JP5663880B2 - Electromagnetic clutch - Google Patents

Description

  The present invention relates to an electromagnetic clutch.

  2. Description of the Related Art Conventionally, an electromagnetic clutch is known that includes an electromagnetic coil, a yoke housing that holds the electromagnetic coil, and an armature that is attracted to the yoke by energization of the electromagnetic coil (see, for example, Patent Document 1).

  The electromagnetic clutch described in Patent Document 1 includes a clutch mechanism between a yoke housing fixed to a non-rotating body and an armature. The clutch mechanism includes a non-rotating body and a rotating body disposed on the inner peripheral side thereof. Are configured to be connectable. When the electromagnetic coil held by the yoke is energized, the armature is drawn toward the yoke and presses the clutch mechanism. Then, the rotating body is prevented from rotating with respect to the non-rotating body.

  The yoke housing is composed of two divided housings that are divided in the axial direction with a housing portion that houses the electromagnetic coil as a boundary. Each of the divided housings is formed in an L-shaped cross section having a flange portion projecting in the radial direction. Yes. And the electromagnetic coil is hold | maintained in the space formed by combining these division | segmentation housings in an axial direction so that it cannot detach | leave.

JP 2008-45619 A

  However, in this yoke housing, the electromagnetic coil is prevented from coming off in the axial direction by the flange portions of the two divided housings, so that the flange portions are arranged on both sides of the electromagnetic coil, and the axial dimension is increased. . For this reason, there has been a design limitation on a device to which the electromagnetic clutch is applied.

  Therefore, an object of the present invention is to provide an electromagnetic clutch in which the axial dimension of a yoke that holds an electromagnetic coil is reduced.

In order to achieve the above object, the present invention provides an annular electromagnetic coil for generating a magnetic force, a yoke having an annular recess that opens in the axial direction of the electromagnetic coil, and holding the electromagnetic coil in the annular recess. An armature that moves axially toward the yoke by the magnetic force of the electromagnetic coil, and an armature that is fixed to a surface of the yoke facing the armature and covers at least a part of the opening of the annular recess. A retaining portion for retaining the armature, a sliding portion formed with a sliding surface that slides with the armature, and a caulking portion that is fixed so as not to rotate relative to the yoke by caulking to the outer peripheral surface of the yoke. and a sliding member having, the crimping portion includes a plurality of projections provided on the radially outer side of the sliding portion, the outer periphery of the yoke of the plurality of projections is bent Or caulking to provide an electromagnetic clutch.

  According to this configuration, the electromagnetic coil is prevented from coming off by the sliding member that slides on the armature.

  In addition, the sliding member may be subjected to a surface treatment that is superior in wear resistance to at least the sliding surface than the side surface of the yoke on the armature side. According to this configuration, durability is improved.

The sliding member includes an outer peripheral side sliding portion in which the sliding portion is provided on the outer peripheral side of the annular recess and an inner peripheral side sliding portion provided on the inner peripheral side of the annular recess. And the retaining portion is formed by integrally connecting the outer peripheral side sliding portion and the inner peripheral side sliding portion, and the plurality of protrusions are provided radially on the outer periphery of the outer peripheral side sliding portion. Good. According to this configuration, the armature frictionally slides on the outer peripheral side and the inner peripheral side of the annular recess.

  According to the present invention, the axial dimension of the yoke holding the electromagnetic coil can be reduced.

FIG. 1: shows the structure of the electromagnetic clutch which concerns on embodiment of this invention, (a) is sectional drawing of an electromagnetic clutch, (b) is AA sectional drawing of (a). FIG. 2 is a front view showing the sliding member according to the embodiment of the present invention. 3A and 3B show the operation of the electromagnetic clutch according to the embodiment of the present invention. FIG. 3A is a cross-sectional view of the electromagnetic clutch, and FIG.

[Embodiment]
FIG. 1A is an overall view showing a schematic configuration of an electromagnetic clutch and its peripheral portion according to an embodiment of the present invention. The electromagnetic clutch 1 functions as a brake device for preventing the shaft 7 as a rotating member from rotating with respect to the casing 6 as a non-rotating member, and is used, for example, to switch a torque transmission path by a planetary gear mechanism. .

  The electromagnetic clutch 1 includes a cam mechanism 2 disposed on the outer periphery of a shaft 7, an electromagnetic coil 4 for operating the cam mechanism 2, a yoke 5 that holds the electromagnetic coil 4, and a side surface of the yoke 5 on the cam mechanism 2 side. And a sliding member 3 fixed to the head.

  The cam mechanism 2 includes an annular armature 20, an annular cam member 21 that faces the armature 20 in the axial direction, and a spherical cam follower 22 disposed between the armature 20 and the cam member 21.

  The cam member 21 has a cam groove 21 a on the surface facing the armature 20, is connected to the shaft 7 so as not to be relatively rotatable, and the snap ring 71 restricts axial movement along the rotational axis O of the shaft 7. ing.

  The armature 20 is made of a magnetic material such as carbon steel, has an inner peripheral cam portion 201, and a friction portion 202 integrally formed on the outer peripheral side of the cam portion 201, and rotates relative to the cam member 21. It is fitted on the shaft 7 so as to be movable in the axial direction. In the cam portion 201, a cam groove 20a is formed at a portion of the cam member 21 that faces the cam groove 21a. The friction portion 202 is formed with a sliding surface 20b that frictionally slides with a sliding member 3 to be described later, on the side surface opposite to the side surface on which the cam groove 20a is formed.

  FIG. 1B is a cross-sectional view taken along the line AA in FIG. 1A for explaining the operation of the cam mechanism 2. The cam groove 20a of the armature 20 and the cam groove 21a of the cam member 21 extend in the circumferential direction, and are formed so that the axial depth is the deepest at the center and becomes shallower toward the circumferential end. The cam follower 22 rolls between the cam groove 21a and the cam groove 20a as the armature 20 and the cam member 21 rotate relative to each other, thereby separating the armature 20 from the cam member 21 in the axial direction. The cam force is generated. The armature 20 can rotate relative to the cam member 21 within a range in which the cam follower 22 rolls in the cam groove 20a and the cam groove 21a.

  The electromagnetic coil 4 is configured by winding a winding 42 around an annular bobbin 41 made of a non-magnetic material such as resin, and a current is supplied to the winding 42 through a wiring (not shown).

  The yoke 5 is integrally formed with a holding portion 51 that holds the electromagnetic coil 4 and a flange portion 52 that is formed to protrude to the inner peripheral side of the holding portion 51. The holding portion 51 is formed with an annular recess 5a that opens to one side in the axial direction (armature 20 side), and the electromagnetic coil 4 is held in the annular recess 5a. The holding part 51 is fixed to the casing 6 with bolts 61.

  A needle roller bearing 72 is disposed so as to contact the side surface of the collar portion 52 facing the cam portion 201 of the armature 20, and the armature 20 is separated from the yoke 5 between the needle roller bearing 72 and the armature 20. A disc spring 73 is disposed to urge the spring.

  The casing 6 has a recess 6a that is recessed in the direction of the rotational axis O of the shaft 7, and one end of the shaft 7 is rotatably supported by a ball bearing 62 that is fitted in the recess 6a.

  The sliding member 3 is fixed to the side surface of the yoke 5 facing the armature 20. The sliding member 3 is fixed so that it cannot rotate relative to the yoke 5 and cannot move in the axial direction by caulking a plurality of protrusions 30 provided on the outer peripheral side to the outer peripheral surface 5 b of the yoke 5.

  FIG. 2 is a front view of the sliding member 3 as viewed from the armature 20 side. The sliding member 3 is in the form of a plate made of a magnetic material such as carbon steel, and has an annular outer peripheral side sliding facing the side surface 51a (shown in FIG. 1) on the outer peripheral side with respect to the opening of the annular recess 5a of the yoke 5. Part 31, an annular inner peripheral sliding part 32 facing the inner peripheral side surface 51 b (shown in FIG. 1) from the opening of the annular recess 5 a of the yoke 5, an outer peripheral sliding part 31, and an inner peripheral A plurality of retaining portions 33 for connecting the side sliding portions 32 are integrally provided. A plurality of protrusions 30 are provided on the outer side of the outer peripheral side sliding portion 31, and these protrusions 30 are bent and caulked to the outer peripheral surface 5 b of the yoke 5.

  Four retaining portions 33 are formed at equal intervals between the outer peripheral side sliding portion 31 and the inner peripheral side sliding portion 32. An arcuate window 33a is formed between the two retaining portions 33 adjacent to each other in the circumferential direction to prevent a short circuit of magnetic flux between the outer peripheral side sliding portion 31 and the inner peripheral side sliding portion 32. Has been.

  A sliding surface 31 a that frictionally slides with the outer peripheral side of the sliding surface 20 b of the armature 20 is formed on the surface of the outer peripheral sliding portion 31 that faces the armature 20. A sliding surface 32a that frictionally slides with the inner peripheral side of the sliding surface 20b of the armature 20 is formed on the facing surface. The sliding surfaces 31a and 32a are subjected to surface treatment for improving wear resistance such as nitriding treatment, DLC (diamond like carbon) film forming treatment, or Nitrotech (registered trademark) treatment. Thereby, the sliding surfaces 31 a and 32 a have higher wear resistance than the side surfaces 51 a and 51 b of the yoke 5.

  The plurality of retaining portions 33, while being fixed to the yoke 5, cover a part of the opening of the annular recess 5 a in the circumferential direction from the inner peripheral side end portion to the outer peripheral side end portion. The electromagnetic coil 4 is prevented from coming off from the location 5a in the axial direction.

(Operation of electromagnetic clutch 1)
When the electromagnetic coil 4 is energized while the shaft 7 is rotating, a magnetic flux M is generated in a magnetic path formed by the yoke 5, the sliding member 3, and the armature 20, as indicated by a broken line in FIG. The armature 20 is drawn toward the yoke 5 side. Then, the sliding surface 20b of the friction portion 202 abuts against the sliding surfaces 31a and 32a of the sliding member 3 and frictionally slides, and the cam member 21 and the armature 20 rotate relative to each other by the frictional force generated by the frictional sliding. A cam force is generated by the cam mechanism 2. The armature 20 is more strongly pressed against the sliding member 3 by this cam force, the frictional force is increased and frictionally engaged, and the shaft 7 is prevented from rotating.

  On the other hand, when the energization of the electromagnetic coil 4 is interrupted, the armature 20 is separated from the sliding member 3 by the biasing force of the disc spring 73 as shown in FIG. Then, as shown in FIG. 3B, the cam follower 22 moves to the deepest part (neutral position) of the cam groove 21a and the cam groove 20a, and the cam force disappears. As a result, the shaft 7 can rotate together with the cam member 21, the cam follower 22, the armature 20, and the disc spring 73.

(Effect of this embodiment)
According to the present embodiment described above, the following effects can be obtained.

(1) The yoke 5 itself is not provided with a configuration for preventing the electromagnetic coil 4 from coming off from the annular recess 5 a, and the electromagnetic coil 4 is prevented from coming off by the plate-like sliding member 3. Therefore, the axial dimension of the yoke 5 can be reduced, and consequently the electromagnetic clutch 1 can be reduced.

(2) Since the magnetic flux M generated when the electromagnetic coil 4 is energized does not include an air gap in the magnetic path, the magnetic resistance of the entire magnetic path is reduced. Therefore, even if the magnetomotive force of the electromagnetic coil 4 is small, it can function as the electromagnetic clutch 1, and the yoke 5 can be downsized by applying the small electromagnetic coil 4.

(3) Since the sliding surface 31a, 32a of the sliding member 3 is subjected to a surface treatment for enhancing wear resistance, durability is improved. If the same surface treatment is performed on the surface of the yoke 5, the surface treatment area increases and the size of the member increases, which causes a cost increase. According to the present embodiment, For example, by fixing a large number of sliding members 3 side by side in the axial direction and performing surface treatment on these sliding members 3 at the same time, an increase in cost can be suppressed.

(4) Since the retaining portion 33 of the sliding member 3 is integrally formed by connecting the outer peripheral side sliding portion 31 and the inner peripheral side sliding portion 32, the sliding member 3 is formed by, for example, pressing. It can be easily molded.

(5) Since the armature 20 is pressed against the sliding member 3 by the cam force of the cam mechanism 2 generated by the relative rotation of the armature 20 with respect to the cam member 21, the electromagnetic coil 4 only brings the armature 20 into contact with the sliding member 3. The electromagnetic clutch 1 can be operated with the magnetic force of. Thereby, the electromagnetic coil 4 and the yoke 5 can be reduced in size compared with the case where the armature is frictionally engaged only by the magnetic force to prevent the shaft 7 from rotating.

[Other embodiments]
As mentioned above, although the cam mechanism and electromagnetic clutch of the present invention have been described based on the above-described embodiment, the present invention is not limited to the above-described embodiment, and can be variously modified without departing from the scope of the present invention. For example, the following modifications are possible.

(1) In the above embodiment, the electromagnetic clutch 1 is configured to press the armature 20 against the yoke 5 by the cam force of the cam mechanism 2, but the electromagnetic clutch 1 does not include the cam mechanism 2, and the electromagnetic coil 4 The armature 20 may be frictionally slid with the sliding member 3 only by magnetic force. In this case, the shaft 7 can be prevented from rotating by making the armature 20 relatively unrotatable and axially movable with the shaft 7 by, for example, spline fitting.

(2) In the above embodiment, the case where the sliding member 3 has the outer peripheral side sliding portion 31 and the inner peripheral side sliding portion 32 has been described, but the sliding member 3 has only one of these. May be configured. For example, when only the outer peripheral side sliding part 31 is provided, the retaining part 33 covers at least a part of the annular recess 5a, not the entire radial direction, thereby preventing the electromagnetic coil 4 from coming off. It can be carried out.

(3) The sliding member 3 is not necessarily made of a magnetic material, and may be a non-magnetic material. If there is no problem in durability, surface treatment for improving wear resistance may not be performed.

  DESCRIPTION OF SYMBOLS 1 ... Electromagnetic clutch, 2 ... Cam mechanism, 3 ... Sliding member, 4 ... Electromagnetic coil, 5 ... Yoke, 5a ... Annular recess, 5b ... Outer peripheral surface, 6 ... Casing, 6a ... Recess, 7 ... Shaft, 20 ... Armature, 20a ... cam groove, 20b ... sliding surface, 21 ... cam member, 21a ... cam groove, 22 ... cam follower, 30 ... projection, 31 ... outer peripheral side sliding part, 31a, 32a ... sliding surface, 32 ... inside Peripheral sliding part 33 ... Preventing part 33a ... Window part 41 ... Bobbin 42 ... Winding 51 ... Holding part 51a, 51b Side face 52 ... Butt part 61 ... Bolt 62 ... Ball bearing 71 ... Snap ring, 72 ... Needle roller bearing, 73 ... Belleville spring, 201 ... Cam part, 202 ... Friction part, M ... Magnetic flux, O ... Rotation axis

Claims (3)

An annular electromagnetic coil that generates a magnetic force;
A yoke having an annular recess opening in the axial direction of the electromagnetic coil, and holding the electromagnetic coil in the annular recess;
An armature that moves axially toward the yoke by the magnetic force of the electromagnetic coil;
The yoke is fixed to the surface facing the armature, and a retaining portion for covering at least a part of the opening of the annular recess and retaining the electromagnetic coil is formed, and a sliding surface sliding with the armature is formed. And a sliding member having a caulking portion fixed so as not to be able to rotate relative to the yoke by caulking to the outer peripheral surface of the yoke ,
The caulking portion is composed of a plurality of protrusions provided radially outside the sliding portion, and the plurality of protrusions are bent and caulked to the outer peripheral surface of the yoke.
Electromagnetic clutch.   2. The electromagnetic clutch according to claim 1, wherein at least the sliding surface of the sliding member is subjected to a surface treatment having higher wear resistance than a side surface of the yoke on the armature side. The sliding member has an outer peripheral side sliding portion where the sliding portion is provided on the outer peripheral side of the annular recess and an inner peripheral side sliding portion provided on the inner peripheral side of the annular recess. , claims the retaining portion is constituted by connecting together the said inner peripheral side sliding portion and the outer peripheral side sliding portion, the plurality of protrusions on an outer periphery of the outer peripheral side sliding portion is provided radially Item 3. The electromagnetic clutch according to Item 1 or 2.

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