JPH03260437A - Car differential device - Google Patents

Abstract

PURPOSE:To lessen the diameter of the screw gear part of side gear while its spline part is secured with a sufficient diameter, by separating the screw gear part of at least one of the side gears of a differential device for car from the spline part in the axial direction. CONSTITUTION:At least on one of the side gears 40, 50, the screw gear parts 42a, 52a are separated from spline parts 41a, 51a in the axial direction. Thereby the wall thicknesses of side gears 40, 50 can not be determined by the diameters of the two. This enables lessening the diameter of the screw gear parts 42a, 52a while the spline parts 41a, 51a of the side gears 40, 50 are secured with a sufficient diameter, which allows in turn lessening of the dia. of a differential device concerned.

Description

[Detailed description of the invention] [Industrial application fields] The present invention relates to a differential device for a vehicle.

[Prior art] A front differential device that absorbs the rotational difference between the left and right front wheels of a vehicle, a rear differential device that absorbs the rotational difference between the left and right rear wheels, and a center that absorbs the rotational difference between the front and rear wheels (7). Differential devices are well known.

Japanese Patent Publication No. 48-16334. No. 49-43323, No. 4
．． The differential device disclosed in Japanese Patent Application No. 9-50625 can increase the drive torque applied to wheels with high road resistance compared to the drive torque applied to wheels with low road resistance. Here, the road resistance is μ·W (μ: coefficient of friction of the road surface, W: load applied to the tire).

The differential device has a housing to which torque is transmitted from the engine, and a pair of shafts passing through the housing. The pair of shafts are arranged in a straight line, each associated with at least one wheel, and their ends are opposed to each other at a distance within the nousing. A pair of side gears is spline-coupled to the ends of these pair of shafts, respectively, to enable rotation transmission between the two. A screw gear portion is formed on the outer periphery of the side gear. Further, a pair of element gears are rotatably supported by the housing. The rotation axis of the element gear intersects with the rotation axis of the side gear. Each element gear has a screw gear section and a cooperating gear section. The screw gear portion of each element gear meshes with the screw gear portion of the corresponding side gear. Cooperative gear portions of the pair of element gears mesh with each other. A differential gear is configured by the meshing of the side gear and the element gear, and the meshing of the element gears.

[Problems to be Solved by the Invention] In the differential device configured as described above, the side gear has a cylindrical shape, a screw gear portion is formed on its outer periphery, and a spline portion is formed on its inner periphery. Since the screw gear portion and the spline portion are located at the same position in the axial direction, the following problem occurred.

In order to obtain the strength of the spline part itself and the strength of the shaft commensurate with the driving torque to be transmitted,
Requires a sufficiently large diameter. Further, the peripheral wall surrounding the spline portion needs to have sufficient thickness to obtain the necessary strength. For this reason, the diameter of the screw gear portion located outside the spline portion becomes larger, and accordingly, the position of the element gear that meshes with the screw gear portion also becomes farther from the rotation axis of the sight gear. As a result, the diameters of the housing that accommodates the side gear and the element gear and the differential case that accommodates this housing become larger.

In this way, because the diameter of the differential device is large,
Either the vehicle height had to be raised or the interior space had to be narrowed vertically.

[Means for Solving the Problems] The present invention has been made to solve the above problems, and the gist thereof is that in at least one side gear, the screw gear portion and the spline portion are separated in the axial direction. A vehicle differential device characterized by:

Function] Since the spline portion and the screw gear portion of the side gear are separated in the axial direction, the wall thickness of the side gear is not determined by the diameters of both. In this way, it is possible to reduce the diameter of the screw gear part while making the diameter of the spline part of the side gear sufficiently thick, and in turn, the diameter of the tephalene/yel device can be reduced.

1 Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 shows a center differential system used in a four-wheel drive vehicle. The left side of this device in the figure is located at the front of the vehicle, and the right side is located at the rear of the vehicle. This device has a housing 10. The housing 10 includes a cylindrical portion 11, end walls 1213 formed at both ends of the cylindrical portion 11, and auxiliary cylindrical portions 14 extending in the axial direction from the end walls 12 and 13, respectively. ．． It has 15. For example, three openings 11a are formed in the cylindrical portion 11.

Openings 12a, 13a with steps 12b, 1.3b are formed in the end walls 12, 13, respectively. Front cylinder part 1
4 has a spline portion 14 on its inner periphery. a is formed.

The housing IO is housed in a differential case (not shown), and is rotatably supported by the differential case by bearing means (not shown) arranged around the outer peripheries of the auxiliary cylinder parts 14 and 15, respectively. Auxiliary cylinder part 1
The end of a hollow/yaft (not shown) is inserted into 4 and splined so that driving torque is transmitted from the engine (power source) to the housing 10 via the clutch, transmission, and hollow shaft. It has become.

A front propeller shaft 20 passes through the opening 12a of the front end wall 12 of the housing 10, and a rear propeller shaft 30 passes through the opening 13a of the rear end wall 13.
is penetrated. These propeller shafts 20, 30 are arranged on a straight line and are rotatably supported by the /% housing 10 via bearings 18, 19 arranged on the outer portions of the openings 12a, 13a in the axial direction. There is. The axis of rotation of the propeller shaft 20.30 coincides with the axis of rotation of the housing 10. The front propeller shaft 20 passes through the above-mentioned hollow/yaft, and is connected to the left and right front wheels via the outer end of the housing and the front differential gear.

The end of the rear propeller shaft 30 outside the housing 10 is connected to left and right rear wheels via a rear differential device.

The other end of the 7" o bellayaft 20.30 is contained within the housing 10 and faces away from each other. Spline portions 20a, 30a are formed on the outer periphery of these ends, respectively. A pair of side gears 4
0.50 are connected to each other.

The front side gear 40 has a first portion 41 along the axial direction.
and a second portion 42. The outer diameter of the first portion 41 of the housing 10 that is closer to the end wall 12 is larger than that of the second portion 42 that is farther from the end wall 12. The first portion 41 has a hole 43 extending in the axial direction from the end surface, and a spline portion 41a is formed on the inner periphery of the hole 43. The second portion 42 has a solid cylindrical shape, and has a screw gear portion 42 on its outer periphery.
a is formed. The end portion of the shaft 20 of the front propeller 7 is inserted into the first portion 41 of the side gear 40, and the connection of the spline portions 41a and 20a of the two enables transmission of rotation between the two.

The rear side gear 50 has the same shape as the front side gear 40, and has a hole 53 formed with a spline portion 51a.
The second portion 52 includes a first portion 51 having a screw gear portion 52a and a second portion 52 having a screw gear portion 52a, and is connected to an end of the rear propeller shaft 30 by a spline.

Three pairs of element gears 60° and 70 are rotatably supported in the housing 10 at positions corresponding to the openings 11a, respectively. As best shown in FIG. 2, the front element gear 60 includes a screw gear portion 61 and spur gear portions 62, 62 (cooperative gear portions) having a larger diameter than the screw gear portion 61 formed at both ends thereof. It is equipped with

A journal pin 65 passes through the element gear 60, and both ends of the journal pin 65 are inserted into holes in the housing 10 (formed on both sides of the opening 11a in the circumferential direction) and supported. . The rotational axis of the element key 760 intersects the rotational axes of the /yant 20.30 and the sight gears 40, 50 at 90 degrees.

The element gear 70 on the rear side is also the element gear 60 on the front side.
It has the same shape as , includes a screw gear part 71 and spur gear parts 72 and 72, and is rotatably supported by the housing 10 via a journal pin 75. The rotation axis of each element gear 70 is a pair of element keys 760.
parallel to the axis of rotation.

The screw gear portion 61 of the front element gear 60 is
It meshes with the screw gear portion 42a of the front sight gear 40. The screw gear portion 71 of the rear element gear 70 meshes with the screw gear portion 52a of the rear sight gear 50. The above pair of element keys 7
The spur gear portions 62, 72 of 60, 70 mesh with each other.

Through these meshes, the differential gear 80
or consists of

A wire 8182 is interposed between the annular step 12b of the end wall 12 and the opposing end surface of the side gear 40. In addition, the step 13b of the end wall 13 and the side gear 50
Washers 83 and 84 are also interposed between the end faces of the . Furthermore, a washer 85 is also interposed between the mutually opposing end surfaces of the side gears 40, 50. Convex portions 4454 are formed on opposing end surfaces of these side gears 40, 50 to enter inside the washer 85 and support it.

In the above configuration, the general operation of the center differential device will first be explained. Driving torque from the engine is transmitted to the housing 10 via a hollow shaft or the like, and further from the housing 10 to the differential lens 7.
is transmitted to the propeller shaft 20.30 via a mechanical gear 80.

When the vehicle is traveling straight without slipping, the differential gear 80 is in a non-differential state in which the element gears 60 and 70 do not rotate.

For example, when the vehicle runs while turning, the differential gear 80 operates and the element gears 60, 70
, thereby absorbing the difference in rotational speed between the front propellant shaft 20 and the rear propellant shaft 30.

In the above non-differential state, the road resistance of the front and rear wheels is the same, or the drive torque applied to the front and rear wheels has reached the limit value (determined by the road resistance) that does not cause slippage. In the state where the housing 10 is not present (hereinafter, these states are referred to as basic states)
The drive torques distributed from to the propeller shaft 20.30 are equal. If the road resistance of the front and rear wheels is different, the distribution ratio of drive torque to the front and rear wheels will be different accordingly.
For example, it varies in the range of 25+75 to 75:25.

The mechanism of the change in the drive torque distribution ratio is well known, so to briefly explain it, the element gears 60, 70
For example, the washer 85 is
A frictional force is generated between the side gears 40 and 50 through the
/ side gear 50 and housing 1 via gears 83 and 84
A frictional force is generated between the end wall I3 of 0 and the end wall I3. These frictional forces and the like cause the above-mentioned change in the torque distribution ratio.

Next, the sight gears 40 and 50, which are the most important components in the present invention, will be explained in detail. In the side gear 40, a spline portion 41a and a screw gear portion 42a
are axially separated.

Therefore, the diameter of the spline portion 41a is not restricted by the diameter of the screw gear portion 42a, and can be made large enough to obtain sufficient strength when transmitting the driving torque from the side gear 40 to the front propeller saw shaft 20. can. In this embodiment, it has approximately the same diameter as the propeller shirt 1-20.

Further, the peripheral wall of the side gear 40 surrounding the spline portion 41a can be made thick enough to obtain sufficient strength. This is because the element gear 60 is not disposed on the outer periphery of this peripheral wall, and its thickness does not directly affect the diameter of the housing 1o.

On the other hand, the diameter of the screw gear part 42a is adjusted to the diameter of the spline part 4.
It can be made smaller without being restricted by the diameter of 1a. In this embodiment, the diameter of the root circle of the screw gear portion 42a is approximately equal to the diameter of the spline portion 41a.

The same applies to the rear side gear 50.

Screw gear portion 42a of side gears 40, 50.

Since the diameter of the element gear 52a is small, the element gears 60, 70 meshing therewith can also be brought closer to the rotation axis of the side gear 40, 50, which in turn allows the diameter of the housing 10 to be reduced, and the diameter of the differential case to be reduced.

Since the diameter of the differential device can be reduced as described above, the height of the vehicle can be reduced and the single compartment can be made wider in the vertical direction. Note that this differential device is longer in the axial direction than the conventional structure (although this is not a problem since there is plenty of space in the vehicle in this direction).

Next, FIG. 3 shows other embodiments of the present invention.

This will be explained based on FIG. In addition, in these embodiments, the same numbers are given to the constituent members corresponding to the embodiments described previously, and detailed explanation thereof will be omitted.

In the embodiment shown in FIG. 3, the diameter of the screw gear portion 52a of the rear side gear 50 is larger than the diameter of the screw gear portion 42a of the front sight gear 40. Therefore, in the basic state, Blobela Shaf 1-20.
The driving torques distributed to the screw gears 30 are different, and the ratio thereof is equal to the ratio of the pitch diameters of the screw gear parts 42a and 52a. To explain in detail, in the above basic state, the housing 1
The driving torque from 0 is distributed to the side gears 40, 50 only via the element gears 60, 70, but in this case,
Force is transmitted from the element gears 60, 70 to the side gears 40, 50 at the contact point of the screw gear parts 42a, 61, the screw gear part 52a.

via 71 contact points. Therefore, the distribution ratio of the driving torque to the side gear 60.70 is equal to the ratio of the distance between the contact point and the rotating shaft, and is substantially equal to the ratio of the pitch diameter of the side gear 60.70.

If the road resistance differs between the front wheels and the rear wheels, the torque distribution ratio in the basic state is used as a reference and changes depending on the road resistance. In this embodiment, as described above, in the basic state, the drive torque is distributed more to the rear propeller shaft 30 and less to the front propeller shaft 20.
The manner in which the drive torque distribution ratio changes is also different from that of the device shown in FIG. In other words, the range of change in the distribution ratio shifts in the direction in which the drive torque to the rear propeller shaft 30 becomes uniform. For example, the torque distribution ratio in the basic state is 45+5
5, the torque distribution ratio is 20.80~70:
Varies up to 30. Furthermore, if the torque distribution ratio in the basic state is 35:65, the torque distribution ratio is 10:90 to 6.
It can change until 0:40.

As described above, the embodiment shown in FIG. 3 can increase the ratio of the drive torque to the rear wheels to the drive torque to the front wheels, and is therefore suitable for vehicles with a large load burden on the rear side. To be more specific, the front wheels, which bear a small load, have low road resistance and the limit value of drive torque that does not cause sling is low, so the drive torque of the front wheels easily reaches this limit value. At this time, the torque distribution ratio changes so that it becomes larger towards the rear wheels. Even if the drive torque to the front wheels is small, the upper limit of the above distribution ratio is, for example, 10:
90, which allows the drive torque to the rear wheels to be up to 9 times the drive torque to the front wheels, making full use of the drive torque from the engine to provide sufficient propulsion to the vehicle. I can do it. In particular, when starting suddenly or climbing up a hill, the load is distributed more toward the rear, resulting in a significant difference in road resistance between the rear and front wheels.Even in this case, however, the above distribution ratio of 10:90 allows the drive from the engine to be This allows maximum use of torque.

In the embodiment of FIG. 3, the ratio of the pitch diameters of the screw gear portions 61.71 of the element gears 60, 70 is equal to the ratio of the pitch diameters of the screw gear portions 42a, 52a. Screw gear part 42a.

52a have the same factors such as module, pressure angle, and helix angle, and differ only in the number of teeth. Further, the screw gear portions 61 and 71 also differ from each other only in number. However, it goes without saying that the shape shown in FIG. 3 is not restrictive in order to perform the above-mentioned distribution of drive torque.

In the case of Fig. 3, it is necessary to make the diameters of the screw gear parts 42a and 52a different in order to obtain the above-mentioned distribution ratio of the driving torque, and in the conventional side gear structure, the diameter of the screw gear part of the rear sight gear is It has to be big. However, by applying the present invention and separating the screw gear part 42a of the front side gear 40 from the spline part 41a in the axial direction, the diameter of the screw gear part 42a can be made sufficiently small, and the diameter of the screw gear part 42a can be made sufficiently small. There is no need to increase the diameter of the screw gear portion 52H of 50.

As a result, the diameter of the differential gear can be reduced. In addition, in this embodiment, the diameter of the differential gear/cell device can be further reduced by applying the present invention to the rear side gear 50 and reducing the diameter of the screw gear portion 52a as in the embodiment shown in FIG. are doing.

In FIG. 3, in the rear sight gear 50, the second
A hole 55 is formed in the portion 52, which is continuous with the hole 53 of the first portion 51 and has a smaller diameter. A small-diameter protrusion 35 extending from the spline portion 30a of the rear propeller shaft 30 is inserted into the hole 55. Thereby, even when force is applied to the side gear 50 from the element gear 70, the rotation axis of the side gear 50 can be aligned with the central axis of the rear propeller shaft 30.

In the embodiment of FIG. 4, like the embodiment of FIG. 3, the distribution of drive torque to the propeller shaft 20, 30 in the basic state is different. However, in this embodiment, only the front sight gear 40 has the spline portion 41a and the screw gear portion 42a separated from each other in the axial direction. On the other hand, a through hole 56 extending in the axial direction is formed in the rear side gear 50, and a spline portion 51a is formed over almost the entire length of the through hole 56. This spline portion 51a
The spline portion 30a of the rear propeller shaft 3O that meshes with this is approximately the same diameter as or longer than the spline portion 41a of the front sight gear 40 and the spline portion 20a of the front propeller shaft 20 that meshes with this, so it is more Can withstand transmission of large drive torque.

The present invention is not limited to the above-mentioned embodiments, and various embodiments are possible. For example, the device shown in FIG. 1 is applicable not only to a center differential device but also to a front differential/yel device 1 and a rear differential device.

[Effects of the Invention] As explained above, in the present invention, it is possible to reduce the diameter of the screw gear part of the side gear without making the diameter of the spline part of the side gear sufficiently large, and as a result, the diameter of the screw gear part of the side gear can be reduced. The diameter of can be reduced.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of a differential gear/cell device according to the present invention, and FIG. 2 is a perspective view showing a state in which side gears and element gears are engaged with each other in the differential device of FIG. 1. FIG. 3 and FIG. 4 are sectional views showing other embodiments of the differential device. 10・Housing, 20.30・Nyaft, 40.5
0...Sight gear, 41a, 51a...Spline part, 42a, 52a Screw gear part, 60.70.
・Element gear, 61.71-screw gear part, 6
2.72... Linkage gear section (sbar gear section), 80 differential gear.

Claims (1)

[Claims] (1) A) A housing to which torque is transmitted from the vehicle's power source. b) a pair of shafts each associated with at least one wheel; The pair of shafts are disposed in line with each other and pass through the housing, and their ends are opposed within the housing. A spline portion is formed on the outer periphery of the end portion of each shaft. c) A pair of side gears each connected to a pair of shafts. This side gear has a screw gear part on the outer periphery and a spline part on the inner periphery. By coupling the side gear and the spline portion of the shaft, rotation transmission between the two becomes possible. d) At least one pair of element gears rotatably supported by the housing. The rotational axis of the element gear intersects with the rotational axes of the shaft and side gear. Each element gear has a screw gear section and a cooperating gear section. The screw gear portion of each element gear meshes with the screw gear portion of the corresponding side gear. Cooperative gear portions of the pair of element gears mesh with each other. In the vehicle differential device having the above configuration,
A vehicle differential device, wherein in at least one side gear, the screw gear portion and the spline portion are separated in the axial direction.