JP2009085387A - Automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably, accurately and finely control a brake having two oil pressure chambers. <P>SOLUTION: An automatic transmission has a brake 70 comprising a plurality of brake linings 74, a piston 77 for pushing the brake linings 74 and two oil pressure chambers 78<SB>1</SB>, 78<SB>2</SB>for pushing the piston 77 so as to disconnect a predetermined rotating element of a change gear mechanism and a transmission case from each other. A hydraulic control means is provided to start supply of the oil pressure to the oil pressure chamber 78<SB>1</SB>and to start supply of the oil pressure to the other oil pressure chamber 78<SB>2</SB>with a delay. A communication path 200 communicating the top position of the oil pressure chamber 78<SB>1</SB>, which is mounted on a vehicle, with the oil pressure chamber 78<SB>2</SB>and having a predetermined flow path resistance is provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an automatic transmission mounted on an automobile, and more particularly to a structure of a transmission mechanism thereof, and belongs to the technical field of an automobile transmission.

  An automatic transmission mounted on an automobile has a plurality of shift stages having different reduction ratios by switching a power transmission path of a transmission mechanism to which engine output rotation is input via a torque converter by selectively engaging a plurality of friction elements. However, in this type of automatic transmission, there is a problem of how to reduce the shock at the time of shifting, that is, the shift shock, in order to improve performance and quality.

  By the way, as described in Patent Document 1, for example, there is an automatic transmission including two hydraulic chambers to which hydraulic pressure for pressing a brake piston is supplied. In the case of such an automatic transmission, it is considered that the shift shock can be reduced by the method described below.

  First, the hydraulic pressure is supplied to one hydraulic chamber, and then the hydraulic pressure is supplied to the other hydraulic chamber after a delay. According to this hydraulic pressure supply method, the piston is pressed by the hydraulic pressure of one hydraulic chamber, and is delayed and pressed by the hydraulic pressure of both hydraulic chambers. That is, the force acting on the piston from the hydraulic pressure of the two hydraulic chambers gradually increases from zero. Become bigger. As a result, the brake engagement operation can be precisely and precisely controlled, and the occurrence of a shift shock that occurs when the hydraulic pressure acts on the piston suddenly increases from zero, which occurs when there is one hydraulic chamber, is suppressed. In addition, since the hydraulic pressure is supplied to both hydraulic chambers after fastening, a required transmission torque capacity is ensured.

JP 2003-278797 A

  However, there is a possibility that even if two hydraulic chambers are provided and the hydraulic pressure is supplied to one hydraulic chamber first and then the hydraulic pressure is supplied to the other hydraulic chamber later, the fastening operation of the brake cannot be accurately and precisely controlled. There is. Thereby, a shift shock may occur. This is because when a vehicle equipped with an automatic transmission stops for a long time, air enters the hydraulic chamber and an oil passage leading to the hydraulic chamber, and the air accumulates in the hydraulic chamber.

  In such a case, even if the hydraulic pressure is precisely controlled by a valve such as a linear solenoid valve or duty solenoid valve, the hydraulic pressure is used to compress the air, so the force acting on the piston corresponds to the valve control. Therefore, the target brake engagement operation cannot be obtained. That is, the effect of having two hydraulic chambers cannot be obtained.

  Therefore, an object of the present invention is to provide an automatic transmission that can stably and precisely control a brake having two hydraulic chambers and can suppress the occurrence of a shift shock.

In order to solve the above-mentioned problem, the invention according to claim 1 of the present application is
An automatic transmission having a plurality of friction plates, a piston for pressing the friction plates, and two hydraulic chambers for pressing the piston, and having a brake for connecting and disconnecting a predetermined rotation element of the transmission mechanism and the transmission case Machine,
Hydraulic pressure control means for starting the hydraulic pressure supply to one of the two hydraulic chambers first, and starting the hydraulic pressure supply to the other hydraulic chamber with a delay; and
A connecting path having a predetermined flow path resistance that connects the uppermost position of the one hydraulic chamber when the vehicle is mounted and the other hydraulic chamber is provided.

According to a second aspect of the present invention, in the automatic transmission according to the first aspect,
A piston cylinder on which the piston slides is provided separately from the transmission case, and is configured to be attached to the transmission case.
The communication path is formed in the piston cylinder.

Furthermore, the invention according to claim 3 is the automatic transmission according to claim 1 or 2,
The communication path is configured by a gap formed between a hole connecting the uppermost position of the one hydraulic chamber and the other hydraulic chamber, and a shaft fitted in the hole. To do.

Furthermore, the invention according to claim 4 is the automatic transmission according to any one of claims 1 to 3,
The two hydraulic chambers are arranged inside and outside at substantially the same position in the axial direction.

In addition, the invention according to claim 5 is the automatic transmission according to any one of claims 1 to 4,
The one hydraulic chamber is disposed inside and the other hydraulic chamber is disposed outside.

In addition, the invention according to claim 6 is the automatic transmission according to any one of claims 2 to 5,
The transmission case has a main body having an opening, and an end cover attached to the main body and closing the opening,
The piston cylinder is attached to the end cover.

  According to the first aspect of the present invention, the two hydraulic chambers are connected by a communication path having a predetermined flow path resistance, that is, a communication path through which air flows but oil having a high viscosity with respect to air hardly flows. Yes. One hydraulic chamber is connected to the other hydraulic chamber via a communication path at the uppermost position (the portion arranged at the uppermost position when the vehicle is mounted), and the hydraulic pressure is supplied earlier than the other by the hydraulic control means. Be started. As a result, the air in one hydraulic chamber is sent to the other hydraulic chamber via the communication path, and the hydraulic pressure in one hydraulic chamber in a state where the air is removed gradually increases and starts to press the piston. The other hydraulic chamber to which the air is sent also compresses the air, and the hydraulic pressure gradually increases behind the one hydraulic chamber and starts to press the piston. That is, in this way, the force that presses the piston is gradually increased from zero without rapidly increasing. In particular, the force pressed by the hydraulic pressure of the hydraulic chamber in a state where air has been removed, in other words, the change in the pressing force to the piston from zero until before pressing by the hydraulic pressure of the other hydraulic chamber is always constant. As a result, a brake having two hydraulic chambers can be stably and accurately controlled, and the occurrence of a shift shock can be suppressed. That is, the effect of having two hydraulic chambers can be reliably obtained.

  According to a second aspect of the present invention, the piston cylinder on which the piston slides is separate from the transmission case and is attached to the transmission case, and a communication path is formed in the piston cylinder. As a result, the productivity (workability) of the automatic transmission is improved as compared with the case where the piston cylinder is integrated with the transmission case and forms a communication path therewith. For example, the other part of the transmission case can be processed while the communication path is formed in the piston cylinder.

  In addition, when the piston cylinder is integrated with the transmission case and forms a communication path therewith, the other automatic transmission parts are functionally unnecessarily changed to enable the formation of the communication path (for example, It is necessary to provide a space for avoiding interference between the tools forming the communication path), but this is not necessary if the piston cylinder and the transmission case in which the communication path is formed are separate. In other words, the transmission is made compact by separating the piston cylinder and the transmission case.

  Further, according to the invention described in claim 3, the communication path is formed between a hole connecting the uppermost position of one hydraulic chamber and the other hydraulic chamber and a shaft fitted in the hole. Consists of gaps. When a communication path having a predetermined flow resistance in which air flows and almost no oil flows is formed by a hole, the hole needs to have a very small diameter, which increases the processing cost. In contrast, when the communication path is formed by the gap between the hole and the shaft inserted into the hole, the processing cost can be reduced.

  Furthermore, according to the invention described in claim 4, the two hydraulic chambers are disposed inside and outside at substantially the same position in the axial direction of the automatic transmission. Thereby, the automatic transmission is made compact in the axial direction.

  In addition, according to the invention described in claim 5, the one hydraulic chamber (the hydraulic chamber connected to the communication path at the uppermost position) is disposed on the inner side, and the other hydraulic chamber is disposed on the outer side. That is, the other hydraulic chamber exists above the uppermost position of one hydraulic chamber. As a result, air easily moves from one hydraulic chamber to the other hydraulic chamber (air hardly accumulates in one hydraulic chamber).

  In addition, according to the invention described in claim 6, the transmission case has a main body having an opening, and an end cover attached to the main body to close the opening, and the piston cylinder is attached to the end cover. It is attached. Accordingly, the piston cylinder and the end cover (in addition to the components of the automatic transmission disposed therebetween) can be integrated as a subassembly. As a result, the assembly of the automatic transmission is improved.

  Embodiments of the present invention will be described below.

  FIG. 1 is a skeleton diagram showing a configuration of an automatic transmission according to an embodiment of the present invention. This automatic transmission 1 is applied to an engine-side mounted vehicle such as a front engine front drive vehicle, The main components include a torque converter 3 attached to the engine output shaft 2 and a transmission mechanism 5 to which the output rotation of the torque converter 3 is input via the input shaft 4. 4 is housed in the transmission case 6 in a state of being arranged on the axis of the shaft 4.

  Then, the output rotation of the transmission mechanism 5 is transmitted to the differential device 9 via the counter drive mechanism 8 from the output gear 7 which is also disposed in the intermediate portion of the input shaft 4 on the axis of the input shaft 4. The left and right axles 9a and 9b are driven.

  The torque converter 3 includes a case 3a connected to the engine output shaft 2, a pump 3b fixed in the case 3a, and opposed to the pump 3b and driven by the pump 3b via hydraulic oil. A turbine 3c, a stator 3e interposed between the pump 3b and the turbine 3c and supported by the transmission case 6 via a one-way clutch 3d to increase torque, and the case 3a and the turbine 3c, and a lock-up clutch 3f that directly connects the engine output shaft 2 and the turbine 3c via the case 3a. Then, the rotation of the turbine 3 c is transmitted to the transmission mechanism 5 through the input shaft 4.

  On the other hand, the transmission mechanism 5 includes first, second, and third planetary gear sets (hereinafter, simply referred to as “first, second, and third gear sets”) 10, 20, and 30, which are included in the transmission case 6. Are arranged in order from the torque converter side (hereinafter referred to as “front side”) on the anti-torque converter side (hereinafter referred to as “rear side”) of the output gear 7.

  A first clutch 40 and a second clutch 50 are disposed on the front side of the output gear 7 as friction elements constituting the transmission mechanism 5, and a first brake 60 is disposed on the rear side of the output gear 7. A second brake 70 (“Brake” in the claims) and a third brake 80 are arranged in order from the front side, and a one-way clutch 90 is arranged in parallel with the first brake 60.

  Each of the first, second, and third gear sets 10, 20, and 30 is a single pinion type planetary gear set, and is engaged with the sun gears 11, 21, and 31 and the sun gears 11, 21, and 31, respectively. A plurality of pinions 12, 22, 32, carriers 13, 23, 33 that respectively support these pinions 12, 22, 32, and ring gears 14, 24, 34 that mesh with the pinions 12, 22, 32, respectively. ing.

  The input shaft 4 is connected to the sun gear 31 of the third gear set 30, the sun gear 11 of the first gear set 10, the sun gear 21 of the second gear set 20, the ring gear 14 of the first gear set 10, and the second gear set 20. The carrier 23, the ring gear 24 of the second gear set 20, and the carrier 33 of the third gear set 30 are connected to each other. The output gear 7 is connected to the carrier 13 of the first gear set 10.

  Further, the sun gear 11 of the first gear set 10 and the sun gear 21 of the second gear set 20 are connected to the input shaft 4 via the first clutch 40 so as to be connectable and disconnectable, and the carrier 23 of the second gear set 20 is The input shaft 4 is connected to the input shaft 4 via the second clutch 50 so as to be connected and disconnected.

  Further, the ring gear 14 of the first gear set 10 and the carrier 23 of the second gear set 20 are connected to the transmission case 6 via the first brake 60 and the one-way clutch 90 arranged in parallel so as to be connected and disconnected. The ring gear 24 of the second gear set 20 and the carrier 33 of the third gear set 30 are connected to the transmission case 6 via the second brake 70 so that they can be connected and disconnected, and the ring gear 34 of the third gear set 30 is It is connected to the transmission case 6 via the third brake 80 so as to be connectable and detachable.

  With the above-described configuration, according to the speed change mechanism 5, the forward 6 speed and the reverse speed are obtained by combining the engagement states of the first and second clutches 40 and 50 and the first, second, and third brakes 60, 70, and 80. The relationship between the combination and the gear position is shown in the fastening table of FIG.

  That is, at the first speed, the first clutch 40 and the first brake 60 are engaged, and the rotation of the input shaft 4 is input to the sun gear 11 of the first gear set 10 and is decelerated by the first gear set 10 with a large reduction ratio. And output from the carrier 13 of the first gear set 10 to the output gear 7. Note that the first brake 60 is engaged only at the first speed at which the engine brake is operated, and at the first speed at which the engine brake is not operated, the one-way clutch 90 is locked to form the first speed.

  In the second speed, the first clutch 40 and the second brake 70 are engaged, and the rotation of the input shaft 4 is input to the sun gear 11 of the first gear set 10 and at the same time via the second gear set 20 the first gear set. The rotation of the input shaft 4 is decelerated at a reduction ratio smaller than the first speed and is output from the carrier 13 of the first gear set 10 to the output gear 7.

  In the third speed, the first clutch 40 and the third brake 80 are engaged, and the rotation of the input shaft 4 is input to the sun gear 11 of the first gear set 10 and simultaneously via the third gear set 30 and the second gear set 20. The rotation of the input shaft 4 is decelerated at a reduction ratio smaller than that of the second gear and is output from the carrier 13 of the first gear set 10 to the output gear 7.

  In the fourth speed, the first clutch 40 and the second clutch 50 are engaged, and the rotation of the input shaft 4 is input to the sun gear 11 of the first gear set 10 and at the same time passes through the second gear set 20 as it is. It is also input to the ring gear 14 of the gear set 10. As a result, the entire first gear set 10 rotates integrally with the input shaft 4, and rotation with a reduction ratio of 1 is output from the carrier 13 to the output gear 7.

  At the fifth speed, the second clutch 50 and the third brake 80 are engaged, and the rotation of the input shaft 4 is input to the ring gear 14 of the first gear set 10 via the second gear set 20 at the same time as the third gear. It is also input to the sun gear 11 of the first gear set 10 via the gear set 30 and the second gear set 20, and the rotation of the input shaft 4 is accelerated and output from the carrier 13 of the first gear set 10 to the output gear 7.

  At the sixth speed, the second clutch 50 and the second brake 70 are engaged, and the rotation of the input shaft 4 is input to the ring gear 14 of the first gear set 10 as it is via the second gear set 20 and at the same time, the second It is also input to the sun gear 11 of the first gear set 10 via the gear set 20, and the rotation of the input shaft 4 is increased at a speed increasing ratio larger than the fifth speed, and the output gear from the carrier 13 of the first gear set 10. 7 is output.

  At the reverse speed, the first brake 60 and the third brake 80 are engaged, and the rotation of the input shaft 4 is input to the sun gear 11 of the first gear set 10 via the third gear set 30 and the second gear set 20. . At this time, when the rotation direction is reversed in the second gear set 20, rotation in the direction opposite to the rotation direction of the input shaft 4 is output from the carrier 13 of the first gear set 10 to the output gear 7.

  As described above, according to this embodiment, the speed change mechanism 5 is configured by using the three single pinion type planetary gear sets 10, 20, 30 and the five friction elements 40, 50, 60, 70, 80. Thus, an automatic transmission capable of six forward speeds and reverse speeds is realized.

  Next, a specific configuration of the second brake 70 disposed on the rear side of the speed change mechanism 5, which is a characteristic part of the present invention, and its periphery will be described with reference to FIGS. 3, 4, and 5 show a state in which the same part in the axial direction of the speed change mechanism 5 is cut at different cross sections in the circumferential direction.

  As shown in FIG. 3, the transmission case 6 includes a main body case 101 (main body in the claims) that houses the speed change mechanism 5, and an end cover 102 that closes an opening on a rear side end surface of the main body case 101. The flange portion around the rear end opening of the main body case 101 and the peripheral edge portion of the end cover 102 are fastened by bolts 103.

  The second gear set 20 and the third gear set 30 are housed in a space formed by the rear side portion of the main body case 101 and the end cover 102, and the second brake 70 is disposed on the outer peripheral side thereof. And the 3rd brake 80 is accommodated.

  Among these, the second brake 70 is configured using a brake housing 110 that is separate from the main body case 101 and the end cover 102. The brake housing 110 has a configuration in which a rear drum 71 and a front piston cylinder 72 constituting the second brake 70 are integrated, and a cylindrical extension 102 a that extends to the front side provided in the end cover 102. The bolts 111 are used to fix them.

  4, the inner peripheral surface of the drum 71 constituting the brake housing 110 and the outer peripheral surface of the hub 73 integral with the ring gear 24 of the second gear set 20 and the carrier 33 of the third gear set 30 are provided. A plurality of friction plates 74 that are alternately engaged with the spline grooves formed in the drum 71 and the hub 73 are disposed therebetween, and at the rear end of the row of these friction plates 74. A retaining plate 75 is arranged, and a spring receiving plate 76 is arranged at the end on the front side.

  The piston cylinder 72 constituting the brake housing 110 includes an inner peripheral surface portion 72a, an outer peripheral surface portion 72b, an intermediate peripheral surface portion 72c that partitions both the peripheral surface portions 72a and 72b inward and outward, and these peripheral surface portions 72a to 72c. The front-side end surface portion 72d to be connected has a cross-sectional shape that is substantially E-shaped open to the rear side. The rear end portion of the outer peripheral surface portion 72b is expanded in diameter, and further extends to the rear side to form the drum 71.

  A piston 77 is disposed on the opened rear side of the piston cylinder 72. The piston 77 has an inner peripheral portion 77a, an outer peripheral portion 77b, and a rear end surface portion 77c that couples both the portions 77a and 77b. By these respective portions, the sectional shape is opened to the front side. It is U-shaped.

An inner peripheral portion 77a of the piston 77 is fitted into a space between the inner peripheral surface portion 72a and the intermediate peripheral surface portion 72c of the piston cylinder 72, and an inner hydraulic chamber (one hydraulic chamber in claims) 78. ₁ and the outer peripheral portion 77b of the piston 77 is fitted into a space between the outer peripheral surface portion 72b and the intermediate peripheral surface portion 72c of the piston cylinder 72, and the outer hydraulic chamber (the other hydraulic chamber in the claims). to form a 78 _2. The brake housing 110 is provided with oil passages 78a ₁ and 78a ₂ for supplying hydraulic pressure to the hydraulic chambers 78 ₁ and 78 ₂ and fastening the friction plate 74, respectively. The reason why the _two hydraulic chambers 78 ₁ and 78 ₂ exist will be described later.

Further, the end surface portion 77 c of the piston 77 is in direct contact with the spring receiving plate 76 disposed at the end portion on the front side of the row of the friction plates 74. As shown in FIG. 5, the spring receiving plate 76 has extensions 76 a extending radially outward at a plurality of locations in the circumferential direction, and the extensions 76 a are formed on the inner peripheral surface of the drum 71 in the brake housing 110. The piston 77 is inserted into the spring chamber 110a provided at a plurality of locations in the circumferential direction, and the piston 77 is placed on the front side, that is, the hydraulic chambers 78 ₁ , 78 between the extension 76a and the rear inner end surface of the spring chamber 110a. A return spring 79 is mounted to urge the hydraulic pressure supplied to the direction ₂ in the direction opposite to the direction in which the hydraulic pressure is supplied.

  On the other hand, as shown in FIG. 4, the third brake 80 includes a hub 81 integrated with the ring gear 34 of the third gear set 30, an outer peripheral surface of the hub 81, and an inner periphery of the cylindrical extension 102 a of the end cover 102. A plurality of friction plates 82 arranged between the surfaces and alternately engaged with the spline grooves formed in the cylindrical extension 102a. The front of the rows of these friction plates 82 A retaining plate 83 is disposed at the end on the side so as to be in contact with the retaining plate 75 of the second brake 70, and a spring receiving plate 84 is disposed at the end on the rear side.

  Further, on the rear side of the spring receiving plate 84, a piston 85 for fastening the plurality of friction plates 82 is disposed. A hydraulic chamber 86 for operating the piston 85 in the fastening direction when hydraulic pressure is supplied; An oil passage 86 a for supplying hydraulic pressure is provided in the end cover 102.

  As shown in FIG. 5, the spring receiving plate 84 has extensions 84a extending radially outward at a plurality of locations in the circumferential direction, and the extensions 84a are the cylindrical extensions 102a of the end cover 102. The piston 85 is inserted into the spring chambers 102b provided at a plurality of positions in the circumferential direction of the inner peripheral surface of the first piston 85 between the extension 84a and the rear side end surface of the brake housing 110 of the second brake 70. In other words, a return spring 87 that urges the hydraulic chamber 86 in a direction opposite to the direction in which the hydraulic pressure is supplied is mounted.

From here, the role (reason for existence) which the two hydraulic chambers 78 ₁ and 78 ₂ play as components of the brake 70 will be described.

FIG. 6 shows the two hydraulic chambers 78 ₁ , 78 ₂ of the brake 70 and their surroundings (a partially enlarged view of FIG. 3). FIG. 7 shows a hydraulic circuit (hydraulic control means in claims) for controlling the hydraulic pressure of the _two hydraulic chambers 78 ₁ and 78 ₂ .

As shown in FIG. 6, the two hydraulic chambers 78 ₁ and 78 ₂ are connected by a communication path 200. Specifically, communication with the brake housing 110 (the piston cylinder 72) of the end surface portion hole 201 formed toward the uppermost position of the hydraulic chamber 78 ₁ from the outer peripheral side of the 72d, the bore 201 and the hydraulic chamber 78 ₂ The hole 202 is in communication.

  A shaft 203 is fitted into the hole 201. Specifically, the space (gap) between the hole 201 and the shaft 203 is sized such that air flows but oil does not flow. In other words, the gap between the hole 201 and the shaft 203 has a predetermined flow path resistance such that air flows but oil having a high viscosity with respect to the air hardly flows. Thereby, the connecting path 200 has a predetermined flow path resistance. Further, a retaining cap 204 is inserted into the hole 201 so that the shaft 203 does not come out of the hole 201.

Further, the two hydraulic chambers 78 ₁ , 78 ₂ are not both at the same time, so that the hydraulic pressure is supplied to _one hydraulic chamber 78 _{1 first} , and then the hydraulic pressure is supplied to the other hydraulic chamber 78 ₂ later. It is configured. Specifically, this is realized by a hydraulic circuit shown in FIG.

As shown in FIG. 7, the hydraulic circuit is arranged between a hydraulic source such as an oil pump and the two hydraulic chambers 78 ₁ and 78 ₂ , and is a linear solenoid that controls the hydraulic value of the hydraulic pressure supplied to the two hydraulic chambers. a valve (LSV) 300, an accumulator 301 for suppressing the occurrence of overshooting and undershooting at the downstream side is arranged (anti hydraulic pressure source side) hydraulic change, provided between the hydraulic chamber 78 ₂ and LSV300 is it and a closing valve 302 which controls supply of hydraulic pressure to the hydraulic chamber 78 _2.

The LSV 300 is configured to control the supply of hydraulic pressure so that the hydraulic pressure in the hydraulic chambers 78 ₁ and 78 ₂ becomes a predetermined value when the brake 70 is in the engaged state. Further, when the brake 70 is brought into a non-engaged state, the supply of hydraulic pressure is limited to be small. When the LSV 300 controls the supply of the hydraulic pressure, the brake 70 is brought into an engaged state or a non-engaged state at a predetermined timing (for example, according to the engagement table shown in FIG. 2, the timing of shifting to the second speed). Is done.

  The accumulator 301 suppresses a rapid increase in hydraulic pressure immediately after the hydraulic pressure is supplied by the LSV 300 (suppresses overshoot) or suppresses a rapid decrease in hydraulic pressure immediately after the supply of hydraulic pressure is limited to a small value ( (Undershoot is suppressed).

Off valve 302 by the hydraulic pressure chamber 78 by the hydraulic pressure supplied to the ₁ (becomes a certain value the hydraulic pressure supplied to the hydraulic chamber 78 ₁₎ valve 303 is pressed, opens (hydraulic pressure source and the hydraulic chamber 78 ₂ ). Otherwise, the valve 304 is pressed by the spring 304 in the direction opposite to the direction in which the hydraulic pressure is applied, and is closed.

According to such a hydraulic circuit, LSV300 for fastening the brake 70 starts to supply the hydraulic pressure (the hydraulic pressure value starts to rise), the hydraulic pressure is supplied first to the pressure chamber 78 _1. Thereby, the air of the uppermost position of the hydraulic chamber 78 ₁ remains before engagement of the brake 70 is sent by the communication passage 200 for communicating the the uppermost position and the hydraulic chamber 78 ₂ in the hydraulic chamber 78 _2.

Hydraulic chamber 78 ₁ air is withdrawn by the communication path 200 hydraulic pressure is gradually increased, the piston 77 begins to be pressed by the hydraulic pressure. Thereby, the piston 77 starts to push the plurality of friction plates 74.

Becomes a certain value the hydraulic chamber 78 ₁ of the hydraulic opening and closing valve 302 is opened, the hydraulic pressure in the hydraulic chamber 78 ₂ begins to be supplied.

The hydraulic chamber 78 ₂ to which the hydraulic pressure is supplied gradually increases in hydraulic pressure, and the air sent from the hydraulic chamber 78 ₁ (including air that remains in the hydraulic chamber 78 ₂ before the brake 70 is engaged) is compressed while the hydraulic pressure is increased. As a result, the piston 77 starts to be pressed. Thereby, the piston 77 starts to push the plurality of friction plates 74.

Taken together, the hydraulic pressure supply is started by LSV300, hydraulic pressure is supplied first to the pressure chamber 78 _1, hydraulic pressure is supplied to the hydraulic chamber 78 ₂ then delays. Therefore, the pressing force from the hydraulic pressure acting on the piston 77 gradually increases from zero. As a result, the brake engagement operation can be precisely and precisely controlled, and the occurrence of a shift shock that occurs when the hydraulic pressure acts on the piston suddenly increases from zero, which occurs when there is one hydraulic chamber, is suppressed. In addition, since the hydraulic pressure is supplied to both the hydraulic chambers 78 ₁ and 78 ₂ after the fastening, a required transmission torque capacity is ensured.

Further, 1 the two hydraulic chambers _78, 78 _2, because they are contacted by communicating passage 200 having a predetermined flow resistance, the hydraulic pressure supply is started by LSV300, air in the hydraulic chamber 78 ₁ is a hydraulic chamber 78 Move to ₂ . This is reliably performed every time the brake 70 is engaged.

If If the communicating passage 200 is not present, so that the air vent of the hydraulic chamber 78 ₁ is not carried out. Therefore, (because the hydraulic pressure is used to compress the air) a change in the force the hydraulic pressure in the hydraulic pressure chamber 78 ₁ by the amount of air pushes the piston 77 will be different, i.e. the pressing by the hydraulic chamber 78 ₂ of the hydraulic zero The change of the pressing force to the piston 77 before the start is not constant. As a result, the two hydraulic chambers 78 ₁ and 78 ₂ are provided, and the hydraulic pressure is first supplied to the hydraulic chamber 78 ₁ , and then the hydraulic pressure is supplied to the hydraulic chamber 78 ₂ later, so that the force pressing the piston 77 is zero. Therefore, there is a possibility that the effect of controlling the brake 70 with high precision and suppressing the occurrence of a shift shock may not be obtained. That is, every time the brake 70 is engaged, the engagement operation is different, and as a result, a shift shock may occur.

Thus, the air in the hydraulic chamber 78 ₁ is provided with a communication path 200 to move in the hydraulic chamber 78 _2, it can stably precisely precisely controls the brake 70 having two hydraulic chambers ₇₈ 1, 78 _2, Generation of shift shock can be suppressed. That is, the effect of having two hydraulic chambers 78 ₁ and 78 ₂ can be obtained with certainty.

  Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment.

For example, in the case of the above-described embodiment, the communication path 200 that connects the two hydraulic chambers 78 ₁ and 78 ₂ is formed in the piston cylinder 72 (brake housing 110), and the piston cylinder 72 and the automatic transmission case 101 are Although separate, the piston cylinder 72 and the case 101 may be the same body. However, when processing the part that becomes the piston cylinder in the automatic transmission case and further processing the communication path, the productivity of the automatic transmission (when the case and the piston cylinder are separated as described above) ( (In the case of the above-described embodiment, other parts of the transmission case 101 can be processed while the connecting path 200 is formed in the piston cylinder 72 (brake housing 110). ).

  In addition, other automatic transmission parts may be changed functionally unnecessarily only to enable the formation of a communication path (for example, a space for avoiding interference of tools forming the communication path is provided). I need it. As a result, the automatic transmission is increased in size (non-compact). Therefore, as in the above-described embodiment, the member in which the communication path is formed (in the above-described case, the piston cylinder 72) is preferably separate from the automatic transmission case.

Further, in the embodiment described above, two hydraulic chambers ₇₈ 1, 78 ₂ communicating passage 200 to contact the hole 201 to contact the two hydraulic chambers ₇₈ 1, 78 _2, shaft 203 is fitted into the hole 201 However, the communication path 200 may be configured in other forms. As another form, for example, it is conceivable to connect the two hydraulic chambers by a hole having a very small diameter in which air flows and oil does not flow. However, a very small diameter hole requires a long processing time, and the processing cost becomes high due to the expensive tool. Therefore, in order to keep the processing cost low, the connecting path is constituted by a gap formed between the hole connecting the two hydraulic chambers and the shaft inserted into the hole as described above. preferable.

Further, in the case of the above-described embodiment, for example, as shown in FIG. 3, the two hydraulic chambers 78 ₁ and 78 ₂ are disposed on the inner side and the outer side at substantially the same position in the axial direction, so that the automatic transmission is axially moved. It is compact about. However, when it is difficult to arrange the two hydraulic chambers inside and outside at substantially the same position in the axial direction due to the configuration of other friction elements or a plurality of gear sets, this arrangement need not be performed. This is because, without this arrangement, the brake, which is the effect of the present invention, can be stably and precisely controlled, and the occurrence of a shift shock can be suppressed.

Furthermore, in the embodiment described above, the hydraulic pressure is supplied to the previously (air vent to) the hydraulic chamber 78 ₁ is inside the hydraulic chamber 78 ₂ oil pressure is supplied then behind are disposed outside . That is, the hydraulic chamber 78 ₂ exists on the uppermost position of the hydraulic chamber 78 ₁ . As a result, the hydraulic chamber 78 ₂ in the air is likely to move from the hydraulic chamber 78 ₁ (on one of the hydraulic chambers 78 ₁ hardly accumulate air.). However, when the arrangement of the two hydraulic chambers is difficult due to the layout of the components of the automatic transmission, the inner and outer arrangements may be reversed. This is because air can be moved by hydraulic pressure even in the reverse case. However, in order to vent the air in one hydraulic chamber to which the hydraulic pressure is supplied first, the one hydraulic chamber to be vented is arranged inside and the other hydraulic chamber is arranged outside as in the above-described embodiment. It is preferable to do this.

  In addition, in the case of the above-described embodiment, the piston cylinder 72 (brake housing 110) in which the communication path 200 is formed is configured to be attached to the end cover 102. As a result, a sub-assembly including the brake housing 110 and the end cover 102 (in addition to that, components of the automatic transmission disposed therebetween) as shown in FIG. 8 is possible. As a result, the assembly of the automatic transmission is improved.

As described above, in the automatic transmission according to the present invention, when a brake element having two hydraulic chambers is provided, the two hydraulic chambers are provided by providing a communication path for air that connects the two hydraulic chambers. The effect of the provision, that is, the brake can be precisely and precisely controlled, and the effect of suppressing the occurrence of a shift shock can be reliably obtained.
Therefore, there is a possibility of being suitably used in the manufacturing industry field of automatic transmissions for automobiles.

1 is a skeleton diagram of an automatic transmission according to an embodiment of the present invention. It is a table | surface which shows the relationship between the combination of fastening of a friction element, and a gear stage. It is sectional drawing of the principal part of the said automatic transmission. It is sectional drawing by another cut surface. It is sectional drawing by another cut surface. FIG. 4 is an enlarged view of two hydraulic chambers of the second brake and the vicinity thereof. It is a figure which shows the hydraulic circuit relevant to two hydraulic chambers It is sectional drawing of the subassembly of an automatic transmission.

Explanation of symbols

70 Brake 74 Friction plate 77 Piston 78 ₁ Hydraulic chamber (one hydraulic chamber)
78 ₂ Hydraulic chamber (the other hydraulic chamber)
200 connections

Claims (6)

An automatic transmission having a plurality of friction plates, a piston for pressing the friction plates, and two hydraulic chambers for pressing the piston, and having a brake for connecting and disconnecting a predetermined rotation element of the transmission mechanism and the transmission case Machine,
Hydraulic pressure control means for starting the hydraulic pressure supply to one of the two hydraulic chambers first, and starting the hydraulic pressure supply to the other hydraulic chamber with a delay; and
An automatic transmission characterized in that a communication path having a predetermined flow path resistance connecting the uppermost position of the one hydraulic chamber when the vehicle is mounted and the other hydraulic chamber is provided. The automatic transmission according to claim 1, wherein
A piston cylinder on which the piston slides is provided separately from the transmission case, and is configured to be attached to the transmission case.
The automatic transmission, wherein the communication path is formed in the piston cylinder. The automatic transmission according to claim 1 or 2,
The communication path is configured by a gap formed between a hole connecting the uppermost position of the one hydraulic chamber and the other hydraulic chamber, and a shaft fitted in the hole. Automatic transmission to do. The automatic transmission according to any one of claims 1 to 3,
The automatic transmission, wherein the two hydraulic chambers are disposed inside and outside at substantially the same position in the axial direction. The automatic transmission according to any one of claims 1 to 4,
The automatic transmission is characterized in that the one hydraulic chamber is disposed on the inner side and the other hydraulic chamber is disposed on the outer side. The automatic transmission according to any one of claims 2 to 5,
The transmission case has a main body having an opening, and an end cover attached to the main body and closing the opening,
The automatic transmission, wherein the piston cylinder is attached to the end cover.

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