JPH0694050A - Electromagnetic clutch - Google Patents

Abstract

PURPOSE:To provide an electromagnetic clutch excellent in assembleability between a rolling bearing supporting a rotor and a boss part, and capable of preventing any drag between the rolling bearing and the boss part from occurring at low cost. CONSTITUTION:A boss part 16 and an inner ring 18 in a rolling bearing 15 are installed in a gently fittable manner. In addition, a groove 20 is installed in and around the boss part 16, while an O-ring 21 is set up in an inner part of this groove 20. This O-ring 21 increases in its volume after the inner ring 18 is assembled to the boss part 16, and this ring 18 is locked to the boss part 16 owing to pressurization by an increase in the volume. Since it is small in its volume before being assembled like this, any possible worsening of assembleability is not incurred and, after assembling, its volume increases, clamping the inner ring 18 to the boss part 18 tight enough, and thus any drag of the inner ring 18 is kept back. Likewise, since no working is applied to the inner ring 18, any possible increase in cost is checkable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic clutch in which a rotor is mounted around a boss portion of a housing of a rotary machine such as a refrigerant compressor or an electric motor via a rolling bearing.

[0002]

2. Description of the Related Art For example, an electromagnetic clutch mounted on a refrigerant compressor of a vehicle refrigeration cycle includes a rotor mounted on a boss portion of a housing of the refrigerant compressor via a rolling bearing. In the rotor of this electromagnetic clutch, the rolling bearing is loosely fitted to the boss portion of the housing in consideration of the assemblability. That is, the inner ring of the rolling bearing is fitted to the outer peripheral surface of the boss portion with a slight gap. Then, after the inner ring is fitted to the boss portion, the inner ring is fixed in the axial direction of the boss portion by a circlip so that the rolling bearing does not fall off from the boss portion.

[0003]

However, since the inner ring of the rolling bearing is fitted in the boss portion with a gap, the rotational torque acting on the rolling bearing is low when the coefficient of thermal expansion of the boss portion is low such as in a low temperature state. When it is large, the inner ring slips around the boss portion. The inner ring is generally made of iron, whereas the boss portion is generally made of soft aluminum, so that the boss portion is worn due to the whirling of the inner ring. If the boss wears, the rotor supported by the rolling bearing may tilt, and the rotor may interfere with the stator or the armature having a coil built in, or the heat generated by this interference may cause a malfunction in the rolling bearing. Therefore, it is conceivable to press fit the inner ring into the boss portion, or to provide the boss portion and the inner ring with projections and depressions extending in the axial direction for fitting. However, if the press-fitting process is adopted, the workability of assembling the inner ring is significantly reduced. Further, providing unevenness extending in the axial direction on both the boss portion and the inner ring leads to an increase in the number of working steps, and in particular, processing the inner ring significantly increases the cost.

The present invention has been made in view of the above circumstances, and an object thereof is to prevent whirling between a boss portion and a rolling bearing at a low cost without impairing workability during assembly. The purpose is to provide an electromagnetic clutch that can

[0005]

The electromagnetic clutch of the present invention employs the following technical means. The electromagnetic clutch includes a rotor mounted on the outer periphery of a boss portion of a housing that covers the rotating shaft of the rotating machine via a rolling bearing that is loosely fitted thereto. The boss has a groove on its outer circumference, and a ring is arranged in the groove. The volume of the ring is increased after the rolling bearing is assembled to the boss portion, and the ring pressurizes the boss portion and the rolling bearing due to the volume increase of the ring.

[0006]

[Function] The rolling bearing is fitted to the boss portion in which the ring is fitted in the groove. At this time, since the ring has not been expanded yet, the rolling bearing can be loosely fitted to the boss portion. After fitting the rolling bearing to the boss, the volume of the ring is increased. Then, due to the increase in the volume of the ring, the ring pressurizes the groove in the boss portion and the rolling bearing, and as a result, the rolling bearing is fixed to the outer periphery of the boss portion.

[0007]

As described above, the electromagnetic clutch of the present invention is designed to increase the volume of the ring and fix the rolling bearing and the boss after the rolling bearing is loosely fitted to the boss. The rolling bearing can be easily assembled to the boss portion, and the inner ring of the rolling bearing can be prevented from running around. Further, since the groove can be formed in the circumferential direction of the boss without processing the inner ring, the cost increase can be suppressed to a low level. In addition, the increase in the volume of the ring is
It is possible to increase the volume of the ring without increasing the cost, such as increasing the volume of the ring by applying oil or infiltrating oil from other parts, or increasing the volume by increasing the temperature due to use. .

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an electromagnetic clutch of the present invention will be described based on an embodiment shown in the drawings. [Structure of Embodiments] FIGS. 1 to 4 show a first embodiment of the present invention, and FIG. 1 is a sectional view of an electromagnetic clutch attached to a refrigerant compressor of a vehicle refrigeration cycle. The electromagnetic clutch 1 of the present embodiment is attached to a refrigerant compressor 2 (an example of a rotating machine) of a vehicle refrigeration cycle, and if necessary, a rotating torque of an engine (not shown) is applied to a rotating shaft 3 of the refrigerant compressor 2. Is to be transmitted to. The electromagnetic clutch 1 includes an electromagnetic coil 5 housed in a stator 4, a rotor 6 that is rotationally driven by an engine, an armature 7 that is attached to the rotor 6 by the magnetic force generated by the electromagnetic coil 5, and the armature 7 that is integral with the armature 7. And a hub assembly 8 that is rotated to transmit rotational power to the rotary shaft 3 of the refrigerant compressor 2.

The electromagnetic coil 5 is formed by winding a conductive wire coated with an insulating film, is housed in a stator 4 made of a magnetic material such as iron and having a U-shaped cross section, and is molded in the stator 4 by a resin member 9 such as epoxy. It is fixed. The stator 4 is fixed to a ring-shaped support member 10, and the support member 10 is fixed to a housing 11 (made of aluminum) of the refrigerant compressor 2 with a circlip 12, whereby the stator 4 is fixed. Fixed to.

The rotor 6 has a pulley 13 around which a multi-stage V-belt (not shown) is wound, and rotates by the rotational power of the engine transmitted via the V-belt. The rotor 6 is made of a magnetic material such as iron, has a U-shaped cross-section for accommodating the stator 4, and one end face in the axial direction is provided as a smooth friction surface. Further, the rotor 6 is provided with elongated holes 4a near the inner circumference and the outer circumference of the friction surface, all around the circumference for bypassing the magnetic path generated when the electromagnetic coil 5 is energized. The rotor 6 includes a rolling bearing 15 on its inner circumference. The rolling bearing 15 is used for the refrigerant compressor 2
The rotor 6 is rotatably supported around the boss portion 16 of the housing 11 that covers the rotating shaft 3, and is composed of an iron outer ring 17, an inner ring 18, and a plurality of balls 19 arranged in two rows. . The outer ring 17 is fixed to the inner circumference of the rotor 6, and the inner ring 18 is fitted to the outer circumference of the boss portion 16. The inner ring 18 is pressed around the boss portion 16 by the volume increase of the O-ring 21 arranged in the groove 20 provided around the boss portion 16 and is fixed to the boss portion 16. Further, the inner ring 18 is fixed in the axial direction of the boss portion 16 by a circlip 22.

The armature 7 is arranged to face the friction surface of the rotor 6 with a predetermined gap, and has a ring shape made of a magnetic material such as iron. The armature 7 is provided with a smooth friction surface on the surface facing the friction surface of the rotor 6. Further, the armature 7 is provided with a long hole 7a for circumscribing a magnetic path generated when the electromagnetic coil 5 is energized, in an intermediate portion of the friction surface over substantially the entire circumference.

The hub assembly 8 comprises an outer hub 23 fixed to the armature 7, an inner hub 24 fixed to the rotary shaft 3 of the refrigerant compressor 2, and a cushion rubber 25 connecting the outer hub 23 and the inner hub 24. It is configured. The outer hub 23 has an annular shape with an L-shaped cross section, and the disc portion has an armature 7 and a plurality of rivets 2.
It is fixed at 6. The inner hub 24 is spline-fitted to the rotary shaft 3 of the refrigerant compressor 2 and rotates integrally with the rotary shaft 3. The cushion rubber 25 is the outer hub 23.
Is fixed to the inner peripheral surface of the inner hub 24 and the outer peripheral surface of the inner hub 24 with a predetermined gap (for example, 0.5 mm) between the friction surface of the rotor 6 and the friction surface of the armature 7 when the energization of the electromagnetic coil 5 is stopped. Is set to keep. Further, the cushion rubber 25 is elastically deformed to allow the armature 7 to be attached to the rotor 6, and when the energization of the electromagnetic coil 5 is stopped, the restoring force of the cushion rubber 25 causes the armature 7 to return to the initial position. It is to restore.

Next, the assembly of the boss portion 16 of the housing 11 and the inner ring 18 of the rolling bearing 15 will be described with reference to FIGS.
Will be explained. The O-ring 21 is a ring-shaped rubber ring, and is arranged in the groove 20 provided around the boss portion 16 and, as described above, the groove 20 of the boss portion 16 and the inner ring 1.
The inner ring 18 is fixed around the boss portion 16 by pressurizing the inner ring 18. The outer peripheral surface of the boss portion 16 has an inner ring 1 for loosely fitting the inner ring 18 of the rolling bearing 15 to the boss portion 16.
A slight gap A is provided on the inner peripheral surface of 8 (see FIG. 3). The inner ring 18 is fixed around the boss portion 16 due to the increase in volume of the O-ring 21 arranged in the groove 20 of the boss portion 16. The O-ring 21 is made of natural rubber or synthetic rubber that contains oil and increases in volume. Examples of rubber that increases its volume and oils that increase the volume of this rubber include natural rubber and mineral oil, ethylene propylene rubber and mineral oil, and silicone rubber and silicone oil. And the O-ring 21 is
It is mounted in the groove 20 with a small volume (see FIG. 2). At this time, the outer diameter of the O-ring 21 protrudes from the outer peripheral surface of the boss portion 16 by a dimension B, which is the dimension B.
8 is provided in a size that does not affect the assembling property.
The inner ring 18 has a boss portion 1 when the volume of the O-ring 21 is small.
6 (see FIG. 3). And the boss portion 16
After assembling the inner ring 18 to, the O-ring 21 is made to contain oil to increase the volume of the O-ring 21 (see FIG. 4). As a result, the inner ring 18 is fixed around the boss portion 16.

An example of means for causing the O-ring 21 to contain oil will be shown. Utilizing the slow volume increase rate of the O-ring 21, apply oil directly to the O-ring 21
Before the volume of the ring 21 increases, the inner ring 18 is attached to the boss portion 16
There is a means of assembling the inner ring 18 to the boss portion 16 by applying oil to the inner circumference of the inner ring 18 also for rust prevention.

[Operation of Embodiment] Next, the operation of the above embodiment will be briefly described. When the electromagnetic coil 5 is de-energized, the cushion rubber 25 keeps the armature 7 apart from the rotor 6, so that the rotational power transmitted from the V-belt to the rotor 6 is transmitted to the armature 7 and the hub assembly 8. Is not transmitted, and only the rotor 6 idles by the rolling bearing 15. When the electromagnetic coil 5 is energized, the armature 7 is attracted to the rotor 6 by the magnetic force generated by the electromagnetic coil 5, and the armature 7 is rotated by the rotor 6.
To be attached to. Then, the rotation of the rotor 6 is transmitted to the rotary shaft 3 of the refrigerant compressor 2 via the armature 7 and the hub assembly 8, and the refrigerant compressor 2 is driven.

[Effects of Embodiment] Due to the increase in the volume of the O-ring 21 arranged between the boss portion 16 and the inner ring 18 of the rolling bearing 15, the fixing force in the rotational direction between the boss portion 16 and the inner ring 18 is increased. . Therefore, when there is a gap between the boss portion 16 and the inner ring 18 in the low temperature state, even when a large rotational torque acts on the rolling bearing 15 or when an excessive vibration acts on the electromagnetic clutch 1, the inner ring 18 There is no slip between the boss portion 16 and the boss portion 16, and the whirling of the inner ring 18 is prevented. As a result, the wear of the boss portion 16 due to the whirling of the inner ring 18 is prevented, so that the inclination of the rotor 6 supported by the rolling bearing 15 due to the wear is suppressed, and the rotor 6 is prevented.
The inclination of the rotor 6 causes the rotor 6 and the armature 7 to move.
Can be prevented from interfering with. Further, by preventing this interference, it is possible to prevent generation of heat due to the interference, and it is possible to prevent occurrence of a defect of the rolling bearing 15 due to heat generation. Further, since the inner ring 18 can be fixed to the boss portion 16 without press-fitting the inner ring 18 into the boss portion 16,
There is no problem that the radial pressure acts on the starting surface of the ball 19 caused by press-fitting the boss 16 into the boss portion 16, the assembling property due to the press-fitting, and the cost increase. Further, since the inner ring 18 is not processed, it is possible to prevent a large increase in cost as compared with the conventional case. Further, when the rotor 6 is assembled to the refrigerant compressor 2, the boss portion 16 is fixed to the inner ring 1
Since there is a slight clearance between the rotor 6 and
The rolling bearing 15 can be easily assembled to the boss portion 16 of the refrigerant compressor 2.

On the other hand, by disposing the O-ring 21 between the boss portion 16 and the inner ring 18, oil leaks to the inner circumference of the friction surface of the electromagnetic clutch 1 through the space between the boss portion 16 and the inner ring 18. Can be prevented. That is, as shown by the one-dot chain line C in FIG. 1, oil entering from outside into the electromagnetic clutch 1, such as engine oil splashing from the outside of the electromagnetic clutch 1 and the refrigerant compressor 2, and two-dot chain line D, Oil that enters the electromagnetic clutch 1 from the refrigerant compressor 2 can be prevented from entering the inner circumference of the friction surface of the electromagnetic clutch 1.

[Second Embodiment] FIGS. 5 and 6 are sectional views of an O-ring 21 showing a second embodiment. O in this example
The ring 21 is made of a shape memory polymer. The O-ring 21 using this shape memory polymer is
After the primary formation (see FIG. 5), heat and load are applied to reduce the volume and cooling (see FIG. 6), and the O-ring 21 is formed into the groove 20.
The inner ring 18 (see the first embodiment) is easily attached to the boss portion 16 (see the first embodiment) in a state of being fitted inside (see the first embodiment). Then, after the inner ring 18 is assembled to the boss portion 16, heat is applied to restore the original primary formed shape (see FIG. 5). That is, the volume of the O-ring 21 is increased by the application of heat, and the inner ring 1
8 is fixed to the boss portion 16. The heating method for restoring the O-ring 21 may be heating before mounting on the vehicle, or heating by heat generated during operation after mounting on the vehicle.

[Modification] In the above embodiments, as a technique for increasing the volume of the ring after the inner ring is assembled to the boss portion, a technique of swelling by adding oil to rubber and a shape memory polymer in the original shape are used. Although the technology to restore it is shown as an example, the ring is made of foam material and expanded by heating or heat generated during use, or the ring is made of unvulcanized rubber and expanded by heating or heat generated during use. Other means may be used to increase the volume of the ring. As an example of the ring of the present invention, an O-ring connected in a ring shape is shown, but a ring having a shape in which a part of the ring is separated may be used. A ball bearing has been shown as an example of the rolling bearing, but it can be applied to other rolling bearings such as a roller bearing. The example in which the present invention is applied to the electromagnetic clutch that connects and disconnects the power of the refrigerant compressor has been shown, but it may be applied to other electromagnetic clutches that connect and disconnect the rotational power, such as a supercharger.

[Brief description of drawings]

FIG. 1 is a sectional view of an electromagnetic clutch (first embodiment).

FIG. 2 is a sectional view of an O-ring before mounting the inner ring (first embodiment).

FIG. 3 is a sectional view of the O-ring immediately after the inner ring is assembled (first
Example).

FIG. 4 is a cross-sectional view of an O-ring having an increased volume after the inner ring is assembled (first embodiment).

FIG. 5 is a cross-sectional view of an O-ring in a state of being primarily formed (second embodiment).

FIG. 6 is a cross-sectional view of the O-ring in a state where the volume before the inner ring is assembled is reduced (second embodiment).

[Explanation of symbols]

 1 Electromagnetic Clutch 2 Refrigerant Compressor (Rotating Machine) 3 Rotating Shaft 6 Rotor 11 Housing 15 Rolling Bearing 16 Boss 20 Groove 21 O-ring

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masafumi Tobayama 1-1, Showa-cho, Kariya city, Aichi Nihon Denso Co., Ltd.

Claims (1)

[Claims] 1. An electromagnetic clutch comprising a rotor mounted via a rolling bearing loosely fitted to the outer periphery of a boss portion of a housing covering a rotary shaft of a rotating machine, wherein the boss portion has a groove on its outer periphery. At the same time, a ring is arranged in the groove, and the volume of the ring is increased after the rolling bearing is assembled to the boss portion, and the volume increase of the ring causes the ring to become the boss portion and the rolling bearing. An electromagnetic clutch for a refrigerant compressor, which pressurizes the refrigerant.