JP2002070889A - Driving force transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving force transmission device in which an electromagnetic driving means can be operated securely, and cost reduction and mass production of an outside driving means can be made possible by forming the outside driving means only with carbon steel for structure. SOLUTION: The driving force transmission device has a friction clutch 34 arranged between an exterior front housing 31a and an interior inner shaft 30b both of which are made of only ferrous material disposed coaxially and relatively movable in each other, attracts an armature 35 toward an electromagnet 35 by forming a magnetic circuit Z by electrification to electromagnet 33, frictionally engages the frictional cutch 34 by means of the attraction, and carries out torque transmission between the front housing 31a and the inner shaft 30b by way of frictional engagement force of the frictional clutch 34. The portion where the magnetic circuit Z is formed in the front housing 31a is made to have less quantities of carbon than in other portions. When the quantity of carbon is reduced, residual magnetization is also reduced correspondingly, and the operation of armature 35 can then be performed securely.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a driving force transmitting device, and more particularly to a driving force transmitting device having a friction clutch (electromagnetic clutch).

[0002]

2. Description of the Related Art Conventionally, as an example of a driving force transmission device, a device proposed in Japanese Utility Model Laid-Open No. 7-14229 has been known.

This driving force transmission device operates by energizing a friction clutch (electromagnetic clutch) disposed between inner and outer rotating members coaxially and relatively rotatable with each other to frictionally engage the friction clutch. It has an electromagnetic driving means for driving.

[0004] An input shaft is integrally formed outside the outer rotating member, and the driving force of the engine is transmitted to the outer rotating member via the input shaft. An armature located inside the outer rotating member and opposed to the friction clutch; an electromagnet located outside the outer rotating member and opposed to the friction clutch across a side wall of the outer rotating member; It is composed of

In the driving force transmission device, a front housing is employed as an outer rotating member, and an inner shaft is employed as an inner rotating member. In the driving force transmission device, a magnetic circuit circulating through the yoke supporting the electromagnet, the front side wall of the front housing, the front housing, the armature, the friction clutch, the front side wall and the yoke is formed by energizing the electromagnetic coil of the electromagnet. Is done. Then, the armature is attracted to the friction clutch side by the magnetic induction action. As a result, the armature presses and frictionally engages the friction clutch, and operates the main clutch mechanism directly by the friction engagement force or via the cam mechanism to connect the front housing and the inner shaft so that torque can be transmitted. .

The input shaft and the front housing are integrally formed of an iron material, and a stainless steel material, which is a non-magnetic material, is welded and fixed to a portion of the front housing facing the armature and the friction clutch.

[0007] The front housing made of an iron material has a characteristic that a residual magnetism is obtained by energizing an electromagnetic coil of an electromagnet. However, by providing the front housing with a stainless material at a portion facing the armature, the armature operates normally without being affected by residual magnetism from the front housing, and reliably transmits torque between the front housing and the inner shaft. It has been like that.

[0008]

However, in the above-mentioned driving force transmission device, since a stainless steel material is partially fixed by welding to a front housing which is mostly made of an iron material, a work cost due to welding is required. Further, the stainless steel material to be welded and fixed has a complicated shape and the material itself is expensive, so that the material cost is high. Although it is conceivable to form the input shaft and the front housing entirely from stainless steel, there is a problem that the material cost increases.

Accordingly, the present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to reliably operate an electromagnetic driving means, and to use an outer rotating member made of only structural carbon steel. Accordingly, it is an object of the present invention to provide a driving force transmission device that can be manufactured at low cost and mass-produced by forming the outer rotating member.

[0010]

In order to achieve the above object, the invention according to claim 1 comprises a friction clutch disposed between both inner and outer rotating members rotatably positioned relative to each other;
In a driving force transmission device provided with an electromagnetic driving means that operates by energization to frictionally engage the friction clutch, a magnetic circuit configuration in which the outer rotating member is a part of a magnetic circuit by the driving means when energized is provided. The outer rotating member is formed of structural carbon steel, and the magnetic circuit component of the outer rotating member has a reduced carbon amount as compared with other portions.

According to a second aspect of the present invention, in the driving force transmission device according to the first aspect, the magnetic circuit component is subjected to a carbon-proof treatment. According to a third aspect of the present invention, in the driving force transmission device according to the first aspect, the magnetic circuit constituting portion is cut after the carburizing process. (Operation) Therefore, in the first aspect of the present invention, while the outer rotating member is made of structural carbon steel, the amount of carbon in the magnetic circuit component is smaller than that of the other parts. Therefore, residual magnetism hardly remains. As a result, when the magnetic circuit is formed by energizing the driving means and the energization is stopped from the state in which the friction clutch is frictionally engaged, residual magnetism hardly remains in the magnetic circuit constituting part. Release the engagement without fail. In addition, since the portion of the outer rotating member other than the magnetic circuit component has a larger amount of carbon than the magnetic circuit component, sufficient strength is obtained to function as a driving force transmitting device.

According to the second aspect of the present invention, in addition to the function of the first aspect, since the magnetic circuit constituting portion is subjected to a carbon prevention treatment, the amount of carbon is made smaller than that of the other portion of the outer rotating member. .

According to the third aspect of the present invention, in addition to the function of the first aspect, the magnetic circuit component is carburized and then cut to reduce the amount of carbon in the outer rotating member compared to other portions. Is done.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows a driving force transmission device according to an embodiment of the present invention. This driving force transmission device 11 is similar to that shown in FIG.
As shown in the figure, the driving force transmission path is provided on the four-wheel drive vehicle 12 in the driving force transmission path to the rear wheels.

The four-wheel drive vehicle 12 includes a driving force transmission device 1
1, a transaxle 13, an engine 14, a pair of front wheels 15, and a pair of rear wheels 16. The driving force of the engine 14 is output to the axle shaft 17 via the transaxle 13 to drive the front wheels 15.

A driving force transmission device 11 is connected to the transaxle 13 via a propeller shaft 18.
The driving force transmission device 11 includes a drive pinion shaft 1
9, a rear differential 20 is connected. The rear wheel 20 is connected to the rear differential 20 via an axle shaft 21. When the propeller shaft 18 and the drive pinion shaft 19 are connected by the driving force transmission device 11 so as to be able to transmit torque, the driving force of the engine 14 is transmitted to the rear wheels 16.

The driving force transmission device 11 is accommodated in a differential carrier 22 together with a rear differential 20, is supported by the differential carrier 22, and is supported by the vehicle body via the differential carrier 22.

Next, the driving force transmission device 11 will be described. As shown in FIG. 1, the driving force transmission device 11 includes an outer case 30a, an inner shaft 30 as an inner rotating member.
b, a main clutch mechanism 30c, a pilot clutch mechanism 30d, and a cam mechanism 30e.

The outer case 30a comprises a bottomed cylindrical front housing 31a as an outer rotating member, and a rear housing 31b screwed into a rear end opening of the front housing 31a and covering the opening. Have been. An input shaft 50 protrudes from a front end of the front housing 31a, and the input shaft 50 is connected to the propeller shaft 18.

The front housing 31a integrally formed with the input shaft 50 is made of, for example, carbon steel for machine structure such as S15C. As shown in FIG. 4, the rear side of the front housing 31a is a magnetic circuit component 55a having a smaller amount of carbon than other portions of the front housing 31a. Hereinafter, the portion of the front housing 31a other than the magnetic circuit forming portion 55a is referred to as a non-magnetic circuit forming portion 55b. As shown in FIG. 1, a stainless steel tubular body 51 which is a non-magnetic material is embedded in a radially intermediate portion of the rear housing 31b, and the tubular body 51 forms an annular non-magnetic portion, which will be described later. A magnetic path Z is formed.

The outer case 30a is rotatably supported on a differential carrier 22 (see FIG. 2) via a bearing (not shown) on the outer periphery of the front end of the front housing 31a. The outer case 30a is supported by a yoke 36 supported by the differential carrier 22 (see FIG. 2) on the outer periphery of the rear housing 31b via a bearing or the like.

The inner shaft 30b is inserted into the front housing 31a through the center of the rear housing 31b in a liquid-tight manner, and is restricted from moving in the axial direction.
b is rotatably supported relative to b. The inner shaft 30b has a drive pinion shaft 19 (FIG. 2).
(See Reference). In FIG. 1, the drive pinion shaft 19 is not shown.

As shown in FIGS. 1 and 3, the main clutch mechanism 30c is a wet-type, multi-plate type friction clutch mechanism having a plurality of inner clutch plates 32a and outer clutch plates 32b.
a is disposed on the back wall side.

Each inner clutch plate 32a constituting the friction clutch mechanism is spline-fitted to the outer periphery of the inner shaft 30b and is mounted so as to be movable in the axial direction. On the other hand, each outer clutch plate 32b is spline-fitted to the inner periphery of the front housing 31a and is movably mounted in the axial direction. Each inner clutch plate 32a and each outer clutch plate 32b
Are alternately positioned and come into contact with each other to frictionally engage with each other, and are separated from each other to be in a non-engagement free state.

The pilot clutch mechanism 30d includes an electromagnet 33, a friction clutch 34, and an armature 35. The electromagnet 33 and the armature 35 constitute driving means.

As shown in FIG. 1, the yoke 36 is axially supported on the differential carrier 22 (see FIG. 2), and is supported so as to be rotatable relative to the outer periphery of the rear end of the rear housing 31b. Have been. An annular electromagnet 33 is fitted to the yoke 36, and the electromagnet 33 is fitted to an annular recess 53 of the rear housing 31b. As a result, the rear housing 31b and the yoke 36
And a predetermined clearance is formed between them.

The friction clutch 34 includes a plurality of inner clutch plates 34a and outer clutch plates 34.
b is configured as a multi-plate friction clutch. Each inner clutch plate 34a is spline-fitted to the outer periphery of a first cam member 37 constituting a cam mechanism 30e described later, and is assembled so as to be movable in the axial direction. On the other hand, each outer clutch plate 34b is spline-fitted to the inner periphery of the front housing 31a and is movably mounted in the axial direction.

The inner clutch plates 34a and the outer clutch plates 34b are alternately positioned, abut against each other and frictionally engage, and are separated from each other to be in a non-engagement free state.

The armature 35 has an annular shape, and is spline-fitted to the inner periphery of the front housing 31a so as to be movable in the axial direction. The armature 35 is located on one side with respect to the friction clutch 34 and faces the friction clutch 34.

As shown in FIG. 3, the yoke 36 and the rear housing 3 are energized by energizing the electromagnetic coil of the electromagnet 33.
1b, friction clutch 34, armature 35, friction clutch 34, between rear housing 31b, yoke 36, or magnetic circuit component 55a of yoke 36, rear housing 31b, front housing 31a (see FIG. 4), armature 35, friction clutch 34 , Rear housing 31b,
A magnetic circuit Z circulating between the yokes 36 is formed.

As shown in FIGS. 1 and 3, the cam mechanism 30e
Is composed of a first cam member 37, a second cam member 38 made of an aluminum material, and a cam follower 39. In the first cam member 37 and the second cam member 38, a plurality of cam grooves (not shown) facing each other are formed on the opposing surfaces at predetermined intervals in the circumferential direction. The first cam member 37 is rotatably fitted to the outer periphery of the inner shaft 30b, and is rotatably supported by the rear housing 31b. Each inner clutch plate 34a is spline-fitted to the outer periphery of the first cam member 37.

The second cam member 38 includes an inner shaft 30b.
Of the inner shaft 3
0b so as to be integrally rotatable. The second cam member 38 is located to face the inner clutch plate 32a of the main clutch mechanism 30c. A ball-shaped cam follower 39 is interposed between the opposed cam grooves of the second cam member 38 and the first cam member 37.

As a result, the armature 35 is positioned on one side of the friction clutch 34 inside the front housing 31a, and the electromagnet 33 is positioned on the other side of the friction clutch 34 outside the front housing 31a across the rear housing 31b. To position.

The rear housing 31b includes the inner shaft 3
0b in a liquid-tight and rotatably fitted state on the outer periphery of
The peripheral portion of the front wall portion is screwed to the front housing 31a. The rear housing 31b is connected to the differential carrier 22 (see FIG. 2) via an oil seal (not shown) on the outer periphery of the rear end of the rear cylinder.
Liquid-tightly and rotatably supported.

In the driving force transmission device 11 as described above, the electromagnet 3 constituting the pilot clutch mechanism 30d is used.
When power is not supplied to the third electromagnetic coil, the magnetic circuit Z is not formed, and the friction clutch 34 is in the non-engaged state. Therefore, the pilot clutch mechanism 30d is in a non-operating state, and the first cam member 37 constituting the cam mechanism 30e is connected to the second cam member 3 via the cam follower 39.
8, and the main clutch mechanism 30c is in a non-operating state. Thus, the four-wheel drive vehicle 12 constitutes a two-wheel drive mode.

On the other hand, when power is supplied to the electromagnetic coil of the electromagnet 33, a magnetic circuit Z is formed in the pilot clutch mechanism 30d, and the electromagnet 33 attracts the armature 35. For this reason, the armature 35 presses the friction clutch 34 to cause frictional engagement, connects the first cam member 37 of the cam mechanism 30e to the front housing 31a side, and
8 and a relative rotation is generated. As a result, in the cam mechanism 30e, the cam follower 39 presses the two cam members 37 and 38 in a direction away from each other.

As a result, the second cam member 38 is pressed toward the main clutch mechanism 30c, and
c is frictionally engaged in accordance with the frictional engagement force of the friction clutch 34 to transmit torque between the outer case 30a and the inner shaft 30b. Thus, the four-wheel drive vehicle 12 constitutes a four-wheel drive drive mode in which the propeller shaft 18 and the drive pinion shaft 19 are not directly connected.

When the current applied to the electromagnetic coil of the electromagnet 33 is increased to a predetermined value, the armature 35
To the suction force. Then, the armature 35 is strongly attracted to the electromagnet 33 side, increasing the frictional engagement force of the friction clutch 34 and increasing the relative rotation between the two cam members 37, 38. As a result, the cam follower 39 increases the pressing force on the second cam member 38 to bring the main clutch mechanism 30c into the connected state. For this reason, the four-wheel drive vehicle 12 includes a propeller shaft 18 and a drive pinion shaft 19.
Constitute a drive mode of four-wheel drive directly connected.

Next, a method of processing the front housing 31a will be described. First, the front housing 31a formed first by casting or the like is formed into a desired shape by cutting. Then, as shown in FIG. 4, a known carbon-proofing agent is applied so as to cover the magnetic circuit constituting portion 55a of the front housing 31a. Next, a known carburizing process is performed on the entire front housing 31a. Then, a carburized layer is formed on the surface of the non-magnetic circuit forming portion 55b, and the amount of carbon is larger than that of the magnetic circuit forming portion 55a. Then, induction hardening is performed on the input shaft 50, and thereafter, the carbon-proofing agent attached to the magnetic circuit component 55a is removed.

As a result, a carburized layer is not formed on the magnetic circuit forming portion 55a of the front housing 31a, while a carburized layer is formed on the non-magnetic circuit forming portion 55b. next,
Driving force transmission device 1 configured as in the first embodiment
The operation characteristic of 1 will be described.

Here, general characteristics of the structural carbon steel will be described. Structural carbon steel has the property that, as the amount of carbon increases, the magnetic flux is more difficult to pass, but once the magnetic flux passes, the residual magnetism tends to take on.

When the electromagnetic coil of the electromagnet 33 is energized, a magnetic circuit Z is formed. At this time, a magnetic flux passes through the magnetic circuit constituting portion 55a of the front housing 31a which is a part of the magnetic circuit Z. Then, when the energization of the electromagnetic coil of the electromagnet 33 is stopped, the magnetic circuit component 55a loses magnetism quickly because the amount of carbon is smaller than that of the nonmagnetic circuit forming portion 55b. Then, the armature 35 of the pilot clutch mechanism 30d reliably releases the friction clutch 34 without being blocked by the residual magnetism.

The base end of the input shaft 50, which is the non-magnetic circuit forming portion 55b, has a sufficient amount of carbon to provide a function as the driving force transmitting device 11 because the amount of carbon is larger than that of the magnetic circuit forming portion 55a. have.

Therefore, according to the driving force transmission device 11 of the first embodiment, the following effects can be obtained. (1) In the present embodiment, the amount of carbon in the magnetic circuit constituting portion 55a in the front housing 31a is formed to be smaller than that in the non-magnetic circuit forming portion 55b. Therefore,
The magnetic circuit constituting section 55a has less residual magnetism than the non-magnetic circuit forming section 55b, and can suppress an adverse effect on the operation of the armature 35. In addition, the front housing 31
Since a can be formed only of inexpensive structural carbon steel, material costs can be reduced and work costs such as welding work can be reduced as compared with the front housing of the conventional driving force transmission device.

(2) In the present embodiment, the input shaft 50 of the front housing 31a is subjected to induction hardening. Therefore, the input shaft 50 of the front housing 31a
Can obtain sufficient strength to fulfill the function of the driving force transmission device 11.

(Second Embodiment) Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. In addition,
The driving force transmission device 61 of the second embodiment employs a front housing 62 obtained by changing the processing method of the front housing 31a of the first embodiment, and the same configuration as that of the first embodiment is the same. Reference numerals are used, detailed descriptions thereof will be omitted, and different points will be described in detail.

A method of processing the front housing 62 of the driving force transmission device 61 according to this embodiment will be described. First, the front housing 62 formed first by casting or the like is formed into a desired shape by cutting. At this time, the magnetic circuit component 55a of the front housing 62 is rough-cut so that the finish cutting can be performed later. Next, a known carburizing process is performed on the entire front housing 62. Then, a carburized layer is formed on the surface of the front housing 62, and the amount of carbon is larger than that inside the front housing 62.

Then, the carburized layer formed on the surface of the magnetic circuit component 55a is removed by finish cutting, and a female screw for screwing the rear housing 31b to the inner peripheral surface of the rear end of the front housing 62 is formed. I do. And
Induction hardening is performed on the input shaft 50.

As a result, a carburized layer is not formed on the magnetic circuit forming portion 55a of the front housing 62, while a carburized layer is formed on the non-magnetic circuit forming portion 55b. Therefore,
The driving force transmission device 61 of the present embodiment has the same functions and effects as those of the driving force transmission device 11 of the first embodiment. (Other Embodiments) Each of the above embodiments may be modified and embodied in the following other embodiments.

In each of the above embodiments, the input shaft 50 is subjected to induction hardening when the front housings 31a and 62 are processed. However, the quenching of the input shaft 50 is not limited to induction hardening, and may be flame quenching.

In each of the above embodiments, the magnetic circuit constituting portion 55a of the front housings 31a and 62 is subjected to high frequency quenching, but may not be quenched. Next, regarding technical ideas other than the inventions described in the claims that can be grasped from the above embodiments and other embodiments,
These effects are described below.

(A) The drive according to claim 1 or 2, wherein the carburizing process is performed on the magnetic circuit constituting part when the carburizing process is performed on the outer rotating member. Power transmission device. With this configuration, a carburized layer is not formed on the magnetic circuit component of the outer rotating member, and a carburized layer can be formed on the surface of the other portion.

(B) The driving force according to (A) or (B), wherein a portion other than the magnetic circuit constituting portion of the outer rotating member is quenched after carburizing. Transmission device. According to this structure, the hardening can be performed in the other portions of the outer rotating member other than the magnetic circuit forming portion as compared with the case where no hardening is performed.

[0055]

According to the first to third aspects of the present invention, the operation of the electromagnetic driving means can be reliably performed, and the outer rotating member is formed only of the structural carbon steel so that the outer rotating member is formed. The members can be reduced in cost and mass-produced.

According to the second aspect of the present invention, by performing the carbon preventing treatment on the magnetic circuit component, the magnetic circuit component can have a smaller carbon amount than other portions of the outer rotating member.

According to the third aspect of the invention, the magnetic circuit component is carburized and then cut to reduce the amount of carbon in the magnetic circuit component compared to other portions of the outer rotating member.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a driving force transmission device according to first and second embodiments.

FIG. 2 is an explanatory diagram of a four-wheel drive vehicle equipped with the driving force transmission device according to the first and second embodiments.

FIG. 3 is a cross-sectional view of a main part of the driving force transmission device according to the first and second embodiments.

FIG. 4 is a sectional view of a front housing in the first and second embodiments.

[Explanation of symbols]

11, 61: driving force transmitting device, 30a: outer case as an outer rotating member, 30b: inner shaft as an inner rotating member, 34: friction clutch, 55a: magnetic circuit component, Z: magnetic circuit.

Claims (3)

[Claims] 1. A driving force transmitting device comprising: a friction clutch disposed between inner and outer rotating members positioned to be relatively rotatable with each other; and an electromagnetic driving means which operates by energization to frictionally engage the friction clutch. In the apparatus, the outer rotating member includes a magnetic circuit component that becomes a part of a magnetic circuit by a driving unit when the power is supplied, wherein the outer rotating member is formed of structural carbon steel, and A driving force transmitting device, wherein the magnetic circuit constituting section has a reduced carbon amount as compared with other portions. 2. The driving force transmission device according to claim 1, wherein the magnetic circuit component is subjected to a carbon-proof treatment. 3. The driving force transmission device according to claim 1, wherein the magnetic circuit component is carburized and then cut.