WO2015132897A1 - Solenoid actuator in which sticking is prevented - Google Patents

Abstract

The solenoid actuator for operating a clutch in a rotating device is equipped with: a solenoid that is symmetrical with respect to the axis; a plunger, which is a plunger that fits together slidably with the solenoid and is able to move in the axial direction from a first position that allows the clutch to be disengaged to a second position in which the clutch is engaged, the plunger being provided with a first portion that is obtained from a magnetic material and fits together with the solenoid slidably facing same, wherein the first portion forms a circle around the axis and has a first end facing the clutch, and with a second portion that is obtained from a non-magnetic material, is fixedly fitted together with the first portion and has a first end section that is parallel to the first end; and a wall surface, which is a wall surface against which the plunger abuts when the plunger is in the second position, the wall surface being provided with a first surface against which the first end section of the second portion abuts and a first surface that is set back in the axial direction from the first surface and for which contact with the first end of the first portion is prevented.

Description

Solenoid actuator that prevents adsorption

The present invention relates to a solenoid actuator that is used in a rotating device such as a differential device or a power take-off unit to operate a clutch therein, and in particular, a solenoid actuator that prevents a plunger from adsorbing to a wall surface of the rotating device due to a magnetic force. About.

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. When the plunger is entirely made of a magnetic material, magnetic flux leaks from the plunger to the rotating device, resulting in energy loss. Therefore, a plunger may be configured by combining a nonmagnetic material such as stainless steel with a magnetic material. Each of these is, for example, an annular shape, and the former is pressed into the latter and fixed. By making the portion made of a magnetic material face the solenoid side and the portion made of a non-magnetic material is in contact with the rotating device, leakage of magnetic flux can be prevented and it can be used efficiently.

Patent Document 1 discloses a related technique.

Japanese Patent Publication No. 2007-92990

In the plunger that combines a nonmagnetic material with a magnetic material, the magnetic material is exposed at the end face. When the plunger moves in the direction in which the clutch is connected, the exposed end surface of the magnetic material comes into contact with the wall surface of the rotating device. At this time, the plunger may be attracted to the wall surface rarely by residual magnetism. This hinders the clutch from being disconnected and may cause the rotating device to operate unintentionally. The present inventors have found problems here and have come up with the present invention to solve them.

According to one aspect of the present invention, a solenoid actuator for operating a clutch in a rotating device is slidably fitted to a solenoid that is symmetrical with respect to an axis, and allows the clutch to be disconnected. The plunger is movable in the axial direction from the first position to the second position where the clutch is engaged, and is a first portion made of a magnetic material and slidably fitted facing the solenoid. A first part having a first end directed to the clutch and having a ring around the shaft, and made of a non-magnetic material and fixedly fitted to the first part, A second portion having a first end along the first end; and a wall surface against which the plunger abuts when the plunger is in the second position, Said first of the second part A wall surface comprising: a first surface with which an end portion abuts; and a first surface that recedes axially from the first surface and prevents the first end of the first portion from abutting. And comprising.

FIG. 1 is a cross-sectional view of a differential apparatus according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the plunger. FIG. 3 is an enlarged sectional view showing the solenoid actuator and its surroundings in an enlarged manner.

Several exemplary embodiments of the present invention are described below with reference to FIGS.

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 is provided with a through hole 37 so as to correspond to this, and the convex portion 77 has its tip exposed to the outside through the through hole 37.

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 contact the convex portions 77 exposed to the outside through the through holes 37. 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 to FIG. 3 in combination with FIG. 1, the solenoid actuator 11 includes a solenoid 13 that is symmetrical with respect to the axis and is annular around the axis. The solenoid 13 is coaxial with the differential case 3 and is disposed adjacent to the right wall 33. The solenoid 13 has an electromagnetic coil 15 for generating a magnetic flux and a core 17 for guiding the magnetic flux.

In order to position the solenoid 13 with respect to the differential case 3, the wall 33 of the differential case 3 includes 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 and the plunger 9 rotate relative to the solenoid 13 that is prevented from rotating.

The core 17 constitutes a magnetic circuit surrounding the electromagnetic coil 15 leaving the gap 19, or the magnetic circuit may include the right wall 33 of the differential case 3 as a part thereof. The wall portion 33 may include a portion 39 protruding toward the core 17, and the gap 19 may be held between the portion 39 and the core 17. The gap 19 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 FIGS. 1 and 3, 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. The end 91P on the side facing the clutch member 71 may be a plane perpendicular to the cylindrical surface, but the edge may be appropriately chamfered.

The outer plunger 91 faces the solenoid 13 and is disposed so as to straddle the gap 19 of the magnetic circuit. The magnetic flux generated by the electromagnetic coil 15 bypasses the gap 19 of the magnetic circuit and flows around the outer plunger 91, and the magnetic flux drives the outer plunger 91 in a direction along the axis. The core 17 and the outer plunger 91 (or the wall portion 33 in addition thereto) constitute a magnetic circuit that forms a closed loop around the electromagnetic coil 15, which is to efficiently use the generated magnetic flux. It is advantageous.

The inner plunger 93 is made of a non-magnetic material such as stainless steel, aluminum alloy, or any engineering plastics, and generally has an annular shape around the shaft. 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 into the outer plunger 91 and is fixedly fitted. On the side facing the clutch member 71, the end portion 93 </ b> P of the inner plunger 93 and the end 91 </ b> P of the outer plunger 91 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.

The claw 95 extends integrally from the end 93P of the inner plunger 93 in the direction along the axis. Preferably, the claw 95 may protrude in the radial direction so as to cover the end 91 </ b> P of the outer plunger 91. The end 91 </ b> P of the outer plunger 91 can abut on the claw 95. 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 end 91 </ b> P may be separated without contacting the claw 95. 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.

The end of the inner plunger 93 opposite to the end 93P may be plastically deformed toward the outer plunger 91 at one or more locations, thereby forming a plurality of crimped portions. Such a caulking portion prevents the outer plunger 91 from being displaced in the axial direction relative to the inner plunger 93.

Referring mainly to FIG. 3, the wall portion 33 of the differential case 3 includes a wall surface 35 on which the plunger 9 can abut. When the plunger 9 is in a position (shown by a solid line in the figure) where the clutch 7 is connected, the plunger 9 abuts against the wall surface 35, and the plunger 9 is allowed to be disconnected from the clutch 7 (in the figure, a dashed line) The plunger 9 is detached from the wall surface 35.

The wall surface 35 includes an outer peripheral surface 41 and an inner peripheral surface 43 that are coaxial with each other. The outer peripheral surface 41 mainly faces the outer plunger 91, and the inner peripheral surface 43 mainly faces the inner plunger 93. The outer peripheral surface 41 and the inner peripheral surface 43 are not the same surface, and the outer peripheral surface 41 recedes from the inner peripheral surface 43 in the axial direction. Therefore, when the plunger 9 abuts against the wall surface 35, the end 93 </ b> P of the inner plunger 93 abuts on the inner peripheral surface 43, but the end 91 </ b> P of the outer plunger 91 is prevented from abutting on the outer peripheral surface 41.

When the plunger 9 is in a position where the clutch 7 is connected, an air gap is maintained between the end 91P of the outer plunger 91 and the outer peripheral surface 41. Such an air gap prevents the plunger 9 from adsorbing to the wall surface 35. On the other hand, such an air gap does not prevent the magnetic flux from jumping between them, and is therefore advantageous in efficiently using the magnetic flux. From the viewpoint of reliably preventing adsorption, the air gap is preferably wide, so the air gap is preferably 0.1 mm or more. In addition, the air gap is preferably 0.5 mm or less, and more preferably 0.2 mm or less, since it is better to be narrow from the viewpoint of efficiently using the magnetic flux.

According to the present embodiment, the outer plunger made of a magnetic material and the differential case do not contact each other, and only the inner plunger made of a non-magnetic material contacts the differential case. Therefore, the plunger is not attracted to the differential case by the residual magnetism. Even if the current to the electromagnetic coil is disconnected, the clutch does not remain connected, and the clutch can be operated as intended by the driver by turning the current on and off.

By the way, it replaces with the above-mentioned embodiment, and the end of an outer plunger may be slightly retracted with respect to the end of an inner plunger, In that case, the outer peripheral surface 41 and the inner peripheral surface 43 are arrange | equalized with the same surface. May be. Even with such a structure, an air gap is secured between the outer plunger and the wall surface, so that the above-described effects can be enjoyed. However, it is difficult to ensure an accuracy of about 0.1 mm in the step of press-fitting the inner plunger into the outer plunger. Even if it is attempted to perform machining again after press-fitting in order to ensure accuracy, the claw protrudes from the end of the inner plunger, and this prevents it from using a lathe for machining the end.

Compared with the processing of the end of the plunger, a lathe can be used for processing the wall surface of the differential case, which can easily achieve an accuracy of about 0.05 mm and is also excellent in productivity. Moreover, if the demand for the accuracy of the inner plunger is low, it is not necessary to use a precision casting method for its production, and it can be produced by cutting from a pipe, for example. This is a significant advantage for productivity. In other words, this embodiment is advantageous in terms of ensuring the accuracy of manufacturing the solenoid actuator and improving 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 solenoid actuator that prevents the plunger from adsorbing to the wall surface of the rotating device is provided.

Claims (4)

A solenoid actuator for operating a clutch in a rotating device,
A solenoid that is symmetrical about the axis;
A plunger slidably fitted to the solenoid and movable in the axial direction from a first position allowing the clutch to be disengaged to a second position for engaging the clutch;
A first portion made of a magnetic material and slidably fitted facing the solenoid, the first portion having an annular shape around the shaft and having a first end directed toward the clutch 1 part and
A second portion made of a non-magnetic material, fixedly fitted to the first portion, and having a first end along the first end;
A wall surface against which the plunger abuts when the plunger is in the second position, the first surface against which the first end of the second portion abuts, and an axis from the first surface A wall surface comprising: a first surface that recedes in a direction and prevents the first end of the first portion from abutting;
Solenoid actuator with 2. The solenoid actuator of claim 1, wherein the second surface is between 0.1 mm and 0.1 mm between the second surface and the first end when the plunger is in the second position. A solenoid actuator dimensioned to hold a 2 mm air gap. The solenoid actuator according to claim 1, wherein the first end of the first portion and the first end of the second portion are aligned on the same plane. 2. The solenoid actuator according to claim 1, wherein the solenoid includes an electromagnetic coil for generating magnetic flux and a core for guiding the magnetic flux, and the core, the plunger, and a wall portion of the rotating device are provided. A solenoid actuator wherein the core surrounds the electromagnetic coil to form a magnetic circuit that forms a closed loop around the electromagnetic coil.

Images