JP2002070894A - Driving power transmission device and torque transmitting adjustment method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving power transmission device capable of obtaining predetermined electric current - torque characteristic without influence for a varied range of magnetic resistance of a magnetic clutch by establishing a shape of an armature. SOLUTION: A driving power transmission device 11 is provided with a friction clutch 34 arranged between an outer case 30a located in the outer side and an inner shaft 30b located in the inner side, which are capable of relatively and coaxially rotating each other, and an armature 35 frictionally engaging the aforementioned friction clutch 34 by operating through turning on electricity to an electric magnet 33. Each plate 34a and 34b of the friction clutch 34 causes to vary magnetic resistance of the magnetic clutch 34 through a varied range of thickness of a whole hardening layer produced on the surface of these plates. Therefore, magnetic resistance of the armature 35 is provided to be bigger than magnetic resistance of the friction clutch 34. A varied range of magnetic resistance of the friction clutch 34 can be cancelled out by setting up plate thickness (shape) of the armature 35.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention 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) and a method of adjusting torque transmission of the driving force transmitting device.

[0002]

2. Description of the Related Art Conventionally, as an example of a driving force transmitting device, a device proposed in Japanese Patent Application Laid-Open No. H11-287258 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. 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, an outer case is used as an outer rotating member, and an inner shaft is used as an inner rotating member. In the driving force transmission device, a magnetic path circulating through the yoke supporting the electromagnet, the front side wall of the outer case, the friction clutch, 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 outer case and the inner shaft so that torque can be transmitted. .

The friction clutch is composed of a number of inner clutch plates and a number of outer clutch plates, and the outer periphery of each plate has a fully cured layer formed by nitriding to harden the surface.

[0006]

Conventionally, since the magnetic resistance of a friction clutch constituting a part of a magnetic path is the largest among all magnetic paths, the thickness of the friction clutch in the nitriding process (total hardened layer) is reduced. Thickness), and the current-transfer torque characteristics also have a problem. The current-
The transmission torque characteristic (hereinafter referred to as the IT characteristic) is a relation between a current flowing through the electromagnetic coil and a transmission torque transmitted from the outer case to the inner shaft when the electromagnetic coil is operated by the current. It is the characteristic expressed. In particular, in the driving force transmission device described above, the variation in the thickness of the entire hardened layer of the friction clutch is amplified by the cam mechanism.
The variation of the IT characteristic is remarkable.

Here, it is conceivable to manage the total thickness of the hardened layer of each plate. However, when measuring the total hardened layer thickness of each plate, the plate must be cut and the cut section must be observed with a microscope or the like, and the plate with the total hardened layer thickness measured is used as a product You will not be able to do it.

For this reason, the variation in the total thickness of the hardened layer of each plate is taken as a matter of course, and the variation in the magnetic resistance of each plate is finely adjusted by finely adjusting the clearance between the front side wall of the outer case and the yoke. The desired magnetic path was formed by canceling each other.

Conventionally, the magnetic resistance of the armature has been set smaller than the magnetic resistance of the friction clutch. As a result, even if the magnetic resistance of the armature slightly increases or decreases, the magnetic resistance does not change enough to affect the magnetic path, while the friction clutch affects the magnetic path by increasing or decreasing the thickness of the entire hardened layer of each plate. The change in the magnetic resistance.

The inventor of the present invention reverses this relationship and changes the shape of the armature so that the reluctance of the armature is set to be larger than the reluctance of the friction clutch. Have found a method capable of adjusting the IT characteristics.

That is, the present invention provides a driving force transmitting device and a driving force transmitting device which can obtain a predetermined current-torque characteristic without being affected by variations in the magnetic resistance of the friction clutch by setting the shape of the armature. An object of the present invention is to provide a torque transmission adjustment method.

[0012]

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;
An electromagnetic drive unit that operates by energization to frictionally engage the friction clutch, the drive unit comprising: an armature located inside the outer rotating member and facing the friction clutch; An electromagnet is provided on the outer side and opposed to the friction clutch with a side wall of the outer rotating member interposed therebetween, and by energizing the electromagnet, the armature is attracted to frictionally engage the friction clutch, and the friction is applied. In the driving force transmission device in which the two rotating members are connected to be able to transmit the torque by the frictional engagement force of the clutch, the shape of the armature is set so that the magnetic resistance of the armature is larger than the magnetic resistance of the friction clutch. Is the gist.

According to a second aspect of the present invention, in the first aspect, the setting of the shape of the armature is to set the thickness of the armature. The invention according to claim 3 is
A gist of the present invention is that a hardened layer is formed on a surface of the friction clutch.

According to a fourth aspect of the present invention, in any one of the first to third aspects, a main clutch mechanism for transmitting torque between the two rotating members and a frictional engagement force of the friction clutch are provided. The gist of the invention is to provide a cam mechanism for pressing the main clutch mechanism accordingly.

According to a fifth aspect of the present invention, there is provided an electromagnetic drive which is disposed between inner and outer rotating members which are rotatably positioned relative to each other, and which is actuated by energization to frictionally engage the friction clutch. And an armature located inside the outer rotating member and facing the friction clutch; and the friction clutch located outside the outer rotating member and sandwiching a side wall of the outer rotating member. The armature is attracted by energizing the electromagnet, the armature is attracted to frictionally engage the friction clutch, and the two rotating members can be torque-coupled by the frictional engagement force of the friction clutch. In the torque transmission adjusting method of the driving force transmission device to be in the state, the shape of the armature is changed so that the magnetic resistance of the armature is larger than the magnetic resistance of the friction clutch. Te, predetermined current - is summarized in that obtaining the torque characteristics.

According to a sixth aspect of the present invention, in the fifth aspect, changing the shape of the armature is changing the thickness of the armature. The invention according to claim 7 is
The gist of the present invention is that a hardened layer is formed on a surface of the friction clutch.

According to an eighth aspect of the present invention, in any one of the fifth to seventh aspects, a main clutch mechanism for transmitting torque between the two rotating members and a frictional engagement force of the friction clutch are provided. The gist of the invention is to provide a cam mechanism for pressing the main clutch mechanism accordingly. (Operation) Therefore, in the invention according to any one of the first to eighth aspects, the variation in the magnetic resistance of the friction clutch is canceled by the magnetic resistance adjustment by setting the shape of the armature.

According to the second or sixth aspect of the present invention, the variation in the magnetic resistance of the friction clutch is canceled by adjusting the magnetic resistance by setting the plate thickness of the armature.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a driving force transmission device according to one embodiment of the invention. As shown in FIG. 2, the driving force transmission device 11 is disposed on a driving force transmission path to a rear wheel of the four-wheel drive vehicle 12.

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 transmitting 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 housed 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 as an outer rotating member, an inner shaft 30b as an inner rotating member, a main clutch mechanism 30c,
A pilot clutch mechanism 30d and a cam mechanism 30e are provided.

The outer case 30a has a bottomed cylindrical front housing 31a and a front housing 31a.
And a rear housing 31b screwed into the rear end opening and covering the opening. The rear housing 31b corresponds to a side wall of the outer rotating member. An input shaft 50 is formed at the front end of the front housing 31a so as to protrude therefrom.
It is connected to.

The front housing 31a and the rear housing 31b integrally formed with the input shaft 50 are made of a magnetic material such as iron (for example, carbon steel S35C, S for mechanical structure).
10C). Rear housing 31
A stainless steel tubular body 51 which is a non-magnetic material is embedded in a radially intermediate portion of b, and the tubular body 51 forms an annular non-magnetic portion.

The outer case 30a is rotatably supported by a differential carrier 22 (see FIG. 2) via bearings (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 prevented 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 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 by 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 an outer clutch plate 34.
b is configured as a multi-plate friction clutch. As shown in FIG. 4, a fully cured layer M is formed on the surface of each of the plates 34a and 34b by nitriding.
The entire cured layer M corresponds to a cured layer. 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 located, abut against each other and frictionally engage, and are separated from each other to be in a non-engagement free state.

The armature 35 is formed in 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. The description of the magnetic resistance of the armature 35 will be described later.

As shown in FIG. 3, by energizing the electromagnetic coil of the electromagnet 33, the yoke 36, the rear housing 3
A magnetic path Z that circulates between the first clutch 1b, the friction clutch 34, the armature 35, the friction clutch 34, the rear housing 31b, and the yoke 36 is formed.

As shown in FIGS. 1 and 3, the cam mechanism 30e
Comprises a first cam member 37, a second cam member 38, 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
1b is rotatably supported. 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 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 outside the front housing 31a across the rear housing 31b. And the rear housing 31b functions as a magnetic path forming member.

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 path 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 38 via the cam follower 39.
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 path 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 causes relative rotation with the second cam member 38. . As a result, the cam mechanism 30
In e, the cam follower 39 presses the two cam members 37 and 38 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, the magnetic resistance of the armature 35 will be described in detail. FIG. 5 shows the armature plate thickness on the horizontal axis, and the vertical axis shows the transmission torque when the same applied current is applied to the electromagnet when the armature has the above-mentioned thickness. Shows the relationship. In the figure, A
The range indicates a portion where the magnetic resistance of the armature is larger than the magnetic resistance of the friction clutch, and the range B indicates a range where the magnetic resistance of the armature is smaller than the magnetic resistance of the friction clutch.

According to the figure, when the armature plate thickness is within the range B, even if the armature plate thickness is changed, there is no change in the transmission torque. This is because the magnetic resistance due to the armature plate thickness is smaller than the magnetic resistance of the friction clutch,
This is because even if the armature plate thickness is changed within the range B, there is no influence. Therefore, in the range B, the magnetic resistance of the friction clutch changes, that is, the magnetic resistance changes due to the variation of the entire hardened layer M of the inner clutch plate 34a and the outer clutch plate 34b due to the nitriding process.

On the other hand, in the range A, the transmission torque increases as the armature plate thickness increases, and the transmission torque decreases as the armature plate thickness decreases. Therefore, in the range A, the transmission torque can be adjusted by controlling the armature plate thickness. In this A range, the magnetic resistance caused by the armature plate thickness is larger than the magnetic resistance of the friction clutch. Therefore, when the armature plate thickness is changed within the A range,
This is because of the effect.

In this embodiment, paying attention to this point, the plate thickness of the armature 35 is adjusted so that the magnetic resistance of the armature 35 is larger than the magnetic resistance of the friction clutch 34. To control the armature plate thickness means to control the effective cross-sectional area of the armature 35 through which the magnetic flux passes.

As a result, 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 magnetic path Z circulating between the rear housing 31b and the yoke 36 is a desired magnetic path Z.

FIG. 6 shows the current supplied to the electromagnetic coil of the electromagnet 33 on the horizontal axis, and the torque (transmitted torque) transmitted from the driving force transmission device 11 to the drive pinion shaft 19 on the vertical axis. According to the present embodiment, the curve CS is a curve drawn when the thickness of the armature 35 is controlled and the thickness of the armature 35 is set when the magnetic resistance of the armature 35 is larger than the magnetic resistance of the friction clutch 34. It is.

On the other hand, the curves CH and CL correspond to the armature 3
5 is of a conventional configuration in which the magnetic resistance of the friction clutch 34 is smaller than the magnetic resistance of the friction clutch 34. The curve CH is a case where the transmission torque is larger than the curve CS due to the thickness variation of the entire hardened layer M of the friction clutch 34, and the curve CL is the curve C
H is a case where only a transmission torque smaller than the curve CS can be obtained due to a variation in the thickness of the entire hardened layer M of the friction clutch 34.

Therefore, the driving force transmission device 11 having the armature 35 set by the above-described method for setting the thickness of the armature 35 can easily obtain a predetermined current-torque characteristic as compared with the related art.

Accordingly, the driving force transmission device 11 of the present embodiment
According to this, the following effects can be obtained. (1) In this embodiment, the magnetic resistance of the armature 35 is made larger than the magnetic resistance of the friction clutch 34 by managing the plate thickness of the armature 35. The thickness of the armature 35 is set so that even if there is a variation in the magnetic resistance of the friction clutch 34 caused by the variation in the thickness of the entire hardened layer M of the friction clutch 34, the armature 35 is not affected by the variation. Therefore, the driving force transmission device 11 is provided with a plate thickness of the armature 35 as compared with the case where the desired magnetic path Z is formed by fine adjustment of the clearance between the front end side wall of the outer case and the yoke which is performed by the conventional driving force transmission device. , A desired magnetic path Z can be easily formed. In addition, in the present embodiment, a predetermined current-torque characteristic can be obtained by changing the plate thickness of the armature 35. (Other Embodiments) The above embodiment may be modified and embodied in the following other embodiments.

In the first embodiment, the armature 35
Is set by changing the plate thickness of the armature 35. Alternatively, the setting of the shape of the armature 35 may be changed by changing holes, holes, grooves, or the outer shape. That is, in the armature 35, a hole,
The effective cross-sectional area through which the magnetic flux passes may be managed by changing the holes, grooves, and external shapes.

[0054]

According to any one of claims 1 to 8,
According to the invention described in the paragraph, by setting the shape of the armature, it is possible to obtain a driving force transmission device having a predetermined current-torque characteristic which is not affected by variations in the magnetic resistance of the friction clutch.

According to the second or sixth aspect of the present invention, a predetermined current-torque characteristic is provided which is not easily affected by variations in the magnetic resistance of the friction clutch due to the setting of the thickness of the armature. As a result, a driving force transmission device is obtained.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a driving force transmission device according to an embodiment.

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

FIG. 3 is a sectional view of a main part of the driving force transmission device according to the embodiment.

FIG. 4 is an explanatory diagram showing all hardened layers of an inner clutch plate and an outer clutch plate in the embodiment.

FIG. 5 is a characteristic diagram showing a relationship between a plate thickness of an armature and a torque in the embodiment.

FIG. 6 is a characteristic diagram showing a relationship between current and torque in the embodiment.

[Explanation of symbols]

11: driving force transmission device, 30a: outer case as outer rotating member, 30b: inner shaft as inner rotating member, 30c: main clutch mechanism, 30e: cam mechanism, 31b: rear housing as side wall of outer rotating member, 33: electromagnet, 34: friction clutch, 35: armature, M: fully cured layer as cured layer.

Claims (8)

[Claims] 1. A driving device comprising: a friction clutch disposed between inner and outer rotating members positioned so as to be able to rotate relative to each other; and an electromagnetic driving means that operates by energization to frictionally engage the friction clutch. An armature located inside the outer rotating member and facing the friction clutch, and an electromagnet located outside the outer rotating member and facing the friction clutch with a side wall of the outer rotating member interposed therebetween. A driving force transmission device that attracts the armature by energizing the electromagnet, frictionally engages the friction clutch, and brings the two rotating members into a connected state capable of transmitting torque by the frictional engagement force of the friction clutch. 3. The driving force transmission device according to claim 1, wherein the shape of the armature is set so that the magnetic resistance of the armature is larger than the magnetic resistance of the friction clutch. 2. The driving force transmitting device according to claim 1, wherein the setting of the shape of the armature includes setting the thickness of the armature. 3. The driving force transmission device according to claim 1, wherein a hardened layer is formed on a surface of the friction clutch. 4. The apparatus according to claim 1, further comprising a main clutch mechanism for transmitting torque between said two rotating members, and a cam mechanism for pressing said main clutch mechanism in accordance with a frictional engagement force of said friction clutch. The driving force transmission device according to any one of the preceding claims. 5. A friction clutch disposed between inner and outer rotary members rotatably positioned relative to each other, and an electromagnetic driving means which is actuated by energization to frictionally engage the friction clutch. An armature located inside the outer rotating member and facing the friction clutch, and an electromagnet located outside the outer rotating member and facing the friction clutch with a side wall of the outer rotating member interposed therebetween. A driving force transmission device that attracts the armature by energizing the electromagnet, frictionally engages the friction clutch, and brings the two rotating members into a connected state capable of transmitting torque by the frictional engagement force of the friction clutch. In the torque transmission adjusting method, the shape of the armature is changed so that the magnetic resistance of the armature is larger than the magnetic resistance of the friction clutch, and the predetermined current-torque is changed. A torque transmission adjusting method for a driving force transmission device, characterized in that a torque characteristic is obtained. 6. The method according to claim 5, wherein changing the shape of the armature includes changing the thickness of the armature. 7. The method according to claim 5, wherein a hardened layer is formed on a surface of the friction clutch. 8. The apparatus according to claim 5, further comprising a main clutch mechanism for transmitting torque between said two rotating members, and a cam mechanism for pressing said main clutch mechanism in accordance with a frictional engagement force of said friction clutch. A torque transmission adjusting method for a driving force transmission device according to any one of the preceding claims.