JPH05280595A - Differential limit characteristic standardizing method - Google Patents

Abstract

PURPOSE:To provide a method for standardizing a differential limit characteristic at a low cost, in a differential gear provided with a differential limiting electromagnetic clutch. CONSTITUTION:In a differential gear for obtaining differential limit torque by connecting a friction clutch 73 of a mechanism part 79, having a differential mechanism 39 and the friction clutch 73 for differential limiting, by magnetic force of an electromagnet, the electromagnet for minimizing a difference between a characteristic of an excitation current, obtained by combining a reference electromagnet 89 with the mechanism part 79, and differential torque limit and a predetermined reference characteristic is selected and combined with this mechanism part 79, so that the differential limit characteristic can be standardized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a differential limiting characteristic standardizing method for a differential device.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No. 63-15449 and Japanese Unexamined Utility Model Publication No. 3-68634 disclose differential devices shown in FIGS. 4 and 5, respectively. The apparatus of FIG. 4 is configured to engage the multi-plate clutch 203 for differential limitation of the differential mechanism 201 with the magnetic force of the electromagnet 205 to perform differential limitation, and the apparatus of FIG. 5 sets the pilot clutch 207 to the electromagnet 209. When the engagement is performed with the magnetic force of, the differential torque of the differential mechanism 211 is applied to the cam 213 to generate a cam thrust force, and the main clutch 215 is engaged to limit the differential.

[0003]

In such a differential device, the reference characteristic of the differential limiting torque to be generated with respect to the exciting current of the electromagnets 205 and 209 is determined. However, the differential mechanisms 201 and 211 have variations in the resistance of each gear meshing portion and the rotation resistance of each gear member, and the clutches 203, 207, and 215 are distorted in the friction plates, the lubrication conditions, or the movement of the armature. There are variations in torque due to factors such as the above, and cams 213 have variations in cam thrust force due to cam angle errors and the like. Also, electromagnet 2
05 and 209 also have variations in magnetic force with respect to the exciting current.

Therefore, the differential device in which these are combined is liable to be out of the standard in the product test, and the yield is poor. However, it is extremely difficult and costly to increase the yield of products by eliminating variations in each element such as clutches and electromagnets.

Therefore, an object of the present invention is to provide a method for standardizing the differential limiting characteristic at low cost in a differential device having an electromagnetic clutch for differential limiting.

[0006]

According to a differential limiting characteristic standardizing method of the present invention, the friction clutch of a mechanism portion having a differential mechanism and a friction clutch for limiting the differential is fastened by a magnetic force of an electromagnet. In a differential device that obtains a differential limiting torque, select an electromagnet that minimizes the difference between the characteristic of the exciting current and differential limiting torque obtained by combining a reference electromagnet with the mechanism section and a predetermined reference characteristic. It is characterized by being combined with this mechanical part.

[0007]

The function of the exciting current and the differential limiting torque is measured by the combination of the mechanism section and the reference electromagnet, and this characteristic is compared with the reference characteristic, and the electromagnet that minimizes the difference is selected and this mechanism section is selected. Combined with. In this way, the total variation of the mechanism part is detected in combination with the reference electromagnet, and this variation is canceled by the variation of the electromagnet. It is possible to obtain the differential limiting characteristic of.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described with reference to FIGS. FIG. 1 shows an apparatus for carrying out the method of the invention, FIG.
Shows a power system of a vehicle using a differential device whose differential limiting characteristic is standardized by this method. Hereinafter, the left and right directions are the left and right directions in FIG. 1, and members and the like without reference numerals are not shown.

As shown in FIG. 3, this power system includes an engine 1, a transmission 3, a propeller shaft 5, a rear differential 7 (a differential device whose differential limiting characteristic is standardized by the method of FIG. 1), rear axles 9, 11. Left and right rear wheels 13,
15, the left and right front wheels 17, 19 and the like.

The differential case 21 of the rear differential 7 is rotatably supported in the differential carrier 23. Differential case 21
A ring gear 25 is fixed to the drive gear, and the ring gear 25 meshes with a drive pinion gear 29 integrated with a drive pinion shaft 27 connected to the propeller shaft 5 side. Thus, the differential case 21 is rotationally driven by the driving force from the engine 1.

As shown in FIG. 1, left and right hubs 31 and 33 are coaxially arranged inside the differential case 21. The hubs 31 and 33 are provided with splines 35 and 37 for connecting to the left and right rear axles 9 and 11, respectively.

In the differential case 21, a planetary gear type differential mechanism 39 is arranged. Internal gear 4
1 is formed on the differential case 21, and the sun gear 43 is formed on the left hub 31. The outer pinion gear 45 is rotatably supported on the outer pinion shaft 47, and the inner pinion gear is rotatably supported on the inner pinion shaft. Both ends of each pinion shaft are swaged to the left and right carriers 49, 51. Each carrier 4
9 and 51 are welded together, and carrier 51 on the right
Is integrally formed with the right hub 33. Washers 53 and 55 are arranged between the pinion gear and the carriers 49 and 51.

The driving force of the engine 1 input to the differential case 21 is from the pinion gear via the sun gear 43 (hub 31) and the carrier 51 (hub 33) to the left and right rear wheels 13, 15.
Will be distributed to. Further, when a driving resistance difference occurs between the rear wheels, the driving force of the engine 1 is differentially distributed to the left and right sides by the rotation and the revolution of the pinion gear.

A multi-plate type main clutch 59 is disposed between the cylindrical portion 57 of the left carrier 49 and the sun gear 43. A washer 61 is arranged on the left side of the main clutch 59, and a shim 63 is arranged on the right side thereof.

A cam ring 65 is provided on the outer peripheral side of the right hub 33.
And a ball cam 67 is formed between the cam ring 65 and the carrier 51. Cam ring 6
A bearing 69 and a washer 71, which block rotation with the differential case 21 and receive a cam reaction force, are arranged on the right of 5. The contact between the ball of the ball cam 67 and the cam surface is adjusted by changing the thickness of the shim 63.

A multi-plate pilot clutch 73 (friction clutch) is arranged between the cam ring 65 and the differential case 21. An armature 75 is arranged on the left side of the pilot clutch 73, and its inner circumference is spline-connected to the cam ring 65. Armature 75 is differential case 2
Pilot clutch 7 by retaining ring 77 attached to 1
It is positioned with respect to 3. The mechanism unit 79 includes the differential mechanism 39, the clutches 59 and 73, the ball cam 67, and the like.
Is configured. The differential case 21 has through holes 81, 8
Lubricating oil flows in and out from 3 to lubricate and cool the mechanism portion 79.

An electromagnet is arranged on the right side of the differential case 21 and is fixed to the differential carrier 23. This electromagnet is composed of a coil and a yoke, and is selected in accordance with the method of the present invention by the device shown in FIG. The pilot clutch 73 for exciting the coil of the electromagnet to attract the armature 75 is engaged, and the cam ring 65 is connected to the differential case 21. When a differential torque is generated in the differential mechanism 39 in this state, the differential torque is applied to the ball cam 67 and the cam thrust force causes the main clutch 59 to be pressed and engaged via the carriers 49 and 51, whereby the respective clutches 59 and 73. This limits the differential of the differential mechanism 39.

When the exciting current is increased, the pilot clutch 73
Is reduced, the cam thrust force of the ball cam 67 is increased, and the engagement force of the main clutch 59 is increased. Further, when the exciting current is reduced, the engaging force of each clutch 59, 73 is reduced. Thus, the differential limiting characteristic between the exciting current (I) and the differential limiting torque (T) as shown in FIG. 2 is obtained. If the differential limiting torque is sufficiently large, the differential rotation between the rear wheels 13 and 15 is locked, and if the differential limiting torque is small, this differential rotation is allowed. When the pilot clutch 73 is disengaged, the cam thrust force disappears and the main clutch 59 is also disengaged, so that the rear wheels 13 and 15 are differentially free.

The exciting current of the electromagnet is manually controlled from the driver's seat or automatically controlled according to road surface conditions, steering conditions and the like. In the vehicle of FIG. 3, even if one of the rear wheels 13 and 15 is idling on a bad road or the like, if the differential of the rear differential 7 is limited, driving force is sent to the rear wheel on the grip side to maintain high running performance. It When the differential limiting force of the rear differential 7 is increased, the straight running stability of the vehicle is improved, and when the differential limiting force is moderately relaxed to allow the differential, smooth and stable turning is transmitted.

The rear differential 7 is thus constructed.

The electromagnet of the rear differential 7 is selected as follows.

As shown in FIG. 1, the differential case 21 has bolts 8
It is fixed to a non-magnetic housing 87 by means of 5, and a reference electromagnet 89 is attached to the housing 87.
The housing 87 is fixed to the test bench. Further, the torque line 91 for testing is attached to the spline 35 of the left hub 31.
Are connected by a spline 93, and the hub 31 is given (differential) rotation by a motor 101 via a torque meter 95, a tachometer 97, a flange joint 99, and a torque shaft 91. As the engaging force of each clutch 59, 73 increases or decreases, the reading of the torque meter 95 changes, and this reading becomes the differential limiting torque (T) of the differential mechanism 39. Also, the electromagnet 89
The coil is excited by the DC power supply 103, and the engaging force of each clutch 59, 73 is adjusted by the change of the exciting current. The change in the exciting current is measured by the ammeter 105. The motor 101 or the like may be connected to the hub 33.

A reference differential limiting characteristic 107 of the exciting current (I) and the differential limiting torque (T) is determined in the rear differential 7 as shown by the shaded area in FIG. Standard electromagnet 8
No. 9 is selected so that the differential limiting characteristic 107 can be obtained when combined with a standard mechanical unit having no variation. As the electromagnet to be combined with the mechanism portion 79, for example, one having a different magnetic force with respect to the exciting current is prepared by gradually changing the number of turns of the coil or the wire diameter.

The mechanical section 79 and electromagnet 89 of the apparatus shown in FIG.
When a characteristic such as the graph 109 in FIG. 2 is obtained in combination with the above, the mechanism is such that the differential limiting torque (T) becomes excessive when a standard magnetic force is applied to the pilot clutch 73. Part 79 is scattered and graph 109
The magnitude of this variation can be known from the magnitude of the difference between the differential limiting characteristic 107 and the differential limiting characteristic 107.
Select one with an appropriately weak magnetic force that cancels out the variation in. Further, when the characteristics as shown by the graph 111 are obtained in combination with the electromagnet 89, similarly, an electromagnet having a strong magnetic force that cancels the variation of the mechanism portion 79 is selected. In each case, the selected electromagnet is combined with the mechanical unit 79 on the test stand, and it is confirmed that the characteristic is within the differential limiting characteristic 107.

As described above, according to the method of the present invention, the variation of the mechanism portion 79 is canceled by the variation of the electromagnet to obtain the reference differential limiting characteristic as the differential device, and the differential mechanism 39 and the clutch 59. , 7
3. Since the variation of the ball cam 67 and the like can be allowed to some extent, the manufacturing cost and the inspection cost can be greatly reduced.

Further, by obtaining the differential limiting characteristic 107, the differential limiting force of the rear differential 7 can be accurately controlled, so that the maneuverability and safety of the vehicle are improved.

The friction clutch for limiting the differential is not limited to the pilot clutch 73 as in the embodiment, but may be the one that limits the differential independently. Further, the magnetic force of the electromagnet may be adjusted by changing not only the electromagnet coil but also the material and shape of the yoke.

[0028]

According to the differential limiting characteristic standardizing method of the present invention, the degree of variation in the mechanism including the differential mechanism and the friction clutch of the differential limiting electromagnetic clutch is combined with the reference electromagnet. By making a judgment and selecting and combining electromagnets that cancel out this variation, a reference differential limiting characteristic can be obtained as a differential device. Therefore, the variation of each element can be tolerated to some extent, so that the cost can be greatly reduced.

[Brief description of drawings]

1 is a cross-sectional view showing an apparatus for carrying out the method of the present invention.

FIG. 2 is a graph showing reference characteristics and characteristics measured by the present invention.

FIG. 3 is a skeleton mechanism diagram showing a power system of a vehicle using a differential device embodying the method of the present invention.

FIG. 4 is a sectional view of a conventional example.

FIG. 5 is a cross-sectional view of another conventional example.

[Explanation of symbols]

 7 Rear differential (differential device) 39 Differential mechanism 73 Pilot clutch (friction clutch) 79 Mechanism section 89 Reference electromagnet 107 Differential limiting characteristic (reference characteristic)

Claims (1)

[Claims] 1. A differential device for obtaining a differential limiting torque by engaging the friction clutch of a mechanical unit having a differential mechanism and a friction clutch for limiting the differential thereof with a magnetic force of an electromagnet to provide a reference electromagnet to the mechanical unit. Differential limiting characteristic characterized by selecting an electromagnet that minimizes the difference between the characteristics of the exciting current and differential limiting torque obtained by combining Characteristic standardization method.