JPS603401Y2 - electromagnetic clutch - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electromagnetic clutch that utilizes the engagement between pawls and grooves.

In a general electromagnetic clutch that uses the mesh between a pawl and a groove, when one side engages while rotating, the faster the rotation speed, and the faster the speed at which the two are brought closer together to engage the pawl and groove. When the pawl and groove engage, the contact area between the pawl and the groove becomes small, making it impossible to achieve reliable engagement.As a result, the pressure on the contact surface due to collision when the pawl and groove engage increases, As a result, the pawls and grooves wear out rapidly, which shortens the life of the electromagnetic clutch.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art and extend the life of the electromagnetic clutch.

The present invention is characterized in that the movement locus of the side surface of the groove relative to the pawl is determined, and the width of the groove is widened to the outside of this locus to ensure that the pawl and groove engage with each other. .

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

FIG. 1 shows a sectional view of the overall configuration of the electromagnetic clutch.

There is a coil 4 inside the housing 5, and both constitute an electromagnet.

Two bearings 6 are press-fitted into the housing 5 via a spacer 9 and positioned with two circlips 10.

The driven side shaft 7 is connected to the housing 5 via the bearing 6.
It is rotatably held and fixed with a nut 8.

The pulley 1 on the driving side is fixed to a bush 13 into which two bearings 6 are press-fitted via a spacer 11, and is rotatably attached to a shaft 7 via the bearings 6.

An armature 2 is provided between the pulley 1 and the housing 5 via a coil spring 3.

The armature 2 has a square hole in its center, and the corners of the shaft 7 allow movement only in the axial direction.

Further, as shown in FIG. 2, the pulley 1 has a pawl, and the armature 2 has a groove.

In order to improve the sharpness of the armature 2 when the electromagnet is de-energized, there is an anti-residual sheet 14, which is a thin non-magnetic sheet, between the armature 2 and the electromagnet.

The boo IJ 1 is constantly rotating, and its pawl engages with the groove of the armature 2 to rotate the shaft 7.

When the electromagnet is excited, the armature 2 is attracted, its groove separates from the claw of the pulley 1, and the shaft 7 stops rotating.

Next, when the electromagnet is deenergized, the armature 2 falls due to its own weight and the restoring force of the coil spring 3, and the reference surface of the armature 2 collides with the upper surface of the claw of the pulley 1.

When the pawl of the pulley 1 comes to the position of the groove of the armature 2, the armature 2 falls again, and the engaging surfaces of the pawl and the groove engage, and the shaft 7 starts rotating again.

FIG. 2 shows the process from when the claw and the groove engage, the excitation of the electromagnet is cut off and the armature 2 falls, until the claw and the groove engage.

In Figure 2, the armature 2 is on the upper side and the pulley 1 is on the lower side.

When the electromagnet is de-energized, the reference plane A1 of amateur 2 mainly
The upper surface H1 of the claw of the pulley 1 collides with the upper surface H1 of the claw of the pulley 1.

Next, each side of the nail G1. Hl, 11 is as shown in Figure 2,
Since it is constantly rotating at a speed of V, it is in direct contact with the reference surface A of armature 2, and after a certain period of time, the claw engages with the groove of armature 2 whose bottom surface is C0, so that armature 2 does not fall. G2 where you start. Move to H2, I2.

The dashed line in FIG. 2 shows the position after movement.

At this point, Amateur 2 starts falling at a falling speed of ■4.

The falling speed ■ is determined by the weight of the armature 2, the restoring force of the coil spring 3, the friction between the armature 2 and the shaft 7, and increases with time.

Therefore, if the distance that the base line surface A1 or El of the armature 2 falls until it contacts the reference surface F2 or J2 of the pulley 1 is h and the time tl, f110■Adt=h (1) Side surface I2 of the claw and surface J2 The intersection point E with the extension of.

From then, let the distance to the intersection J2+ of the side surface D1 of the groove and the surface E1 be 1, and let the time for the pulley 1 to move this distance 1 be t2, then t2 = 17v,
(2) becomes.

Next, for convenience of explanation, the pulley 1 is assumed to be fixed, and the engagement state of the pawl and groove is shown in FIG. 3 when the armature 2 is assumed to have a relative speed of .

The solid line of the pulley 1 corresponds to the dashed-dotted line in FIG.

Figure 3 shows Amateur 2 with conventional grooves.
The relationship is t□>t2.

In other words, the armature 2 falls at a falling speed vA, and before the reference surface A1 or E□ of the armature 2 collides with the reference surface F2 or J2 of the pulley 1, the side surface D□ of the groove collides with the side surface ■2 of the claw. .

As a result, the height of the claw at the collision part is smaller than h.

In addition, the speed at the time of collision between the claw and the groove is the composite speed of (1) and (9), which is faster than Vp.

The arrows indicate the locus of motion of each surface B□, C1, and D of the groove at this time, and the position of amateur 2 at the time of the collision is indicated by a dashed line.

FIG. 4 shows an armature 2 having grooves according to the present invention, which satisfies the relationship of chi 〉chi.

That is, the groove of amateur 2 is widened so that 11VP>hlvA is satisfied.

As a result, the reference surface A1' or E□' of the armature 2 always collides with the reference surface F2 or J2 of the pulley 1 before the engaging surfaces of the pawl and the groove collide.

The arrows indicate the locus of movement of each surface of the groove at this time, and the position of the armature 2 at that time is indicated by a chain line.

Here, the falling speed vA of the amateur 2 is O.

Next, the side surface D2' of the groove collides with the side surface (2) of the pawl at a speed Vp, and the pawl and groove engage with each other.

Compared to the conventional meshing state, the contact area between the pawl and the groove is wide, and the collision speed between the pawl and the groove is slow.

As described above, according to the present invention, the width of the groove is expanded to extend beyond the locus of movement of the tip of the nail relative to the groove, the nail and the groove are reliably engaged, and the contact surface pressure and collision speed caused by the collision between the nail and the groove are increased. Since we were able to lower this, we were able to extend the life of the electromagnetic clutch.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the electromagnetic clutch of the present invention;
2 and 3 are detailed views for explaining the engagement between the pawl and the groove, and FIG. 4 is a detailed view for explaining the interlocking between the pawl and the groove according to the present invention. In the figure, 1 is a pulley, 2 is an armature, 3 is a coil spring, 4 is a coil, 5 is a housing, 6 is a bearing, 7 is a shaft, 8 is a nut, 9.11 is a spacer, 10 is a circlip, 12 is a bolt, 13 is a bushing, and 14 is an anti-residual sheet.

Claims (1)

[Claims for Utility Model Registration] A pulley that constantly rotates at a speed of V and has a pawl protruding from a reference surface, and an armature that is supported so as to be movable forward and backward relative to the pulley and has a groove recessed from the reference surface. When the clutch is connected, the upper surface of the claw first contacts the reference surface of the armature, and then when the pulley rotates and the claw faces the groove of the armature, the armature approaches the pulley and the claw and groove engage. The electromagnetic clutch is configured to transmit power by the following: after the upper surface of the pawl contacts the reference surface of the armature, the pulley rotates and the pulley and the reference surface of the armature begin to approach each other. The distance between the meshing surfaces is 1, the distance between the reference surfaces of the pulley and the armature is h, and the speed at which the armature approaches the pulley from the time of contact is ■9
Then, the electromagnetic clutch is characterized in that the width of the groove of the armature is widened so that 11VP>hlVA.