JPH02304221A - Electromagnetic clutch - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electromagnetic clutch that transmits and interrupts rotational power.

[Prior art 1] Conventionally, electromagnetic clutches installed in the refrigerant compressor of a vehicle refrigeration cycle are equipped with a balancing mechanism to balance the dynamic imbalance that occurs inside the refrigerant compressor when the refrigerant compressor is driven. There is.

An example of an electromagnetic clutch having this balanced v1 side will be briefly explained based on FIG. 5.

A clutch rotor 102 rotatably supported via a rolling bearing 101 is disposed around the outer periphery of the annular excitation coil 100 .

The clutch rotor 102 has an axial end surface (left end surface in FIG. 5) formed as a friction surface, and a pulley 103 formed on the outer peripheral surface.

g of the clutch rotor 102 in the axial direction! Facing the rubbing surface,
A suction plate 106 rotatably provided integrally with the drive shaft 105 of the refrigerant compressor 104 is arranged.

This suction plate 106 is moved by the elastic force of the plate spring 107.
It is biased in a direction away from the friction surface of the clutch rotor 102, and is positioned in the axial direction by a rubber stopper 109 attached to the plate hub 108.

The plate hub 108 is connected to the drive shaft 10 of the refrigerant compressor 104.
balance way) 108a, which is assembled to the inner hub 110 fixed to 5 and functions as the above-described balance mechanism;
is provided.

The balance weight 108a is provided by enlarging a part of the outer periphery of the plate hub 108 into an arc shape, and has approximately the same size in the radial direction as the suction plate 106 in order to suppress the function as a balance mechanism with a minimum increase in weight. It is set in.

When the excitation coil 100 is energized, the excitation coil 1
Since magnetic force is generated in 00, the attraction plate 106 which is a magnetic material
However, the clutch rotor 10 resists the elastic force of the leaf spring 107.
It is adsorbed by 2.

As a result, the rotational power of the engine transmitted to the pulley 103 is transmitted to the drive shaft 105 of the refrigerant compressor 104 via the suction plate 106.

[Problems to be Solved by the Invention] For the plate hub 108 described above, a low carbon steel plate such as 5pcc <cold rolled steel plate) is used in consideration of strength, cost, workability, etc.

For this reason, when the excitation coil 100 is energized and the attraction plate 106 is attracted to the clutch rotor 102, a plate hub made of a magnetic material is placed near the original magnetic circuit shown by the F& line in FIG. 108, a magnetic circuit passing through the play 1 to the hub 108 is formed, as shown by the dashed line in FIG. 5, and leakage of magnetic flux occurs.

As a result, the amount of magnetic flux in the original magnetic circuit is reduced, and an attractive force is generated between the plate hub 108 and the suction plate 106, resulting in a problem in that the transmission torque of the clutch is reduced.

Therefore, conventionally, the magnetic force of the excitation coil 100 is increased.
Technical measures have been taken, such as increasing the friction area between the clutch rotor 102 and the suction plate 106, and making the plate hub 108 from a non-magnetic material such as stainless steel.

However, such conventional technology has problems such as an increase in the size of the electromagnetic clutch due to an increase in the friction area and an increase in the magnetic force of the excitation coil 100, and an increase in cost due to the use of non-magnetic materials. Ta.

The present invention has been made based on the above circumstances, and an object thereof is to provide an electromagnetic clutch that suppresses a decrease in transmission torque without increasing the size or cost.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes: an annular excitation coil that generates magnetic force when energized; and a magnetic excitation coil that is rotatably supported via a bearing. A clutch rotor forming a part of the excitation coil is disposed facing the clutch rotor in the axial direction and has a magnetic cutoff elongated hole formed in the circumferential direction. In an electromagnetic clutch equipped with a suction plate that is attracted to the rotor side and a plate hub provided with a stopper that positions the suction plate in the axial direction, the plate hub is made of a magnetic material and The technical means is that an elongated hole is formed in the circumferential direction at approximately the same position as the magnetic shielding elongated hole.

[Operation] In the electromagnetic clutch of the present invention having the above configuration, the attraction plate is attracted to the clutch rotor when the exciting coil is energized and a magnetic force is generated. At this time, since the plate hub made of a magnetic material is present near the magnetic circuit passing through the clutch rotor and the suction plate, the magnetism of the excitation coil acts on the plate hub.

However, since the plate hub has a circumferentially elongated hole formed at approximately the same position as the magnetic blocking elongated hole formed in the suction plate, the magnetism acting on the plate hub is blocked by the elongated hole. As a result, the amount of magnetic flux leaking due to the magnetism acting on the plate hub can be significantly reduced.

[Effects of the Invention] The present invention having the above-mentioned effects can reduce the deflection of magnetic flux by simply forming elongated holes for magnetic shielding in the plate 1 to the hub. It is possible to use a magnetic material (for example, a low carbon steel plate) that is cheaper, stronger, and easier to work with than non-magnetic materials.

In addition, since the leakage of magnetic flux is reduced, the amount of magnetic flux in the original magnetic circuit is suppressed, and the attraction force between the plate hub and the suction plate is reduced, so it is possible to suppress a decrease in the transmitted torque. can. Therefore, there is no need to increase the magnetic force of the excitation coil or to expand the friction area between the clutch rotor and the suction plate.

As a result, the amount of transmitted torque can be suppressed without increasing the size of the electromagnetic clutch or increasing costs.

[Example] Next, the electromagnetic clutch of the present invention will be described based on an example shown in page 12.

In this embodiment, an electromagnetic clutch 1 is attached to a refrigerant compressor 2 of a refrigeration cycle for a vehicle.
! 12, a front view of the electromagnetic clutch 1 housed in the second
The figure shows a side sectional top view of the electromagnetic clutch.

Does electromagnetic clutch 1 compress the refrigerant? f! It is attached to the drive shaft 3 (see FIG. 2) of No. 2, and transmits or cuts off the rotational output of an engine (not shown) to the drive shaft 3 as necessary.

As shown in FIG. 2, the electromagnetic clutch 1 of this embodiment is roughly divided into an excitation coil 4, a stator housing 5 and an inner housing 6 that support the excitation coil 4, and the rotational output of the engine is transmitted to rotate the electromagnetic clutch 1. The clutch rotor 7 receives the rotational power of the clutch rotor 7, and the drive shaft 3
and a rotating body 8 that rotates together with the rotating body 8.

The excitation coil 4 is a well-known coil made by winding a conductive wire coated with an insulating film around a resin bobbin 9, and generates magnetic force when energized. This m5rli coil 4 has an epoxy resin 10
It is fixed using a mold.

The stator housing 5 is made of a magnetic material such as iron, and is press-fitted around an inner housing 6 fixed to the housing 11 of the refrigerant compressor 2 .

The inner housing 6 has a cylindrical portion 6a that covers the outer periphery of the drive shaft 3.
Like the stator housing 5, it is made of a magnetic material f1 such as iron. A shaft seal 12 that makes sliding contact with the outer circumferential surface of the drive shaft 3 is attached to the inner periphery of the cylindrical portion 6a, and is provided to prevent lubricating oil from the refrigerant compressor 2 side or refrigerant from leaking.

The clutch rotor 7 has an annular U-shaped cross section that covers the excitation coil 4 from the front (left side in FIG. 2), and has a pulley formed on its outer peripheral surface, on which a multistage V-belt (not shown) is passed. ing.

An outer ring 14a of a rolling bearing 14 mounted on the outer periphery of the cylindrical portion 6a of the inner housing 6 is mounted on the inner periphery of the clutch rotor 7.
is press-fitted and fixed. Therefore, C, the clutch rotor 7 is
It is supported to rotate r1 via a rolling bearing 14, and is rotated by the rotational power of the engine transmitted via a multistage V-belt. Note that the inner ring 14b of the rolling bearing 14 is fixed to the cylindrical portion 6a by a lower threaded member 15.

The clutch rotor 7 is made of a magnetic material such as iron, and has a front end (left side in FIG. 2) as a smooth friction surface. Furthermore, magnetic shielding elongated holes 16 and 17 are formed around the entire circumference near the inner circumference and the outer circumference of the front end face.

The above-mentioned screw member 15 has a small diameter portion 15a and a large diameter portion 15b.
A male thread 15C is formed on the outer periphery of the small diameter portion 15a to be screwed into a female thread (see FIG. 2) 6b formed on the inner periphery of the tip of the cylindrical portion 6a of the inner housing 6. .

When this screwing member 15 is fixed to the inner housing 6 by screwing the male thread 15C of the small diameter portion 15a to the female thread 6b of the cylindrical portion 6a, the rear side (right side in FIG. 2) end face of the large diameter portion 15b is The rolling bearing 14 is fixed by coming into contact with the side surface of the inner ring 14b of the rolling bearing 14. At this time, a minute gap is formed between the outer circumferential surface of the large diameter portion 15b and the inner circumferential surface of the clutch rotor 7. There is.

The rotating body 8 includes an inner hub 19 fixed to the end of the drive shaft 3 by bolts 18, and a hollow disc-shaped suction plate 21 coupled to the inner hub 19 via three leaf springs 20.
Stopper 22 that positions the suction plate 21 in the axial direction
It is composed of a plate hub 23 and the like.

In addition, the inner hub 19, the leaf spring 20, and the leaf spring 20
and the suction plate 21 are fixed by rivets 24 and 25, respectively.

The suction plate 21 is arranged to face the friction surface of the clutch rotor 7, and is urged in a direction away from the m1 plane by the elastic force of the leaf spring 20.

The suction plate 21 is made of a magnetic material such as iron, and has a smooth friction surface at its rear end facing the friction surface of the clutch rotor 7. Further, as shown in FIG. 1, the suction plate 21 is formed with a magnetic shielding elongated hole 26 that blocks the magnetism acting on the suction plate 21 over almost the entire circumference of the suction plate 21. The long magnetic shielding hole 26 is formed at a substantially intermediate position between the magnetic shielding elongated hole 16 formed near the inner circumference of the clutch rotor 7 and the magnetic blocking elongated hole 17 formed near the outer circumference.

The stopper 22 is made of an elastic material such as rubber, and is fixed to the plate hub 23 by press fitting.

This stopper 22 positions the suction plate 21 when the suction plate 21 urged by the leaf spring 20 comes into contact with it, and when the excitation coil 4 is stopped energizing, the friction surface of the suction plate 21 and the clutch rotor 7 The gap with the friction surface is approximately 0.5
Keep it at 1-.

The plate hub 23 is made of a low carbon steel plate such as a 5PCC material (cold rolled steel plate) in terms of strength, cost, and workability. As shown in FIG. 1, this plate hub 23 is integrally provided with a balance weight 23a for balancing the dynamic imbalance that occurs inside the refrigerant compressor 2 when the refrigerant compressor 2 is driven.

In this plate hub 23, the balance weight 23a is provided with approximately the same size as the suction plate 21 in the radial direction in order to suppress the increase in weight due to the provision of the balance weight 23a.

In addition, this plate hub 23 has, in the radial direction,
Two elongated holes 27 are formed in the circumferential direction at approximately the same positions as the magnetic shielding elongated holes 26 formed on the suction plate 21.

The elongated hole 27 has the same width as the magnetic shielding elongated hole 26 formed in the suction plate 21 in order to form the magnetic circuit of the excitation coil 4. It is desirable that the size is larger than that. Also, considering low-cost press processing, it is desirable to form the plate hub 23 in thickness, but on the other hand,
Considering the strength and the reduction in the effect of the balance weight 23a due to the formation of the elongated hole 27, it is better to make the width of the elongated hole 27 narrower.

Therefore, in this embodiment, the width of the elongated hole 27 is set to approximately the same width as the magnetic shielding elongated hole 26 formed in the suction plate 21 .

Note that the width of the connecting portion 23b that connects the inner circumferential side and the outer circumferential side of the plate hub 23 separated by the elongated hole 27 is preferably narrow in terms of forming a magnetic circuit.

Therefore, from the standpoint of strength and processing, the width is set to the minimum necessary.

Next, the operation of the above embodiment will be briefly explained.

The magnetic force generated by energizing the excitation coil 4 attracts the attraction plate 21 toward the clutch rotor 7 against the elastic force of the leaf spring 20 . As a result, the friction surface of the clutch rotor 7 and the friction surface of the suction plate 21 come into close contact and frictionally engage with each other, so that the rotational power of the engine transmitted via the pulley 13 is transferred to the drive shaft 3 of the refrigerant compressor 2. transmitted to.

Furthermore, when the excitation coil 4 is de-energized, the magnetic force generated by the excitation coil 4 disappears, and the suction plate 21, which had been attracted toward the clutch rotor 7, is moved to the clutch rotor by the elastic force of the leaf spring 20. It is displaced from the rotor 1 to a position where it comes into contact with the stopper 22 of the plate hub 23.

As a result, the rotational power of the engine transmitted to the clutch rotor 7 is no longer transmitted to the drive shaft 3 of the refrigerant compression 812.

In the above-described operation, when the excitation coil 4 is energized, a magnetic circuit as shown by the broken line in FIG. 2 is formed around the excitation coil 4, but the plate hub 23 is made of a magnetic material. Since the plate hub 23 is made of a certain low carbon steel plate, the magnetism of the FDx magnetic coil 4 acts on the plate hub 23 as well. In this case, by forming a balance weight 23a on the plate hub 23, the size of which is approximately the same in the radial direction as the suction plate 21, conventionally,
A magnetic path passing through the balance weight 23a was formed, and the amount of magnetic flux in the original magnetic circuit was reduced, but in this example,
The two elongated holes 27 formed in the plate hub 23 allow
C. Since the magnetism acting on the plate hub 23 is blocked, leakage of magnetic flux can be significantly reduced.

As a result, it is possible to suppress a decrease in the amount of magnetic flux in the original magnetic circuit, and it is also possible to reduce the attraction force generated between the plate hub 23 and the attraction plate 21, thereby suppressing a decrease in transmission torque. I can do it.

In this way, in this embodiment, there is no need to increase the magnetic force of the excitation coil 4 or increase the friction area between the clutch rotor 7 and the suction plate 21 in order to suppress a decrease in the transmitted torque. As a material for the plate hub 23, a magnetic material (in this embodiment, a low carbon steel plate) can be used, which is cheaper, stronger, and easier to work than non-magnetic materials such as stainless steel.

Therefore, a decrease in transmission torque can be suppressed without increasing the size of the electromagnetic clutch 1 or increasing costs.

A second embodiment of the present invention is shown in FIGS. 3 and 4. FIG. 3 is a front view of the electromagnetic clutch 1, and FIG. 4 is a side sectional view of the electromagnetic clutch from above.

In this embodiment, an auxiliary balance weight 28 is provided on the plate hub 23.

As shown in FIG. 4, the auxiliary balance weight 28 is fixed to the rear @ (or the front side) of the plate hub 23 by spot welding or the like.

In this embodiment, as shown in FIG. 3, if the inner peripheral edge of the auxiliary balance weight 28 is closer to the center than the elongated hole 27 formed in the plate hub 23,
Play 1 - Similarly to the elongated hole 27 of the hub 23, an elongated hole 29 for magnetic shielding is formed.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 show a first embodiment of the present invention.
The figure is a front view of the electromagnetic clutch, and FIG. 2 is a side and upper sectional view of the electromagnetic clutch. 3 and 4 show a second embodiment of the present invention, FIG. 3 is a front view of the electromagnetic clutch, and FIG. 4 is a front view of the electromagnetic clutch.
The figure is a side sectional top view of the electromagnetic clutch. FIG. 5 is a side sectional top view of an electromagnetic clutch showing the prior art. In the figure 1... Electromagnetic clutch 4... Excitation coil 7...
・Clutch rotor 14...Rolling bearing (bearing) 2
1... Suction plate 22... Stopper 23.
...Plate hub 2G...Magnetic shielding long hole 21.
・Long size

Claims (1)

[Scope of Claims] 1) (a) an annular excitation coil that generates magnetic force when energized; (b) rotatably supported via a bearing and forming part of the magnetic path of the excitation coil; (c) a clutch rotor that is arranged to face the clutch rotor in the axial direction, and has a magnetic shielding elongated hole formed in the circumferential direction, and that is attracted to the clutch rotor side by energizing the excitation coil; and (d) a plate hub provided with a stopper for axially positioning the suction plate, wherein the plate hub is made of a magnetic material and has a radial connection with the magnetic shielding elongated hole. An electromagnetic clutch characterized by elongated holes formed in the circumferential direction at approximately the same positions.