JPS588998Y2 - Electromagnetic coupling device - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an electromagnetic coupling device, particularly to an improvement in mounting a surge absorbing element that absorbs a surge generated when the power supply to an electromagnetic coil is cut off.

In this type of electromagnetic coupling device, an annular friction plate is attached to a drive shaft connected to a drive source so as to be slidable in the axial direction, and a ring-shaped friction plate is attached to a load shaft opposite to this friction plate with an axial gap therebetween. Another annular lining is fixed.

In this operation, the friction plate is moved in the axial direction by the attraction force of the electromagnetic coil and is coupled to the lining, thereby transmitting the rotational force on the driving side to the load.

Here, in this electromagnetic coupling device, the transmission and release of the rotational force from the drive shaft to the load shaft is performed by energizing or deenergizing the electromagnetic coil, and when the electromagnetic coil is deenergized to repeat this process, At both ends of the electromagnetic coil,
A surge voltage is induced, and this voltage increases as the breaking current value and inductance of the electromagnetic coil increase, and
It may reach 0V or more.

Therefore, this surge voltage has an adverse effect such as shortening the life of the switch contact in the controller connected to the electromagnetic coil and causing breakdown of the semiconductor withstand voltage.

Therefore, it is necessary to connect a surge absorption element to both ends of the electromagnetic coil to absorb the surge voltage.

However, this type of electromagnetic coupling device is of the nature of being handled as a single unit, separate from the control device that controls it.
When the button is pressed on the user's side, the user may forget to connect the surge absorbing element or may make a mistake in connecting it.

This invention provides an excellent electromagnetic coupling device that was created in view of the above-mentioned circumstances.

An embodiment of the friction type electromagnetic coupling device shown in FIG. 1, particularly applied to a clutch, will be described below.

In the figure, reference numeral 1 denotes a stator having a concave opening, and a through hole 1a is formed on the outer circumferential side of the stator.

2 is an electromagnetic coil built in the recess of this electronic 1;
4 is a resin for fixing the electromagnetic coil 2 in the recess of the stator 1, and 4 is a driven shaft supported by the stator 1 via a bearing 5, which is fitted onto a load shaft (not shown).

6 and 7 are C-shaped retaining rings for stopping the bearing 5, 8 is a holder for fixing the stator 1, 9 is a connected plate which is the first connecting body fixed to the driven shaft 4, and 10 is a connected plate. A lining fitted into the annular groove of the connected plate 9; 11 a drive shaft which is a second connection main body rotationally driven by a drive source (not shown); 11a a spline formed on the outer periphery of the drive shaft 11; 12 is a boss, and 12a is a spline formed on the inner circumference of the boss 12, which fits into the spline 11a and supports the boss 12 so as to be slidable in the axial direction.

A friction plate 13 faces the lining 10 with an axial gap g, and is fixed to the boss 12 with a bolt 14 and a spring washer 15.

16 is a cooling fin provided on the friction plate 13 to improve heat dissipation; 17 is a semi-fixed annular slider that is tightened with a constant pressure on the outer periphery of the spline 11a; As it wears out,
The axial gap g is kept constant by sliding on the spline 11a.

Reference numeral 18 denotes a return spring that presses the boss 12 and the friction plate 13 toward the side opposite to the lining 10, and the slider 17 constitutes an automatic gap adjustment device.

Reference numeral 19 denotes a surge absorbing element housed in the recess of the stator 1 together with the electromagnetic coil 2, and is, for example, a diode.

A lead wire 20 connects the diode 19 to both ends of the electromagnetic coil 20, and is led out of the stator 1 via a grommet 21.

An electrical connection diagram of the electromagnetic coil 2, the diode 19, and the switch 22 that controls the coupling state is shown in FIG.

Next, the operation will be explained.

First, when the control switch 22 is opened and the electromagnetic coil 2 is deenergized, the friction plate 12 is returned to the lining 10 by the return spring 18.
They are opposed to each other with a gap g between them.

Next, when the control switch 22 is closed and DC power is supplied from the power supply, the electromagnetic coil 2 is energized and a magnetic flux Φ is generated.
A magnetic flux Φ is generated in the illustrated magnetic path, and the friction plate 13 is attracted to the stator 1 side by the electromagnetic attraction force, and the lining 10 is
is combined with

Then, rotational force is transmitted from the drive shaft 11 to the driven shaft 4 via the friction plate 13 lining 10 and the connected plate 9.

After that, when the control switch 22 is opened to release the transmission from the drive shaft 11 to the driven shaft 4, a back electromotive force is generated at both ends of the electromagnetic coil 2 based on the cutoff current value and the inductance of the electromagnetic coil. That is, a surge voltage is induced.

Then, this surge voltage is quickly absorbed by the diode 19 and disappears.

Note that there is no particular limitation on the surge absorbing element other than the diode 19 as long as it has characteristics equivalent to or better than the diode 19.

Furthermore, it can be applied to all electromagnetic coupling devices such as brakes other than clutches and magnetic particle types other than friction types.

As mentioned above, this invention houses an electromagnetic coil and a surge absorption element that absorbs the surge of the electromagnetic coil in the recess of the magnetic member, and it is easy to forget to connect the surge absorption element to the control device or to connect it incorrectly. Inconveniences are definitely eliminated, and a practical effect can be obtained that can reliably prevent the adverse effects of surge voltage, such as shortening the life of the switch contacts in the controller and causing voltage breakdown of semiconductors.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing an embodiment of this invention, and FIG. 2 is an electrical connection diagram for power supply to the electromagnetic coil 2 shown in FIG. In the figure, 1 is a stator, 1a is a through hole, 2 is an electromagnetic coil, 4 is a driven shaft, 9 is a connected plate, 10 is a lining,
11 is a drive shaft, 12 is a boss, 13 is a friction plate, 19 is a diode, 20 is a lead wire, 21 is a grommet, and 22 is a control switch. The same reference numerals in each figure indicate the same parts.

Claims (1)

[Scope of utility model registration request] a magnetic member having a concave-shaped opening; a first connecting body disposed adjacent to the magnetic member and having a friction surface; a second connection body having a friction surface facing the friction surface with a predetermined axial gap therebetween; The first connecting body is housed in the recess of the magnetic member and is supplied with power by the power source. An electromagnetic coupling device comprising an electromagnetic coil that controls the coupling state of each friction surface of the second coupling main body, and a surge absorption element that is housed in a recess of the magnetic member and absorbs a surge generated by deenergization of the electromagnetic coil. .