JPH10184867A - Band brake supporting device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid increase in a size of a supporting device as much as possible when a drum of a band brake is offset and supported by means of a multishaft structure shaft. SOLUTION: An automatic transmission is provided with a brake drum 31 connected to a rotation element S2 and a brake band B-2 provided with a brake band 32 for fastening the brake drum 31. The brake drum 31 is offset in the axial direction and is supported in a hollow first shaft 16 via a first bearing 51, and the first shaft 16 is supported in a second shaft 14 via a second bearing 52 arranged in the axial directional position overlapping the band brake B-2 in the diameter direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a band brake for an automatic transmission, and more particularly to a band brake supporting device for supporting a drum of the brake on a shaft.

[0002]

2. Description of the Related Art In an automatic transmission, a band brake is used as a frictional engagement element for locking a rotating member of the transmission case, and a drum of such a band brake is generally provided with a radially inner supporting portion. Is supported by the transmission case via a bearing at a position within the axial width of the brake drum, so that the moment force around the support portion due to the radial force applied to the drum when the brake band is fastened does not act on the bearing portion. I have. As a band brake support device having such a configuration, a conventional Japanese Patent Application Laid-Open No.
There is a technique disclosed in Japanese Patent Application Laid-Open No. 129442/1992. With such a configuration, the load on the bearing portion can be reduced, and the brake drum support structure can be simplified.

[0003]

By the way, it is good that the brake drum can be supported by a radially inward portion within its axial width as in the prior art. In some cases, it is necessary to adopt a configuration in which the support portion is not the automatic transmission case but a rotating shaft. In this case, due to restrictions such as the connection relationship of the rotating shaft and the arrangement of other rotating members, the brake band is not axially offset from the inner surface of the brake band engaging surface but is axially offset with respect to the engaging surface to support the bearing or the like. The members have to be arranged. In this case, a moment force corresponding to the offset amount acts on the bearing as a support member, and it is inevitable that the bearing becomes large.However, in the case of a multi-shaft rotary shaft, the rotary shaft supporting the brake drum is used. The large moment force that acts also affects other rotating shafts, and depending on the support configuration, there is a possibility that the support member of the other rotating shafts may also become large.

Accordingly, the present invention provides a band brake supporting device which can minimize the size of a band brake drum in an automatic transmission when the band brake drum is axially offset and supported by a rotating shaft having a multi-axis structure. The first object is to provide

[0005] Next, the present invention relates to the above supporting device,
A second object is to make the support structure more compact by arranging a bearing in association with another band brake support structure.

A third object of the present invention is to apply the above supporting device to a specific gear train.

[0007]

SUMMARY OF THE INVENTION In order to achieve the first object, the present invention provides a brake drum connected to a rotating member of an automatic transmission, and tightens the brake drum to lock it to a transmission case. An automatic transmission having at least a first band brake having a brake band
A hollow first shaft that supports the brake drum via a first bearing, and a second shaft that supports the first shaft via a second bearing.
A shaft, and the second bearing is disposed at an axial position overlapping the first band brake in a radial direction.

Next, in order to achieve the second object, the automatic transmission is provided with a second rotating member connected to another rotating member of the transmission.
A second band brake having a brake drum, wherein the first shaft is connected to a second brake drum,
The second band brake is disposed axially side by side with respect to the first band brake, and between the first axis and the second axis,
The third bearing is provided at an axial position overlapping the second band brake in the radial direction.

Then, in order to achieve the third object,
The two rotating members are components of a planetary gear set, and the planetary gear set is a component thereof.
A small-diameter pinion gear and a large-diameter pinion gear that are connected and integrated with each other and supported by a carrier, a large-diameter first sun gear that meshes with the small-diameter pinion gear, and a small-diameter second sun gear that meshes with the large-diameter pinion gear. A brake drum of the first band brake is connected to the first sun gear, a second brake drum is connected to the second sun gear, and the first band brake is radially outside of the second sun gear. The second band brake is located on the first
And the first bearing is arranged on the inner peripheral side of the large-diameter first sun gear.

[0010]

According to the structure of the first aspect,
The first bearing for the first shaft as an intermediate shaft that supports the first band brake on the second shaft is disposed offset in the axial direction with respect to the first band brake.
It is unavoidable that a large moment force corresponding to the offset amount acts on the bearing of, and it must be large,
Since the second bearing for supporting the first band brake via the first shaft is disposed so as to radially overlap the first band brake at the axial position, a large moment acts on the second bearing. Not so, can be downsized,
As a result, the structure for supporting the first band brake can be made small overall.

Further, according to the second aspect of the present invention, when two adjacent brake drums are supported by a multi-axis structure, the support structure of the first band brake is compact as a whole for the above-described reason. In addition to
The second bearing is arranged to overlap with the first band brake in the axial position, so that the third bearing is disposed inside the second band brake, whereby the second band brake is disposed. , The amount of offset of the third bearing with respect to the third bearing can be reduced, so that the moment force applied to the third bearing can be reduced, and the third bearing can also be made compact. In this case, the load applied to the first brake drum does not act much on the third bearing because the second bearing is close to the first band brake.
There is no need to increase the size of the third bearing for the first brake drum. Therefore, both the second and third bearings disposed between the first shaft and the second shaft can have a compact configuration, and the support structure for both brakes can be made compact as a whole. .

In a further specific arrangement according to the third aspect of the present invention, the first bearing, which is offset in the axial direction with respect to the first band brake and becomes large, is provided with a small-diameter pinion gear. Can be arranged in a surplus space on the inner periphery of the first sun gear having a large diameter for meshing with the automatic transmission. By making effective use of the space associated with the planetary gear set, it is possible to make the entire automatic transmission compact. it can.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing embodiments. As shown in cross section in FIG.
This device includes a first band having a brake drum 31 connected to a rotating member (a sun gear S2 in the present embodiment) of an automatic transmission, and a brake band 32 for tightening the brake drum 31 and locking the brake drum 31 to a transmission case (not shown). A brake (B-2) is provided. The supporting device is a hollow first shaft (a sun gear shaft) 16 that supports the first brake drum 31 via the first bearing 51.
And a second shaft supporting the first shaft 16 via the second bearing 52.
A shaft (input shaft in the present embodiment) 14, and according to the present invention, the second bearing 52 is provided with a first band brake (B-
It is arranged at an axial position overlapping radially with 2).

Further, the automatic transmission has a second band brake (B-1) having a second brake drum 41 connected to another rotating member (a sun gear not shown in the present embodiment) of the automatic transmission. The sun gear shaft 16 as a first shaft is connected to a second brake drum 41,
The band brake (B-1) is arranged in the axial direction with respect to the first band brake (B-2), and is disposed between the sun gear shaft 16 and the input shaft 14 as the second shaft. A third bearing 53 is provided at an axial position overlapping the band brake (B-1) in the radial direction.

In the support device constructed as described above, the radial force applied to the brake drum 31 by the fastening of the first band brake (B-2) is represented by F, and the two reaction points of the first bearing 51 receiving this force. Of the first bearing 51 from the action points of F1 and F2 and the radial force F, respectively.
Assuming that the axial distances to the two reaction force points are moment arms a and b, first, from the balance of the moments, the relationship of F. (a + b) -F1.b = 0 F.a-F2.b = 0 is established. I do. When these are arranged, F1 = {(a + b) / b} · F F2 = (a / b) · F Here, the moment arm a and the moment arm b are determined by the offset amount of the first bearing 51 with respect to the axial position of the first band brake (B-2). An increase in the forces F1 and F2 is inevitable.

The radial force F acting on the first bearing 51 in this manner is converted into two forces F by the brake drum 31.
1 and F2, and also acts on the second brake drum 41. Due to these forces, reaction forces F3 and F4 are also generated in the second and third bearings 52 and 53 as shown in FIG. These reaction forces F3 and F4 are represented by c1 and d, respectively, of the moment arms from the point of action of the force F1, and the second bearing 52 is F1.d-F3. (C + d) + F2. ( b−d) = 0 Regarding the third bearing 53, the relationship of F2 · (b + c) + F4 · (c + d) −F1 · c = 0 is established. When this is arranged, F3 = ｛(a + d) / (c + d) )｝ · F F4 = {(ca) / (c + d)} · F Here, when each of the moment arms a to d is replaced with a + d = f and ca−e = e as shown in FIG.
d = e + f, and when this is substituted into the above equation, F3 = {f / (e + f)}. FF F4 = {e / (e + f)}. F Therefore, if the moment arm e is sufficiently smaller than the moment arm f, F3 {F, F4}
As 0, almost the entire load when the first band brake (B-2) is engaged can be received by the second bearing 52 via the first bearing 51.

Next, as shown in FIG.
1) When a radial force F acts on the brake drum 41 at the time of engagement, reaction forces F5 and F6 are generated on the second and third bearings 52 and 53, respectively. Assuming that the respective moment arms at the point of action of the radial force F are g + h and h, the reaction forces F5 and F6 are: F · (g + h) −F6 · g for the second bearing 52 because of the moment balance. = 0 Also, for the third bearing 53, F · h−F5 · g = 0. When these are arranged, F5 = (h / g) · F F6 = {(g + h) / g} · F Therefore, if the moment arm h is sufficiently smaller than the moment arm g, F5 ≒ 0, F6 ≒
As F, almost the entire load at the time of engagement of the second band brake (B-1) can be received by the third bearing 53.

Thus, in the configuration of the above embodiment, the first
Of the first bearing 51 with respect to the band brake (B-2).
When the first bearing 51 must be arranged offset in the axial direction, a large moment acts on the first bearing 51, so that the first bearing 51 becomes relatively large. Of the first band brake (B
-2) is arranged so as to overlap with the axial position, so that a large moment does not act on the second bearing 52,
The configuration can be small.

Further, two adjacent brake drums 3
When the first bearing 41 and the second bearing 41 are received in a multi-shaft structure, the second bearing 52
Is disposed so as to overlap with the first band brake (B-2) in the axial direction, so that the third bearing 53 can be disposed inside the second band brake (B-1). . In that case, the second band brake (B-1) and the third band brake (B-1)
Since the offset of the bearing 53 becomes small, the third bearing 53 can also have a compact configuration. The load applied to the first Breky drum 31 is the third bearing 5
The first brake drum 3
There is no need to increase the size of the bearing for 1. Therefore, the first
Both the second and third bearings 52, 53 disposed between the shaft 16 and the second shaft 14 can have a compact configuration, and the support structure can be made compact as a whole.

[0020]

FIG. 5 shows an embodiment in which the above configuration is applied to a specific gear train of an automatic transmission T. In the automatic transmission T, basically, input clutches (C-1, C-2) are arranged at both ends of a transmission mechanism M, and hydraulic servos 21, 22 of these clutches are embedded in a transmission case 10, Each brake for achieving the forward gear (B-1 _, B-2, B-3)
All as a band brake planetary gear set M
It is arranged on the outer peripheral side of 1, M2, and M3 and takes out the output from the central part of the transmission mechanism M, and is characterized in that the transmission mechanism M is downsized close to its limit.

The transmission mechanism M of the automatic transmission T is constructed by connecting each element of a so-called two-stage planetary gear set M1 and M3 connected to a carrier ring gear to two input clutches (C-C).
1, C-2) and two brakes (B-3, BR) to provide a mechanism that can achieve three forward speeds and one reverse speed, a one-stage planetary gear set M2 and two brakes By adding (B-1 _and B-2) and performing related control of the two planetary gear sets M1 and M2, the gear train is configured to obtain fourth and fifth speeds in an overdrive configuration.

According to such a configuration, both gear sets M1,
The pinion gears P1, P2 of M2 are connected and integrated, and the respective ring gears R1, R3 of both gear sets M1, M3.
And the carriers C3 and C1 are connected to each other, and the gear set M
The first sun gear S1 and the carrier C1 are connected to an input shaft 14 connected to a turbine shaft of a torque converter (not shown) via clutches (C-1, C-2), respectively, as input elements. The mutually connected ring gear R1 and carrier C3 are connected to an output gear 19 as an output element.

Regarding the relationship between each gear set and the engagement element, the sun gear S1 of the gear set M1 is connected to the brake (B-
According to 1), the sun gear S2 of the gear set M2 is moved by the brake (B-2), and the sun gear S3 of the gear set M3 is moved.
Is the transmission case 1 by the brake (B-3).
0 and can be locked to the transmission case 1 by a brake (BR).
0 can be locked.

More specifically, the sun gear S1 is connected to the input shaft 1
4 through a sun gear shaft 16 fitted on the outer periphery of the clutch (C).
-1), the carrier C1 is connected to the clutch (C-2) via a carrier shaft 17 fitted on the outer periphery of the input shaft 14, and the sun gear S3 is connected to a sun gear shaft 18 fitted on the outer periphery of the carrier shaft 17. Through the brake (B-3). The brake (BR) has a meshing brake configuration. The output gear 19 is
It is connected to a differential via a counter gear (not shown).

The transmission configured as described above supplies hydraulic pressure to hydraulic servos corresponding to each clutch and brake under the control of a hydraulic control device (not shown) to engage and disengage each clutch and brake. Achieve each gear. That is, the first speed is achieved when the clutch (C-1) is engaged and the brake (B-3) is engaged. At this time, the rotation of the input shaft 14 is controlled by the clutch (C-
1), enters the sun gear S1, and is output to the output gear 19 as the rotation of the carrier C3, which is the most decelerated rotation by fixing the sun gear S3 by the engagement of the brake (B-3). On the other hand, the second speed is achieved by engagement of the clutch (C-2) and engagement of the brake (B-3). At this time, the input that has entered the carrier shaft 17 via the clutch (C-2) directly enters the ring gear R3 via the carrier C1, and the sun gear S3 fixed by the engagement of the brake (B-3) serves as a reaction force element. Is output to the output gear 19 as the differential rotation of the carrier C3. For the third speed, both clutches (C-1, C-2)
Is achieved by the direct connection of the first planetary gear set M1. At this time, the rotation of the input shaft 14 is directly output to the output gear 19 as the rotation of the carrier C3.

The fourth speed by overdrive is achieved by engagement of the clutch (C-2) and engagement of the brake (B-1) for fixing the sun gear S1. At this time, the input shaft 14
Of the pinion gear P1 with respect to the rotation of the carrier C1.
Is transmitted from the carrier C3 to the output gear 19 as the rotation of the ring gear R1 whose rotational speed has been increased. On the contrary,
In the fifth speed, the engagement of the clutch (C-2) and the brake (B
In this case, the rotation of the input shaft 14 is rotated with respect to the rotation of the carrier C1 by the rotation of the small-diameter pinion gear P2 which takes a reaction force to the larger-diameter sun gear S2 than when the fourth speed is achieved. The rotation of the ring gear R1 is further increased and transmitted from the carrier C3 to the output gear 19.

The reverse is achieved by the engagement of the clutch (C-1) and the engagement of the brake (BR). At this time, the carrier C1 is fixed against the input of the sun gear S1 and the speed is reduced in reverse. The rotation of the ring gear R1 is output from the output gear 19 via the carrier C3.

In the automatic transmission T having such a configuration, the present invention relates to a configuration in which both rotating members are connected to the planetary gear sets M2 and M1.
Of the planetary gear sets M2, M1
Are a small-diameter pinion gear P2 and a large-diameter pinion gear P1 that are connected and integrated with each other and supported by the carrier C1.
And a large-diameter first sun gear S2 meshing with the small-diameter pinion gear P2, and a small-diameter second sun gear S1 meshing with the large-diameter pinion gear P1. Also, the first
The brake drum 31 as the brake drum of the first
, A brake drum 41 serving as a second brake drum is connected to the second sun gear S1, and the first band brake (B-2) is disposed radially outward of the second sun gear S1. , The second band brake (B-1) is disposed on a side adjacent to the first sun gear S2, and the first bearing 51 is provided with a large-diameter first sun gear S2.
Is arranged on the inner peripheral side of the.

In this transmission, as described above, the gear sets M1 and M1 for achieving the fourth speed and the fifth speed are used.
In order to obtain an overdrive gear ratio using the difference in the outer diameters of the pinion gears P1 and P2 between M2, the pinion gears P1 and P2 having different diameters are directly connected to each other and a common carrier C is used.
1, the transmission case 1 has sun gears S1 and S2 meshing with them as reaction elements.
The brake drums 31, 41 of the band brakes (B-2, B-1) which are locked to 0 must be supported on the shaft through one of the two pinion gears P1, P2. (B-2) Brake drum 3
It is not possible to directly support the shaft 1 radially inward.

Therefore, the brake drum 31 is supported at an offset position on the sun gear shaft 16 as a hollow first shaft via the first bearing 51, and the sun gear shaft 16 is connected to the first band brake (B-2) by a diameter. Input shaft 1 as a second shaft via a second bearing 52 arranged at an axial position overlapping in the direction
4, the brake drum 41 is supported between the sun gear shaft 16 and the input shaft 14 by a third bearing 53 at an axial position overlapping the second band brake (B-1) in the radial direction. The application of the configuration is effective.

Further, according to the above configuration, in addition to the specific effects described in the description of the above embodiment, the arrangement is particularly offset in the axial direction with respect to the first band brake (B-2). The first bearing 51, which must be stopped,
The planetary gear set M is arranged so as to fill an extra space on the inner peripheral side of the first sun gear S2, which necessarily has a large diameter to mesh with the small diameter pinion gear P2.
2 and the advantage of a compact configuration that effectively uses space is obtained.

Although the present invention has been described in detail with reference to the embodiments, the present invention may be embodied by variously changing the specific structure within the scope of matters described in the individual claims. can do.

[Brief description of the drawings]

FIG. 1 is a sectional view of a band brake support device according to an embodiment of the present invention, in which a reaction force generated in a first bearing is added.

FIG. 2 is an explanatory view showing reaction forces generated in second and third bearings of the support device.

FIG. 3 is an explanatory view showing reaction forces generated in second and third bearings of the above-mentioned support device by changing the notation of a moment arm.

FIG. 4 is an explanatory diagram showing a force applied to a second and third bearings of the support device when a second band brake is engaged.

FIG. 5 is a partial sectional view showing an embodiment of the automatic transmission to which the above invention is applied.

[Explanation of symbols]

 T Automatic transmission M1, M2 Planetary gear set C1 Carrier P1 Large-diameter pinion gear P2 Small-diameter pinion gear S1 Second sun gear (other rotating member) S2 First sun gear (rotating member) B-1 Second band brake B- 2 First band brake 10 Case 14 Input shaft (second shaft) 16 Sun gear shaft (first shaft) 31 Band drum 32 Brake band 41 Second band drum 51 First bearing 52 Second bearing 53 Third bearing

Claims (3)

[Claims] At least a first brake drum having a brake drum connected to a rotating member of an automatic transmission and a brake band for tightening the brake drum and locking the brake drum to a transmission case.
An automatic transmission including a band brake, comprising: a first hollow shaft supporting the brake drum via a first bearing; and a second shaft supporting the first shaft via a second bearing. The band brake supporting device for an automatic transmission, wherein the second bearing is disposed at an axial position overlapping the first band brake in a radial direction. 2. The automatic transmission includes a second band brake having a second brake drum connected to another rotating member of the transmission, wherein the first shaft is connected to a second brake drum. The second band brake is disposed axially side by side with respect to the first band brake, and an axial position between the first shaft and the second shaft that radially overlaps with the second band brake. The band brake support device for an automatic transmission according to claim 1, wherein a third bearing is provided on the band brake. 3. The planetary gear set as a component of the planetary gear set, wherein the planetary gear set has a small-diameter pinion gear and a large-diameter pinion gear that are connected and integrated with each other and supported by a carrier. A first sun gear having a large diameter that meshes with the pinion gear, and a second sun gear having a small diameter that meshes with the large diameter pinion gear. A brake drum of the first band brake is connected to the first sun gear, and a second sun gear is provided. Is connected to the second sun gear, the first band brake is arranged radially outward of the second sun gear, and the second band brake is arranged on the side adjacent to the first sun gear. The band brake supporting device for an automatic transmission according to claim 2, wherein the first bearing is provided on an inner peripheral side of the large-diameter first sun gear.