JP2002181080A - Driving force transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent magnetic flux leakage of a driving force transmission device and to improve dimensional accuracy without needing cost increase. SOLUTION: In the driving force transmission device provided with an electromagnet 7 for frictionally engaging a friction clutch 5 made of many frictional plates, an outside rotating member 1 is constituted of a cylindrical front housing 2a and a rear housing 2b for covering the front housing 2a. Both of the housings 2a and 2b are made of magnetic bodies and are joined via a shim 2c made of non-magnetic substance. A plurality of shims 2c having thickness X of different axial directions are prepared and a shim 2c having optimum thickness is selected among them.

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.

[0002]

2. Description of the Related Art As a conventional driving force transmission device, there is one disclosed in Japanese Utility Model Laid-Open No. 6-58242.

The driving force transmission device includes inner and outer rotating members coaxially and relatively rotatable with each other, and an electromagnetic driving means which operates by energization to frictionally engage a pilot clutch. The driving means includes the pilot clutch and the armature located inside the outer rotating member, and an electromagnet located outside the outer rotating member and opposed to the pilot clutch with a side wall of the outer rotating member interposed therebetween. Have been.

The outer rotating member is made of a magnetic material and includes a cylindrical front housing having a bottom and a rear housing for covering the front housing as main components. A non-magnetic clutch drum is fitted to a portion of the front housing where the pilot clutch is engaged, and both housings are welded via the clutch drum to prevent magnetic flux leakage.

In this driving force transmission device, when energized, the cam mechanism adjacent to the pilot clutch is disposed opposite to the pilot mechanism with the cam mechanism interposed therebetween in accordance with the resultant force of the frictional system of the pilot clutch. The main clutch mechanism is frictionally engaged to transmit torque.

[0006]

In the above example, a clutch drum made of a non-magnetic material such as stainless steel was used as a spline for a pilot clutch. Stainless steel has the same coefficient of thermal expansion as iron and is easily welded to iron. Cost was high. Although there is an example in which the entire front housing is formed of aluminum, which is a non-magnetic material, it cannot be used when the front housing requires strength because it does not have sufficient rigidity.

[0007] In addition, although many components such as a friction plate and a cam mechanism constituting the main clutch have manufacturing tolerances, after assembly, the tolerances of the stacked components are summed up. Therefore, the variation in the axial dimension increases for each product. For example, when the sum of the axial dimensions of the parts is larger than the median tolerance, the gap between the friction plates becomes narrow. In this case, even if the magnetic circuit is not formed, the friction plates are easily engaged with each other, and the current-transmission torque characteristics become unstable.

Conversely, when the sum of the axial dimensions of the parts is smaller than the median tolerance, the gap between the friction plates becomes large. In this case, even if the power is supplied, the friction plates are hardly engaged with each other, and the current-transmission torque characteristics become unstable. As described above, it has been a problem to eliminate the variation in the dimension in the axial direction caused by the overlap of the manufacturing tolerance of each part.

[0009] The current-transfer torque characteristics referred to here are the current when the current flows to the electromagnetic coil of the electromagnet,
This is a characteristic showing the relationship with the torque transmitted from the outer rotating member to the inner rotating member at that time.

[0010] Accordingly, the present invention has been made in view of the above-mentioned circumstances, and has as its object to reliably operate an electromagnetic driving means, to reduce the cost, and to reduce the cost. An object of the present invention is to provide a driving force transmission device in which variations in the length in the direction are suppressed.

[0011]

In order to solve the above-mentioned problems, the invention according to claim 1 is provided with an inner rotating member and an outer rotating member positioned to be rotatable relative to each other, and disposed between these rotating members; A plurality of friction plates adjacent to the inside of the wall surface of the outer rotating member, and electromagnetic driving means positioned outside the wall surface and operated by energization to frictionally engage a friction clutch including the plurality of friction plates. In the driving force transmission device provided, the outer rotating member includes a cylindrical front housing made of a magnetic material and having a cylindrical shape, and a rear housing having the wall surface and covering the front housing,
The two housings are joined via a shim made of a non-magnetic material.

According to a second aspect of the present invention, in the driving force transmission device according to the first aspect, between the inner and outer rotating members,
A main clutch mechanism that transmits torque between the two rotating members by frictional engagement, a pilot clutch mechanism that operates by energization to perform frictional engagement, and a pilot clutch that is located between the main clutch mechanism and the pilot clutch mechanism. A cam mechanism for converting a frictional engagement force of a clutch mechanism into a pressing force with respect to the main clutch mechanism, wherein the pilot clutch mechanism includes the friction clutch and the driving means.

According to a third aspect of the present invention, in the driving force transmission device according to the first or second aspect, the shim includes an adjusting portion sandwiched between end surfaces of the two housings in the axial direction, and the two housings. And a fitting portion fitted between them.

[0014]

According to the first aspect of the present invention, since the shim formed of a non-magnetic material is disposed between the front housing and the rear housing, it is possible to prevent magnetic flux leakage from the rear housing to the front housing. ,
The axial dimension inside the housing can be adjusted.

According to the second aspect of the present invention, the driving force has a structure in which the total variation in the manufacturing tolerance of the axial dimension is large, that is, a structure in which the components such as the main clutch mechanism and the cam mechanism are stacked in the axial direction. In the transmission device,
Variations in the axial dimension can be absorbed by the shim, and the gap between the friction plates and the play of the cam mechanism can be easily adjusted, and a stable current-transmission torque characteristic can be obtained.

According to the third aspect of the present invention, the axial dimension inside the housing can be adjusted by the shim adjusting portion, and the alignment of the two housings is facilitated by the shim fitting portion.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a driving force transmitting device according to an embodiment of the present invention. This driving force transmission device
As shown in FIG. 2, it is arranged on a driving force transmission path to a rear wheel side in a four-wheel drive vehicle. Note that members and the like without reference numerals are not shown.

As shown in FIG. 2, the four-wheel drive vehicle includes a driving force transmission device 10, a transaxle 21, an engine 22, a pair of front wheels 24b, and a pair of rear wheels 28b.
And The transaxle 21 integrally includes a transmission, a transfer, and a front differential. The driving force of the engine 22 is output to both axle shafts 24a via the transaxle 21 to drive the left and right front wheels 24b.

The transaxle 21 is connected to a driving force transmission device 10 via a propeller shaft 25, and the driving force transmission device 10 is connected to a rear differential 27 via a drive pinion shaft 26. . A rear wheel 28b is connected to the rear differential 27 via an axle shaft 28a. The propeller shaft 25 and the drive pinion shaft 26
Is connected to the driving force transmission device 10 so that torque can be transmitted, the driving force of the engine 22 is output to both axle shafts 28a via the rear differential 27 to drive the rear wheels 28b.

The driving force transmitting device 10 is housed in a differential carrier 23 together with a rear differential 27, is supported by the differential carrier 23, and is supported by the vehicle body via the differential carrier 23.

Next, the driving force transmission device 10 will be described with reference to FIG. The driving force transmission device 10 includes an outer case 1 as an outer rotating member, an inner shaft 3 as an inner rotating member, a main clutch mechanism 4, a pilot clutch mechanism 6, and a cam mechanism 9.

The outer case 1 is an outer rotating member, and has a bottomed cylindrical front housing 2a and a rear housing 2 for covering a rear end opening of the front housing 2a.
b, the front housing 2a and the rear housing 2b
And a shim 2c interposed therebetween. An input shaft 50 protrudes from a front end of the front housing 2a, and the input shaft 50 is connected to a propeller shaft 25 not shown in FIG. See FIG.

The shim 2c in the outer case 1 is a press-formed plate made of a non-magnetic material such as stainless steel.
As shown in FIG. 3, it has an adjusting part 52 and a fitting part 51. As the shim 2c, a plurality of types of the shims 2c having different thicknesses X are prepared, and selected and assembled according to an assembling procedure described later. The front housing 2a and the rear housing 2b are made of an iron-based metal material that is a magnetic material.
As shown in FIG. 1, a cylindrical body 30 made of a nonmagnetic material is embedded in a radially intermediate portion of the rear housing 2b.
The cylindrical body 30 forms an annular non-magnetic portion, and has a magnetic path Z described later.
Is formed.

The outer case 1 is rotatably supported on the outer periphery of the front end of the front housing 2a via a differential carrier 23 and a bearing (not shown) with respect to FIG. Also, outer case 1
Is supported by a yoke 11 supported by a differential carrier 23 (see FIG. 2) via a bearing or the like on the outer periphery of the rear housing 2b.

The inner shaft 3 penetrates the center of the rear housing 2b in a liquid-tight manner, and
a and is rotatably supported relative to both housings 2a and 2b in a state where movement in the axial direction is restricted. The tip of the drive pinion shaft 26 shown in FIG. 2 is inserted into the inner shaft 3.
The drive pinion shaft 26 is not shown in FIG.

The main clutch mechanism 4 disposed on the back wall side of the front housing 2a is a friction clutch mechanism and includes a number of inner clutch plates 4a and outer clutch plates 4b.

Each of the inner clutch plates 4a constituting the main clutch mechanism 4 is spline-fitted to the outer periphery of the inner shaft 3 and is mounted so as to be movable in the axial direction. On the other hand, each outer clutch plate 4b is spline-fitted to the inner periphery of the front housing 2a and is movably mounted in the axial direction. The inner clutch plates 4a and the outer clutch plates 4b are arranged alternately and abut against each other to frictionally engage, and are separated from each other to be in a non-engagement free state.

The pilot clutch mechanism 6 includes an electromagnet 7, a pilot clutch 5, and an armature 8.

The yoke 11 is axially supported by the differential carrier 23, and is rotatably supported on the outer periphery of the rear end of the rear housing 2b via a bearing. An electromagnet 7 as an annular driving means is fitted to the yoke 11, and the electromagnet 7 is inserted into an annular recess formed outside the wall surface of the rear housing 2b (right side in FIG. 1) with a small gap. Are fitted.

The pilot clutch 5 is configured as a multi-plate friction clutch composed of a plurality of inner clutch plates 5a and outer clutch plates 5b. Each inner clutch plate 5a is spline-fitted to the outer periphery of a first cam member 9a constituting a cam mechanism 9 described later, and is movably assembled. On the other hand, each outer clutch plate 5b is spline-fitted to the inner periphery of the front housing 2a, and is assembled so as to be movable in the axial direction.

Each inner plate 5a and each outer plate 5b constituting the pilot clutch 5 are alternately positioned inside the wall surface of the rear housing 2b (left side in FIG. 1), and come into contact with each other to frictionally engage with each other. At the same time, they are separated from each other to be in a non-engaged free state.

The armature 8 has an annular shape, is spline-fitted to the inner periphery of the front housing 2a, and is assembled so as to be movable in the axial direction. The armature 8
Is located on one side of the pilot clutch 5 inside the front housing 2a, and faces the electromagnet with the pilot clutch 5 and the wall surface of the rear housing 2b interposed therebetween.
The electromagnet 7 is located outside the outer case 1 on the other side of the pilot clutch 5 with the rear housing 2b interposed therebetween.

By energizing the electromagnetic coil of the electromagnet 7, as shown in FIG. 4, the yoke 11, the rear housing 2b, the pilot clutch 5, the armature 8, the pilot clutch 5, the rear housing 2b, and the yoke 11 is formed.

The cam mechanism 9 includes a first cam member 9a and a second cam member 9a.
It is composed of a cam member 9b and a cam follower 9c. In the first cam member 9a and the second cam member 9b, a plurality of cam grooves (not shown) facing each other are formed on the facing surfaces at predetermined intervals in the circumferential direction. First cam member 9a
Is rotatably fitted to the outer periphery of the inner shaft 3 and rotatably supported by the rear housing 2b. Each inner clutch plate 5a is spline-fitted to the outer periphery of the first cam member 9a.

The second cam member 9b is spline-fitted to the outer periphery of the inner shaft 3, and is assembled so as to be integrally rotatable with the inner shaft 3. The second cam member 9b is arranged to face the inner clutch plate 4a of the main clutch mechanism 4. A ball-shaped cam follower 9c is interposed in the opposed cam grooves of the second cam member 9b and the first cam member 9a.

The rear housing 2b is fitted to the outer periphery of the inner shaft 3 in a liquid-tight and rotatable manner, and is fitted to the shim 2c at the outer peripheral left wall. Further, the rear housing 2b is liquid-tightly and rotatably supported by the differential carrier 23 via an oil seal (not shown) on the outer periphery of the rear end of the rear cylinder portion.

The drive transmission device 10 constructed as described above
The operation of will be described.

When power is not supplied to the electromagnetic coil of the electromagnet 7 constituting the pilot clutch mechanism 6,
No magnetic circuit Z is formed, and pilot clutch 5 is in a disengaged state. As a result, the pilot clutch mechanism 6
Is a non-operating state, and the first
The cam member 9a can rotate integrally with the second cam member 9b via the cam follower 9c, and the main clutch mechanism 4 is in a non-operating state. Therefore, the four-wheel drive vehicle constitutes a two-wheel drive mode.

On the other hand, when the electromagnetic coil of the electromagnet 7 is energized, a magnetic circuit Z is formed in the pilot clutch mechanism 6, and the electromagnet 7 attracts the armature 8. For this reason, the armature 8 presses the pilot clutch 5 to cause frictional engagement, and the first cam member 9a of the cam mechanism 9 is connected to the front housing 2a side to rotate relative to the second cam member 9b. Cause. As a result, in the cam mechanism 9, the cam follower 9c presses the two cam members 9a and 9b in a direction away from each other.

For this reason, the second cam member 9b is pressed toward the main clutch mechanism 4, and the main clutch mechanism 4 is frictionally engaged according to the resultant force of the friction system of the pilot clutch 5,
The torque is transmitted between the outer case 4b and the inner shaft 4a. As a result, the four-wheel drive vehicle constitutes a drive mode of the four-wheel drive vehicle in which the propeller shaft 25 and the drive pinion shaft 26 are semi-directly connected.

When the current applied to the electromagnetic coil of the electromagnet 7 is increased to a predetermined value, the attractive force of the electromagnet 7 on the armature 8 increases. Then, the armature 8 is strongly attracted to the electromagnet 7 side to increase the frictional resultant force of the pilot clutch 5 and increase the relative rotation between the cam members 9a and 9b. As a result, the cam follower 9c increases the pressing force on the second cam member 9b to bring the main clutch mechanism 4 into the connected state. Thus, the four-wheel drive vehicle constitutes a four-wheel drive drive mode in which the propeller shaft 25 and the drive pinion shaft 26 are directly connected.

Here, the shim 2c will be described. As shown in FIG. 3, the shim 2c is formed into a concentric cylindrical shape having an L-shaped cross section and a large diameter portion and a small diameter portion on its outer peripheral surface by pressing a plate material made of a nonmagnetic material such as stainless steel. I have. The shim 2c has an adjusting portion 52 composed of a large diameter portion and both side surfaces thereof and a fitting portion 51 composed of a small diameter portion and its inner and outer peripheral surfaces, and is classified into a plurality of types in which the axial dimension X of the adjusting portion 52 is different. Have been. The shim 2c may be manufactured by another manufacturing method such as cutting.

Next, assembling of the shim 2c will be described with reference to FIG.
This will be described with reference to FIG. After the inner shaft 3 is inserted into the front housing 2a, the main clutch 4, the cam 9, the armature 8, the pilot clutch 5, and the thrust bearing 12 are sequentially stacked.

Thereafter, the shim 2c is aligned with the opening of the front housing 2a, and then the rear housing 2b is aligned with the shim 2c. That is, the outer periphery 41 of the fitting portion 51 of the shim 2c is fitted to the inner peripheral surface of the opening of the front housing 2a, and the side surface 42 of the adjusting portion 52 of the shim 2c is brought into contact with the end of the front housing 2a. Contact Next, the outer peripheral surface of the rear housing 2b is fitted to the inner peripheral surface 43 of the fitting portion 51, and the end of the rear housing 2b is brought into contact with the side surface 44 of the adjusting portion 52 of the shim 2c.
After that, the adjusting portion 52 of the shim 2c and a portion that comes into contact with the adjusting portion 52,
That is, the outer peripheral surfaces of the ends of the front housing 2a and the rear housing 2b are welded and joined. In addition, this joining
Instead of welding, for example, an adhesive may be applied to the fitting surfaces of the shim 2c or the housings 2a and 2b, and these may be integrated.

When the above-described shim 2c is assembled, as shown in FIG. 5, the main clutch 4, the cam 9, the armature 8 and the main clutch 4 are provided inside the front housing 2a.
The pilot clutch 5 and the thrust bearing 12 are sequentially stacked. And the front housing 2a
And the thrust bearing 12 arranged next to the cam 9 in the axial direction is detected by a measuring device, and an appropriate thickness X of the adjusting portion 52 of the shim 2c is selected from the detected value.

For example, when the sum of the axial dimensions of the respective friction plates of the main clutch 4, the cam mechanism 9, the thrust bearing 12, and the like is small, the distance Δ becomes large, so that the friction plates of the inside of the front housing 2a become large. Adjusting section 5 of shim 2c so that the density (gap) is approximately the same as usual.
2 having a small axial dimension X is used. At this time, the rear housing 2b is fitted to the left side in the drawing, that is, the rear side of the front housing 2a.

When the total axial dimension of each of the friction plates of the main clutch 4, the cam mechanism 9, the thrust bearing 12, and the like is large, the distance Δ is small, and the density of each friction plate inside the front housing 2a is small. The adjustment part 52 of the shim 2c having a large dimension X in the axial direction is used so that the (gap) is substantially the same as that of the normal case. At this time, the rear housing 2b is located on the right side of the drawing,
a on the opening side.

As described above, by interposing the shim 2c made of a non-magnetic material between the housings 2a and 2b,
The magnetic flux moves from the rear housing 2b to the front housing 2a.
In addition, the density of the friction plate becomes constant by selecting and assembling the shim 2c, so that the current-transmission torque characteristic is stabilized. The pilot clutch 5
The amount of magnetic flux leakage from the spline to the front housing 2a is not very large, but if necessary, if the spline is provided with missing teeth or the like to reduce the contact area between the pilot clutch 5 and the front housing 2a, the spline Magnetic flux leakage can be reduced.

In this embodiment, since the shim 2c is arranged between the front housing 2a and the rear housing 2b of the outer case 1, the magnetic flux leakage is reduced by the minimum non-magnetic material, and the operation of the armature 8 is performed. Can be suppressed from being adversely affected.

In addition, the thickness X of the adjusting portion 52 of the shim 2c is set in a plurality of ranks. As a result, variations in the total axial dimension of the friction plates 4a and 4b in the main clutch mechanism 4 and the components such as the cam mechanism 9 and the thrust bearing 12 are absorbed by the thickness X of the adjusting portion 52 of the shim 2c. Therefore, the axial density of the friction plate can be easily adjusted.

Further, the shim 2c is provided with a fitting portion 51,
Since the front housing 2a, the shim 2c, and the rear housing 2b are stacked without any gap in the axial direction, the center alignment of the two housings 2a and 2b becomes easy.

In this embodiment, the shape of the fitting portion 51 of the shim 2c is cylindrical, but may be other shapes such as a cone.

[0054]

As is clear from the above description, according to the structure of the present invention, it is possible to suppress the magnetic flux leakage and to eliminate the variation in the axial dimension in the device, so that the current-transmission torque can be minimized. Characteristics can be stabilized.

[Brief description of the drawings]

FIG. 1 is a sectional view of a portion showing a driving force transmission device according to an example of the present invention.

FIG. 2 is a skeleton diagram of a vehicle equipped with the driving force transmission device.

FIG. 3 is a perspective view of a shim located between a front housing and a rear housing constituting an outer case of the driving force transmission device.

FIG. 4 is an imaginary view of a magnetic path formed when the driving force transmission device is energized.

FIG. 5 is a diagram showing an axial distance Δ between an opening wall surface of a front housing and a thrust bearing, which is measured when an appropriate shim thickness is selected in the driving force transmission device.

[Explanation of symbols]

Reference numeral 10: driving force transmission device, 1: outer case, 2a ...
Front housing, 2b ... Rear housing, 2c ...
Shim, 3 ... inner shaft, 51 ... fitting part, 52 ...
Adjustment unit

Claims (3)

[Claims] 1. An inner rotating member and an outer rotating member which are positioned so as to be relatively rotatable, a number of friction plates disposed between the rotating members and adjacent to the inside of a wall surface of the outer rotating member; An electromagnetic drive means, which is located on the outside and is actuated by energization to frictionally engage the friction clutch composed of the plurality of friction plates, wherein the outside rotation member is made of a magnetic material and has a cylindrical shape. A driving force transmission device, comprising: a front housing having a rectangular shape; and a rear housing having the wall surface and covering the front housing. The two housings are joined via a shim made of a non-magnetic material. . 2. A drive force transmitting device according to claim 1, wherein a main clutch mechanism for transmitting torque between said inner and outer rotating members by frictional engagement between said inner and outer rotating members, and a frictional clutch operated by energization. A pilot clutch mechanism that performs engagement, and a cam mechanism that is located between the main clutch mechanism and the pilot clutch mechanism and that converts a frictional engagement force of the pilot clutch mechanism into a pressing force on the main clutch mechanism. A driving force transmission device, wherein a clutch mechanism includes the friction clutch and the driving means. 3. The driving force transmitting device according to claim 1, wherein the shim is fitted between the two housings in an axial direction between an adjusting portion sandwiched between end surfaces of the two housings. A driving force transmission device comprising: a joint portion.