JPH0625723Y2 - Band brake device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a band brake device.

(B) Conventional Technology As a conventional band brake device, for example, Japanese Patent Laid-Open No. 60-
There is one disclosed in Japanese Patent No. 84452. The band brake device shown therein is engaged at two shift speeds, that is, the second speed and the fourth speed. For this reason, the hydraulic servo system has two
It has two pistons, a first speed piston and a fourth speed piston. At the 2nd speed, only the 2nd speed piston works,
In the fourth speed, hydraulic pressure acts on both the second speed piston and the fourth speed piston. The two pistons are coaxially arranged, and exert a pushing force on one end of the band, and a reaction force acting on the band is supported by an anchor pin that supports the other end of the band. The reason why the two hydraulic pistons are used as described above is that the torque capacity of the band brake is different between the second speed and the fourth speed. That is, the torque capacity required to stop the rotating drum at the 4th speed is smaller than the torque capacity necessary at the 2nd speed, but at the 4th speed, the reaction force of the rotating drum at the time of driving from the engine side. Since the supporting direction is on the trailing side with respect to the hydraulic piston, on the other hand, in the second speed, it is the opposite direction to the leading side, and therefore the hydraulic piston pushing force in the fourth speed needs to be increased. For this reason, it is necessary to increase the diameter of the fourth speed piston, which requires a large space for the entire hydraulic servo device. The present invention aims to solve such problems. Japanese Patent Laid-Open No. 60-37444 discloses a hydraulic device for detecting a reaction force of a brake band, which is provided on an anchor portion opposite to a side where a servo piston is provided. Aims to detect the completely synchronized state by the hydraulic device so that the shift timing becomes appropriate, and is not for solving the above-mentioned problems.

(D) Means for Solving the Problems The present invention solves the above problems by arranging two hydraulic pistons in directions opposite to each other and operating as a leading brake in any gear shift. That is, in the band brake device according to the present invention, hydraulic servo pistons capable of exerting a pushing force are provided at both ends of the band, and one of the two or more gear stages has one hydraulic servo piston. Supply hydraulic pressure,
No hydraulic pressure is supplied to the other hydraulic servo piston, and the hydraulic servo piston is operated as a fixed fulcrum. At the other of the two or more speed stages, the hydraulic pressure is supplied to the other hydraulic servo piston.
A hydraulic control device is provided to supply hydraulic pressure to one hydraulic servo piston so that it does not supply hydraulic pressure but operates as a fixed fulcrum. Is composed of.

(E) Action In the second speed, a pushing force acts on the band from the second speed piston, and the fourth speed piston acts as a fixed side fulcrum that supports the reaction force. As a result, the band operates in a leading state and a predetermined torque capacity is obtained. Next, at the 4th speed,
The hydraulic pressure acts on the piston for the fourth speed, and then the pushing force acts on the band. On the other hand, the second speed piston side is the fixed side fulcrum. As a result, the band operates in the leading state even at the fourth speed. As a result, the band operates in the leading state in any case, so that the pressure receiving area of the fourth speed piston may be relatively small, and the required space is reduced.

(F) Embodiment FIG. 2 shows a frame diagram of an automatic transmission (automatic transaxle). The automatic transmission coupled to the engine 10 mounted laterally with respect to the vehicle, that is, in a direction orthogonal to the vehicle front-rear direction, has a torque converter 12, a planetary gear speed change mechanism 14, a differential mechanism 16, and the like. Torque converter 1 to which the rotation from the engine 10 is input
2 has a pump impeller 18, a turbine runner 20, a stator 22, and a lockup clutch 24. The turbine runner 20 is connected to the input shaft 26, the rotational force is transmitted from the pump impeller 18 to the input shaft 26 via fluid in a state where the lockup clutch 24 is released, and the lockup clutch 24 is engaged. Then, the rotational force is mechanically input to the input shaft 26. The lockup clutch 24 operates by the differential pressure between the apply chamber T / A and the release chamber T / R. The torque converter 12 is configured to drive the oil pump 28. The planetary gear speed change mechanism 14 has a first planetary gear set G ₁ and a second planetary gear set G ₂ , and the first planetary gear set G ₁
Is the first sun gear S ₁ and the first internal gear R
₁ and a first pinion carrier PC ₁ that supports a first pinion gear R ₁ that meshes with both gears S ₁ and R ₁ at the same time, and the second planetary gear set G ₂ includes a second sun gear S ₂ , The second internal gear R ₂ , and both gears S
And it is configured to ₂ and _{R 2} simultaneously meshed second pinion gear _{P 2} from the second pinion carrier PC ₂ which supports. The first sun gear S ₁ is always connected to the input shaft 26, and the first pinion carrier PC ₁ and the second internal gear R ₂ are always connected to the output side 30. First
The internal gear R ₁ includes a forward one-way clutch F / O and a forward clutch F / O arranged in series.
It can be connected to the second pinion carrier PC ₂ via C and via an overrun clutch O / C arranged in parallel with these. The second sun gear S ₂ is connectable to the input shaft 26 via the reverse clutch R / C, and
The pinion carrier PC ₂ can be connected to the input shaft 26 via the high clutch H / C. The second sun gear S ₂ can be fixed to the stationary portion by a band brake B / B, and the second pinion carrier PC ₂ has a low one-way clutch L / O and a low and reverse brake L & R / B arranged in parallel with each other. It can be fixed to the stationary part via and. An output gear 32 is provided integrally with the output shaft 30. An idler gear 34 is provided so as to engage with the output gear 32, and a reduction gear 36 is connected to the idler gear 34 via an idler shaft 35 so as to rotate integrally. The reduction gear 36 meshes with the ring gear 38 of the differential mechanism 16. The drive shafts 40 and 42 project left and right from the differential mechanism 16, and the left and right front wheels are connected thereto.

The planetary gear disguise mechanism 14 includes clutches F / C and H /
C, O / C and R / C, brake B / B and L & R /
B and the one-way clutches F / O and L / O are operated in various combinations to produce planetary gear sets G ₁ and G.
₂ elements (S ₁ , S ₂ , R ₁ , R ₂ , PC ₁ and PC
The rotation state of ₂ ) can be changed, and thereby the rotation speed of the output shaft 30 with respect to the input shaft 26 can be variously changed. That is, each clutch, brake, etc.
Move forward 4 by operating the combination shown in the figure.
The first speed can be obtained. It should be noted that in FIG. 3, the mark ◯ indicates that the clutch and the brake are engaged, and in the case of a one-way clutch, the engaged state. Also,
In the band brake B / B column, 2A, 3R, and 4A are respectively the second speed apply chamber 2A and the third speed release chamber 3 of the hydraulic servo device that operates the band brake B / B.
The R and fourth speed apply chambers 4A are shown, and the mark ◯ indicates that hydraulic pressure is being supplied. Further, α ₁ and α ₂ are the ratios of the numbers of teeth of the sun gears S ₁ and R _{2 to} the numbers of teeth of the internal gears R ₁ and R ₂ , respectively, and the gear ratio is the output shaft 3
It is the ratio of the rotation speed of the input shaft 26 to the rotation speed of 0.

By the operation of the planetary gear speed change mechanism 14 as described above, the rotation of the input shaft 26 undergoes a predetermined speed change and is output to the output shaft 30. The rotational force of the output shaft 30 is transmitted to the ring gear 38 of the differential mechanism 16 via the output gear 32, the idler gear 34, and the reduction gear 36. As a result, the left and right front wheels can be driven via the drive shafts 40 and 42. By doing so, it is possible to perform automatic forward four-speed shift with overdrive.

FIG. 4 shows a hydraulic circuit of a hydraulic control device for controlling the power transmission mechanism.

This hydraulic control device includes a pressure regulator valve 50, a manual valve 52, a throttle valve 54, a throttle modifier valve 56, a pressure modifier valve 58, a lockup control valve 60, a governor valve 62, a 1-2 shift valve 64, 2
-3 shift valve 66, 3-4 shift valve 68, 3-
2 timing valve 70, 4-2 sequence valve 7
2, 1st speed fixed range pressure reducing valve 74, speed cut valve 76, overrun clutch control valve 7
8, 1-2 accumulator valve 80, kick-down modifier valve 82, overdrive inhibitor solenoid 84, ND accumulator 88, and servo release accumulator 90 are provided, and these valves and the like are shown in FIG. The oil pump O / P, the apply chamber T / A and the release chamber T / R of the torque converter 12, the clutches R / C, H / are connected as shown.
Three chambers 2A, 3R and 4A of C, O / C and F / C, brake L & R / B, and band brake B / B are also connected as shown. With this configuration,
Depending on the vehicle speed and the throttle opening of the engine, the clutch R / C, H / C, O / C and F / C, and the brake L &
R / B and B / B operate as in the table above.

FIG. 1 shows a band brake device B / B. A band 104 is wound around the outer circumference of the rotary drum 102 in the casing 100. The tip of the second speed piston stem 106 is pressed against one end 104a of the band 104, and the tip of the fourth speed piston stem 108 is pressed against the other end 104b. The fourth speed piston stem 108 is connected so as to move integrally with a fourth speed piston 112 provided in a cylinder 110 provided in the casing 100. The fourth speed piston 112 has a return spring 114.
Is always receiving a return force. The cylinder 110 is closed by a cover 118 fixed by a snap ring 116. As a result, the fourth speed piston 11
The 4th-speed apply chamber 4A is formed on the cover 118 side of No. 2. The chamber 119 on the opposite side of the fourth speed piston 112 is always drained. The aforementioned piston stem 106
A second speed piston 120 is connected to. The second speed piston 120 has a large diameter portion and a small diameter portion. The large diameter portion is fitted to the cylinder 122 formed in the casing 100, and the small diameter portion is fitted to the servo retainer 124 assembled to the casing 100. Have been combined. A third speed release chamber 3R is formed on the large diameter portion side of the second speed piston 120, and a second speed apply chamber 2A is formed between the large diameter portion and the small diameter portion of the second speed piston 120. The second speed piston 120 is constantly subjected to the returning force by the return spring 126.

Next, the operation of this embodiment will be described. In the second speed, hydraulic pressure is supplied to the second speed apply chamber 2A, while the third speed release chamber 3R is drained. In addition, the 4th-speed apply chamber 4A is also drained. Therefore, in this state, the hydraulic pressure acting on the second speed piston 120 acts on the band 104 via the piston stem 106, and the band 104 is fastened to the rotating drum 102. The rotating drum 102 receives a torque in the clockwise direction in FIG. 1 when the engine is driven at the second speed. The reaction force of the force acting on the band 104 is the fourth speed piston stem 108 and the fourth speed piston 112.
Will be mechanically supported via. Ie 4
The speed piston stem 108 will act as an anchor pin. Therefore, the band 104 is fastened in the leading state, and a boosting action due to the torque acting on the rotary drum 102 is obtained, so that a sufficient torque capacity is obtained.

At the third speed, the hydraulic pressure is also supplied to the third speed release chamber 3R while the hydraulic pressure is being supplied to the second speed apply chamber 2A.
The hydraulic pressure in the third speed release chamber 3R acts on the large diameter portion of the second speed piston 120, while the hydraulic pressure in the second speed apply chamber 2A is two.
Since it acts between the large diameter portion and the small diameter portion of the speed piston 120, the second speed piston 120 moves to the release side and the band 1
04 is released.

In the fourth speed, the hydraulic pressure supply state of the second speed apply chamber 2A and the third speed release chamber 3R is the same as that of the third speed, that is, the hydraulic pressure is supplied to both chambers. Is supplied. The hydraulic pressure in the fourth speed apply chamber 4A acts on the fourth speed piston 112, and the hydraulic pressure generated thereby acts on the band 104 via the fourth speed piston stem 108. On the other hand, the second speed piston stem 106 is mechanically supported by the casing 100 via the second speed piston 120. Therefore, in this case, the fourth speed piston stem 108 is on the pushing force acting side, and the second speed piston stem 106 is on the fixed side. In the engine driven state at the fourth speed, the rotary drum 102 receives a counterclockwise torque in FIG. Therefore, even in this case, the band 10
4 will operate in the leading state.

After all, in the second speed, the band 104 operates in the leading state by the hydraulic pressure acting on the second speed piston 120,
Further, in the fourth speed, the band 104 similarly operates in the leading state by the hydraulic pressure acting on the fourth speed piston 112. Therefore, in any case, since the band 104 operates in the leading state with a large torque capacity, the pressure receiving areas of the second speed piston 120 and the fourth speed piston 112 may be relatively small, and the space required for these is small. Decrease. In particular, the diameter of the fourth speed piston 112 becomes smaller, and moreover, as compared with the conventional case where the second speed piston 120 and the fourth speed piston 112 are arranged in two stages on the same side, the casing 100 of the casing 100 is made smaller. Since the casing 100 is arranged on both sides, the protrusion of the casing 100 to the side is reduced, and the mounting performance of the automatic transmission is improved.

(G) Effect of the Invention As described above, according to the present invention, the two hydraulic servo pistons are arranged at both ends of the band so that the pushing force can be applied in opposite directions. The hydraulic transmission can be operated in a state, and the diameter of the hydraulic servo piston can be reduced to downsize the automatic transmission.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a skeleton diagram of an automatic transmission, FIG. 3 is a diagram showing a combination of elements operating at each shift stage, and FIG. 4 is a diagram showing a hydraulic circuit. Is. 102 ... rotary drum, 104 ... band, 112 ... 4th speed piston, 120 ... 2nd speed piston.

Claims (1)

[Scope of utility model registration request] 1. A band brake device for fixing a rotating member of an automatic transmission at two or more gear stages, wherein reaction force states from the rotating member are opposite to each other in the two or more gear stages. In the band brake device having the following gear stages, hydraulic servo pistons capable of exerting a pushing force are provided at both ends of the band, and one of the two or more gear stages has one hydraulic servo piston. The hydraulic pressure is supplied to the other hydraulic servo piston without being supplied to the other hydraulic servo piston, and the hydraulic servo piston is operated as a fixed-side fulcrum. There is a hydraulic control device that supplies hydraulic pressure to the hydraulic servo piston so that it operates as a fixed-side fulcrum without supplying hydraulic pressure. A band brake device characterized by being configured such that all of them are fastened in a leading state in each stage.