part 9a made of a highly magnetic material and a pin body 9b made of a non-magnetic material, and are joined together by press-fitting (FIG. 6).

The pin 9 is held in place by a stopper 10 and a spring 11 that biases the pin 9 away from the rotor 3. The stopper 10 is made of a non-magnetic material and is fixed to the armature 4 with a plurality of bolts 12 (FIG. 2).

The positional relationship between the pin 9 on the armature side and the pin hole 3e on the rotor side will be explained with reference to FIG. 1.

As shown in the drawing, when the pin 9 is fitted into the pin hole 3e and the rotational force is transmitted from the rotor 3 to the rotating shaft 103, the rotational force F that acts on the contact point P between the pin 9 and the pin hole 3e. The positions of the pin 9 and the pin hole 3e are determined such that the direction is tangential to the rotational direction D of the rotor 3.

The positions of the pin 9 and the pin hole 3e can be determined as follows.

That is, the radius of the pin is rl, and the radius of the pin hole 3e is r
2. Let the distance of the contact point P between the pin and pin hole from the rotational axis center ○ be R1, the distance from the center of the pin 9 from the axial center ○ be Rl, and the distance from the center of the pin hole 3e from the axial center ○ be R2. ,
In order for the rotational force F to be in the tangential direction, it must be as follows.

Since the diameters of the pin 9 and the pin hole 3e are determined depending on the shape of the electromagnetic clutch, r, l and r2R are given constant values, so R1 and R2 are adjusted to satisfy the above two equations. By determining the value of , the position of the pin 9 and pin hole 3e from the rotation axis center 0 is determined.

In the electromagnetic clutch constructed in this way, when the excitation coil 2 is energized when the compressor is started, magnetic flux is generated as shown by the broken line 1 in FIG. 3, and the armature 4 is immediately attracted to the rotor 3. is added. As a result, the leaf spring 6 is elastically bent, and the armature 4 moves in the axial direction, causing the rotor I of the rotor 3! i! It comes into close contact with the rubbing surface 3b by suction.

This close contact between the armature 4 and the rotor 3 reduces the resistance of the magnetic circuit and further increases the amount of magnetic flux.

As a result, the magnetic flux flowing through the pin attracting portion 9a increases, and an attractive force that exceeds the spring biasing force of the spring 11 that holds the pin 9 acts.

Here, if the positions of the pin hole 4b of the armature 4 and the pin hole 3e of the rotor do not match, the tip of the pin body 9b will be located on the guide plane of the rotor 3. The pin 9 contacts the surface portion 3f and does not come into close contact with the armature 4. When the rotation further progresses and the pin hole 4b on the armature side and the pin hole 3e on the rotor side coincide, the pin body 9b fits into the pin hole 3e, and the pin 9 comes into close contact with the armature 4.

The driving force transmitted from the rotor 3, which is driven by an automobile engine (not shown) via a belt, is transmitted to the compressor shaft 103 via the rotor pin hole 3e, pin body 9b, armature 4, leaf spring 6, and hub 7. .

When transmitting the rotational force from the rotor 3 to the rotating shaft 103 via the pin 9, the direction of the rotational force F acting on the contact point between the pin 9 and the pin hole 3e is tangential to the rotational direction D of the rotor 3. Therefore, no component force is applied to the rotating shaft 103 in the radial direction. Therefore, since the rotation shaft 103 is not bent in the radial direction and eccentric rotation is not caused, the generation of vibration and noise due to this eccentric rotation is reduced, and there is no load on the pin 9 that causes it to tilt, resulting in damage. is prevented. In this way, the rotating glaze 103 can reliably transmit rotational force from the rotor 3 via the pin 9 and can rotate smoothly.
This reduces noise and improves the durability of the bearing.

When stopping the operation of the compressor, the excitation coil 2 is de-energized to eliminate the magnetic flux. As a result, the pin 9 is separated from the armature 4 by the restoring force of the spring {1, and the armature 4 is separated from the rotor 3, so that no driving force is transmitted.

Here, the gap between the armature 4 and the rotor 3 is set to the minimum value in consideration of operability and vibration resistance. 5
It is about mrII. On the other hand, the gap between the armature 4 and the pin 9 is determined from the allowable surface pressure between the pin and the rotor 3 after operation, and is approximately 2 mm. The spring force is determined based on each vibration resistance and operability. The spring constant of the leaf spring 6 that holds the armature 4 is about 10 kg/mm, and the spring constant of the spring 11 that holds the pin 9 is about 0.
It is about 3 kg/mm.

FIGS. 7 and 8 show rotors according to other embodiments of the present invention, each showing a rotor in which a pin and a pin hole are combined into one.

In the second embodiment shown in FIG. 7, the pin hole 3e is circular, and in the third embodiment shown in FIG. 8, the pin hole 3e has an elliptical shape with a long sleeve in the radial direction of the rotation axis.

The second and third embodiments described above aim to reduce the number of parts by combining a pin and a pin hole. Since the transmission portion of the rotational force is biased, applying the arrangement of pins and pin holes as in the present invention is particularly effective in preventing vibration of the rotating shaft and damage to the pin.

〔Effect of the invention〕

Since the present invention has the above-described structure and operation, when the rotation is transmitted to the driven body, the pin attached to the armature fits into the pin hole provided on the rotor side, and the connection between the armature and rotor is established. Since the engagement is strong, torque can be transmitted through the pin without relying solely on frictional force and suction force as in the conventional case, and therefore a large torque can be transmitted. Moreover, when torque is transmitted through this pin, no force is generated on the rotating shaft that would cause it to rotate eccentrically, which reduces the generation of vibration and noise, which does not adversely affect the bearings that support the rotating shaft. This will improve its durability. Further, since no excessive load is applied to the pin, damage to the pin can be prevented, and the electromagnetic clutch can be used for a long period of time.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the main parts of an embodiment of the present invention, Fig. 2 is a front view of the embodiment of the invention, Fig. 3 is a sectional view taken along the line E-E in Fig. 2, and Fig. 4 is a 3. FIG. 5 is a front view of the armature as seen from arrow C in FIG. 3. FIG. 6 is an enlarged sectional view of the pin in the same embodiment. The figure is a front view of a rotor according to a second embodiment of the present invention, FIG. 8 is a front view of a rotor according to a third embodiment of the same as above, and FIG. 9 shows the action of rotational force in a conventional N magnetic clutch using a pin. It is an explanatory diagram. DESCRIPTION OF SYMBOLS 1... Stator housing, 2... Excitation coil, 3b... Rotor friction surface, 4... Armature, 4b... Round hole for pin, 10... Stopper, 103... Rotating shaft. 3... Rotor, 3e... Pin hole, 4a... Long hole for magnetic isolation, 9... Pin, 11... Spring,

Claims (1)

[Claims] 1. A stator having an excitation coil, a rotor that is rotated by a rotational force from a drive source and has a friction surface on one side, and a rotor that has a friction surface opposite to the friction surface of the rotor and is located between the rotor and the rotor. an armature attached to the rotating shaft with a gap therebetween so as to be movable in the axial direction;
The excitation coil is activated to bring the friction surface of the armature into contact with the friction surface of the rotor to transmit the rotation of the rotor to the rotating shaft, and the armature is biased away from the friction surface of the rotor. and a pin hole corresponding to the pin is provided in the friction surface of the rotor, so that the pin fits into the pin hole when the excitation coil is activated, and the rotational force from the rotor is In the electromagnetic clutch, the electromagnetic clutch is configured to be transmitted to the rotating shaft via a pin, such that the direction of the rotational force of the rotor acting on the contact point between the pin and the pin hole is tangential to the rotational direction of the rotor. An electromagnetic clutch characterized in that the pin and pin hole are arranged.