JP3777399B2 - Driving force transmission device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a driving force transmission device, and more particularly to a driving force transmission device having a friction clutch (electromagnetic clutch).
[0002]
[Prior art]
Conventionally, what is proposed in Japanese Utility Model Publication No. 7-14229 is known as an example of a driving force transmission device.
[0003]
This driving force transmission device includes a friction clutch (electromagnetic clutch) disposed between both inner and outer rotating members that are coaxially and relatively rotatable with each other, and an electromagnetic type that operates by energization to frictionally engage the friction clutch. The drive means is provided.
[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. The drive means is located inside the outer rotating member and faces the friction clutch; an electromagnet located outside the outer rotating member and faces the friction clutch across the side wall of the outer rotating member; It is composed of
[0005]
In the driving force transmission device, a front housing is adopted as the outer rotating member, and an inner shaft is adopted as the inner rotating member.
In the drive force transmission device, a magnetic circuit that circulates 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 magnetic induction. As a result, the armature presses and frictionally engages the friction clutch, and the main clutch mechanism is actuated directly or via the cam mechanism by this friction engagement force to connect the front housing and the inner shaft so that torque can be transmitted. .
[0006]
The input shaft and the front housing are integrally formed of an iron material, and a stainless material, which is a nonmagnetic material, is welded and fixed to a portion of the front housing that faces the armature and the friction clutch.
[0007]
By the way, a front housing made of an iron material has a characteristic of having residual magnetism when energized to an electromagnetic coil of an electromagnet. However, by providing a stainless steel material in a portion of the front housing that faces 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. Has been.
[0008]
[Problems to be solved by the invention]
However, in the above driving force transmission device, since the stainless steel material is partially welded and fixed to the front housing made of iron material, the work cost for welding is high. Further, the stainless steel material to be fixed by welding has a complicated shape and the material itself is expensive, so that the material cost is high. Although it is conceivable that the input shaft and the entire front housing are made of stainless steel, there is a problem that the material cost increases.
[0009]
Accordingly, the present invention has been made in view of the above-described circumstances, and the object thereof is to reliably operate the electromagnetic driving means, and the outer rotating member is formed only from structural carbon steel. Accordingly, an object of the present invention is to provide a driving force transmission device capable of reducing the cost and mass production of the outer rotating member.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, there is provided a friction clutch disposed between the inner and outer rotating members positioned so as to be rotatable relative to each other, and the friction clutch engaged by energization to frictionally engage the friction clutch. In the driving force transmission device including the electromagnetic driving means, the outer rotating member includes a magnetic circuit component that becomes a part of a magnetic circuit by the driving means when energized, and the outer rotating member is structural carbon. The gist is that the magnetic circuit constituent part is made of steel and the amount of carbon in the outer rotating member is smaller than that in other parts.
[0011]
The gist of the invention according to claim 2 is that, in the driving force transmission device according to claim 1, the magnetic circuit component is subjected to a carbon-proofing treatment.
The gist of the invention according to claim 3 is that, in the driving force transmission device according to claim 1, the magnetic circuit component is cut after carburizing.
(Function)
Therefore, in the first aspect of the present invention, the outer rotating member is made of structural carbon steel, but the magnetic circuit constituent part has a smaller amount of carbon than other parts, so that the residual magnetism is reduced. Is hard to remain. As a result, when the energization is stopped after the magnetic circuit is formed by energizing the drive means and the friction clutch is frictionally engaged, the residual magnetism hardly remains in the magnetic circuit component. Release the engagement securely. In addition, since the carbon 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 can be obtained to fulfill the function as a driving force transmission device.
[0012]
In addition to the effect | action of Claim 1, in the invention of Claim 2, since the said magnetic circuit structure part performs a charcoal-proof process, the amount of carbon is made smaller than the other part in an outer side rotation member.
[0013]
In addition to the effect | action of Claim 1, in the invention of Claim 3, after the said magnetic circuit structure part carburizes, it cuts the amount of carbons from the other part in an outer side rotation member by cutting.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS.
[0015]
FIG. 1 shows a driving force transmission device according to an embodiment of the present invention. As shown in FIG. 2, the driving force transmission device 11 is disposed in a driving force transmission path to the rear wheel side in the four-wheel drive vehicle 12.
[0016]
The four-wheel drive vehicle 12 includes a driving force transmission device 11, 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.
[0017]
A driving force transmission device 11 is connected to the transaxle 13 via a propeller shaft 18, and a rear differential 20 is connected to the driving force transmission device 11 via a drive pinion shaft 19. A rear wheel 16 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 that torque can be transmitted, the driving force of the engine 14 is transmitted to the rear wheel 16.
[0018]
The driving force transmission device 11 is accommodated in the differential carrier 22 together with the rear differential 20, supported by the differential carrier 22, and supported by the vehicle body via the differential carrier 22.
[0019]
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 30b as an inner rotating member, a main clutch mechanism 30c, a pilot clutch mechanism 30d, and a cam mechanism 30e.
[0020]
The outer case 30a includes a bottomed cylindrical front housing 31a as an outer rotating member, and a rear housing 31b that is screwed into a rear end opening of the front housing 31a and covers the opening. . An input shaft 50 projects from the front end portion of the front housing 31a, and the input shaft 50 is connected to the propeller shaft 18.
[0021]
The front housing 31a in which the input shaft 50 is integrally formed is made of 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 parts of the front housing 31a. Hereinafter, the part other than the magnetic circuit component 55a in the front housing 31a is referred to as a non-magnetic circuit forming part 55b. As shown in FIG. 1, a stainless steel cylinder 51, which is a nonmagnetic material, is embedded in a radial intermediate portion of the rear housing 31b. The cylinder 51 forms an annular nonmagnetic portion, which will be described later. A magnetic path Z is formed.
[0022]
The outer case 30a is rotatably supported on the outer periphery of the front end portion of the front housing 31a with respect to the differential carrier 22 (see FIG. 2) via a bearing (not shown). The outer case 30a is supported on the outer periphery of the rear housing 31b by a yoke 36 that is supported by the differential carrier 22 (see FIG. 2) via a bearing or the like.
[0023]
The inner shaft 30b penetrates the central portion of the rear housing 31b in a liquid-tight manner and is inserted into the front housing 31a. The inner shaft 30b is relative to the front housing 31a and the rear housing 31b in a state where movement in the axial direction is restricted. It is rotatably supported. The tip of the drive pinion shaft 19 (see FIG. 2) is inserted into the inner shaft 30b. In FIG. 1, the drive pinion shaft 19 is not shown.
[0024]
As shown in FIGS. 1 and 3, the main clutch mechanism 30c is a wet multi-plate friction clutch mechanism, and includes a large number of inner clutch plates 32a and outer clutch plates 32b, which are arranged on the back wall side of the front housing 31a. It is installed.
[0025]
Each inner clutch plate 32a constituting the friction clutch mechanism is assembled by being spline-fitted to the outer periphery of the inner shaft 30b 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 assembled so as to be movable in the axial direction. The inner clutch plates 32a and the outer clutch plates 32b are alternately positioned so as to come into contact with each other and frictionally engage with each other, and are separated from each other to be in an unengaged free state.
[0026]
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.
[0027]
As shown in FIG. 1, the yoke 36 is supported along the axial direction with respect to the differential carrier 22 (see FIG. 2), and is supported so as to be rotatable relative to the outer periphery of the rear end portion of the rear housing 31b. . An annular electromagnet 33 is fitted on the yoke 36, and the electromagnet 33 is fitted in an annular recess 53 of the rear housing 31b. As a result, a predetermined clearance is formed between the rear housing 31b and the yoke 36.
[0028]
The friction clutch 34 is configured as a multi-plate friction clutch including a plurality of inner clutch plates 34a and an outer clutch plate 34b. 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 assembled so as to be movable in the axial direction.
[0029]
The inner clutch plates 34a and the outer clutch plates 34b are alternately positioned so as to come into contact with each other and frictionally engage with each other, and are separated from each other to be in a non-engaged free state.
[0030]
The armature 35 has an annular shape and is assembled so as to be movable in the axial direction by being spline-fitted to the inner periphery of the front housing 31a. The armature 35 is located on one side of the friction clutch 34 and faces the friction clutch 34.
[0031]
As shown in FIG. 3, by energizing the electromagnetic coil of the electromagnet 33, the yoke 36, the rear housing 31b, the friction clutch 34, the armature 35, the friction clutch 34, the rear housing 31b, between the yoke 36, or the yoke 36, the rear housing. 31b, a magnetic circuit component 55a (see FIG. 4) of the front housing 31a, the armature 35, the friction clutch 34, the rear housing 31b, and the magnetic circuit Z that circulates between the yoke 36 are formed.
[0032]
As shown in FIGS. 1 and 3, the cam mechanism 30 e includes 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 in the circumferential direction 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 34 a is splined to the outer periphery of the first cam member 37.
[0033]
The second cam member 38 is spline-fitted to the outer periphery of the inner shaft 30b, and is assembled to the inner shaft 30b so as to be integrally rotatable. The second cam member 38 is positioned to face the inner clutch plate 32a of the main clutch mechanism 30c. A ball-shaped cam follower 39 is interposed in the cam grooves of the second cam member 38 and the first cam member 37 facing each other.
[0034]
As a result, the armature 35 is located on one side of the friction clutch 34 inside the front housing 31a, and the electromagnet 33 is located on the other side of the friction clutch 34 with the rear housing 31b sandwiched outside the front housing 31a.
[0035]
The rear housing 31b is screwed to the front housing 31a at the peripheral edge portion of the front side wall portion thereof in a state of being fluid-tightly and rotatably fitted to the outer periphery of the inner shaft 30b. The rear housing 31b is supported in a liquid-tight and rotatable manner on the differential carrier 22 (see FIG. 2) via an oil seal (not shown) on the outer periphery of the rear end portion of the rear cylinder portion.
[0036]
In the driving force transmission device 11 as described above, the magnetic circuit Z is not formed when the electromagnetic coil of the electromagnet 33 constituting the pilot clutch mechanism 30d is not energized, and the friction clutch 34 is in the non-engaged state. It is in. Therefore, the pilot clutch mechanism 30d is in an inoperative state, and the first cam member 37 constituting the cam mechanism 30e can rotate integrally with the second cam member 38 via the cam follower 39, and the main clutch mechanism 30c. Is inactive. For this reason, the four-wheel drive vehicle 12 constitutes a two-wheel drive mode.
[0037]
On the other hand, when the electromagnetic coil of the electromagnet 33 is energized, 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 and frictionally engages the friction clutch 34, connects the first cam member 37 of the cam mechanism 30e to the front housing 31a side, and causes relative rotation with the second cam member 38. . As a result, in the cam mechanism 30e, the cam follower 39 presses both the cam members 37 and 38 away from each other.
[0038]
As a result, the second cam member 38 is pressed toward the main clutch mechanism 30c, causing the main clutch mechanism 30c to frictionally engage according to the friction engagement force of the friction clutch 34, and the torque between the outer case 30a and the inner shaft 30b. Make a transmission. Therefore, 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.
[0039]
Further, when the current applied to the electromagnetic coil of the electromagnet 33 is increased to a predetermined value, the attractive force of the electromagnet 33 to the armature 35 increases. The armature 35 is strongly attracted toward the electromagnet 33, increasing the frictional engagement force of the friction clutch 34, and increasing the relative rotation between the cam members 37 and 38. As a result, the cam follower 39 increases the pressing force with respect to the second cam member 38 to bring the main clutch mechanism 30c into the coupled state. For this reason, 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 directly connected.
[0040]
Next, a method for processing the front housing 31a will be described.
First, the front housing 31a formed by casting or the like is first formed into a desired shape by cutting. And as shown in FIG. 4, a well-known carburizing agent is apply | coated so that the magnetic circuit structure part 55a of the front housing 31a may be covered. 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 constituting portion 55a. And induction hardening is performed with respect to the input shaft 50, and the carbon-proof agent adhering to the magnetic circuit structure part 55a is removed after that.
[0041]
As a result, a carburized layer is not formed on the magnetic circuit component 55a of the front housing 31a, whereas a carburized layer is formed on the non-magnetic circuit forming portion 55b.
Next, an operation characterized by the driving force transmission device 11 configured as in the first embodiment will be described.
[0042]
Here, general characteristics of structural carbon steel will be described. Structural carbon steel has the characteristic that, as the amount of carbon increases, the magnetic flux is less likely to pass, but once the magnetic flux passes, the residual magnetism is more likely to occur.
[0043]
When the electromagnetic coil of the electromagnet 33 is energized, the magnetic circuit Z is formed. At this time, the magnetic flux passes through the magnetic circuit component 55a of the front housing 31a that is a part of the magnetic circuit Z. When the energization of the electromagnetic coil of the electromagnet 33 is stopped, the magnetic circuit component 55a has less carbon than the non-magnetic circuit forming portion 55b, so the magnetism disappears quickly. Then, the armature 35 of the pilot clutch mechanism 30d reliably releases the friction clutch 34 without being blocked by residual magnetism.
[0044]
Further, the base end portion of the input shaft 50 which is the non-magnetic circuit forming portion 55b has a carbon amount larger than that of the magnetic circuit constituting portion 55a, so that it has sufficient strength to fulfill the function as the driving force transmission device 11. ing.
[0045]
Therefore, according to the driving force transmission device 11 of the first embodiment, the following effects can be obtained.
(1) In this embodiment, the carbon amount of the magnetic circuit component 55a in the front housing 31a is formed to be smaller than that of the non-magnetic circuit forming portion 55b. Therefore, the magnetic circuit constituting unit 55a has less residual magnetism than the non-magnetic circuit forming unit 55b, and the adverse effect on the operation of the armature 35 can be suppressed. In addition, since the front housing 31a can be formed only from 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 a conventional driving force transmission device.
[0046]
(2) In the present embodiment, induction hardening is applied to the input shaft 50 of the front housing 31a. 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.
[0047]
(Second Embodiment)
A second embodiment embodying the present invention will be described below with reference to FIGS. The driving force transmission device 61 of the second embodiment employs a front housing 62 in which the processing method of the front housing 31a of the first embodiment is changed, and the configuration similar to that of the first embodiment is used. The same reference numerals are assigned, detailed description thereof is omitted, and different points are described in detail.
[0048]
A processing method of the front housing 62 of the driving force transmission device 61 of the present embodiment will be described.
First, the front housing 62 formed by casting or the like is first formed into a desired shape by cutting. At this time, the magnetic circuit component 55a of the front housing 62 is roughed 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.
[0049]
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 on the inner peripheral surface of the rear end portion of the front housing 62 is formed. Then, induction hardening is performed on the input shaft 50.
[0050]
As a result, a carburized layer is not formed on the magnetic circuit component 55a of the front housing 62, whereas 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 operations and effects as the driving force transmission device 11 of the first embodiment.
(Other embodiments)
Each of the above embodiments may be embodied by changing to the following other embodiments.
[0051]
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 quenching, and may be quenching by flame quenching.
[0052]
In each of the embodiments described above, the induction hardening is performed on the magnetic circuit component 55a of the front housings 31a and 62. However, it is not necessary to perform the quenching.
Next, technical ideas other than the invention described in the claims that can be grasped from the respective embodiments and other embodiments will be described below together with their effects.
[0053]
(A) When the carburizing process is performed on the outer rotating member, the carburizing process is performed on the magnetic circuit constituent part. The driving force transmission device according to claim 1 or 2, . If comprised in this way, a carburized layer will not be formed in the magnetic circuit structure part of an outer side rotation member, but a carburized layer can be formed in the surface of another part.
[0054]
(B) The driving force transmission device according to claim 2 or (a), wherein the outer rotating member other than the magnetic circuit component is subjected to a quenching process after carburizing. If comprised in this way, in other parts other than the magnetic circuit structure part of an outer side rotation member, it can harden | cure compared with the case where it does not quench.
[0055]
【The invention's effect】
According to the first to third aspects of the present invention, the operation of the electromagnetic driving means can be reliably performed, and the cost of the outer rotating member can be reduced by forming the outer rotating member only with structural carbon steel. Can be mass-produced.
[0056]
According to the second aspect of the present invention, the magnetic circuit component can reduce the amount of carbon as compared with other portions of the outer rotating member by performing the carbon-proof processing on the magnetic circuit component.
[0057]
According to the third aspect of the invention, by cutting the magnetic circuit constituent part after carburizing, the magnetic circuit constituent part can reduce the amount of carbon compared to other parts 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 a driving force transmission device according to first and second embodiments.
FIG. 4 is a cross-sectional view of a front housing in the first and second embodiments.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11, 61 ... Driving force transmission apparatus, 30a ... Outer case as outer side rotation member, 30b ... Inner shaft as inner side rotation member, 34 ... Friction clutch,
55a ... Magnetic circuit component, Z ... Magnetic circuit.

Claims (3)

In a driving force transmission device comprising a friction clutch disposed between inner and outer rotating members positioned so as to be relatively rotatable with each other, and an electromagnetic driving means that is operated by energization to frictionally engage the friction clutch.
The outer rotating member includes a magnetic circuit component that becomes a part of the magnetic circuit by the driving means during the energization,
The driving force transmitting device according to claim 1, wherein the outer rotating member is made of structural carbon steel, and the magnetic circuit component of the outer rotating member has a smaller amount of carbon than other portions. The driving force transmission device according to claim 1, wherein the magnetic circuit component has been subjected to a carbon-proofing process. The driving force transmission device according to claim 1, wherein the magnetic circuit component is cut after carburizing.

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