JPH0582511B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD This invention relates to a brake device that prevents rotation of a planetary gear element such as a sun gear in a planetary gear mechanism in order to set a predetermined gear stage in an automatic transmission for a vehicle, and particularly relates to a band brake device. be. BACKGROUND TECHNOLOGY As is well known, automatic transmissions for automobiles use two or three sets of planetary gear mechanisms or differential gear mechanisms. and the carrier and ring gear; in the case of a differential gear mechanism, the ring gear and a pair of side gears that mesh with it)
By fixing one of the elements and using the other two elements as an input member and an output member, an appropriate speed ratio can be obtained. An example of this is shown in the 4th section.
The gear transmission shown here is schematically shown in the figure, and is configured to use two sets of planetary gear mechanisms 1 and 2 to obtain four forward gears and one reverse gear, including overdrive. be. That is, the first clutch C1 is connected between the input shaft 4 connected to the torque converter 3 and the sun gear 5 of the first planetary gear mechanism 1 on the left side in FIG.
is provided, and a second clutch C2 is provided between the second planetary gear mechanism 2 and the carrier 6,
Furthermore, a third clutch C3 is provided between the second planetary gear mechanism 2 and the sun gear 7. Further, the carrier 8 in the first planetary gear mechanism 1 is connected to an output member 9 such as a counter gear, while the carrier 8 in the first planetary gear mechanism 1 is connected to an output member 9 such as a counter gear.
It is connected to the ring gear 10 of the planetary gear mechanism 2, and the ring gear 11 of the first planetary gear mechanism 1 is connected to the carrier 6 of the second planetary gear mechanism 2. Ring gear 11 in first planetary gear mechanism 1
A first one-way clutch F1 is provided between the case 12 and the carrier 6 of the second planetary gear mechanism 2 integrated therewith to prevent reverse rotation (rotation in the opposite direction to the rotation direction of the input shaft 4). A first brake B1, which is a multi-disc brake, is provided in parallel with the first one-way clutch F1. Further, a second brake B2, which is a band brake that prevents rotation of the sun gear 7 of the second planetary gear mechanism 2, is provided between the case 12 and the third clutch C3. 4th clutch C4 in parallel with 4th clutch C4 and sun gear 7 in series with 4th clutch C4.
A second one-way clutch F2 is provided to prevent relative rotation in the positive direction with respect to the input shaft 4 of the input shaft 4. The gears set in the automatic transmission equipped with the gear transmission described above are as shown in Table 1.
A mark indicates an engaged state, a blank indicates a non-engaged state, and an (◯) indicates an engaged state during engine braking.

[Table] As shown in Table 1, if the first clutch C1 is engaged and input is applied to the sun gear 5 of the first planetary gear mechanism 1, the accompanying reverse rotation of the ring gear 11 will be caused by the first clutch C1 being engaged.
As a result, the first planetary gear mechanism 1 performs a deceleration action and becomes the first forward speed. In this case, engine braking can be applied by engaging the first brake B1 and fixing the ring gear 11 in either the forward or reverse direction. In the state of the first forward speed, the sun gear 7 of the second planetary gear mechanism 2 rotates in the reverse direction, but if this is fixed by the second brake B2, the second forward speed is established. Furthermore, when the second clutch C2 is engaged and the second brake B2 is released, the input is from two elements in each planetary gear mechanism 1, 2, so the whole unit rotates as a unit, and therefore the speed of increase/deceleration is increased. In other words, the gear ratio is "1", which is the third forward speed. In this state, the fourth clutch C4 is engaged. When the first clutch C1 is released in this third forward speed state, since the fourth clutch C4 is engaged, the second one-way clutch F2 is engaged, and the sun gear 7 is substantially shifted to the input shaft 4. forward third connected to
speed is maintained. Therefore, if the second brake B2 is applied from this state, the second one-way clutch F2 is disengaged and the sun gear 7 is prevented from rotating in the forward direction, and as a result, the gear ratio is greater than "1". It becomes 4th gear (overdrive stage). When going backwards, the third clutch C3 is engaged to receive input from the sun gear 7 in the second planetary gear mechanism 2, and the first brake B1 prevents the forward rotation of the carrier 6, so that the ring gear 10, that is, the output member 9
rotates in the opposite direction and becomes reverse gear. By the way, an important issue in automatic transmissions is to perform smooth gear shifts without so-called gear shifting shocks, and for this purpose, one-way clutches have traditionally been incorporated into gear transmissions, and timing valves and accumulators have been frequently used in hydraulic control circuits. The aim is to optimize the timing of clutch and brake engagement. However, frequent use of one-way clutches, timing valves, etc. increases the number of components of the automatic transmission, leading to an increase in weight and a rise in price. Therefore, the applicant has already proposed a brake device that can effectively eliminate the shift shock without complicating the overall mechanism.
No. 62-101477). In this brake device, a servo cylinder that operates a push rod for tightening the brake band is movable back and forth, and a valve mechanism is built into the servo cylinder, so that the rotating body (that is, the brake drum) moves in the opposite direction to the tightening direction by the push rod. When it rotates, the servo cylinder moves and the valve mechanism opens to exhaust the servo oil pressure and release the brake. Therefore, with this brake device,
Since the brake can be released by rotating the brake drum, a shift shock can be avoided without using a complicated mechanism such as a timing valve. Problems to be Solved by the Invention However, the above-mentioned brake device already proposed by the present applicant may be modified, for example, by the second brake B2 shown in FIG.
When used as a push rod, this second brake B2 brakes the reverse rotation direction in the second forward speed, and brakes the forward rotation direction in the fourth forward speed, so the hydraulic pressure for pressing the push rod and Although it is necessary to appropriately control the hydraulic pressure that presses the servo cylinder according to the braking direction, a suitable hydraulic control device for performing such hydraulic control has not been developed so far. This invention was made against the background of the above-mentioned circumstances, and has a one-way characteristic and can perform braking in either forward or reverse directions depending on the set gear stage, thereby reducing shift shock. It is an object of the present invention to provide a braking device for an automatic transmission that can be easily applied. Means for Solving the Problems In order to achieve the above-mentioned object, the present invention improves the above-mentioned brake device proposed by the present applicant so that it is operated by hydraulic pressure generated during normal gear shifting. This structure simplifies the hydraulic control mechanism and its control method. More specifically, the device of the present invention arranges a brake band on the outer peripheral side of a rotating body placed in a case, and brings the ends of the brake band closer together by an anchor rod and a push rod, thereby tightening the brake band. In a braking device that brakes a rotating body by tightening, a hydraulic cylinder that moves back and forth in a tangential direction of the rotating body is arranged in the case at a position opposite to the anchor rod, and the push rod is attached to the piston of the hydraulic cylinder. The hydraulic cylinder and the anchor rod are connected so as to move together, and a first oil chamber is formed on the opposite side of the hydraulic cylinder from the push rod across the piston. forming a second oil chamber on the opposite side of the push rod;
Furthermore, a valve mechanism is provided that opens the valves to communicate with each oil chamber when the fluid pressure cylinder retreats toward the second oil chamber, and the first oil chamber is supplied with line hydraulic pressure for setting a predetermined gear position. A line hydraulic oil passage is connected to the second oil chamber, and a switching valve is connected to the second oil chamber to switch the second oil chamber into communication with the line hydraulic oil passage and the exhaust pressure oil passage, and further this switching valve is connected to the second oil chamber. , a predetermined shift signal oil pressure is used as a first control pressure, and the line oil pressure is used as a second control pressure opposing the first control pressure;
The present invention is characterized in that the second oil chamber is communicated with the line hydraulic oil passage when the control pressure reaches a specified pressure and when the first control pressure is not acting. Function In the brake device of the present invention, no matter whether hydraulic pressure is supplied to either the first oil chamber or the second oil chamber, a pressing force is generated that pushes the push rod toward the anchor rod, which acts to tighten the brake band. When the cylinder is rotating in the direction opposite to the tightening direction by the push rod (de-energization direction), a load acts on the fluid pressure cylinder in the direction of retracting it, and therefore the hydraulic pressure in the second oil chamber is discharged. If so, the hydraulic cylinder moves back and the valve mechanism opens, so that the hydraulic pressure in the first oil chamber is exhausted through the second oil chamber, and the brake band is not tightened, that is, braking is not performed. In addition, the second
With the oil chamber communicating with the line hydraulic oil passage,
When line hydraulic pressure is supplied to the line hydraulic oil passage to set a predetermined gear, the hydraulic pressure in the first oil chamber and the second oil chamber increases, and the brake band is tightened by the push rod. Rotation in the direction is also braked. When a shift occurs in this state and the line oil pressure is exhausted, the oil pressure is released from each oil chamber at a speed comparable to that of the line oil pressure that accompanies the gear shift, and the tightening of the brake band is gradually released. Furthermore, when the line hydraulic pressure is supplied to the first oil chamber, if the switching valve is switched to connect the second oil chamber to the exhaust pressure oil passage, for example, a drain, the fluid pressure cylinder can move backward, so the rotating body is de-energized. When rotated in the direction, the valve mechanism opens and pressure is also exhausted from the first oil chamber.
Braking will no longer be applied. When the rotating body starts rotating in the energy direction in this state, the fluid pressure cylinder moves forward and the valve mechanism closes accordingly.
A pressing force is generated to press the push rod, and braking is performed. Therefore, in the brake device of the present invention, when setting a predetermined gear stage, the switching valve is operated to discharge pressure from the second oil chamber, so that the rotating body can be controlled without changing the hydraulic pressure supply state. The brake can be automatically released as the rotation starts in the de-energy direction, and the rotation in the energy direction can be automatically braked. In the device of the present invention, the above-described hydraulic pressure is supplied to the first oil chamber and the second oil chamber.
Since the exhaust pressure is controlled by the hydraulic pressure generated during normal gear shifting operations, no special control mechanism or control method is required. Embodiments Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows the second embodiment of the present invention shown in FIG.
FIG. 3 is a sectional view showing an example applied to brake B2, as seen from the input shaft 4 side. The brake drum 20, which is a rotating body, is connected to the third clutch C3 described above.
This brake drum 20 is connected to the sun gear 7 of the second planetary gear mechanism 2 and housed inside a transmission case 21, and a brake band 22 is arranged on the outer circumferential side of the transmission case 21. . Both ends of the brake band 22 are arranged to be close to each other and face each other, and one end, that is, the first anchor part 23 is connected to a cap 24 having a spherical or arcuate receiving surface at the tip of an anchor rod 25. It is supported by pressing. The anchor rod 25 is housed in a hollow portion formed in the transmission case 21 in the tangential direction of the brake drum 20 so as to move back and forth in its axial direction, that is, in the tangential direction of the brake drum 20. The rightward movement end) is defined by an adjustment bolt 26, and the outer circumferential side is sealed by an O-ring 27. Note that the tip of the anchor rod 25 has a flange portion 2 that protrudes in the radial direction.
A connecting rod 29 passes through and is fixed to the flange portion 28, and the tip of the connecting rod 29 is slidable into a hole 30 formed in the transmission case 21 parallel to the anchor rod 25. Therefore, the tip of the connecting rod 29 serves as a guide pin. Further, the other end of the brake band 22, that is, the second anchor portion 31 presses a push rod 34 attached to a piston 33 of a hydraulic servo cylinder 32 provided in the transmission case 21 at a position substantially opposite to the anchor rod 25. It is maintained by this. The hydraulic servo cylinder 32 is housed in a hollow part 35 formed in the transmission case 21 so as to be able to move back and forth, and has a rear end (an end opposite to the push rod 34 with the piston 33 in between). An annular stopper 36 is disposed in close contact with the inner circumferential surface, and a valve sleeve 37 that protrudes on both front and rear sides in the axial direction is disposed on the inner circumferential side of the stopper 36, and is movable back and forth. A cylindrical portion on the rear end side of the piston 33 is in sliding contact with the inner circumferential surface of the valve sleeve 37 while maintaining liquid tightness. As shown enlarged in FIG. 2, a slight gap is formed between the outer circumferential surface of the valve sleeve 37 and the inner circumferential surface of the stopper 36, forming an oil passage 38. Uchistoppa 3
The portion protruding forward (to the right in FIGS. 1 and 2) from 6 extends outward in the radial direction, and the surface of the extending portion 39 that faces the front of the stopper 36 is the same as the stopper 36. 36, the oil passage 38 between the inner circumferential surface of the stopper 36
is starting to close. Therefore, here the valve sleeve 37 is used as a valve body, and the stopper 36
A valve mechanism 41 is constructed with a valve seat 40 on the front side. The rear end (left end in FIG. 1) of the hollow part 35 that houses the above-mentioned hydraulic servo cylinder 32 is sealed by a case cover 42, and therefore, inside the hollow part 35, The first oil chamber 43 between the piston 33 and the stopper 36 and the stopper 36
and a second oil chamber 44 between the case cover 42 and the case cover 42 are formed. The length of the valve sleeve 37 protruding toward the second oil chamber 44 is set to such a length that the valve sleeve 37 comes into contact with the case cover 42 within the movable range of the hydraulic servo cylinder 32. The valve is configured to be opened by moving the servo cylinder 32 backward. Further, one end of the connecting rod 29 is attached to the hydraulic servo cylinder 32, and the other end of the connecting rod 29 is fixed to the anchor rod 25 as described above. are adapted to move back and forth in the tangential direction of the brake drum 20 as a unit. Further, in the hydraulic servo cylinder 32, in front of the piston 33, a return spring 45 is arranged to push the piston 33 back toward the left in FIG. A line hydraulic oil passage 46 that supplies line hydraulic pressure when setting the second forward speed and the fourth forward speed is connected to the first oil chamber 43. The line hydraulic oil passage 46 is connected to, for example, a 1-2 shift valve and a 3-4 shift valve (not shown), and is supplied with line hydraulic pressure when the second forward speed is set and when the fourth forward speed is set. The oil passage may be branched from the oil passage. This line hydraulic oil passage 46 is provided with an orifice 47 and an accumulator 48 . On the other hand, the second
The oil chamber 44 is connected to a portion of the line hydraulic oil passage 46 closer to the first oil chamber 43 than the accumulator 48 via a switching valve (brake servo sequence valve) 49 . This switching valve 49 is constructed by moving a spool 50 whose lands have the same cross-sectional area, so that the first port 51 communicates with the second oil chamber 44.
is switched to communicate with either the second port 52 to which the line hydraulic oil path 46 is connected and the drain port 53, and a spring 54 that presses the spool 50 is arranged on one end side of the spool 50. At the same time, a first control pressure port 55 is formed at the location where this spring 54 is accommodated, and the line hydraulic oil passage 46 is branched and connected to this port. Further, a control hydraulic oil passage 57 is connected to a second control pressure port 56 on the opposite side of the spring 54 . This control hydraulic oil passage 57 is for applying a shift signal hydraulic pressure generated, for example, in the second and third forward speeds to the second control pressure port 56, and is for switching a predetermined engagement element such as a clutch. The signal hydraulic oil passage 58 that leads to the shift valve (not shown) branches at a position beyond the orifice 59. A solenoid valve 60 is interposed which is turned OFF quickly to close the oil passage leading to the drain. That is, this solenoid valve 60 is a solenoid valve for speed change control that is generally used in a hydraulic control device of a conventional electronically controlled automatic transmission. An annular groove 62 is formed in the transmission case 21 in correspondence with a small hole 61 formed in the hydraulic servo cylinder 32 to supply and discharge hydraulic pressure to and from the first oil chamber 43, and the line is inserted into the annular groove 62. Although the hydraulic oil passage 57 is in communication, the widths of the small hole 61 and the annular groove 62 do not match when the hydraulic servo cylinder 32 moves backward, and the first oil chamber 43
and the line hydraulic oil passage 46 are set to be cut off. Next, the operation of the brake device configured as described above will be explained. The second brake B2 in FIG. 4, in which the above brake device is used, is engaged at the second forward speed and the fourth forward speed to set the respective gears, as shown in Table 1. The operation of upshifting to the following gears and downshifting from these gears will be explained. The state of the electromagnetic valve 60 for each shift pattern, the port in the switching valve 49 with which the first port 51 communicates, and the presence or absence of braking are shown in Table 2.

【table】

[Table] When shifting up from 1st gear to 2nd gear, the solenoid valve 60 is turned OFF when the gear change is determined.
The shift signal hydraulic pressure acts on the second control pressure port 56 of the switching valve 49, and as a result, the spool 50 moves to the left side in FIG. It communicates with port 53. That is, the pressure is exhausted from the second oil chamber 44. At the same time, in the line hydraulic oil passage 46,
For example, a 1-2 shift valve (not shown) is switched to generate line oil pressure for setting the second speed, so line oil pressure is supplied to the first oil chamber 43. As a result, the piston 33 of the hydraulic servo cylinder 32 moves to the right in FIG. 1 and begins to tighten the brake band 22 via the push rod 34. In that case, the brake drum 20 is rotating (reversely rotating) in the direction indicated by the symbol A, but this rotation direction is the so-called energy direction that coincides with the tightening direction by the push rod 34, and the brake drum 20 and the brake band 22 are As a result of the frictional force generated between them, the hydraulic servo cylinder 32 is moved to the right in FIG. Therefore, in addition to the increase in the tightening force by the push rod 34, the so-called winding force of the brake drum 20 causes the brake band 22 to tightly wrap around the brake drum to perform braking. In this case, line oil pressure is supplied to the first oil chamber 43 via the accumulator 48, so the oil pressure increases slowly depending on the characteristics of the accumulator 48. Therefore, the output member 9
Since sudden torque fluctuations do not occur, shift shock can be reduced. Further, as the oil pressure supplied to the first oil chamber 43 gradually increases, the oil pressure of the first control pressure port 55 in the switching valve 49 also gradually increases, and the pressing force due to the oil pressure applied to the first control pressure port 55 and the spring 54 increases. When the pressure exceeds the pressing force due to the shift signal oil pressure applied to the second control pressure port 56, the spool 5
0 is moved to the right side in FIG. 1 (the position shown on the upper side in FIG. 1), and as a result, the second oil chamber 44 communicates with the line hydraulic oil passage 46, and the line oil pressure is also applied to the second oil chamber 44. Supplied. Therefore, after the shift is completed, the backward movement of the hydraulic servo cylinder 32 is the second
Because it is prevented by the oil pressure in the oil chamber 44,
For example, even if the brake drum 20 attempts to rotate (forward rotation) in the direction indicated by reference numeral B in FIG. 1 in an engine braking state, the hydraulic servo cylinder 32 does not move backward and maintains the braking state of the brake drum. On the other hand, when downshifting from 2nd gear to 1st gear, the solenoid valve 60 is activated as the gear change is determined.
Switched from OFF to ON, and line hydraulic oil line 4
The line hydraulic pressure is discharged from 6 by, for example, the switching operation of the 1-2 shift valve. Switching valve 49
When the solenoid valve 60 is turned ON, the gear shift signal oil pressure that was acting on the second control pressure port 56 no longer acts, but does not operate in particular.
Therefore, the second oil chamber 44 remains in communication with the line hydraulic oil passage 46 via the first port 51 and the second port 52. Therefore, the hydraulic pressure in each oil chamber 43, 44 in the hydraulic servo cylinder 32 is discharged via the line hydraulic oil passage 46, and the pressing force of the push rod 34, that is, the tightening force of the brake band 22 is eliminated, so that the brake drum 20 is applied or released, the brake drum 20 begins to rotate in reverse, and the first speed is set. In that case, since the accumulator 48 acts, each oil chamber 43,
44 gradually decreases according to the characteristics of the accumulator 48, and as a result, the brake drum 20
Since the brake is released slowly, the shift shock associated with downshifting from second gear to first gear is reduced. In the second speed state, the solenoid valve 60 is activated as described above.
Although it is set to OFF and the shift signal oil pressure is acting on the first braking pressure port 56, the line oil pressure for setting the second speed is acting on the first control pressure port 55, so the spool 50 is The brake drum 20 is moved to the right side, and reverse rotation of the brake drum 20 is prevented. Even if it is determined to shift to the third forward speed in this state, the solenoid valve 60 remains OFF, but for example, by operating a 2-3 downshift (not shown), water is discharged from the line hydraulic oil passage 46. Therefore, the oil pressure in each oil chamber 43, 44 is
It gradually decreases according to the characteristics of No. 8. As the oil pressure in the line hydraulic oil passage 46 decreases, the switching valve 49
When the pressure in the first control pressure port 55 of the spool 50 decreases, the shift signal hydraulic pressure acting on the second control pressure port 56 of the spool 50 moves it to the left side in FIG. is the first port 5
1 and drain port 53. In this state, the brake band 22 is in contact with the brake drum 20 by pressing the push rod 34 only with the hydraulic pressure in the first oil chamber 43, and therefore the clutch in the third clutch C3 for setting the third speed is pressed. When the torque reaches the turbine torque, the brake drum 20 begins to rotate forward (rotation in the de-energy direction) in the direction indicated by the symbol B in FIG. 1, and accordingly, the hydraulic servo cylinder 32
Due to the pressure being exhausted from the second oil chamber 44, the first
It is moved backwards to the left in the figure. When the hydraulic servo cylinder 32 retreats to a certain extent, the valve sleeve 37 comes into contact with the case cover 42 and its extended portion 39 separates from the valve seat 40 of the stopper 36 as shown in FIG. 62 and the first oil chamber 43 is cut off from the line hydraulic oil passage 46, the oil in the first oil chamber 43 is rapidly exhausted via the oil passage 38 and the second oil chamber 44, As a result, the pressing force of the push rod 34 is eliminated, and the braking of the brake drum 20 is released. In other words, when shifting up from 2nd gear to 3rd gear, the brake drum 20 starts rotating and releases its braking. In other words, it acts as a one-way clutch, so the second clutch C2 The timings of engagement and release of the second brake B2 are perfectly matched, and the shift shock is greatly improved. Even when shifting from the third forward speed to the second speed, the solenoid valve 60 is maintained in the OFF state.
Further, line hydraulic pressure is supplied to the line hydraulic oil passage 46 by operating a 2-3 shift valve, for example. The shift to the second gear is interrupted and line hydraulic pressure begins to be supplied to the line hydraulic oil passage 46, and as a result, the hydraulic pressure in the first oil chamber 43 begins to rise in accordance with the characteristics of the accumulator 48, and as a result, the second clutch C2
until the brake drum 20 is fully released.
is rotating in the forward direction, but when frictional force is generated between the brake band 22 and the brake drum 20 due to an increase in the oil pressure in the first oil chamber 43 in this state, the hydraulic servo cylinder 32 stops the rotation of the brake drum 20. The valve sleeve 37 is moved backward by the force, and as a result, the valve sleeve 37 comes into contact with the case cover 42 and the oil passage 3
Open 8. Therefore, at this point, even if the first
Even if hydraulic pressure is supplied to the oil chamber 43, the brake band 22 contacts the brake drum 20 based on the hydraulic pressure, and the pressure is discharged from the first oil chamber 43 as described above, and as a result, the brake band 22 acts as a brake. The brake drum 20 is repeatedly brought into contact with and separated from the drum 20, but the brake drum 20 is not braked. When the second clutch C2 is gradually released and its clutch torque decreases, the brake drum 20
As mentioned above, is reverse rotation (rotation in the energy direction)
Begin to. Since the brake band 22 is in contact with the brake drum 20 at this time, the hydraulic servo cylinder 32 is moved to the right in FIG. Therefore, since the oil passage 38 from the first oil chamber 43 to the second oil chamber 44 is closed, the oil pressure in the first oil chamber 43 increases rapidly, tightening the brake band 22 and braking the brake drum 20. . When the oil pressure in the first braking pressure port 55 in the switching valve 49 increases to a certain degree as the oil pressure in the first oil chamber 43 increases, the spool 50 is moved to the right side in FIG. 46 to supply line hydraulic pressure to the second oil chamber 44. That is, since the backward movement of the hydraulic servo cylinder 32 is prevented, forward rotation of the brake drum 32 is also prevented, and as a result, the engine brake can be applied in the second speed. That is, in the case of upshifting from 2nd speed to 3rd speed, braking is automatically released as the brake drum 20 starts to rotate forward, and in the case of downshifting from 3rd speed to 2nd speed, When the brake drum 20 attempts to rotate in the opposite direction, the brake drum 20 is automatically braked, and thus functions as a one-way clutch (one-way brake), thereby reliably and easily reducing shift shock. can. After downshifting to the second speed, hydraulic pressure is supplied to the second oil chamber 44 to cancel the one-way characteristic. Next, explaining the case of upshifting to 4th speed, when it is determined that upshifting is required in the 3rd speed state, the solenoid valve 60 is switched ON, and as a result, the shift signal oil pressure is applied to the second control pressure port 56. Since it no longer functions, the spool 50 of the switching valve 49 moves to the right in FIG. Also, the line hydraulic oil passage 46
Line hydraulic pressure is supplied to the line hydraulic pressure by operating a solenoid valve (not shown). Therefore, each oil chamber 4
3 and 44 are supplied with slow hydraulic pressure according to the characteristics of the accumulator 48. In this case, the brake drum 20 rotates in the de-energy direction, but the second oil chamber 44 is also supplied with hydraulic pressure to prevent the hydraulic servo cylinder 32 from moving backward, so the brake band 22 is loosened. As the brake drum 20 is tightened, forward rotation of the brake drum 20 is gradually prevented. Also, when downshifting from 4th gear to 3rd gear, the solenoid valve 60 changes from ON to
However, since line oil pressure is acting on the first control pressure port 55 of the switching valve 49,
Spool 50 remains pressed to the right position in FIG. Therefore, the pressure is slowly discharged from each oil chamber 43, 44 via the line hydraulic oil passage 46. Also, as the oil pressure in the line hydraulic oil passage 46 decreases, the first control pressure port 5 in the switching valve 49
When the hydraulic pressure of 5 becomes low to a certain extent, the spool 50
is moved to the left side in FIG. Exhausted pressure. In this state, a load is applied to the hydraulic servo cylinder 32 from the brake drum 20 in the direction of moving it backward, so the pressure is discharged from the second oil chamber 44, causing the hydraulic servo cylinder 32 to move backward,
As in the case of shifting up to the third speed described above, the valve sleeve 37 is relatively pushed and the first oil chamber 43 communicates with the second oil chamber 44, and as a result, the first oil chamber 43 is also rapidly moved. Pressure is exhausted and brake drum 2
0 is released, and the brake drum 20 begins to rotate forward. In other words, the third speed is set. Therefore, the above-mentioned brake device can function as both a brake with unidirectional characteristics and a brake without unidirectional characteristics depending on the hydraulic pressure supply state, and as a result, it is possible to function as both a brake with unidirectional characteristics and a brake without unidirectional characteristics. Not only can it be used for braking, but it can also effectively prevent shift shock by optimizing the timing of braking and braking release. In addition, the supply and exhaust pressure of hydraulic pressure to perform such operations is based on the shift signal hydraulic pressure and line hydraulic pressure for setting each gear stage, so there is no need for a special hydraulic control device or control method, and the equipment and Both control methods can be simplified. In the above embodiment, the shift signal hydraulic pressure applied to another predetermined shift valve is used as the shift signal hydraulic pressure applied to the second control pressure port 56 of the switching valve 49, but in this invention, other predetermined friction pressure is used. The line oil pressure applied to the hydraulic servo mechanism of the engagement device may be used as the shift signal oil pressure. Although the above embodiment is an example applied to a so-called electronically controlled automatic transmission that changes gears by operating the solenoid valve 60, the brake device of the present invention can also be applied to a hydraulically controlled automatic transmission. . FIG. 3 is a schematic diagram showing an example of this, and the first clutch C1 in FIG. 3 is the first clutch C1 in FIG. 4 described above, and is replaced by the second clutch C2 in the third forward speed. Others are engaged as shown in Table 1 above. That is, the first clutch C1 is engaged in each of the first to third gears, and released in the fourth and reverse gears. This first clutch C1 has
An oil passage 63 (tentatively referred to as a first clutch oil passage) is connected to supply line oil pressure for engaging this from a shift valve (not shown), and this first clutch oil passage 63 is connected to An orifice 64 and an accumulator 65 are installed in this order, and a control hydraulic oil passage 57 that communicates with the second control pressure port 56 in the switching valve 49 is located in front of the orifice 64 in the first clutch oil passage 63 (relative to the orifice 64). (on the opposite side from the accumulator 65). That is, in the example shown in FIG. 3, the clutch oil pressure of the clutch released at the gear position where forward rotation (rotation in the de-energization direction) is to be performed is used as the shift signal oil pressure for the switching valve 49.
Therefore, the operation table according to the above-mentioned Table 2 in this embodiment is as shown in Table 3. In addition, the "signal pressure" column in Table 3 is a column indicating whether or not the clutch hydraulic pressure for the first clutch C1 is generated in the control hydraulic oil path 57, and "ON" indicates whether the clutch hydraulic pressure for the first clutch C1 is generated in the control hydraulic oil path 57.
1 indicates that the clutch hydraulic pressure is supplied and the equivalent hydraulic pressure is acting on the switching valve 49 as the shift signal hydraulic pressure, and "OFF" indicates that the shift signal hydraulic pressure is not acting.

[Table] As is clear from the above explanation and Table 3, the first clutch C1 is maintained in an engaged state at each gear from the first to the third gear, so that between these gears During the speed change, the switching operation of the switching valve 49 is performed only by the hydraulic pressure supplied from the line hydraulic oil passage 46. That is, in the state of the first forward speed, line oil pressure is supplied to the first clutch C1 via the first clutch oil passage 63, so oil pressure acts on the second control pressure port 56 of the switching valve 49, and this On the other hand, no oil pressure is supplied to the line hydraulic oil passage 46, and therefore the spool 50 of the switching valve 49 is positioned to the left as shown on the lower side in FIG. The brake band 2 is in a released state. In this state, the brake drum 20 is rotating in the opposite direction (rotating in the energy direction). When a shift-up from the first gear to the second gear occurs, line hydraulic pressure is supplied to the line hydraulic oil passage 46, and as a result, the hydraulic pressure in the first oil chamber 43 is increased to the line hydraulic pressure according to the characteristics of the accumulator 48. . Therefore, the push rod 34 is in the third position along with the piston 33.
The brake band 22 is gradually tightened by moving to the right in the figure, but since the brake drum 20 is rotating in the energy direction (reverse rotation), the brake band 22 comes into contact with the brake drum 20, and the brake drum 20 tightens. The brake band 22 is strongly tightened to wrap around the brake band 22, thereby braking the brake drum 20. On the other hand, as the oil pressure in the first oil chamber 43 gradually increases, the first control pressure port 55 in the switching valve 49
When the hydraulic pressure increases to a certain extent, the force pushing the spool 50 in the right direction in FIG. 3 becomes stronger than the pushing force caused by the shift signal hydraulic pressure acting on the second control pressure port 56. As shown on the upper side, it moves to the right, and the second oil chamber 44 is also brought into communication with the line hydraulic oil passage 46. That is, after the shift to the second speed occurs, line hydraulic pressure is supplied to each oil chamber 43, 44, and the backward movement of the hydraulic servo cylinder 32 is prevented, and the forward rotation of the brake drum 20 due to, for example, an engine braking state is prevented. It also prevents When downshifting from 2nd gear to 1st gear,
Since the pressure is discharged from the line hydraulic oil passage 46, the oil pressure in each oil chamber 43, 44 gradually decreases according to the characteristics of the accumulator 48. In response, the piston 33, that is, the push rod 34, is pushed back by the return spring 45, so that the braking of the brake drum 20 is released slowly so as not to cause a shift shock. and the first control pressure port 5
5 becomes low to a certain extent, the spool 50 moves to the left side in FIG. The oil chamber 44 is rapidly evacuated. When shifting up from 2nd speed to 3rd speed, pressure is discharged from the line hydraulic oil passage 46, so pressure is gradually discharged from each oil chamber 43, 44 according to the characteristics of the accumulator 48, and the switching valve 49 is also discharged. When the hydraulic pressure acting on the first control pressure port 55 becomes low to some extent, the spool 50 moves to the second control pressure port 55.
6 moves to the left side in FIG. 3, and as a result, the pressure is rapidly discharged from the second oil chamber 44. Therefore, when the oil pressure of the second clutch C2 increases and its clutch torque exceeds the turbine torque, the brake drum 20 begins to rotate forward (rotation in the de-energization direction). Along with this, a load that causes the hydraulic servo cylinder 32 to move backward is applied, so that the hydraulic servo cylinder 32 moves backward due to the pressure being discharged from the second oil chamber 44, and the above-mentioned embodiment As in,
The oil passage 38 that communicates the first oil chamber 43 and the second oil chamber 44 opens, and pressure is also exhausted from the first oil chamber 43. That is, when the brake drum 20 attempts to rotate forward, the braking is automatically released. In addition, when downshifting from 3rd gear to 2nd gear, line hydraulic pressure is supplied to the line hydraulic oil passage 46 from a shift valve, etc., and in that state, the spool 5
0 is located as shown below in Figure 3, and the second
Since the port 52 is closed, first the first oil chamber 43
Hydraulic pressure is supplied to If the brake drum 20 is rotating forward in this state, the hydraulic servo cylinder 3
2 moves backward by receiving force from the brake drum 20, pressure is also exhausted from the first oil chamber 43 as described above, and no braking is performed. and second clutch C
When the clutch pressure of 2 decreases and the brake drum 20 attempts to rotate in the reverse direction, the brake drum 20 tries to wrap around the brake band 22, and the hydraulic servo cylinder 32 is moved forward, causing the valve mechanism 4 to move forward.
1 remains closed, the oil pressure in the first oil chamber 43 increases rapidly and reverse rotation of the blade ram 20 is prevented. That is, in the case of downshifting to the second speed, braking of the brake drum 20 automatically occurs as the brake drum 20 attempts to rotate in the opposite direction. When the oil pressure of the first control pressure port 55 in the switching valve 49 increases to a certain extent as the oil pressure in the first oil chamber 43 increases, the spool 50 moves to the right side in FIG. It is made to communicate with the hydraulic oil passage 46. Therefore, after a downshift to the second speed occurs, line hydraulic pressure is supplied to each oil chamber 43, 44 to perform braking, so the brake drum 20 due to engine braking, etc. Also prevents forward rotation. When shifting up from 3rd gear to 4th gear, the first clutch C1 is released and the second brake B2 is engaged (however, in this case,
Even if the first clutch C1 is released, the one-way clutch F2 is engaged and in operation), so that pressure is discharged from the control hydraulic oil passage 57 and line oil pressure is supplied to the line hydraulic oil passage 46. become. Therefore, in the switching valve 49, since hydraulic pressure no longer acts on the second control hydraulic port 56, the spool 50 moves to the right side in FIG. The line hydraulic oil passage 46 is communicated through the line hydraulic oil passage 46. Therefore, the line hydraulic pressure for setting the fourth speed is simultaneously supplied to each oil chamber 43, 44, thereby preventing forward rotation of the brake drum 20. In addition, each oil chamber 43, 44 in this case
According to the characteristics of the accumulator 48, hydraulic pressure is gradually supplied to the engine, and the one-way clutch F2 is naturally released, so that sudden braking does not occur and the shift shock is reduced. On the other hand, when shifting down from 4th gear to 3rd gear, the line oil pressure is sent to the first clutch C1, and the oil pressure acts on the second control pressure port 56 of the switching valve 49, and the line oil pressure is also applied to the second control pressure port 56 of the switching valve 49. Hydraulic oil line 46
Pressure is released from the Therefore, immediately after a gear shift is determined, the force that moves the spool 50 to the right in FIG. However, when the hydraulic pressure acting on the second control pressure port 55 in the switching valve 49 decreases to a certain extent, the spool 50 is moved to the left side in FIG. 3 by the hydraulic pressure acting on the second control pressure port 56. is,
As a result, the second oil chamber 44 communicates with the drain and is rapidly evacuated. In this state, there is no action to prevent the backward movement of the hydraulic servo cylinder 32, so the hydraulic servo cylinder 32 moves backward as the brake drum 20 rotates forward, and as a result, the valve mechanism 41 opens as described above. Since the pressure is also exhausted from the 1 oil chamber 43, the braking of the brake drum 20 is released. As described above, the brake device of the present invention acts as a brake with unidirectional characteristics or a brake without unidirectional characteristics according to each gear stage without using electrical means, thereby reducing shift shock. can be achieved with a simple configuration. Incidentally, each of the above-mentioned embodiments is an example in which braking is required to be performed at a plurality of gears. (D) When braking is performed only in one predetermined gear in the range, the shift signal oil pressure to the switching valve 49 is supplied via a manual valve used in a normal automatic transmission. It is also possible to use drained line hydraulic pressure. Furthermore, the brake device of the present invention is not limited to the above-described embodiments, and can be used as a brake means for any appropriate gear transmission. Effects of the Invention As is clear from the above description, in the brake device of the present invention, the supply and discharge of hydraulic pressure to the first and second oil chambers, the hydraulic pressure for setting each gear stage, and the shift signal hydraulic pressure to the switching valve. Therefore, no special hydraulic control equipment or control method is required, and therefore the overall configuration can be simplified and its reliability is high. Also, since it can function as both a brake with one-way characteristics and a normal brake without one-way characteristics, you will be able to control the timing of braking and braking release yourself at a specific gear. Therefore, the one-way clutch, which is disposed in parallel with the brake device, can be omitted, thereby simplifying the device, reducing its weight, and reducing its cost. Furthermore, since the brake device of the present invention can perform timing control by itself, it is possible to omit timing control valves such as upshift timing valves and downshift timing valves that were conventionally used. Effects such as being able to simplify the configuration of the hydraulic control circuit can also be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention, FIG. 2 is a partially enlarged sectional view showing the valve mechanism thereof, FIG. 3 is a sectional view showing another embodiment of the invention, and FIG. FIG. 1 is a skeleton diagram showing an example of a gear transmission for an automatic transmission into which the brake device of the invention can be incorporated. 20... Brake drum, 21... Transmission case, 22... Brake band, 23
...First anchor part, 25...Anchor rod,
29...Connection rod, 31...Second anchor part,
32... Hydraulic servo cylinder, 33... Piston, 34... Push rod, 37... Valve sleeve, 38... Oil passage, 40... Valve seat, 41...
Valve mechanism, 43...first oil chamber, 44...second oil chamber,
46...Line hydraulic oil path, 49...Switching valve, 55
...First control pressure port, 56...Second control pressure port, 57...Control hydraulic oil path.

Claims (1)

[Scope of Claims] 1. A brake band is arranged on the outer circumference side of a rotating body arranged in a case, and both ends of the brake band are brought close to each other by an anchor rod and a push rod to tighten the brake band and stop the rotating body. In a brake device for braking, a fluid pressure cylinder that moves back and forth in a tangential direction of the rotating body is arranged in a position facing the anchor rod in the case, the push rod is attached to the piston of the fluid pressure cylinder, and the hydraulic cylinder and the anchor rod so as to move together, and a first oil chamber is formed on the opposite side of the hydraulic cylinder from the push rod across the piston, and the push rod is connected to the hydraulic cylinder so as to move together. A second oil chamber is formed on the side opposite to the second oil chamber, and a valve mechanism is provided that opens the oil chambers to communicate with each other when the fluid pressure cylinder retreats toward the second oil chamber, and the first oil chamber is A line hydraulic oil passage for supplying line oil pressure for setting a predetermined gear is connected, and the second oil chamber is communicated with the line hydraulic oil passage and a discharge pressure oil passage by switching the second oil chamber to the line hydraulic oil passage and the exhaust pressure oil passage. The switching valve is connected to a switching valve that sets a predetermined shift signal oil pressure as a first control pressure, and sets the line oil pressure as a second control pressure opposing the first control pressure, so that the second control pressure is set to a specified level. A brake device for an automatic transmission, characterized in that the second oil chamber is communicated with the line hydraulic oil passage when the pressure is increased and when the first control pressure is not applied.