JP2017003059A - Automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic transmission improved in the controllability of engagement control of friction engagement elements at cold start.SOLUTION: An automatic transmission 10 comprises an input shaft 12 which is connected to a power source without interposing a fluid transmission device, an output shaft 13 outputting power, a transmission mechanism 20 including plural friction engagement elements, an oil pan 14 provided below the transmission mechanism 20, and an oil pump 32 for supplying hydraulic oil from the oil pan 14 to the friction engagement elements, in which when starting, a predetermined friction engagement 21 among the plural friction engagement elements is put in a slip state, and the hydraulic oil is supplied for cooling to the predetermined friction engagement 21. A hydraulic oil suction port 42a of the oil pump 32 is disposed at a position directly under the predetermined friction engagement 21 in the oil pan 14.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an automatic transmission, and more particularly to an automatic transmission in which a transmission mechanism is connected to a power source without a fluid transmission device.

  Conventionally, an automatic transmission mounted on a vehicle is connected to a power source (for example, an engine) via a torque converter disposed on the power source side of the speed change mechanism including a planetary gear mechanism and a hydraulic friction engagement element. By using the torque converter, a smooth shift operation that suppresses the shift shock and a good vehicle start operation due to creep and torque increase are realized.

  However, with the recent increase in the number of stages of automatic transmissions and the improvement in controllability of the engagement control of friction engagement elements, problems related to shift shocks and starting operations have been improved, and the need for torque converters has been reduced. . That is, the shift shock can be suppressed by reducing the reduction ratio step between the respective shift stages by increasing the number of stages and improving the controllability of the engagement control of the friction engagement elements. In addition, the speed reduction ratio of the first speed can be set large by the multi-stage, and the necessity for the torque increasing action is reduced.

  On the other hand, there is a strong demand for improving the fuel efficiency performance of an engine and improving the onboard performance of an automatic transmission, and the abolition of a torque converter having large dimensions and weight is desired.

  Patent Document 1 discloses an automatic transmission that has a multi-stage (6-speed or 8-speed) shift stage and has a damper disposed on the power source side of the transmission mechanism in place of the torque converter. According to this automatic transmission, a creep ratio is set by setting a large reduction ratio when starting the vehicle and connecting a start brake, which is one of a plurality of frictional engagement elements that are engaged when the vehicle starts, in a slip state. As a result, a start operation that does not require a torque converter is realized.

  Here, the slip state of the frictional engagement element means that the friction plate engaged with one rotating member and the friction plate engaged with the other rotating member (one in the case of a brake is a fixed member) are pressed against each other. The state of relative rotation.

JP 2009-236234 A

  By the way, in an automatic transmission equipped with a torque converter, the hydraulic oil is agitated while circulating between the pump impeller and the turbine runner in the torque converter, and the temperature of the hydraulic oil increases. In the stall state where the turbine runner is rotating and stopped, the temperature raising action is high. For this reason, even when cold, the temperature of the hydraulic oil rises to a required temperature when the vehicle starts, but if the torque converter is abolished, the temperature of the hydraulic oil may not rise when cold.

  Here, the hydraulic oil is generally selected such that the lower the temperature, the higher the viscosity, and the proper viscosity at the temperature in the normal operating state. For this reason, when it is cold, the viscosity of the hydraulic oil is high and the controllability of the engagement control of the frictional engagement element is deteriorated, so that a shift shock occurs, and if it is attempted to avoid this, the shift time becomes longer. In any case, good shift control becomes difficult.

  As a result, when the engine is cold, for example, idle stop control that requires quick engagement of the frictional engagement element when the engine is started is prohibited. Further, when the viscosity of the hydraulic oil is high, the agitation resistance by the gear in the transmission mechanism increases, and the viscous resistance between the friction plates in the friction engagement element in the non-engaged state increases. These cause an increase in engine load, resulting in a problem that the fuel efficiency of the engine deteriorates.

  In other words, as described above, when the torque converter is eliminated, the temperature rise effect of the hydraulic oil by the torque converter cannot be obtained, and the above-described problem due to the temperature of the hydraulic oil not rising at the time of cold becomes remarkable.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and in an automatic transmission in which a speed change mechanism is connected to a power source without going through a fluid transmission device, control of the fastening control of the frictional engagement element during the cold state. The purpose is to improve the performance.

  First, the invention according to claim 1 of the present application includes an input unit connected to a power source without using a fluid transmission device, an output unit for outputting power to the drive wheel side, and a plurality of frictional engagement elements. A transmission mechanism that forms a power transmission path between the input unit and the output unit, a hydraulic oil storage unit provided below the transmission mechanism, and the hydraulic oil stored in the hydraulic oil storage unit as the friction An oil pump for supplying to the fastening element, and when starting, a predetermined friction fastening element of the plurality of friction fastening elements is brought into a slip state, and the hydraulic oil is cooled in the predetermined friction fastening element. The hydraulic oil suction port of the oil pump is disposed at a position directly below the predetermined frictional engagement element in the hydraulic oil reservoir.

  According to a second aspect of the present invention, in the automatic transmission according to the first aspect, a control valve unit that controls supply of the hydraulic oil to the plurality of frictional engagement elements is provided below the transmission mechanism. The hydraulic oil suction port is disposed below the control valve unit, and a penetrating portion that vertically passes through the control valve unit at a position directly below the predetermined frictional engagement element in the control valve unit. Is provided.

  According to a third aspect of the present invention, in the automatic transmission according to the first aspect, a control valve unit that controls supply of the hydraulic oil to the plurality of frictional engagement elements is provided below the transmission mechanism. And the hydraulic oil suction port is disposed below the control valve unit, and the control valve unit is offset so as to avoid a gap between the predetermined frictional engagement element and the hydraulic oil suction port. It is characterized by being provided.

  According to a fourth aspect of the present invention, in the automatic transmission according to any one of the first to third aspects, the hydraulic oil suction port is opened upward. .

  The invention according to claim 5 includes an input unit connected to a power source without going through a fluid transmission device, an output unit for outputting power to the drive wheel side, and a plurality of frictional engagement elements. A transmission mechanism that forms a power transmission path between the output portion and the output section; a hydraulic oil storage section provided below the transmission mechanism; and the hydraulic oil stored in the hydraulic oil storage section as the friction engagement element And an oil pump for supplying the hydraulic pump to a predetermined frictional engagement element of the plurality of frictional engagement elements when starting, wherein a hydraulic oil suction port of the oil pump is provided. The hydraulic oil that is supplied to the predetermined frictional engagement element for cooling and discharged from the predetermined frictional engagement element at the start is provided so as to be directly introduced.

  According to the invention of each claim of the present application, the following effects can be obtained by the above configuration.

  According to the first aspect of the present invention, since the hydraulic oil suction port is disposed immediately below the predetermined frictional engagement element, the hydraulic oil discharged from the predetermined frictional engagement element is directly supplied to the hydraulic oil suction port. Can be introduced. As a result, it is possible to preferentially supply the hydraulic oil heated to the frictional engagement element through the oil pump due to the frictional heat generated in the predetermined frictional engagement element that is brought into the slip state at the start. Therefore, since the hydraulic oil whose viscosity has been reduced by the temperature rise can be preferentially supplied to the frictional engagement element, the controllability of the engagement control of the frictional engagement element can be improved at an early stage even when it is cold.

  As a result, for example, when the drive source is an engine, the start delay of the idle stop control can be suppressed at the time of cold start, the lengthening of the shift time can be suppressed early, and the friction in the non-engaged state can be suppressed. The viscous resistance between the friction plates in the fastening element can be reduced. Therefore, the fuel efficiency performance of the engine at the time of cold start can be improved.

  According to the second aspect of the present invention, even when the control valve unit is disposed immediately below the predetermined frictional engagement element, the hydraulic oil discharged from the predetermined frictional engagement element is operated via the penetration portion. Can guide to the oil inlet.

  According to the third aspect of the present invention, the control valve unit does not block introduction of the hydraulic oil discharged from the predetermined frictional engagement element into the hydraulic oil suction port.

  According to the invention described in claim 4, the hydraulic oil discharged from the predetermined frictional engagement element among the hydraulic oil stored in the hydraulic oil reservoir is supplied from the hydraulic oil suction port opened upward in the downward direction. Easy to inhale preferentially.

  Further, according to the invention described in claim 5, by directly introducing the hydraulic oil that has been discharged from the predetermined frictional engagement element that is in a slip state at the time of starting and that has been heated, from the hydraulic oil suction port, Hydraulic oil can be effectively supplied to the oil pump.

  That is, according to the automatic transmission according to the present invention, in the automatic transmission in which the speed change mechanism is connected to the power source without the fluid transmission device, the heated hydraulic oil can be supplied to the frictional engagement element. In addition, it is possible to improve the controllability of the engagement control of the friction engagement element at the time of cold.

1 is a diagram illustrating a schematic configuration of an automatic transmission according to an embodiment of the present invention. FIG. 3 is a side cross-sectional view of the automatic transmission showing the periphery of the oil pan. It is a figure similar to FIG. 2 which shows the modification of an oil strainer. It is a figure similar to FIG. 2 which shows the case where the control valve unit is arrange | positioned over the downward direction of the predetermined friction fastening element in a side view. FIG. 3 is a view similar to FIG. 2, showing a case where the control valve unit is not disposed below the transmission mechanism.

  Hereinafter, an automatic transmission according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 shows a schematic configuration of an automatic transmission 10 according to an embodiment of the present invention. As shown in FIG. 1, an automatic transmission 10 is a vertical-type automatic transmission that is mounted on a vehicle and has an axial center extending in the longitudinal direction of the vehicle body. A power transmission path between an input shaft 12 (input unit) connected to 1 through a damper 2, an output shaft 13 (output unit) that outputs power to the drive wheel side, and the input shaft 12 and the output shaft 13. And a transmission mechanism 20 that forms That is, the automatic transmission 10 is connected to a power source without a fluid transmission device (torque converter).

  The transmission mechanism 20 includes a plurality of planetary gear mechanisms (not shown) and a plurality of hydraulic friction engagement elements (not shown) such as clutches and brakes, and selectively engages these friction engagement elements by hydraulic control. Thus, a plurality of reduction ratios (transmission ratios) corresponding to a plurality of shift speeds are realized by switching the power transmission path via each planetary gear mechanism. The frictional engagement element is configured as a multi-plate type including a plurality of friction plates.

  The automatic transmission 10 also includes a hydraulic oil supply unit 30 that supplies hydraulic oil to the transmission mechanism 20. The hydraulic oil supply unit 30 includes an oil pan 14 (hydraulic oil storage unit), an oil strainer 40, an oil pump 32 that is rotationally driven by the input shaft 12, and a control valve unit 33. The oil pump 32 is an oil pan. The hydraulic oil stored in 14 is sucked through the oil strainer 40 and supplied to the transmission mechanism 20 through the control valve unit 33.

  The oil pan 14 is attached to the lower part of the transmission case 11 and stores a predetermined amount of hydraulic oil. The hydraulic oil supplied to the control valve unit 33 or the transmission mechanism 20 is discharged from these oil pans. 14 is collected.

  The control valve unit 33 is attached to the lower part of the transmission case 11 and is accommodated in the oil pan 14, and the hydraulic oil discharged from the oil pump 32 is adjusted to the line pressure to adjust the control oil. Pressurized hydraulic oil is selectively supplied to the hydraulic chambers of the friction engagement elements for hydraulic control, and the friction plates and planetary gears of the friction engagement elements are used to cool and lubricate the hydraulic oil drained during pressure regulation. It is designed to be supplied to the mechanism. Further, the control valve unit 33 is not limited to the oil drained at the time of pressure regulation as the cooling and lubrication hydraulic oil, and may supply hydraulic oil whose pressure and supply amount are adjusted.

  FIG. 2 is a side sectional view of the automatic transmission 10 showing the periphery of the oil pan 14, and is a frictional engagement element that is controlled to be engaged when the vehicle starts (that is, to realize a shift stage when the vehicle starts). A predetermined frictional engagement element 21 that is in a slip state when the vehicle starts is also shown. In the present embodiment, the predetermined frictional engagement element 21 is, for example, a hydraulic brake, but is not limited thereto, and may be a hydraulic clutch.

  The lower part of the predetermined frictional engagement element 21 is covered with the transmission case 11, and a space in which the predetermined frictional engagement element 21 is accommodated through the case through opening 11 a formed in the transmission case 11, and the oil pan 14. Is communicated with the inside of the top and bottom.

  The predetermined frictional engagement element 21 includes a rotation member 21a, a rotation side friction plate 21b engaged with the rotation member 21a, a fixed side friction plate 21c engaged with the transmission case 11 as a fixed member, and a piston 21d. And the hydraulic chamber 21e, and the piston 21d presses the friction plates 21b and 21c against each other by increasing the hydraulic pressure in the hydraulic chamber 21e with hydraulic oil supplied via the control valve unit 33.

  In addition, by adjusting the hydraulic pressure in the hydraulic chamber 21e, the rotation side friction plate 21b can be engaged with the fixed side friction plate 21c in a slip state. In the slip state, frictional heat is generated between the rotating side friction plate 21b and the fixed side friction plate 21c, so that the hydraulic oil is cooled between the friction plates 21b and 21c from the control valve unit 33 to ensure durability. It is supplied for lubrication.

  The hydraulic oil supplied between the friction plates 21b and 21c is heated by the frictional heat generated between the friction plates 21b and 21c, and is lowered downward from the predetermined friction fastening element 21 through the case through opening 11a. It is discharged and collected in the oil pan 14.

  The oil strainer 40 includes a strainer body 41, a hydraulic oil suction portion 42 that introduces hydraulic oil into the strainer main body 41, and an oil pump introduction portion 43 that introduces hydraulic oil from the strainer main body 41 to the oil pump 32. In the embodiment, the oil pump introduction portion 43 is attached to the control valve unit 33.

  The strainer body 41 is flat below the control valve unit 33 and is disposed along the bottom surface of the oil pan 14. The strainer main body 41 filters the hydraulic oil introduced from the hydraulic oil suction portion 42 and supplies the oil pump 32. A filter (not shown) for preventing foreign matter from entering the camera is incorporated.

  The hydraulic oil suction portion 42 extends in a substantially horizontal direction from one end portion of the strainer body 41, and a suction port 42a is formed at the tip portion thereof. The hydraulic oil in the oil pan 14 passes through the suction port 42a. It is supposed to be sucked into. The suction port 42 a opens at a position directly below the predetermined frictional fastening element 21.

  As shown by the white arrow in FIG. 2, the hydraulic oil discharged from the predetermined frictional engagement element 21 flows downward in the oil pan 14 and directly from the suction port 42a of the oil strainer 40 disposed at the position immediately below. Are sucked in and introduced into the oil pump 32.

  According to this embodiment, during the operation of the automatic transmission 10, the hydraulic oil stored in the oil pan 14 is sucked by the oil pump 32, and a plurality of frictional engagement elements are provided as fastening hydraulic pressures via the control valve unit 33. It is selectively supplied, and a gear position according to the driving state is realized. Further, hydraulic fluid is supplied for cooling and lubrication to the friction plate of the frictional engagement element, the meshing portion of the gear, the bearing portion, and the like.

  In particular, the predetermined frictional engagement element 21 that is controlled to be in a slip state when the vehicle is started has a large amount of hydraulic oil for cooling in order to cool the frictional heat generated between the rotation-side friction plate 21b and the fixed-side friction plate 21c by the slip. To be supplied. The hydraulic oil heated up by this cooling is discharged from the predetermined frictional engagement element 21 and collected in the oil pan 14. In this case, as indicated by the white arrow in FIG. 2, the hydraulic oil discharged from the predetermined frictional engagement element 21 flows downward in the oil pan 14, and the oil strainer 40 disposed at the position immediately below the oil pan 14. It is directly sucked from the suction port 42 a and introduced into the oil pump 32. As a result, the hydraulic oil that has been discharged from the predetermined frictional engagement element 21 and has been heated is preferentially sucked into the oil pump 32 through the hydraulic oil suction port 42a.

  Therefore, in the present embodiment, the suction port 42a of the hydraulic oil suction portion 42 is disposed immediately below the predetermined frictional engagement element 21, so that the hydraulic oil stored in the oil pan 14 is discharged from the predetermined frictional engagement element 21. The hydraulic oil can be introduced directly into the suction port 42a of the hydraulic oil suction portion 42. As a result, the hydraulic oil supplied from the oil pump 32 is supplied to the predetermined frictional engagement element 21 that is slipped when the vehicle starts and is heated by frictional heat generated between the friction plates 21b and 21c of the predetermined frictional engagement element 21. It can be effectively supplied to the frictional engagement element.

  Therefore, since the hydraulic oil whose viscosity has been lowered by the temperature rise can be supplied to the frictional engagement element in preference to the low-temperature hydraulic oil stored in the oil pan 14, the frictional engagement element can be engaged even during cold start. Controllability of control can be improved early.

  As a result, for example, when the drive source is an engine, the start delay of the idle stop control can be suppressed at the time of cold start, the lengthening of the shift time can be suppressed early, and the friction in the non-engaged state can be suppressed. The viscous resistance between the friction plates in the fastening element can be reduced. Therefore, the fuel efficiency performance of the engine at the time of cold start can be improved.

  It should be noted that the control valve unit 33 is located from the position immediately below the predetermined frictional engagement element 21 to the input shaft 12 side (left side in the figure) so as to avoid a gap between the predetermined frictional engagement element 21 and the suction port 42a of the hydraulic oil suction part 42. It is arranged offset. For this reason, the control valve unit 33 does not block the introduction of the hydraulic oil discharged from the predetermined frictional engagement element 21 to the suction port 42a of the hydraulic oil suction portion 42.

  FIG. 3 shows oil strainers 50 and 60 according to deformation. FIG. 3A shows the oil strainer 50, and FIG. 3B shows the oil strainer 60. As shown in FIG. As shown in FIG. 3A, the oil strainer 50 is different from the oil strainer 40 in that the strainer body 51 is formed integrally with the oil pan 14. Further, as shown in FIG. 3B, the oil strainer 60 is different from the oil strainer 40 in that the strainer body 51 is located above the control valve unit 33.

  However, in any case, the suction ports 52a and 62a of the hydraulic oil suction portions 52 and 62 are common to the oil strainer 40 in that the suction ports 52a and 62a are disposed immediately below the predetermined frictional fastening element 21. That is, it is only necessary that the suction ports 52a and 62a of the hydraulic oil suction portions 52 and 62 are arranged at positions immediately below the predetermined friction fastening element 21, and the position and attachment of the strainer main bodies 51 and 61 are not particularly limited. .

  Further, as shown in FIG. 3B, the suction port 62a of the hydraulic oil suction portion 62 of the oil strainer 60 is provided so as to open upward. Thereby, the hydraulic oil discharged from the predetermined frictional engagement element 21 and flowing downward can be sucked in more effectively.

  FIG. 4 shows a case where the control valve unit 33 is not arranged so as to avoid a gap between the predetermined frictional engagement element 21 and the suction port 42a of the hydraulic oil suction part 42, that is, in a side view shown in FIG. The case where it overlaps and positions between the predetermined friction fastening element 21 and the suction inlet 42a is shown. 4A shows a state in which the oil strainer 40 is attached below the control valve unit 33, and FIG. 4B shows a case in which the oil strainer 50 is formed integrally with the oil pan 14. Is shown.

  In this case, as shown in FIG. 4, the control valve unit 33 is formed with a through-hole 33 a penetrating the control valve unit 33 vertically at a position directly below the predetermined frictional engagement element 21.

  By forming the penetrating portion 33a in the control valve unit 33, even when the control valve unit 33 is disposed immediately below the predetermined friction engagement element 21, the predetermined friction engagement is performed as indicated by the white arrow in FIG. The hydraulic oil discharged from the element 21 can be introduced into the suction ports 42a and 52a of the hydraulic oil suction parts 42 and 52 through the penetration part 33a. That is, the control valve unit 33 does not block the introduction of the hydraulic oil discharged from the predetermined frictional engagement element 21 to the suction port 42a of the hydraulic oil suction portion 42.

  FIG. 5 shows a case where the control valve unit 33 is not disposed below the speed change mechanism 20.

  In the above embodiment, the input transmission 12 and the output shaft 13 are described as an example of an automatic transmission for a rear-wheel drive vehicle arranged on the same axis, but the present invention is not limited to this, and the present invention is not limited to this. It can also be applied to an automatic transmission.

  Further, in the above-described embodiment, the case where the speed change mechanism 20 includes a planetary gear mechanism has been described as an example. However, the present invention is not limited thereto, and is applicable to a case where a counter gear mechanism is included. is there. Even in this case, the oil guide may be configured to guide the hydraulic oil discharged from the friction engagement element that is brought into the slip state among the friction engagement elements that are controlled to be engaged when the vehicle starts to the suction portion of the oil pump. .

  In the above embodiment, the case where the control valve unit 33 is located below the speed change mechanism 20 has been described as an example. However, the present invention is not limited to this, and as shown in FIG. However, the present invention can also be applied to the case where it is attached to a side portion other than the lower side of the speed change mechanism 20, for example.

  Various modifications and changes may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

  As described above, according to the automatic transmission according to the present invention, in the automatic transmission in which the transmission mechanism is connected to the power source without the fluid transmission device, the heated hydraulic fluid is supplied to the friction engagement element. As a result, the controllability of the engagement control of the frictional engagement element in the cold state can be improved at an early stage, which may be suitably used in this kind of manufacturing technology field.

DESCRIPTION OF SYMBOLS 10 Automatic transmission 11 Transmission case 11a Case through opening 12 Input shaft 13 Output shaft 14 Oil pan 20 Transmission mechanism 21 Predetermined frictional engagement element 30 Hydraulic oil supply part 32 Oil pump 33 Control valve unit 33a Through part 40 Oil strainer 41 Strainer body 42 Hydraulic oil suction part 42a Hydraulic oil suction port 43 Oil pump introduction part

Claims (5)

An input connected to a power source without a fluid transmission device;
An output unit for outputting power to the drive wheel side;
A speed change mechanism including a plurality of frictional engagement elements and forming a power transmission path between the input portion and the output portion;
A hydraulic oil reservoir provided below the transmission mechanism;
An oil pump for supplying the hydraulic oil stored in the hydraulic oil reservoir to the frictional engagement element;
An automatic transmission in which a predetermined friction engagement element among the plurality of friction engagement elements is brought into a slip state at the time of starting, and the hydraulic oil is supplied to the predetermined friction engagement element for cooling,
2. The automatic transmission according to claim 1, wherein a hydraulic oil suction port of the oil pump is disposed immediately below the predetermined frictional engagement element in the hydraulic oil reservoir. A control valve unit that controls supply of the hydraulic oil to the plurality of friction engagement elements is provided below the transmission mechanism,
The hydraulic oil suction port is disposed below the control valve unit; and
In the control valve unit, a penetrating portion that vertically penetrates the control valve unit is provided at a position directly below the predetermined frictional engagement element.
The automatic transmission according to claim 1. A control valve unit that controls supply of the hydraulic oil to the plurality of friction engagement elements is provided below the transmission mechanism,
The hydraulic oil suction port is disposed below the control valve unit; and
The control valve unit is provided offset so as to avoid a gap between the predetermined frictional engagement element and the hydraulic oil suction port.
The automatic transmission according to claim 1. The hydraulic oil suction port is opened upward.
The automatic transmission according to any one of claims 1 to 3. An input connected to a power source without a fluid transmission device;
An output unit for outputting power to the drive wheel side;
A speed change mechanism including a plurality of frictional engagement elements and forming a power transmission path between the input portion and the output portion;
A hydraulic oil reservoir provided below the transmission mechanism;
An oil pump for supplying the hydraulic oil stored in the hydraulic oil reservoir to the frictional engagement element;
An automatic transmission in which a predetermined frictional engagement element among the plurality of frictional engagement elements is brought into a slip state when starting,
The hydraulic oil suction port of the oil pump is provided so that the hydraulic oil that is supplied to the predetermined frictional engagement element for cooling and discharged from the predetermined frictional engagement element when starting is directly introduced. Automatic transmission characterized by.

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