JPH02225843A - Worm gear type differential gearing - Google Patents

Abstract

PURPOSE:To reduce the abrasion of a gear surface of worms and worm wheels, and improve the lubricating ability and the heat radiatability by engaging one worm wheel to one pinion worm. CONSTITUTION:The driving torque input to a differential case 23 is equally distributed in two and transmitted from each left side worm wheel gear shaft 33L, 33'L, 33''L to a left side accelerator shaft 25L through each worm wheel gear 34L, 34'L, 34''L and each pinion wore gear 29L, 29'L, 29''L and an output wore gear 26L, and from right side gear shafts 33R, 33'R, 33''R to a right side shaft 25R through each wheel gear 34R, 34'R, 34''R and each pinion gear 29R, 29'R, 29''R and an output gear 26R. About each pair of wore wheel gear, the worm wheel gears 34L, 34'L, 34''L are respectively engaged with the left side pinion gears 29L, 29'L, 29''L and the right side worm wheel gear 34R, 34'R, 34''R are respectively engaged with the right side pinion gears 29R- 29''R.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a worm gear type differential gear device.

(Conventional technology) Generally, as a worm gear type differential gear device.

So-called Torsen def and night def are known.

As a conventional Torsen differential, US Pat. No. 4.491.
There is one described in No. 035. As shown in FIG. 4, this conventional Torsen differential consists of a left axle 2L and a right axle 2R that are rotatably fitted to the differential case 1 from the left and right so as to be coaxial, and the inner ends of the left and right small axles 2L and 2R. The left and right worm gears 3L, 3R, each spline-fitted to the
Three pairs of left and right worm wheel gears 4L, 4R are rotatably attached to the differential case 1 and mesh with the left and right worm gears 3L, 3R, a thrust element 5 and a left worm gear 3 are interposed between the left and right worm gears 3L, 3H.
Thrust bearing 6 interposed between L and the inner wall of differential case 1
．． and a spacer 7 interposed between the right worm gear 3R and the inner wall of the differential case 1.

This Torsen differential is a left and right wheel differential limiting device (LS
D), the rotational torque transmitted to the differential case l via the ring gear 8 is transmitted to the worm wheel gears 4L, 4R and the worm gears 3L, 3R, respectively.
The torque is transmitted to the left and right axles 2L and 2R via No relative rotation occurs between the axles 2L and 2H.

However, when a rotation difference occurs between the left and right axles 2L and 2H due to the inner wheel difference, such as when the vehicle is cornering, the rotation of the worm gear on the high rotation side (outer wheel) rotates one of the worm wheel gears that meshes with it. The rotation of one of the two worm wheel gears is transmitted in reverse rotation to the other worm wheel gear that meshes with the worm gear on the low rotation side (inner ring) via spur gears 4La and 4Ra that mesh with each other. This allows the rotational speed of the left and right axles to be adjusted in accordance with the difference between the inner wheels when the vehicle turns, allowing the vehicle to turn smoothly.

In addition, when this Torsen differential is used as a torque distribution device (center differential) of a four-wheel drive vehicle, the tooth surface friction torque generated between one worm gear 3L, 3R and both worm wheel gears 4L, 4R acts on the front and rear wheels. The torque is distributed according to the load ratio.

In addition, as a conventional night differential, the patent application was published in 1983.
There is one described in No. 00670. As shown in FIGS. 5 and 6, this "conventional night differential" has a gear support 11
The output shafts 12A are arranged such that they can rotate freely and face each other.
and 12B are attached, and output helical gears 13 are respectively attached to the tips of the output shafts 12A and 12B within the gear support 11.
A and 13B are integrally molded or spline-fitted to rotate together, and these output helical gears 13A and 1
3B includes a pair of worm gears (14A, 14B), (1
4c, 14D) are engaged. Then, one worm gear of each pair of worm gears (in the illustrated example, worm gears 14B and 14c, 14A and 14D)
) each have an axis perpendicular to the axis of the worm gear.

15B meshes with the worm wheel gear f8A or 16B rotatably supported within the gear support 11.

This night differential is used as a torque distribution device (center differential) for four-wheel drive vehicles or as a left-right wheel differential limiting device (LSD).
When used as a re-output shaft 12A, 12B
When the rotation speeds of the two output shafts 12A are equal, each gear in the gear support 11 does not rotate relative to each other but rotates integrally.
, 12B have different rotational speeds, relative rotation occurs between each gear in the gear support ll, resulting in one output shaft 12A, 12.
Torque distribution corresponding to the load ratio between B is performed.

(Problem to be Solved by the Invention) However, in the conventional worm gear type differential gear device as described above, in the case of the Torsen differential shown in FIG. Gears 4L and 4R are in mesh with each other, and in the case of the night differential shown in FIGS. 5 and 6, the worm wheel gear 1
Two worm gears each for 6A and 16B (
14B, 14C) or (14A, 14D) were in mesh with each other, so in the case of a Torsen differential, it was a worm gear 3L.

In the case of a night differential, the tooth surfaces of worm wheel gears 16A and 16B are severely worn, and the lubricity and heat dissipation of the tooth surfaces of worm gears 3L and 3R or worm wheel gears 16A and 1I3B are severe. The disadvantage was that the southern part was damaged quickly.

The present invention has been made in order to eliminate the drawbacks of the worm gear type differential gears as described above.

That is, an object of the present invention is to provide a worm gear type differential gearing device that has less wear on the tooth surfaces of the worm gear and the worm wheel gear, and has good lubricity and heat dissipation.

(Means for Achieving the Object) In order to achieve the above object, the present invention provides a pair of axle shafts rotatably attached to a gear support and coaxially arranged to face each other.

A pair of output worm gears are attached to the inner end of the axle shaft so as to rotate integrally with each other, and the pair of output worm gears are attached to the inner wall of the gear support at the outer peripheral position of the pair and are arranged parallel to the axis of the output worm gear. m number of journal shafts, multiple pairs of pinion worm gears rotatably fitted to each journal shaft, and rotatable so that the axis extends perpendicularly to each journal shaft on the inner wall of the gear support. A plurality of pairs of worm wheel gears are attached to the worm wheel gears and are arranged in parallel along the axial direction of the journal shaft so as to form a pair for each journal shaft. It has a plurality of pairs of gears rotatably attached, one pinion worm gear of each pair of pinion worm gears meshes with one output worm gear, the other pinion worm gear meshes with the other output worm gear, and each In the worm wheel gear pair, one worm wheel gear meshes with one pinion worm gear of a corresponding pinion worm gear pair, and the other worm wheel gear meshes with the other pinion worm gear, and the plurality of pairs of gears mesh with each other for each pair. It is characterized in that they mesh (claim 1).

A preferred embodiment is one in which three pairs of pinion worm gears are arranged at equal angular positions around the output worm gear (Claim 2). Furthermore, there is a device in which the axis of the worm wheel gear extends in the radial direction of the axle shaft (wJ claim). Further, a thrust member (such as a washer) is interposed between each pair of pinion worm gears (claim 4).

(Function) In the above-mentioned worm gear type differential gear device, a pair of worm wheel gears is provided correspondingly to each pair of pinion worm gears, and the worm wheel gear (-) meshes with the pinion worm gear (-). There is.

When the loads on the axle shafts on both sides are equal, each output worm gear, pinion worm gear, worm wheel gear, and gear in the gear support do not rotate relative to each other, and the axle shaft rotates integrally with the gear support. The drive torque input to the axle shaft is equally distributed to both axle shafts.

Furthermore, if the loads applied to the axle shafts on both sides are different, relative rotation will occur between the gears in the gear support.
Rotational torque generated by the relative rotational difference between the axle shaft with a higher load (lower rotational speed) and the gear support.

One output worm gear that rotates integrally with this axle shaft One pinion worm gear of each pinion worm gear pair that meshes with this one output worm gear Each worm wheel gear pair that meshes one-on-one with each one of these pinion worm gears One of the worm wheel gears One gear that rotates integrally with this one worm wheel gear - The other gear that meshes with this one gear - Each of the other worm wheel gears that rotate integrally with this other gear This other The other pinion worm gear meshes one-on-one with the worm wheel gear of the other pinion worm gear. Rotate faster relative to the gear support by the relative rotational difference between one axle shaft and the gear support.

This allows it to function as a differential gear device.

In addition, when the load on one axle shaft is removed, due to the function as a differential gear device as described in -1-, all of the drive torque applied manually to the gear support is transferred to the axle shaft on the unloaded side. When the gears in the gear support rotate relative to each other, the information is transmitted to the shaft.
South side FI that occurs at the meshing part between each pinion worm gear and worm wheel gear! ! The friction torque and the thrust friction torque generated between the pinion worm gears in each pinion worm gear pair limit the drive torque transmission to the unloaded axle shaft side, thereby reducing the drive force to the other side axle shaft. Torque transmission is ensured and it functions as a differential limiting fA position.

(Example) The present invention will be described in more detail below based on an example shown in one drawing.

1 and 2 show an embodiment in which a worm gear type differential gear device according to the present invention is used as a limited slip differential device (LSD) for left and right wheels, in which a gear support 21
consists of a differential case 23 and a differential case cover 24 that are integrally fixed to each other by bolts 22, and left and right axle shafts 25L and 25R, which are arranged coaxially and facing each other, respectively, rotate on the differential case 23 and the differential case cover 24. It is inserted freely.

The axle shafts 25L, 25H each have an output worm gear 2 at its inner end within the gear support 21.
8L and 26R are spline-coupled so that they rotate together, and tires 27L and 27R are attached to their outer ends, respectively.

In the gear support 21, an output worm gear 28L,
At the outer circumferential position of 26R, there are three
Book journal shafts 28A, 28B.

A pair of pinion worm gears (29L, 29R) are attached to each of the journal shafts 28A, 28B, and HC.

(29'L, 29'R), (29'L, 29
'R) are rotatably fitted with spacers 30 in between to prevent interference between the gears in each pair. Of these pairs of pinion worm gears, the outer ends of the left pinion worm gears 29L, 29'L, and 29'L in FIG. 1 mesh with the left output worm gear 28L, and the right pinion worm gears 29R, 29'R, and 29 The outer end of 'R meshes with the right output worm gear 2BR.

Furthermore, the axial direction extends perpendicularly to the radial direction of the differential case 23, that is, the axial direction of each journal shaft 28A, 28B, and 28C, and the outer end is connected to the inner wall of the differential case 23 by a slotted bin 31, and the inner end is connected to the center block 32. fixed to each journal shaft 2.
Three pairs of worm wheel gear shafts (33L, 33R), (33'L) are arranged in parallel along the axial direction of 11A, 28B, and 211C.

33'R), (33'L, 33'R) are arranged in pairs between each journal shaft 28A, 28B, 28C. In addition, center block 3
2 are held in place relative to the differential case 23 by being bridged by each worm wheel gear shaft.

And these three pairs of worm wheel gear shirts 1-
(33L, 33R), (
33'L, 33'R), (3
3'L.

33'R) are each equipped with a worm wheel gear (34L).

34R), (34'L, 34'R), (
34'L, 34'R) and a flat gear (or helical gear) integrally molded on the rear end of each worm wheel gear.
35L, 35R).

(35'L, 35'R), (35'L, 35
'R) is fitted with rotation θ.

In addition, each spur gear (35L, 35R), (35'
L.

A thrust washer 36 is interposed between each of the worm wheel gears (35'R), (35'L, 35'R) and the inner wall of the differential case 23 to prevent interference with the differential case 23. 34R), (
34'L, 34'R).

(34'L, 34'R) and the center block 32 are each provided with a thrust washer 37 to prevent interference with the center block 32.

Each spur gear (35L, 35R), (35'L,
35'R).

(35'L, 35'R) mesh with each other in each pair.

Eight pairs of worm wheel gears integrated with this spur gear rotate in conjunction with each other.

The eight pairs of worm wheel gears include one worm wheel gear 34L (left side in FIG. 1) for each pair.

34'L, 34'L are pinion worm gears 29L, 29'L, 29'L on one side (left side in Figure 1) and worm wheel gears 34R, 34'R on the other side (right side).
, 34'R is the other (right side) pinion worm gear 29
R, 29'R.

It meshes with 29'R.

In the worm gear type differential gear device, when the vehicle is traveling straight, the tires 27L and 27R on both sides rotate at the same speed, and the output worm gear 28 in the gear support 21 rotates at the same speed.
L, 2OR, pinion worm gear (29L, 2
9R), (29'L, 29'R), (
29'L.

29'R), worm wheel gear (34L, 3
4R).

(34'L, 34'R), ($4'L, 34
'R) and spur gears (35L, 35R), (
35'L, 35'R), (35'L.

35'R) rotates integrally with the gear support 21 without any relative rotation between the gears. Therefore, the driving torque manually applied to the differential case 23 is transferred from the worm wheel gear shafts 33L, 33'L, 33'L on the left side of FIG. 1 to the worm wheel gears 34L, 34'L, 34'L.

Each pinion worm gear 29L, 29'L, 29'
L and output worm gear 26L to the left axle shaft 25L, and from each worm wheel gear 33R, 33'R, 33'R on the right side to each worm wheel gear 34R, 34'R, 34'R, each pinion worm gear 29R, The power is equally distributed and transmitted to the right axle shaft 25H via 29'R, 29'R and the output worm gear 2BR.

However, when a rotation difference occurs between the left and right tires 27L and 27H when the vehicle is cornering, a relative rotation occurs between each gear in the gear support 21, and the driving torque input to the differential case 23 is transmitted to the left and right tires 27L and 27H. The left and right axle shafts 25L are distributed in proportion to the rotation difference of 27R.
, 25R. For example, in FIG. 1, if the left tire 27L is the inner tire, the axle shaft 25
The rotation of L is slower than the rotation of the differential case cover 24, and the rotational torque generated by the rotation difference is transferred from the left output worm gear 2BL to each of the left pinion worm gears 29.
L.

29'L, 29'L-Left side wheel gear 34
L.

34'L, 34'L-Left spur gear 35L, 35'L
, 35'L - Right side spur gear 35R, 35'R, 35'
R-Right side worm wheel gear 34R, 34'R, 34
'R-pinion worm gear 29R, 29'R, 29'
R to the right output worm gear 28R, and the right axle shaft 25R is rotated faster than the differential case 23 by the rotation difference on the left side. The same applies when turning in the opposite direction. As a result, the difference between the inner wheels during cornering is adjusted, and the function as a differential gear device is exhibited.

In addition, this worm gear type differential gear system is suitable for use in situations where either the left or right tires 27L or 27R lose their grip and spin (for example, during extreme turns or when the left and right road surface friction coefficients are significantly different). In the event that the tire accelerates at the bottom of the tire, or if the wheels fall off, it functions as a differential limiting device that limits the transmission of drive torque to the tire on the side that is losing grip.

In other words, 1. For example, if the left tire 27L in FIG. 25R), the rotation speed of the left axle shaft 2SL becomes faster relative to the differential case cover 24.

More drive torque is transmitted to the left tire 27L side. However, such right tire 2
When driving torque is transmitted to the left tire 27L as a rotation difference occurs between the left tire 27L and the pinion worm gears 29R, 229'R, 29'R and the worm wheel gears 34R, 34'R.

34'R and each worm wheel gear 34L,
34'L, 34'L and pinion worm gear 29L,
29'L.

29'L, and the left pinion worm gear 29L in the 6th pair.

29'L, 29'L and right side pinion gear 29
The transmission of drive torque from the differential case 23 to the left tire 27L is limited by the thrust friction torque generated by the thrust washer 30 interposed between the R229'R and R229'R as the relative rotation occurs between the R229'R and R229'R. Ru. Conversely to the above, when the right tire 27R loses its grip and is spinning, the transmission of drive torque to the right tire 27R is similarly restricted.

Therefore, even if one tire loses its grip and is spinning while the other tire is almost at a standstill, all of the drive torque is prevented from being transmitted to the tire that is spinning. The transmission of drive torque to the tire on the other side maintaining grip is ensured.

In the above embodiment, the worm gear type differential vehicle device of the present invention was used as a limited slip differential device (LSD) for left and right wheels, but it can also be used as a torque distribution device (center differential) for a four-wheel drive vehicle. Of course, it can be used, and the same function can be achieved in this case as well.

Furthermore, in the above embodiment, each wheel gear shaft is arranged in the radial direction of the axle shaft.
If the worm wheel gear shafts are each at right angles to the journal shaft.

As shown in FIG. 3, it does not necessarily have to coincide with the radial direction of the axle shaft.

Further, it is possible to implement the invention if there are two or more pairs of pinion worm gears and worm wheel gears.

(Effects of the Invention) As described above, the worm gear type differential gear device according to the present invention has the functions of both a differential device and a differential limiting device. Wheel gears are provided correspondingly, and the worm wheel gear (-) meshes with the pinion worm gear (-), so there is less wear on the tooth surfaces of the worm gear and worm wheel gear, and excellent lubricity and It can provide heat dissipation and greatly improve the durability of the south side of the gear.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing one embodiment of the present invention. Fig. 2 is a sectional view taken along the line ■-■ in Fig. 1, Fig. 3 is a schematic diagram showing another embodiment, Fig. 4 is a side sectional view showing a conventional example, and Fig. 5 is a sectional view showing another conventional example. The side sectional view shown in FIG. 6 is a sectional view taken along the line VI-VI in FIG. 5. 25L, 25R...Axle shaft 28L, 2G
R...Output worm gear 27L, 27R...Tire 28A, 28B, 28C...Journal shaft 29
L, 29R, 29'L, 29'R, 29'L. 291R... Binion Usu-Mugia 30... Thrust washer 34L, 34R, 34'L, 34'R, 34'L. 34'R... Worm wheel gear 35L, 35R, 35'L, 35'R, 35'L. 35'R...Spur gear

Claims (1)

[Scope of Claims] 1) A pair of axle shafts that are rotatably attached to a gear support and coaxially arranged to face each other, and a pair of axle shafts that are attached to inner ends of the axle shafts so as to rotate together with each other. an output worm gear, a plurality of journal shafts attached to the inner wall of the gear support body at the outer peripheral position of the pair of output worm gears and arranged parallel to the axis of the output worm gear, and a pair of journal shafts rotatably fitted to each of the journal shafts. A plurality of pairs of combined pinion worm gears are rotatably attached to the inner wall of the gear support so that the axis extends perpendicularly to each journal shaft, and a pair is formed for each journal shaft along the axial direction of the journal shaft. It has a plurality of pairs of worm wheel gears arranged in parallel, and a plurality of pairs of gears rotatably attached to the inner wall of the gear support so as to rotate together with each of the worm wheel gears, and each pair of pinion worm gears. One of the pinion worm gears meshes with one output worm gear, the other pinion worm gear meshes with the other output worm gear, and in each worm wheel gear pair, one worm wheel gear corresponds to one of the corresponding one pinion worm gear pair. A worm gear type differential gear device, characterized in that one worm wheel gear meshes with the other pinion worm gear, and the plurality of pairs of gears mesh with each pair. 2) The worm gear type differential gearing apparatus according to claim 1, wherein the three pairs of pinion worm gears are arranged at equiangular positions around the output worm gear. 3) The worm gear type differential gear device according to claim 1 or 2, wherein the axis of the worm wheel gear extends in the radial direction of the axle shaft. 4) The worm gear type differential gear device according to claim 1, wherein a thrust member is interposed between each pair of pinion worm gears.