JPS6246016Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention has built-in magnetic powder that transmits or interrupts torque, and transmits torque when the load is less than a predetermined value, and when the load is greater than the predetermined value. The present invention relates to a torque limiter used as a load brake for paper feeding in a copying machine, which interrupts torque transmission, and particularly relates to an improved torque limiter that can interrupt torque transmission even at a low torque setting value. .

[Prior art and its problems] When the load exceeds the magnetic coupling force of magnetic powder particles interposed between the input side rotating member and the output side rotating member or fixed member, which has been generally used in the past. A torque limiter as shown in FIG. 3, which is a vertical cross-sectional side view of the upper half, has been proposed as a simplified and more compact structure of the torque limiter that causes idle rotation.

As shown in the figure, this torque limiter includes an inner annular member A made of a non-magnetic material to which a boss 2 made of a magnetic material that is fitted onto a rotating shaft 1 is fixed to a stop portion, and an inner annular member A that is built in the inner annular member A. An even number of permanent magnet pieces 3 whose end faces 3a are closely fixed to the boss 2 and whose polarities are alternately reversed and are arranged along a plane perpendicular to the rotating shaft 1; an outer end face 3b of the permanent magnet pieces; an outer annular member B made of a magnetic material, which is disposed concentrically with the inner annular member A on the outside of the inner annular member A through magnetic powder particles 4 in the gap, and is supported so as to freely rotate with respect to the rotating shaft 1; A hollow portion is formed between each side surface in the axial direction of member A,
The outer annular member B is provided with annular plates 5 made of a non-magnetic material fixed to both sides in the axial direction, and the hollow portion, that is, the inner annular member A is connected to both axial side surfaces of the annular plate 5. An annular felt 6 is interposed therebetween in contact with the inner surface of the ring plate 5 to prevent magnetic particles from spilling into the cavity. Therefore, in such a torque limiter, a frictional force is generated between the felt and the ring plate, and this frictional force naturally has a relatively large effect as the torque decreases, so this torque limiter is used at low torques. When the torque limiter cuts off the rotational force at a predetermined low torque value, even if the rotational force to be cut off by the torque limiter exceeds the low torque setting value, the frictional force still prevents the rotational force from being cut off by the torque limiter. The disadvantage was that it was transmitted.

[Purpose of the invention and constituent requirements]

The purpose of this invention is to provide a torque limiter that does not have the above-mentioned drawbacks, that is, can smoothly cut off torque transmission even if the torque value to be cut off is set low. It is characterized in that the magnet pieces are attached to the inner surface of the ring plate at intervals from both axial side surfaces of the inner annular member.

[Examples and effects based on the examples]

Next, an embodiment of the torque limiter of this invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the torque limiter of this invention in a side view of the upper half of the torque limiter, and FIG. 2 shows a cross-sectional view taken along the line of FIG. 1.

As shown in the figure, a boss 8 made of magnetic material is fixed to the rotating shaft 7 by press-fitting with serrations, etc.
There are four recesses 8a on the outer peripheral surface of the
are formed, and an inner end surface 9a of a first permanent magnet piece 9 having the same diameter and equal length is fitted into each of the recesses 8a,
Its inner end surface 9a is adhesively fixed to the boss 8.
In this case, a recess 8 is formed on the outer peripheral surface of the boss 8 made of magnetic material.
The inner end surface 9a of the permanent magnet piece 9 may be directly inserted and fixed without forming the permanent magnet piece 9.

On the axis of the boss 8, there is an inner annular piece made of a non-magnetic material, on the inner surface of which recesses 10a each having a semicircular cross section that enclose each of the first permanent magnet pieces 9 are formed in a radial arrangement divided into four equal angles. 10, 10 are arranged and are integrally fixed face-to-face to form an inner annular member C containing the boss 8 and the first permanent magnet piece 9.

The inner annular member C has a boss 8 manufactured in advance.
It is also possible to form an annular member in which the magnet is cast, holes are provided in a radial arrangement at predetermined positions, and permanent magnet pieces 9 are embedded in each of these holes.

On the other hand, an outer annular member D made of a magnetic material is arranged concentrically with the inner annular member C, the inner circumferential surface of which is exposed to the outer circumferential surface of the inner annular member C with a slight distance therebetween.

The outer annular member D has ring plates 1 made of a non-magnetic material disposed on the same axis on both sides in the axial direction.
1 and 11 are fixed to each other, and the outer annular member D thereof is integrally supported with the ring plate 11 so as to be freely rotatable with respect to the rotating shaft 7.

For example, synthetic resin or stainless steel is used to manufacture the inner annular member C and the ring plate 11, but any other non-magnetic material can be used as long as it has the required mechanical strength. .

If the outer peripheral surface of the outer annular member D is coated with a rubber layer or the like, it can be used, for example, as a paper feed roller in a copying machine.

The outer end surface 9b of the permanent magnet piece 9 built in the inner annular member C is in a depressed position than the outer peripheral surface of the inner annular member C, and the outer end surface 9b of each permanent magnet piece 9
A required amount of magnetic powder particles 12 are interposed between b and the inner circumferential surface of the outer annular member D.

Both axial side surfaces of the inner annular member C and the 2
A cavity is formed between the inner surface of the ring plate 11, and a second cavity is formed on the inner surface of the ring plate 11 to prevent the magnetic powder particles from spilling into the cavity. Rubber magnet 13, which is a permanent magnet piece of
are fixed to both side surfaces of the inner annular member C at intervals.

In this embodiment, the first permanent magnet piece 9 has a cylindrical shape, but it goes without saying that the first permanent magnet piece 9 may have a prismatic shape or any other suitable shape.

The torque limiter of this invention has the above-mentioned configuration, and the magnetic flux of the first permanent magnet piece 9 magnetizing the magnetic powder grains 12 is transmitted to two adjacent permanent magnet pieces as shown in FIG. 9, 9, approximately 1/4 part of the boss 8 between these two permanent magnet pieces, and approximately 1/4 part of the outer annular member D, and particularly passes through the magnetic powder particles 12 with high density and is strong. Therefore, when the inner annular member C is rotated by power, the outer annular member D also rotates integrally with the inner annular member unless the bond between the magnetic powder particles 12 is broken.

Therefore, for example, if the outer annular member D is a paper feed roller of a copying machine or the like, this outer annular member D
Paper feeding continues as long as the resistance is within a range that does not break the bond of the magnetic powder particles 12, and when the resistance exceeds the range, that is, the bond of the magnetic powder particles corresponding to a predetermined torque setting value is interrupted. If the force is exceeded, the bond between the magnetic powder particles 12 will be broken, the outer annular member D will idle, and the torque transmission will be cut off.

This invention is based on the torque limiter mentioned above.
A permanent magnet piece 13 is adopted as a member to prevent the magnetic powder grains 12 from falling into the empty space,
Since the permanent magnet piece 13 is mounted on the ring plate 11 without contacting both sides of the inner ring member C facing it, and the inner ring member C is made of a non-magnetic material, the permanent magnet piece 13 is It spills into the hollow portion without creating any friction between it and the opposite side surfaces of the inner annular member C, and without creating any magnetic coupling force between it and the inner annular member C. magnetic particles can be captured by magnetic adsorption.

[Overall effect of the idea]

As is clear from the above explanation, in this invention, the permanent magnet piece provided to prevent magnetic powder particles from falling out has a distance from both sides of the opposing inner annular member made of non-magnetic material. When the critical torque value for cutting off torque transmission is set to a low value because it is fixed on the ring plate with an opening, and as a result, no interference due to friction or magnetic attraction force occurs between the both sides and the permanent magnet piece. Also, torque transmission can be smoothly interrupted at a predetermined torque setting value.

[Brief explanation of the drawing]

Fig. 1 is a side view of the upper half of the torque limiter according to the present invention; Fig. 2 is a cross-sectional view of the upper half of the conventional torque limiter; FIG. In the drawings, 1, 7... Rotating shaft, 2, 8... Boss, 3, 9,
13...Permanent magnet piece, 4,12...Magnetic powder grain,
5, 11... Ring plate, 6... Felt, A, C...
Inner annular member, B, D...outer annular member.

Claims (1)

[Scope of utility model registration request] An inner annular member made of a non-magnetic material having a boss made of a magnetic material fixed to the center thereof, which is fitted to the rotating shaft; and an inner annular member made of a non-magnetic material and having an inner end surface closely fixed to the boss. , and an even number of first permanent magnet pieces arranged along a plane perpendicular to the rotation axis with their polarities alternately reversed, and magnetic powder particles between the outer end surface of the first permanent magnet piece and the outer end surface of the first permanent magnet piece. between an outer annular member made of a magnetic material, which is disposed outside and concentrically with the inner annular member and is supported so as to freely rotate with respect to the rotating shaft, and both axial side surfaces of the inner annular member. In a torque limiter provided with ring plates made of a non-magnetic material each forming a hollow part and fixed to both sides in the axial direction of the outer annular member, the inner surface of the ring plate facing the hollow part and the inner annular member The torque limiter is characterized in that second permanent magnet pieces are respectively fixed to the inner surface of the ring plate with a gap left between them.