WO2015107695A1 - Plunger used in solenoid - Google Patents

Abstract

The plunger used in a solenoid that is symmetric about an axis is provided with: a first portion, which is mated with the solenoid to be slidable and comprises a magnetic material, assuming a circular shape around the axis and having a first edge and, on the side opposite from the first edge in the direction of the axis, a second edge; a second portion, which is mated with the first part and comprises a non-magnetic material, provided with one or more claw portions that extend from a first edge portion on the first edge along the axis; and a plurality of staked portions that deform plastically from the second portion to overlap with the second edge in order to prevent the first portion from being displaced in a direction along the axis.

Description

Plunger used for solenoid

The present invention relates to a plunger used for a solenoid actuator for operating a clutch, and more particularly to a plunger used for a solenoid actuator for operating a clutch of a rotating device such as a lock-up differential for a vehicle or a power take-off unit.

Automobiles often use several rotating devices with built-in clutches, such as differential devices and power take-off units. A solenoid actuator may be used to operate these clutches. In the solenoid actuator, a plunger including a magnetic material is driven by a magnetic force, and when the plunger presses a clutch member, the clutch is connected and disconnected.

On the other hand, rotating devices such as differential devices and power take-off units are made of high-strength steel such as chrome / molybdenum steel, and are themselves magnetic. If the entire plunger is made of a magnetic material, the plunger may be fixed to the rotating device by the residual magnetism. In order to prevent the plunger from sticking and to prevent the magnetic flux from leaking and efficiently use the plunger, the plunger may be configured by combining a magnetic material with a nonmagnetic material such as stainless steel.

Patent Document 1 discloses a related technique.

Japanese Patent Publication No. 2007-92990

In the plunger, the nonmagnetic material and the magnetic material are joined by, for example, a so-called “tight fit” by press fitting. If the respective dimensional tolerances are managed appropriately, the connection by interference fit will achieve practically no problem fixing.

】 Plungers are used in a wide temperature range from low temperatures in extremely cold regions to high temperatures under severe operating conditions. A considerable difference in the linear expansion coefficient is found between the magnetic material and the nonmagnetic material. When attempting to utilize the plunger over a wider temperature range, it should be noted that thermal expansion / contraction affects the fit. Moreover, since the plunger by repeatedly pressing the clutch member can be deformed, such deformation can also affect the fitting. The inventors have found that these can be a source of problems from the point of view of ensuring further stability for the solenoid actuator.

The present invention has been made in view of the above problems.

According to one aspect of the present invention, a plunger used for a solenoid that is symmetrical with respect to an axis is a first portion that is made of a magnetic material and is slidably fitted to the solenoid, and is a circle around the axis. A first portion having a first end and a second end opposite to the first end in the direction of the axis; and made of a non-magnetic material; A second part fitted into the part, the second part comprising one or more claws extending along the axis from the first end along the first end; and the first part A plurality of caulking portions that are plastically deformed from the second portion and cover the second end so as to prevent displacement in the direction along the axis.

FIG. 1 is a cross-sectional view of a differential device in which a plunger according to an embodiment of the present invention is used. FIG. 2 is an exploded perspective view showing only the plunger and the clutch member. FIG. 3 is an exploded perspective view of the plunger. FIG. 4A is a longitudinal cross-sectional view of the plunger taken from a cross-section through the pawl. FIG. 4B is a schematic plan view of the plunger, and particularly shows a relationship between the claw and the caulking portion. FIG. 5A is a schematic cross-sectional view of an inner plunger and an outer plunger before press-fitting. FIG. 5B is a schematic cross-sectional view showing a stage in which the crimping pin comes into contact with one end of the inner plunger in the press-fitting process. FIG. 5C is a schematic cross-sectional view showing a state in which the crimping pin is pushed in from the end of the inner plunger by a predetermined depth in the press-fitting process.

Several exemplary embodiments of the present invention are described below with reference to FIGS. 1-5C.

The embodiment will be described by taking a bevel gear type lock-up differential device as an example, but the embodiment of the present invention is not necessarily limited thereto. This embodiment can be diverted to other rotating devices such as a free running differential device and a power take-off unit. Further, although an example in which the differential device is applied to an axle is given, it may be applied to another shaft such as a propeller shaft. Further, in the following description, the right and left are only for convenience, and the present embodiment does not depend on the direction. Furthermore, about some structures, the aspect which replaced the inside and outside is also possible.

Referring to FIG. 1, a differential device 1 includes a differential case 3 that can rotate around an axis, a differential gear set 5 accommodated therein, a clutch 7, and a solenoid actuator 11 that operates the clutch 7. .

The differential case 3 includes a case body and a cover body that covers one end of the case body, and the gear set 5 and the clutch member 71 are accommodated therein. Each of the case body and the cover body includes a boss portion 31 projecting in the axial direction, and the boss portion 31 is rotatably supported by the carrier through a bearing, so that the differential case 3 is rotatable around its axis. is there. Normally, the differential case 3 rotates by receiving torque from the engine / motor of the vehicle, and the differential gear set 5 and the clutch member 71 housed therein rotate together with the differential case 3.

In the case of the bevel gear type as an example, the differential gear set 5 includes a plurality of pinion gears 51 and a pair of side gears 53 and 55 engaged with these. The side gears 53 and 55 are coupled to the right axle and the left axle, respectively, and distribute the received torque to them differentially.

A clutch member 71 is accommodated in the differential case 3 so as to face the right side gear 53. The clutch member 71 is slidably fitted to the right side gear 53, for example, and is movable in the axial direction.

The right side gear 53 includes clutch teeth 73 on the side facing the clutch member 71. The clutch member 71 includes corresponding clutch teeth 75 so as to face the clutch member 71. That is, the combination of the right side gear 53 and the clutch member 71 constitutes the clutch 7. When the clutch member 71 moves toward the right side gear 53 and the clutch teeth 73 and 75 are connected to each other, the clutch 7 limits the differential between the side gears 53 and 55. At this time, the differential device 1 is locked up.

The clutch member 71 includes a plurality of convex portions 77 on the side opposite to the clutch tooth 75 side. The differential case 3 includes a through hole 33 corresponding to the differential case 3, and the protrusion 77 has its tip exposed to the outside through the through hole 33.

Referring to FIG. 2 in combination with FIG. 1, the plunger 9 includes a plurality of claws 95 so as to correspond to the convex portions 77, and the claws so as to come into contact with the convex portions 77 exposed to the outside through the through holes 33. 95 is arranged. When the solenoid actuator 11 drives the plunger 9 in the direction along the axis toward the clutch member 71, the claw 95 presses the convex portion 77, whereby the clutch 7 is connected. When the plunger 9 moves in the opposite direction, the clutch 7 is disconnected. Details of the structure of the plunger 9 will be described later.

Referring back to FIG. 1, the solenoid actuator 11 includes a solenoid 13 that is symmetric about an axis and that is annular around the axis. The solenoid 13 is coaxial with the differential case 3 and is disposed adjacent to the right wall portion thereof. The solenoid 13 includes an electromagnetic coil 41 and a core 17 that guides the magnetic flux generated by the electromagnetic coil 15.

In order to position the solenoid 13 with respect to the differential case 3, the wall portion of the differential case 3 may be provided with a groove running in the circumferential direction, and the core 17 may be slidably fitted thereto. Further, the core 17 is prevented from rotating with respect to a carrier (stationary member) that houses the differential device 1. That is, the differential case 3 rotates relative to the solenoid 13 that is prevented from rotating.

The core 17 constitutes a magnetic circuit that surrounds the electromagnetic coil 15 leaving a gap, but such a magnetic circuit may include the right wall portion of the differential case 3 as a part thereof. The gap is inside the electromagnetic coil 15 in the illustrated example, but may be outside.

The plunger 9 is slidably fitted to the solenoid 13 so as to face the solenoid 13. The plunger 11 is preferably slidably fitted to and supported by the boss portion 31 of the differential case 3.

Referring to FIG. 2 in combination with FIG. 1, the plunger 9 generally includes a first portion 91 and a second portion 93 fitted thereto. Since the first portion 91 faces the solenoid 13 and is outside in the present embodiment, it is referred to as an outer plunger in the following description. The second portion 93 is called an inner plunger.

The outer plunger 91 is made of a magnetic material and has an annular shape around the axis. The inner periphery is a cylindrical surface parallel to the axis, and is adapted to receive the inner plunger 93 inserted in the axial direction. Both ends 91P and 91S may be planes orthogonal to the cylindrical surface, but the edges may be appropriately chamfered. In the illustrated example, the inner peripheral edge of the end 91 </ b> S opposite to the claw 95 is chamfered to form an inclined surface 91 </ b> C.

The outer plunger 91 faces the solenoid 13 and is disposed so as to straddle the gap of the magnetic circuit. The magnetic flux generated by the electromagnetic coil 15 bypasses the gap of the magnetic circuit and flows around the outer plunger 91, and the magnetic flux drives the outer plunger 91 in the direction along the axis.

Referring to FIG. 3 in combination with FIG. 2, the inner plunger 93 is made of a non-magnetic material and is generally annular around the axis. The outer periphery is a simple cylindrical surface that can be fitted with the outer plunger 91, but the inner periphery can have irregularities as appropriate. Such unevenness is advantageous in reducing friction with respect to the boss portion 31 and holding the lubricating oil. Except for the structure related to the claw 95 and the unevenness described above, both ends of the inner plunger 93 may be flat surfaces orthogonal to the cylindrical surface.

The inner plunger 93 is press-fitted and fitted into the outer plunger 91. On the side facing the clutch member 71, the end 91 </ b> P of the outer plunger 91 and the end 93 </ b> P of the inner plunger 93 along the same are substantially flush with each other. Alternatively, the end portion 93P of the inner plunger 93 may slightly protrude from the end 91P. If protruding, the inner plunger 93 preferentially contacts the differential case 3, and thus a slight gap is secured between the outer plunger 91 and the differential case 3. This is advantageous in preventing the outer plunger 91 from adhering to the differential case 3 due to residual magnetism.

4A and 4B in combination with FIGS. 2 and 3, the claw 95 extends integrally from the end 93 </ b> P of the inner plunger 93 in the direction along the axis. Preferably, the claw 95 may protrude in a radial direction so as to cover the end 91P of the outer plunger 91, and the protruding portion may include a surface 95A facing in the direction of the end 91P. The end 91P of the outer plunger 91 can abut on the surface 95A. If they are in contact, it is possible to prevent the outer plunger 91 from being displaced in the axial direction relative to the inner plunger 93. Alternatively, the surface 95A of the claw 95 may be separated without contacting the end 91P. If it is not in contact, the outer plunger 91 does not bear the reaction force that has driven the clutch member 71 via the claw 95, so that the deformation of the outer plunger 91 can be prevented.

In the inner plunger 93, the end 93S opposite to the end 93P protrudes slightly from the end 91S along the outer plunger 91. The outer peripheral surface of the inner plunger 93 is plastically deformed from the end portion 93S toward the end 91S, thereby forming a plurality of crimping portions 97 and covering the end 91S of the outer plunger 91. The caulking portion 97 prevents the outer plunger 91 from being displaced in the axial direction relative to the inner plunger 93, and particularly prevents the outer plunger 91 from being displaced in a direction away from the claw 95.

The nail | claw 95 and the crimping part 97 may have a specific positional relationship in the circumferential direction. Referring to FIG. 4B, when a range in which the edges on both sides are extended in the circumferential direction with respect to one claw 95 as a range D, one or more selected from a plurality of caulking portions 97 is selected. , It can be arranged in this range D. The caulking portion 97 disposed in the range D bears the reaction force received by the claw 95 without offset through the outer plunger 91. This is advantageous in preventing the plunger 9 from being deformed and preventing the outer plunger 91 from being displaced. A larger number of caulking portions 97 arranged in the range D is more advantageous for preventing deformation, and is preferably two or more. Of course, one or more crimping portions 97 can be formed outside the range D.

As already described, the caulking portion 97 is formed by plastic deformation, but such plastic deformation can be caused simultaneously in the process of press-fitting the inner plunger 93 into the outer plunger 91.

First, referring to FIG. 5A, the outer plunger 91 and the inner plunger 93 are each dimensioned to have an interference fit relationship. The inner plunger 93 is press-fitted into the outer plunger 91 from an end 93 </ b> S opposite to the claw 95. The outer plunger 91 may be fixed and the inner plunger 93 may be press-fitted, or vice versa. Or you may pressurize both simultaneously.

Next, referring to FIG. 5B, when the rod-like tool 100 is brought into contact with the end 93S of the press-fitted inner plunger 93 and the inner plunger 93 is further press-fitted, the portion in contact with the tool 100 undergoes plastic deformation. This plastically deformed portion covers the end 91S, and if an inclined surface 91C is formed, it partially bites into a groove formed by the inclined surface 91C and the inner plunger 93.

Next, referring to FIG. 5C, when the tool 100 bites into the end portion 93S by the length P, the press-fitting is stopped. As already described, at this time, the end 91 </ b> P of the outer plunger 91 may contact the surface 95 </ b> A of the claw 95 or may be separated without contacting.

When the tool 100 is removed, as shown in FIG. 4A, the outer plunger 91 and the inner plunger 93 are fixed to each other in a tight fitting relationship, and the plurality of caulking portions 97 that are plastically deformed from the inner plunger 93 are replaced by the outer plunger 91. The outer plunger 91 is prevented from being displaced in the direction along the axis.

The outer plunger 91 and the inner plunger 93 are not only fixed to each other by interference fit, but also fixed by a plurality of caulking portions 97 plastically deformed from the inner plunger 93. The reaction force received by the claw 95 particularly acts on the range D behind the claw 95 to promote the deformation of the outer plunger 91 and the inner plunger 93. Is distributed and bears a reaction force, thereby preventing deformation and loosening of the interference fit. Therefore, the outer plunger 91 is effectively prevented from being displaced with respect to the inner plunger 93.

As described above, since the mutual fixation is strengthened, the stability is improved over a wider temperature range from a low temperature in an extremely cold region to a high temperature under severe operating conditions. Alternatively, the condition of the interference fit can be relaxed as the fixation is strengthened. This makes it possible to relax tolerances in dimensional accuracy, which is advantageous in terms of productivity.

Also, the caulking part can be formed at the same time during the press-fitting process. That is, the fixing of the outer plunger and the inner plunger is strengthened without additional members, means and devices for fixing. Since this embodiment does not require a special process for forming these additional members, means, and devices, this embodiment is extremely advantageous in terms of productivity.

Although the present invention has been described with reference to preferred embodiments, the present invention is not limited to the above embodiments. Based on the above disclosure, a person having ordinary skill in the art can implement the present invention by modifying or modifying the embodiment.

A plunger that can guarantee further stability is provided.

Claims (6)

1. A plunger used for a solenoid that is symmetrical about an axis,
   A first portion made of a magnetic material and slidably fitted to the solenoid, forming a ring around the shaft, a first end, and the first end in the direction of the shaft A first portion having an opposite second end; and
   A second portion made of a non-magnetic material and fitted to the first portion, the first portion including one or more claws extending from the first end portion along the first end along the axis. 2 part,
   A plurality of caulking portions that are plastically deformed from the second portion and cover the second end to prevent the first portion from being displaced in a direction along the axis;
   Plunger with
2. 2. The plunger according to claim 1, wherein the second portion includes a second end portion along the second end, and the plurality of caulking portions are obtained by plastic deformation of the second end portion. There is a plunger.
3. The plunger according to claim 1, wherein one or more selected from the plurality of caulking portions are arranged in a range in which edges on both sides are extended in a direction along the axis in the circumferential direction of each claw. Plunger.
4. The plunger according to claim 3, wherein two or more selected from the plurality of caulking portions are arranged in each of the ranges.
5. The plunger according to claim 1, wherein the second part is press-fitted into the first part to form an interference fit.
6. The plunger according to claim 1, wherein the claw protrudes so as to cover the first end but does not contact the first end.

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