JP2018080722A - Engagement/release mechanism for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engagement/release mechanism which is simple in a structure, light in weight and excellent in controllability.SOLUTION: An engagement/release mechanism 10 comprises: a cushion spring 15 which is elastically deformed by a pressing force generated by the press of a clutch pack 13 by a piston 14, and imparts a reaction force to the clutch pack 13; a spline groove 14c formed at an internal peripheral face of the piston 14; and a spline groove 12a formed at an external peripheral face of a hub 12, and engaged with the spline groove 14c. The engagement/release mechanism 10 is friction-engaged with the clutch pack 13 by the pressing force of the piston 14 and the reaction force of the cushion spring 15 accompanied by the movement of the piston 14, and after a gear change stage is formed by connecting a plurality of gears, the spline groove 14c and the spline groove 12a are engaged with each other accompanied by the movement of the cushion spring 15 of the piston 14 having the elastic deformation toward the clutch pack 13.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an engagement / disengagement mechanism for an automatic transmission used for an automatic transmission of a vehicle.

  Conventionally, for example, an automatic transmission clutch as disclosed in Patent Document 1 below is known. In this conventional clutch for automatic transmission, a piston with a smaller diameter is arranged between the drum and the piston. In this conventional automatic transmission clutch, a first hydraulic chamber is formed between the drum and the piston, and a second hydraulic chamber is formed between the piston and the small-diameter piston. ing.

  Thus, by supplying the hydraulic pressure to one or both of the first and second hydraulic chambers, the pressure receiving area is changed with a constant hydraulic pressure, and a fastening force corresponding to each gear stage is generated. That is, for a gear stage that requires a large fastening force, hydraulic pressure is supplied to the first and second hydraulic chambers, and in addition to the piston or the piston, a small-diameter piston presses the friction engagement portion with a large fastening force. On the other hand, since it is necessary to finely adjust the fastening force at the time of gear shifting control when engaging the clutch, only the piston or the small-diameter piston is supplied by supplying hydraulic pressure to the first hydraulic chamber or the second hydraulic chamber. Thus, the friction engagement portion is pressed.

JP 2004-52805 A

  By the way, in the conventional automatic transmission clutch (engagement / disengagement mechanism), the first hydraulic pressure is used to change the fastening force by at least one of the piston and the small-diameter piston according to the magnitude of the transmitted power (torque). It is necessary to supply hydraulic pressure to each of the chamber and the second hydraulic chamber. For this reason, hydraulic paths for supplying hydraulic pressure from the pump to the first hydraulic chamber and the second hydraulic chamber are required, and an oil path, a valve, and the like must be provided for each hydraulic path. Therefore, the size of the engagement / disengagement mechanism is increased, and as a result, the automatic transmission itself is increased in size.

  The present invention has been made to solve the above problems. That is, an object of the present invention is to provide an automatic transmission engagement / disengagement mechanism that has a simple structure, is small and light, and has excellent controllability.

  In order to solve the above problems, an invention of an engagement / disengagement mechanism for an automatic transmission according to a first aspect of the present invention includes a cylindrical drum fixed to a first rotating shaft, and accommodated coaxially with the drum inside the drum. The cylindrical hub fixed to the second rotating shaft and the drum and the hub rotate together by friction engagement between the inner peripheral portion of the drum and the outer peripheral portion of the hub. A friction engagement member that allows relative rotation between the drum and the hub by releasing the friction engagement, and an outer engagement portion that engages with the drum-side engaged portion provided inside the drum. And is fixed to the drum so that it can move along the axis of the drum and cannot rotate relative to the drum, and moves along the direction of the axis to press the frictional engagement member and the frictional engagement member. A cylindrical piston separated from the piston, and the piston presses the frictional engagement member. Alternatively, an automatic transmission engagement / disengagement mechanism for switching the gear position of the automatic transmission by separating the piston from the friction engagement member, and an inner engagement portion provided on an inner peripheral portion of the piston and an outer periphery of the hub And a hub side engaged portion that engages with the inner engaging portion so that the piston can be moved along the axis and is not relatively rotatable around the axis, The piston moves toward the friction engagement member after the friction engagement member is frictionally engaged by the pressing force of the piston pressing the friction engagement member as the piston moves to form a shift stage of the automatic transmission. Thus, the inner engagement portion and the hub side engaged portion are configured to engage with each other.

  According to this, after the frictional engagement member is frictionally engaged by the pressing force of the piston and the shift stage of the automatic transmission is formed, the inner engagement portion of the piston and the hub-side engaged portion of the hub are moved relative to each other. It can be engaged non-rotatably. As a result, the piston and the hub, i.e., the drum and the hub are directly connected, and power (torque) can be transmitted between the first rotating shaft and the second rotating shaft. For this reason, after the shift stage is formed, large power (torque) can be transmitted by the engagement between the inner engagement portion and the hub-side engaged portion without depending on the friction engagement of the friction engagement member. it can. Accordingly, since the inner engagement portion and the hub side engaged portion can be engaged to directly connect the drum and the hub, there is no need to provide a plurality of pistons to transmit a large power (torque), and There is no need to provide a plurality of hydraulic paths. Furthermore, since the frictional force (fastening force) of the frictional engagement member can be set to a magnitude necessary for formation of the shift stage, the size of the frictional engagement member can be reduced. Accordingly, the downsizing of the automatic transmission can be achieved.

It is a skeleton figure which shows the structure of an automatic transmission. It is sectional drawing for demonstrating the structure of the engagement / disengagement mechanism of FIG. It is sectional drawing for demonstrating the action | operation at the time of the shift start of the engagement / disengagement mechanism of FIG. It is sectional drawing for demonstrating the action | operation at the time of the completion of gear shifting of the engagement / disengagement mechanism of FIG. It is sectional drawing for demonstrating the meshing engagement of the engagement / disengagement mechanism of FIG. It is sectional drawing for demonstrating the structure of the engagement / disengagement mechanism which concerns on the 1st modification of embodiment. It is sectional drawing for demonstrating the structure of the engagement / disengagement mechanism which concerns on the 2nd modification of embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that, in the following embodiments and modifications, the same or equivalent parts are denoted by the same reference numerals in the drawings. Each figure used for explanation is a conceptual diagram, and the shape of each part may not necessarily be exact.

  First, the configuration of the automatic transmission 1 including the automatic transmission engaging / disengaging mechanism 10 (hereinafter simply referred to as “engaging / disengaging mechanism 10”) of the present embodiment will be described. As shown in FIG. 1, an output from an engine (not shown) as a drive source is shifted from a torque converter 2 via an automatic transmission 1 and transmitted to a differential (not shown). The automatic transmission 1 includes an input shaft 3 that is an output shaft of the torque converter 2, an output shaft 4 that is coupled to the axle, a first row of planetary gears G1 that are coupled to the input shaft 3, and a second row of planetary gears. A gear G2 and a third row planetary gear G3 are provided.

  The automatic transmission 1 includes a first friction clutch C1, a second friction clutch C2, a third friction clutch C3, a first friction brake B1, a second friction clutch C1, and a second friction engagement element. A friction brake B2 and a case 5 for housing these are provided. The automatic transmission 1 switches the gear position and the predetermined shift pattern by selecting engagement / release of the first friction clutch C1 to the third friction clutch C3, the first friction brake B1, and the second friction brake B2. It is supposed to be. The first friction clutch C1 to the third friction clutch C3, the first friction brake B1, and the second friction brake B2 are each brought into an engaged state and supplied by setting the supplied hydraulic pressure to a high pressure. When the hydraulic pressure is set to a low pressure, the release state is established.

  The planetary gear G1 in the first row is fixed to the case 5 with a sun gear S1 that rotates integrally with the input shaft 3, a ring gear R1, a pinion gear PG1 disposed between the sun gear S1 and the ring gear R1, and the case 5. And a carrier PC1 that rotatably supports the pinion gear PG1. The planetary gear G2 in the second row rotates integrally with the sun gear S2 that rotates integrally with the input shaft 3 via the first friction clutch C1 and the shaft 6, and rotates with the ring gear R1 via the third friction clutch C3 and the shaft 7, or Input is performed via a ring gear R2 fixed to the case 5 via the first friction brake B1, a pinion gear PG2 disposed between the sun gear S2 and the ring gear R2, the second friction clutch C2 and the shaft 8. A carrier PC2 that rotates integrally with the shaft 3 and rotatably supports the pinion gear PG2 is provided. The planetary gear G3 in the third row is fixed to the case 5 through the first friction clutch C1 and the shaft 6 and through the sun gear S3 that rotates together with the input shaft 3 and the carrier PC2 or through the second friction brake B2. Ring gear R3, pinion gear PG3 disposed between sun gear S3 and ring gear R3, and carrier PC3 that rotates integrally with output shaft 4 and rotatably supports pinion gear PG3. Yes.

  The automatic transmission 1 is a transmission capable of forming a forward six-speed reverse gear stage having reverse, neutral, 1st to 4th speed underdrive, and 5th and 6th speed overdrive. . Specifically, in the automatic transmission 1, when only the third friction clutch C3 and the second friction brake B2 are engaged, the rotation of the output shaft 4 is reversed with respect to the input shaft 3 so that the vehicle travels in reverse. It has become. Further, when only the second friction brake B2 is engaged, it is neutral. When only the first friction clutch C1 and the second friction brake B2 are engaged, the first speed is achieved, and when only the first friction clutch C1 and the first friction brake B1 are engaged, the second speed is achieved. Yes. Further, when only the first friction clutch C1 and the third friction clutch C3 are engaged, the third speed is achieved, and when only the first friction clutch C1 and the second friction clutch C2 are engaged, the fourth speed is achieved. Yes. Furthermore, when only the second friction clutch C2 and the third friction clutch C3 are engaged, the fifth speed is achieved, and when only the second friction clutch C2 and the first friction brake B1 are engaged, the sixth speed is achieved. Yes.

  As described above, when the vehicle achieves the first to sixth gears traveling forward, at least one of the first friction clutch C1 and the second friction clutch C2 is engaged. For this reason, in this embodiment, the engagement / disengagement mechanism 10 is applied to the first friction clutch C1 and the second friction clutch C2, and the first friction clutch C1 will be described below as an example. The engagement / disengagement mechanism 10 can be applied to the third friction clutch C3, the first friction brake B1, and the second friction brake B2.

  As shown in FIGS. 1 and 2, the engagement / disengagement mechanism 10 includes a drum 11 that is fixed to an input shaft 3 as a first rotation shaft and rotates integrally with the input shaft 3. The drum 11 is provided in a cylindrical shape, and accommodates a hub 12, a clutch pack 13 as a friction engagement member, and a piston 14 therein. The cylindrical hub 12 is accommodated coaxially with the drum 11, is fixed to the shaft 6 as the second rotation shaft, and rotates integrally with the shaft 6. The hub 12 is provided with a spline groove 12a as a hub-side engaged portion on the outer peripheral portion.

  The clutch pack 13 includes a plurality of annular friction plates 13a and a plurality of annular separation plates 13b. In the present embodiment, as shown in FIG. 2, the plurality of friction plates 13 a are arranged in the direction of the axis of the drum 11 with respect to the spline groove 11 a serving as the drum-side engaged portion provided in the inner peripheral portion of the drum 11. It is possible to move along the axis, and to be relatively non-rotatable around the axis. Further, in the present embodiment, as shown in FIG. 2, the plurality of separate plates 13 b are connected to the hub 12 (with respect to the spline groove 12 a constituting the hub side engaged portion provided on the outer peripheral portion of the hub 12. In other words, the drum 11 is provided so as to be movable along the axis direction and not to be rotatable around the axis line. Each of the plurality of separate plates 13b is alternately arranged while facing each of the plurality of friction plates 13a, and is stacked between the plurality of friction plates 13a. The clutch pack 13 is in contact with a stopper 11b fixed to the inner peripheral portion of the drum 11, and movement along the direction of the axis is restricted.

  The cylindrical piston 14 is provided with a spline groove 14a as an outer engaging portion on the outer peripheral portion. The piston 14 engages and engages with the spline groove 11a provided in the inner peripheral portion of the drum 11 so that the piston 14 can move along the axis of the drum 11 and cannot rotate relative to the drum 11 around the axis. Is provided. In the present embodiment, the piston 14 has a hydraulic chamber 14b. As a result, the drum 11 is moved along the direction of the axis by the hydraulic pressure supplied to the hydraulic chamber 14b by a hydraulic system (not shown). Furthermore, the piston 14 is provided with a spline groove 14c as an inner engagement portion on the inner peripheral portion. As will be described later, the spline groove 14c presses the clutch pack 13 along the direction of the axis of the piston 14, and then meshes with and engages with the spline groove 12a that is a hub-side engaged portion provided in the hub 12.

  In addition, the engagement / disengagement mechanism 10 of the present embodiment has a cushion spring 15 as a reaction member provided between the clutch pack 13 and the piston 14. The cushion spring 15 is an annular disc spring, and is provided on the outer peripheral portion so as to be movable along the axis of the drum 11 with respect to the spline groove 11a of the drum 11 and not rotatable relative to the axis. . The cushion spring 15 is pressed and elastically deformed by the movement of the piston 14 toward the clutch pack 13, and applies a force generated by the elastic deformation, that is, a reaction force against the pressing force of the piston 14 to the clutch pack 13.

  The engagement / disengagement mechanism 10 of the present embodiment configured as described above is, for example, when the fifth speed or the sixth speed is formed as the shift stage of the automatic transmission 1 and the first friction clutch C1 is in the disengaged state (released state). The hydraulic pressure is not supplied to the hydraulic chamber 14b of the piston 14. Thereby, as shown in FIG. 2, the piston 14 is located at a retracted position (backward in FIG. 2) along the direction of the axis of the drum 11. Therefore, in this case, the piston 14 is separated from the cushion spring 15, does not press the clutch pack 13, and the friction plate 13 a and the separate plate 13 b constituting the clutch pack 13 do not frictionally engage.

  On the other hand, when 1st speed-4th speed is formed as the shift stage of the automatic transmission 1, the first friction clutch C1 is changed from the disengaged state (released state) to the engaged state (connected state). In this case, the hydraulic pressure is supplied to the hydraulic chamber 14b of the piston 14, and the piston 14 moves forward (forward in FIG. 3) along the direction of the axis of the drum 11, as shown in FIG. As a result, the piston 14 contacts the cushion spring 15 and presses the inner peripheral portion of the cushion spring 15. Since the movement of the clutch pack 13 along the direction of the axis is restricted by the stopper 11b, the cushion spring 15 is elastically deformed by the pressing force of the piston 14 and applies a reaction force to the friction plate 13a of the clutch pack 13. Therefore, the friction plate 13a starts frictional engagement by contacting and pressing the adjacent separate plate 13b, and the pressed separate plate 13b contacts and presses the adjacent friction plate 13a.

  As a result, when the shift is started, in the clutch pack 13, the alternately arranged friction plates 13 a and separate plates 13 b are caused by the pressing force applied from the piston 14 and the reaction force applied from the cushion spring 15. Friction engagement. In this case, the clutch pack 13 is given a pressing force, that is, a reaction force of the piston 14 via the elastically deformed cushion spring 15, so that the frictional engagement between the friction plate 13a and the separate plate 13b is gently formed. Is done. As a result, the power (torque) transmitted from the input shaft 3 to the shaft 6 gradually increases. In other words, the power (torque) transmitted from the input shaft 3 to the shaft 6 gradually increases as the hydraulic pressure supplied to the hydraulic chamber 14b of the piston 14 increases.

  When the friction engagement between the friction plate 13a and the separation plate 13b in the clutch pack 13 is completed, the shift is completed as shown in FIG. In this state, power (torque) is transmitted from the input shaft 3 to the shaft 6 by frictional engagement in the clutch pack 13. That is, at the time when the shift is completed, as shown in FIG. 4, the spline groove 12a provided in the hub 12 and the spline groove 14c provided in the piston 14 are not yet engaged and engaged.

  After the shift is completed, the piston 14 further presses the cushion spring 15 and elastically deforms it, so that when the piston 14 moves along the direction of the axis toward the clutch pack 13, as shown in FIG. The groove 12a and the spline groove 14c of the piston 14 are engaged with each other. As a result, power (torque) is generated from the piston 14 to the hub 12, that is, from the input shaft 3 to the shaft 6, through the meshing engagement (spline fitting) between the spline groove 12 a and the spline groove 14 c. Communicated. In this case, since the spline groove 12a and the spline groove 14c are mechanically engaged and engaged by spline fitting, a large power (torque) can be transmitted from the input shaft 3 to the shaft 6. When the spline groove 12a of the hub 12 and the spline groove 14c of the piston 14 are engaged with each other, no relative rotation occurs between the hub 12 and the piston 14 due to the frictional engagement of the clutch pack 13. Therefore, the spline groove 12a of the hub 12 and the spline groove 14c of the piston 14 are surely engaged and engaged (spline fitting).

  In the automatic transmission 1, when the next shift stage is formed, the supply of hydraulic pressure to the hydraulic chamber 14b is cut off, and the piston 14 moves backward. As a result, the meshing engagement between the spline groove 12a of the hub 12 and the spline groove 14c of the piston 14 is released. Further, the friction engagement in the clutch pack 13 is also released.

  As can be understood from the above description, according to the engagement / disengagement mechanism 10 of the above-described embodiment, the cylindrical drum 11 fixed to the input shaft 3 that is the first rotation shaft, and the drum inside the drum 11 11 is provided between the inner peripheral part of the drum 11 and the outer peripheral part of the hub 12 and is provided between the inner peripheral part of the drum 11 and the outer peripheral part of the hub 12. The clutch 11 is a friction engagement member that allows the drum 11 and the hub 12 to rotate relative to each other and the frictional engagement is released to allow relative rotation between the drum 11 and the hub 12. 11 has a spline groove 14a that is an outer engaging portion that engages with a spline groove 11a that is a drum-side engaged portion provided inside the outer peripheral portion, and is movable along the direction of the axis of the drum 11. Relative rotation around drum 11 and axis A cylindrical piston 14 which is fixedly disabled and moves along the direction of the axis to press the clutch pack 13 and separate from the clutch pack 13, and the piston 14 presses the clutch pack 13, or This is an automatic transmission engagement / disengagement mechanism that switches the gear position of the automatic transmission 1 when the piston 14 is separated from the clutch pack 13.

  The engagement / disengagement mechanism 10 includes a spline groove 14c, which is an inner engagement portion provided in the inner peripheral portion of the piston 14, and an outer peripheral portion of the hub 12, and is capable of moving the piston 14 along the axis and around the axis. And a spline groove 12a that is a hub-side engaged portion that meshes and engages with the spline groove 14c so as not to rotate relative to the spline groove 14c, and the clutch pack is pressed by the pressing force of the piston 14 pressing the clutch pack 13 as the piston 14 moves. After the frictional engagement 13 forms the gear stage of the automatic transmission 1, the piston 14 moves toward the clutch pack 13 so that the spline groove 14c and the spline groove 12a are engaged with each other.

  According to this, after the clutch pack 13 is frictionally engaged by the pressing force of the piston 14 and the reaction force of the cushion spring 15 to form the gear stage of the automatic transmission 1, the spline groove 14c of the piston 14 and the hub 12 are The spline groove 12a can be engaged and engaged. Thereby, the piston 14 and the hub 12, that is, the drum 11 and the hub 12 are directly connected, and power (torque) can be transmitted between the input shaft 3 and the shaft 6. For this reason, after the shift stage is formed, large power (torque) can be transmitted by the meshing engagement of the spline groove 14c and the spline groove 12a without depending on the frictional engagement of the clutch pack 13. Therefore, since the spline groove 14c and the spline groove 12a are meshed and engaged to directly connect the drum 11 and the hub 12, it is not necessary to provide a plurality of pistons 14, for example, in order to transmit large power (torque). Further, it is not necessary to provide a plurality of hydraulic chambers 14b constituting the hydraulic path. Furthermore, the frictional force (fastening force) of the clutch pack 13 can be set to a magnitude necessary for formation of the shift stage. Thereby, for example, the size of the clutch pack 13 can be reduced by reducing the number of the friction plates 13a and the separate plates 13b or by reducing the radial dimensions of the friction plates 13a and the separate plates 13b. Therefore, the automatic transmission 1 can be reduced in size.

  Further, in this case, the engagement / disengagement mechanism 10 includes a cushion spring 15 that is a reaction force member that is elastically deformed by the pressing force of the piston 14 and applies a reaction force to the clutch pack 13. The clutch pack 13 is frictionally engaged by the pressing force of 14 and the reaction force of the cushion spring 15 to form a gear stage of the automatic transmission 1, and the piston 14 is elastically deformed toward the clutch pack 13 with the cushion spring 15 being elastically deformed. The spline groove 14c and the spline groove 12a are engaged by moving.

  According to this, in the formation of the shift stage of the automatic transmission 1, the cushion spring 15 is elastically deformed to apply a reaction force to the clutch pack 13, so that the pressing force when the piston 14 presses the clutch pack 13 is reduced. The clutch pack 13 can be gently engaged with the change. As a result, the transmission of power (torque) between the hub 12 and the piston 14, that is, the input shaft 3 and the shaft 6, can be gradually changed. It can be finely adjusted. In addition, even after the shift is completed, the piston 14 can move (advance) toward the clutch pack 13 by elastically deforming the cushion spring 15, so that the spline groove 14c and the spline groove 12a can be securely connected. It can be engaged and engaged.

  In this case, the spline groove 14c is provided on the inner peripheral portion of the piston 14 as the inner engaging portion, and the spline groove 12a is provided on the outer peripheral portion of the hub 12 as the hub-side engaged portion, and the spline groove 14c and the spline groove 12a are engaged with each other. Can be engaged. As a result, the spline groove 14c and the spline groove 12a which are engaged with each other can be provided very easily, and the piston 14 and the hub 12, that is, the drum 11 and the hub 12 can be directly connected. Therefore, the input shaft 3 and the shaft 6 can be directly connected reliably, and a large power (torque) can be transmitted between the input shaft 3 and the shaft 6.

  In these cases, the cushion spring 15 can be provided between the clutch pack 13 and the piston 14. Thereby, the pressing force of the piston 14 is applied to the clutch pack 13 as a reaction force via the cushion spring 15. Therefore, the cushion spring 15 can be reliably elastically deformed. As a result, the friction plate 13a and the separate plate 13b in the clutch pack 13 can be gently frictionally engaged, and the shift stage of the automatic transmission 1 can be smoothly smoothed. Can be formed. Further, since the piston 14 can move (advance) while elastically deforming the cushion spring 15, the piston 14 can advance toward the clutch pack 13 even after the shift stage is formed. Therefore, the spline groove 14c provided in the piston 14 and the spline groove 12a provided in the hub 12 can be reliably engaged and engaged.

(First modification of the above embodiment)
In the above embodiment, the cushion spring 15 is provided between the clutch pack 13 and the piston 14. In this case, as shown in FIG. 6, the cushion spring 15 can be provided between the stopper 11 b fixed to the inner peripheral portion of the drum 11 and the clutch pack 13. In this case, when the piston 14 presses the clutch pack 13, the cushion spring 15 is elastically deformed between the moving (advancing) clutch pack 13 and the stopper 11 b and applies a reaction force to the clutch pack 13. be able to. In addition, when the piston 14 moves (advances) together with the clutch pack 13 after the shift is completed, the cushion spring 15 is elastically deformed, so that the spline groove 12a provided in the hub 12 and the spline groove 14c provided in the piston 14 are formed. Intermeshing engagement is possible. Therefore, even in the case of this first modification, the same effect as the above embodiment can be obtained.

(Second modification of the above embodiment)
In the above embodiment, the cushion spring 15 is provided between the clutch pack 13 and the piston 14. In the first modification, the cushion spring 15 is provided between the stopper 11 b fixed to the inner peripheral portion of the drum 11 and the clutch pack 13. In these cases, instead of or in addition to providing the disc spring cushion spring 15, a reaction force portion is provided on the separate plate constituting the clutch pack 13, and the separate plate provided with the reaction force portion is provided. It is also possible to generate a reaction force against the pressing force by being elastically deformed by the pressing force of the piston 14.

  In the second modification, as shown in FIG. 7, an annular separate plate 13c having an uneven shape (wave shape) in the circumferential direction is provided. In this case, in the separate plate 13c, the portion connecting the contact portions that come into contact with the adjacent friction plates 13a becomes the reaction force portion 13c1. Accordingly, in this case, the separate plate 13c functions as a reaction force member. Thus, when the separation plate 13c has an uneven shape in the circumferential direction, when the pressing force of the piston 14 is applied to the clutch pack 13, the separate plate 13c is stretched in the circumferential direction so that the uneven shape becomes a planar shape. The reaction force portion 13c1 is elastically deformed. As a result, the contact area (friction area) between the friction plate 13a and the separate plate 13c gradually increases, and the friction force of the clutch pack 13 gradually decreases with respect to the change in the pressing force of the piston 14, that is, the change in the hydraulic pressure in the hydraulic chamber 14b. Increase.

  Accordingly, at the start of shifting, the power (torque) transmitted from the input shaft 3 to the shaft 6 can be gradually increased by the piston 14 coming into contact with the clutch pack 13. Further, the elastic movement of the separation plate 13c allows the movement (advance) of the piston 14 after the completion of the shift. Therefore, after the shift is completed, the spline groove 12a provided in the hub 12 and the spline groove 14c provided in the piston 14 can mesh and engage with each other, so that large power (torque) can be transmitted from the input shaft 3 to the shaft 6. Can be communicated to. Therefore, also in this second modification, the same effect as in the above embodiment and the first modification can be obtained.

  The present invention is not limited to the above embodiment and each of the above modifications, and various modifications can be adopted without departing from the object of the present invention.

  For example, in the above embodiment and each modification, the cushion spring 15 or the separate plate 13c, which is a reaction force member, is provided. In this case, the cushion spring 15 and the separate plate 13c can be omitted. Even when the cushion spring 15 and the separate plate 13c are omitted, the spline groove 14c that is the inner engagement portion and the spline groove 12a that is the hub side engaged portion are engaged with each other as the piston 14 moves (advances). Can be engaged. Therefore, in this case as well, the piston 14 and the hub 12, that is, the drum 11 and the hub 12 can be directly connected, so that the input shaft 3 and the shaft 6 can be connected directly. A large power (torque) can be transmitted to 6.

  Further, in the above-described embodiment and each modified example, the plurality of friction plates 13a constituting the clutch pack 13 are fixed to the inner periphery of the drum 11 so as to be movable along the direction of the axis and not relatively rotatable around the axis. The plurality of separate plates 13b constituting the clutch pack 13 are fixed to the outer periphery of the hub 12 so as to be movable along the direction of the axis and not relatively rotatable around the axis. In this case, a plurality of separate plates 13b constituting the clutch pack 13 are fixed to the inner peripheral portion of the drum 11 so as to be movable along the direction of the axis and not relatively rotatable around the axis, and the clutch pack is fixed to the outer periphery of the hub 12 It is also possible to fix the plurality of friction plates 13a constituting 13 in such a way that they can move along the direction of the axis and cannot rotate around the axis.

  Moreover, in the said embodiment and each modification, piston 14 has the hydraulic chamber 14b, and it was made to move with the hydraulic pressure supplied to the hydraulic chamber 14b. In this case, the piston 14 may be configured to move by a method other than hydraulic pressure, for example, by electric drive.

DESCRIPTION OF SYMBOLS 1 ... Automatic transmission, 2 ... Torque converter, 3 ... Input shaft, 4 ... Output shaft, 5 ... Case, 6 ... Shaft, 7 ... Shaft, 8 ... Shaft, 10 ... Automatic transmission / disengagement mechanism, 11 ... Drum , 11a: spline groove (drum side engaged portion), 11b ... stopper, 12 ... hub, 12a ... spline groove (hub side engaged portion), 13 ... clutch pack (friction engaging member), 13a ... friction plate , 13b ... separate plate, 13c ... separate plate (reaction member), 14 ... piston, 14a ... spline groove (outer engagement portion), 14b ... hydraulic chamber, 14c ... spline groove (inner engagement portion), 15 ... cushion Spring (reaction member), B1 ... first friction brake, B2 ... second friction brake, C1 ... first friction clutch, C2 ... second friction clutch, C3 ... third friction clutch, G1 Planetary gear, G2 ... Planetary gear, G3 ... Planetary gear, PC1 ... Carrier, PC2 ... Carrier, PC3 ... Carrier, PG1 ... Pinion gear, PG2 ... Pinion gear, PG3 ... Pinion gear, R1 ... Ring gear, R2 ... Ring gear, R3 ... Ring gear, S1 ... Sun gear, S2 ... Sun gear, S3 ... Sun gear

Claims (4)

A cylindrical drum fixed to the first rotating shaft;
A cylindrical hub accommodated coaxially with the drum inside the drum and fixed to a second rotating shaft;
Provided between the inner periphery of the drum and the outer periphery of the hub, the drum and the hub are integrally rotated by friction engagement, and the friction engagement is released to release the friction engagement. A friction engagement member that allows relative rotation between the drum and the hub;
An outer engaging portion that engages with a drum side engaged portion provided inside the drum has an outer peripheral portion that is movable along the direction of the axis of the drum and is relatively relative to the drum and the axis. A cylindrical piston that is fixed to be non-rotatable, moves along the direction of the axis, presses the friction engagement member, and separates from the friction engagement member;
An automatic transmission engagement / disengagement mechanism that switches the gear position of the automatic transmission when the piston presses the friction engagement member or the piston moves away from the friction engagement member;
An inner engaging portion provided on an inner peripheral portion of the piston;
A hub-side engaged portion that is provided on an outer peripheral portion of the hub, and that engages with the inner engagement portion so that the piston can move along the axis and cannot rotate relative to the axis.
The automatic transmission and disengagement mechanism is:
After the friction engagement member is frictionally engaged by the pressing force of the piston pressing the friction engagement member with the movement of the piston to form the shift stage of the automatic transmission,
An automatic transmission engagement / disengagement mechanism configured to engage the inner engagement portion and the hub-side engaged portion by moving the piston toward the friction engagement member. A reaction force member that elastically deforms by the pressing force of the piston and applies a reaction force to the friction engagement member;
As the piston moves, the friction engagement member is frictionally engaged by the pressing force of the piston and the reaction force of the reaction force member to form the shift stage of the automatic transmission,
The said piston moves toward the said friction engagement member with the said elastic deformation of the said reaction member, The said inner side engaging part and the said hub side engaged part are engaged. Engagement / release mechanism for automatic transmission.   The automatic transmission engagement / disengagement mechanism according to claim 1, wherein the outer engagement portion and the hub-side engaged portion are spline grooves that engage with each other.   The engagement / disengagement mechanism for an automatic transmission according to claim 2, wherein the reaction member is provided between the friction engagement member and the piston or between the friction engagement member and the drum.

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