JP2002235832A - Differential gear with reduction gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lighten a structure of a differential gear with a reduction gear. SOLUTION: This differential gear with the reduction gear has a differential function for reducing a speed and outputting the torque to first and second shafts when the torque is inputted, and comprises a reduction gear mechanism 11 and a differential gear mechanism 12. The reduction gear mechanism 11 has a first sun gear 15 to which the torque is inputted, a first planetary gear 16 engaged with the first sun gear 15, a carrier 27 for supporting the first planetary gear 16, and a ring gear 17 engaged with the first planetary gear 16. The differential gear mechanism 12 has a second planetary gear 21 and a third planetary gear 22 supported by the carrier 27 and engaged with each other, a second sun gear 23 engaged with the second planetary gear 21 and further engaged with the first shaft, and a third sun gear 24 engaged with a third planetary gear 22 and engaged with a second shaft.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a differential with a reduction gear.

[0002]

2. Description of the Related Art Generally, in an FF vehicle, power from a prime mover is transmitted to a transmission, decelerated by a counter gear, and input to a differential. However, in the case of a large prime mover, a transmission requiring a space in the axial direction is offset from the rotational axis of the prime mover, and is arranged coaxially with a differential with a reduction gear. Especially in electric vehicles, a differential unit with a reduction gear is arranged coaxially with the electric motor to reduce the weight, and the axial compactness is required to secure the space for the constant velocity ball joint that transmits power to the tire. Required first.

[0003]

As a differential with a speed reducer, a normal bevel gear is used for the differential, a carrier of the differential is extended in the axial direction, and a planetary gear is arranged on the carrier. The gearbox engages with the ring gear, inputs the sun gear, and has a reduction gear with the ring gear fixed.

However, a differential using a bevel gear has a side gear, a pinion gear, and a side gear in the axial direction, and three gears are arranged in the axial direction. At the same time, there is a problem that the weight increases.

An object of the present invention is to reduce the weight of the structure of a differential with a reduction gear.

[0006]

According to a first aspect of the present invention, there is provided a differential device with a speed reducer having a differential function of, when torque is input, decelerating and outputting torque to the first and second shafts. Yes, it has a speed reduction mechanism and a differential mechanism. A speed reduction mechanism configured to: a first sun gear to which a torque is input;
It has a first planetary gear that meshes with the first sun gear, a carrier that supports the first planetary gear, and a ring gear that meshes with the first planetary gear. The differential mechanism includes a second planetary gear and a third planetary gear that are supported by the carrier and mesh with each other, a second sun gear that meshes with the second planetary gear and meshes with the first shaft, and a second gear that meshes with the third planetary gear and meshes with the second shaft. 3 sun gears.

In this differential with a speed reducer, one of the first sun gear and the ring gear is input and the other is fixed. When power is input to the first sun gear, for example,
The speed is reduced via the planetary gears and the ring gear and transmitted to the carrier. In the carrier, the second planetary gear and the third planetary gear mesh with each other,
Each rotates in the opposite direction. Therefore, the second sun gear and the third sun gear rotate in opposite directions, and the power is distributed to the first and second shafts and output.

In this differential with a reduction gear, the differential mechanism and the reduction mechanism share a carrier, so that the weight of the entire apparatus is reduced. In the differential with a reduction gear according to claim 2, in claim 1, the carrier is a pair of members disposed on both axial sides of the first planetary gear, the second planetary gear, and the third planetary gear; A fixing member for fixing the pair of members to each other. The fixing member supports at least one of the first planetary gear, the second planetary gear, and the third planetary gear.

In this differential with a reduction gear, the carrier is divided into two parts and connected by the shaft of the planetary gear, so that the weight of the carrier itself is reduced. In the differential device with a speed reducer according to the third aspect, in the first or second aspect, the second
The planetary gears and the third planetary gear rotate around axes parallel to each other.

[0010] According to a fourth aspect of the present invention, there is provided a differential with a speed reducer.
When the torque is input, the speed decreases and the first and second
An apparatus having a differential function of outputting torque to a shaft, comprising a speed reduction mechanism and a differential mechanism. The reduction mechanism is
It comprises a planetary gear mechanism having a first planetary gear. The differential mechanism includes a second planetary gear and a third planetary gear that mesh with each other.
It comprises a planetary gear mechanism having a planetary gear. The first planetary gear, the second planetary gear, and the third planetary gear are supported by a common carrier.

[0011] In this differential with a speed reducer, the differential mechanism and the speed reduction mechanism share a carrier, so that the weight of the entire apparatus is reduced.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (1) Configuration FIG. 1 shows a drive device for an electric vehicle employing a first embodiment of the present invention.

This device has a motor 2 disposed in a housing 1 and a speed reducer 3 with a differential. The speed reducer with differential 3 is a device having the speed reducer mechanism 11 and the differential mechanism 12 integrally. Since the members are shared with each other, weight reduction is achieved and further downsizing in the axial direction can be realized. ing.

FIG. 2 is a schematic longitudinal sectional view of the speed reducer 3 with a differential. 2 is the rotation axis of the speed reducer 3 with a differential, the motor 2 side (the left side in FIG. 2) is the axial input side, and the opposite side (the right side in FIG. 2) is the opposite axial side. I do.

As shown in FIGS. 3 and 4, the reduction mechanism 11 mainly includes a first sun gear 15 and a first planetary gear 1.
6 and a ring gear 17. The first sun gear 15 is connected to the cylindrical output shaft 5 of the motor 2. The first planetary gear 16 meshes with the first sun gear 15. Specifically, as shown in FIG. 4, the outer teeth 16a of the first planetary gear 16 mesh with the outer teeth 15a of the first sun gear 15. 1st planetary gear 16
Are arranged in a plurality (three), and are rotatably supported by a planet carrier 27 (described later). The ring gear 17 is
It is fixed to the housing 1 and its rotation is prohibited, and meshes with the first planetary gear 16. Specifically, FIG.
As shown in the figure, the inner peripheral teeth 17a of the ring gear 17 mesh with the outer peripheral teeth 16a of the first planetary gear 16. The first planetary gear 16 and the ring gear 17 are relatively short members in the axial direction.
(Described later).

The first planetary gear 16 comprises a gear body and a shaft 35 extending therethrough, and a needle bearing 71 is arranged between the two.
The differential mechanism 12 mainly includes a second sun gear 23, a third sun gear 24, a second planetary gear 21, and a third planetary gear 22. The second sun gear 23 and the third sun gear 24 are arranged in the axial direction with respect to the first sun gear 15, and have the same number of teeth. The second sun gear 23 is arranged between the first sun gear 15 and the third sun gear 24.

The second planetary gear 21 and the third planetary gear 22 have a pair of structures that mesh with each other.
Actually, a plurality of pairs (three pairs) are provided. Each pair is first
It is arranged between the planetary gears 16 in the circumferential direction. Note that the second planetary gear 21 and the third planetary gear 22
The diameter of the first sun gear 15 is smaller than that of the first planetary gear, and the first sun gear 15 does not interfere with the ring gear 17 as shown in FIGS.

The second planetary gear 21 and the third planetary gear 22 are arranged close to the second carrier component 29 similarly to the first planetary gear 16.
The second planetary gear 21 extends further to the opposite side in the axial direction than the first planetary gear 16, and the third planetary gear 2
The reference numeral 2 extends further to the opposite side in the axial direction than the second planetary gear 21.

The engagement between the second planetary gear 21 and the third planetary gear 22 will be described in more detail. The outer peripheral teeth 21a are formed on the second planetary gear 21 over the entire axial direction, and the third planetary gear 22
A first outer peripheral tooth 22a is formed at the axial input side end, and a second outer peripheral tooth 22b is formed at the axially opposite end. That is, a portion from which the teeth are cut off is secured at the axially intermediate portion of the third planetary gear 22. First outer peripheral teeth 22
a meshes with the outer peripheral teeth 21 a of the second planetary gear 21. In addition, the number of teeth of both is the same. The portion of the third planetary gear 22 where the second outer peripheral teeth 22b are formed extends further in the axially opposite direction than the second planetary gear 21.

A plurality of pairs of second and third planetary gears 2
Each of the first and second 22 is rotatably supported by a planet carrier 27 (described later). The second planetary gear 21
Is composed of a gear body and a shaft 33 extending therethrough, and a needle bearing 72 is arranged between the two. The third planetary gear 22 includes a gear body and a shaft 34 extending therethrough, and a needle bearing 73 is arranged between the two.

The second planetary gear 21 is a second sun gear 2
3 is engaged. Specifically, a portion of the second planetary gear 21 on the opposite side in the axial direction of the outer teeth 21 a meshes with the outer teeth 23 a of the second sun gear 23.

The third planetary gear 22 is a third sun gear 2
4 is engaged. Specifically, the second outer teeth 22 b of the third planetary gear 22 are connected to the outer teeth 2 of the third sun gear 24.
4a. The outer teeth 23a of the second sun gear 23 correspond to the portions of the third planetary gear 22 from which the outer teeth have been cut off, so that they do not interfere with each other.

As described above, the differential mechanism 12
Planetary gears (second and third planetary gears 21 and 22) meshing with each other in a plurality of pairs in the same carrier (planetary carrier 27), and two sun gears (second and third sun gears 23 and 2) meshing with them at different axial positions.
4).

The second sun gear 23 is connected to one output shaft 6, and the third sun gear 24 is connected to the other output shaft 7. One output shaft 6 penetrates the inside of the output shaft 5 of the motor 2, is rotatably supported by the housing 1, and has an end protruding from the housing 1 to the outside. The other output shaft 7 is rotatably supported by the housing 1, and its end protrudes outside the housing. in this way,
The two output shafts 6 and 7 of the speed reducer with differential 3 are arranged coaxially with the output shaft 5 of the motor 2.

The planet carrier 27 will be described. The planet carrier 27 includes first to third planetary gears 16 and 2.
It is a member for rotatably supporting 1 and 22. The planet carrier 27 is mainly composed of a pair of carrier components 28 and 29 arranged apart from each other in the axial direction. The pair of carrier constituent members 28 and 29 are plate-shaped members. The first carrier component 28 includes the third sun gear 24.
Is an annular member arranged near the opposite side in the axial direction. As shown in FIG. 6, a plurality of flat surfaces 41 and first bosses 4
2 and a second boss 43 are formed. The flat surface 41 corresponds to the third planetary gear 22, and has a shaft support hole 44 into which one end of the shaft 34 of the third planetary gear 22 is inserted. A thrust washer 61 is disposed between the flat surface 41 and the end surface of the third planetary gear 22. The first boss 42 corresponds to the second planetary gear 21, protrudes from the flat surface 41 toward the input side in the axial direction, and has a shaft support hole 45 into which one end of the shaft 33 of the second planetary gear 21 is inserted. I have. Also, the end face of the first boss 42 and the second
A thrust washer 62 is disposed between the planetary gear 21 and the end face thereof. The second boss 43 corresponds to the first planetary gear 16. The second boss 43 projects further toward the input side in the axial direction than the first boss 42.
5 has a shaft support hole 46 into which one end is inserted. Also,
A thrust washer 63 is arranged between the end face of the second boss 43 and the end face of the first planetary gear 16.

As shown in FIG. 7, holes 48, 49 and 50 into which the shafts 34, 33 and 35 are inserted are formed in the second carrier component member 29. Further, thrust washers 64, 65, 66 are disposed between the second carrier component 29 and the planetary gears 16, 21, 22, respectively.

As shown in FIG.
The portion supporting the planetary gear 16 is a large-diameter portion 35b having a larger diameter than other portions and having stepped portions formed at both ends. The distal end face of the second boss 43 of the first carrier component 28 and the end face of the second carrier component 29 abut on both ends of the large diameter portion 35b, respectively. Are positioned so that they do not approach each other further in the axial direction.

The axial end surfaces of the holes 46 and 50 are tapered, and the caulked portions 35a at both ends of the shaft 35 are in contact with each other. As described above, the two carrier components 28 and 29 cannot be separated in the axial direction by the shaft 35. The shafts 33 and 34 are press-fitted into the respective holes.
Alternatively, each hole is swaged at a portion not shown.

As described above, since the two carrier components 28 and 29 are fixed to each other in the axial direction by using the shaft of the planetary gear, there is no connecting portion as compared with the conventional integrated planetary carrier. The gap between the first planetary gear 16 and the second and third planetary gears 21 and 22 in the rotation direction of the axis O can be reduced. When the gap becomes smaller, the diameter of the carrier constituting members 28 and 29 also becomes smaller, and the entire apparatus is downsized.

The first carrier component 28 is supported by the housing 1 via a first bearing 30, and the second carrier component 29 is supported by the housing 1 via a second bearing 31. In the structure described above, the speed reduction mechanism 11 and the differential mechanism 12 share the planet carrier 27, and the entire device is made compact. In other words, by integrating the speed reduction mechanism 11 into the differential mechanism 12, downsizing, in particular, reduction in axial dimension is achieved. (2) Operation Power from the motor 2 is input to the first sun gear 15, decelerated via the first planetary gear 16 and the ring gear 17, and transmitted to the planet carrier 27. Then, the second planetary gear 21 and the third planetary gear 22 rotate the second sun gear 23 and the third sun gear 24, respectively, and power is output to the output shafts 6, 7.

Next, the operation when an operating force is applied to the left and right tires, such as when the vehicle turns a curve, will be described. In the planet carrier 27, since the second planetary gear 21 and the third planetary gear 22 are meshed with each other, they rotate in opposite directions. Therefore, the second sun gear 23
And the third sun gear 24 rotate in opposite directions, respectively, and the power is distributed to the output shafts 6 and 7. Here, since the second planetary gear 21 and the third planetary gear 22 have the same number of teeth, and further, the second sun gear 23 and the third sun gear 24 have the same number of teeth, a 1: 1 differential is obtained.

To summarize the above, the power is supplied to the speed reduction mechanism 11.
(The first sun gear 15, the first planetary gear 16, the ring gear 17) and the differential mechanism 12 (the second sun gear 23, the third sun gear 24) via the planet carrier 27 shared by the reduction mechanism 11 and the differential mechanism 12. , The second sun gear 23, the third
Sun gear 24). (3) Effect Weight Reduction and Compactness By sharing the carrier of the speed reducer and the differential device, the entire device is reduced in weight and further compact.

Further, the carrier component member 28 divided into two parts,
The weight of the planet carrier 27 itself can be reduced by fixing the shaft 29 to the shaft 35 of the first planetary gear 16. As a result, a differential with a reduction gear can be obtained in the same axial space as a conventional differential using a bevel gear and a differential using a helical LSD planetary gear.

Ease of Carrier Connection Method Conventional Differential Device and Helical LS Using Bevel Gear
In the differential device using the planetary gear of D, the carrier is divided into two parts in the axial direction and connected by several bolts on the circumference. On the other hand, in the present invention, the carrier component 2 is divided into two parts in the axial direction only by caulking the shaft 35 of the first planetary gear 16.
8, 29 are connected. As a result, there is no need for screw processing and bolts for connection, and the cost is reduced. (4) Other Embodiments The power input is the ring gear 17 and the first sun gear 15
May be fixed. In that case, the reduction ratio is smaller than in the above-described embodiment.

In the above embodiment, the differential with a reduction gear according to the present invention is employed in a gearbox of a transmission motor used in an electric vehicle. This is because the present invention is the most suitable embodiment in that compactness and weight reduction as an FF vehicle are required.

On the other hand, the differential with a speed reducer according to the present invention can also be applied to a normal automatic transmission or a manual transmission.

[0037]

According to the differential with a reduction gear according to the present invention,
Since the differential mechanism and the reduction mechanism share a carrier, the weight of the entire apparatus is reduced.

[Brief description of the drawings]

FIG. 1 is a schematic view of a drive device for an electric vehicle according to an embodiment of the present invention.

FIG. 2 is a schematic longitudinal sectional view of a differential with a reduction gear according to the present invention, and is a sectional view taken along the line ZYO of FIG. 3;

FIG. 3 is a schematic plan view of a differential with a reduction gear.

FIG. 4 is a sectional view taken along the line XO in FIG. 3;

FIG. 5 is a sectional view taken along line VV of FIG. 4;

FIG. 6 is an E view of FIG. 3;

FIG. 7 is a view as viewed in the direction of arrow F in FIG. 3;

[Explanation of symbols]

 Reference Signs List 3 speed reducer with differential 11 speed reduction mechanism 12 differential mechanism 15 first sun gear 16 first planetary gear 17 ring gear 21 second planetary gear 22 third planetary gear 23 second sun gear 24 third sun gear 27 planet carrier

Claims (4)

[Claims] 1. A device having a differential function of decelerating when torque is input and outputting torque to first and second shafts, wherein a first sun gear to which torque is input and a first sun gear to A first planetary gear meshing with the first planetary gear, a carrier supporting the first planetary gear, and a ring gear meshing with the first planetary gear; a second planetary gear and a third planetary gear supported by the carrier and meshing with each other; And a differential mechanism having a second sun gear meshing with the second planetary gear and meshing with the first shaft, and a third sun gear meshing with the third planetary gear and meshing with the other of the second shaft. Machined differential. 2. The carrier comprises: a pair of members disposed on both axial sides of the first planetary gear, the second planetary gear, and the third planetary gear; and a fixing member for fixing the pair of members to each other. And the fixing member is at least one of the first planetary gear, the second planetary gear, and the third planetary gear.
The differential device with a speed reducer according to claim 1, wherein the differential device supports one of the gears. 3. The differential device with a speed reducer according to claim 1, wherein the second planetary gear and the third planetary gear rotate about axes parallel to each other. 4. A device having a differential function of decelerating when torque is input and outputting torque to the first and second shafts, comprising: a reduction mechanism comprising a planetary gear mechanism having a first planetary gear; A differential mechanism comprising a planetary gear mechanism having a second planetary gear and a third planetary gear meshing with each other, wherein the first planetary gear, the second planetary gear and the third planetary gear are supported by a common carrier. A differential gear equipped with a speed reducer.