JPH02125170A - Automatic transmission - Google Patents

Abstract

PURPOSE:To perform the shift-down to a shift stage not provided in a main transmission by operating an auxiliary transmission to a reduction stage in response to the preset shift pattern when performing the shift-down to the shift stage lower by one from the fourth speed or the fifth speed. CONSTITUTION:A planetary gear device having a ring gear 96 attaining shift stages of four forward speeds and a reverse speed as an output member is provided on a main transmission 4, and a reduction planetary gear device having a ring gear 101 connected to the ring gear 96 as an input member and attaining a reduction stage or a directly coupled stage is provided on an auxiliary transmission 10. Ordinarily, the auxiliary transmission 10 is selectively operated at the reduction stage or the directly coupled stage only when the main transmission 4 is selected to the first speed or the second speed to attain five forward speeds. When the shift-down is performed to the shift stage lower by one stage from the fourth speed or the fifth speed, the auxiliary transmission 10 is operated to the reduction stage in response to the preset shift pattern, and the shift- down is performed to the shift stage with the shift ratio different from that of the shift stage of the main transmission 4. The power characteristic and the fuel consumption or the like can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic transmission equipped with a starting device and a planetary gear device.

[Prior art]

An automatic transmission in which a main transmission equipped with a starting device and a planetary gear set and an auxiliary transmission equipped with a planetary gear set for deceleration are connected in series is disclosed, for example, in Patent Application Publication No. 502274 of 1988. There is.

The above publication shows a skeleton of a transmission in which a reduction gear is connected after a main transmission with four forward speeds. As is clear, only one of the gears operates the speed reducer in one gear to obtain five forward gears.

[Problem to be solved by the invention]

When the present invention achieves five forward speeds by combining a main transmission with four forward speeds and a sub-transmission which is a speed reducer, the main transmission is always in first or second gear. The auxiliary transmission is operated only in low gears to achieve 5 forward speeds, and when downshifting from the 4th or 5th high gear, the auxiliary transmission is activated in deceleration gear according to a preset shift pattern. An object of the present invention is to provide an automatic transmission that is operated to shift down to a gear position having a gear ratio different from that of the gear ratio of a main transmission.

[Means to solve the problem]

In the automatic transmission of the present invention, the main transmission (4) has a forward
It is equipped with a planetary gear device whose output member is a ring gear (96) that achieves a gear stage of 1 speed and 1 reverse speed.

The auxiliary transmission (10) is equipped with a planetary gear device for reduction that achieves a reduction gear or a direct gear by using a ring gear (101) connected to a ring gear (96) of the main transmission as an input member, and is normally connected to the main transmission (4). ) is selected as 1st or 2nd gear, the auxiliary transmission (10) is selectively operated in the reduction gear or direct gear, thereby achieving 5th forward speed and also changing from 4th or 5th gear. When downshifting to the next lower gear, the auxiliary transmission (10) is activated to a reduction gear according to a preset gear shift pattern, thereby changing the gears of the main transmission (4). The gear ratio is configured to shift down to a gear position having a different gear ratio.

Note that the above-mentioned symbols in parentheses are in contrast to the drawings, but do not limit the configuration in any way.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

Figure 2 shows the skeleton of an automatic transmission, in which the automatic transmission 1 includes a torque converter 2, which is a starting device, and a transmission 3.
Equipped with. The transmission 3 is a main transmission 4 arranged concentrically.
and an auxiliary transmission 10, the main transmission 4 achieves four forward speeds and one reverse speed, and the auxiliary transmission 10 achieves two speeds, a direct connection with a reduction ratio of 1 and a reduction ratio of 1 or more. Achieve. The transmission 3 uses five clutches, three brakes, and three one-way clutches as frictional engagement elements.

The torque converter 2 includes a converter case 21 that is an input member connected to the crankshaft of the engine, and the converter case 21 drives a pump impeller 22 . The hydraulic oil pressurized by the pump impeller 22 passes through the stator 23 supported by the case 3o of the transmission 3 via the one-way clutch 24, drives the turbine runner 27, and transmits power to the turbine output shaft 28. A lock-up clutch 26 for coupling is provided between the pump impeller 22 and the turbine output shaft 28, and the converter case 21 and the output shaft 28 are directly coupled when necessary.

The output shaft 28 of the torque converter 2 acts as an input shaft of the main transmission 4, and this input is transmitted to the clutch drum 40 of the first clutch 41.

The first clutch 41 is a forward clutch that is always activated when the vehicle is moving forward, and power is transmitted via the clutch hub 43 to an outer race 46 that is integrated with the clutch hub 43 of the first one-way clutch 45. An inner race 47 of the one-way clutch 45 drives a large sun gear shaft 48 and a large sun gear 49 that is integrated with the large sun gear shaft 48 . The first one-way clutch 45 operates between 1st and 4th speeds.

A second clutch 52 is disposed inside the drum 40 of the first clutch 41 . The second clutch 52 is a clutch that operates in the fourth and fifth speeds, and the clutch hub 53 is connected to an intermediate shaft 55, and the intermediate shaft 55 supports the carrier 54 of the planetary gear device 80.

The drum 40 of the first clutch 41 is the fifth clutch 65
drum 60. The fifth clutch 65 is a so-called coast clutch that transmits torque from the wheel side to the engine side, and its hub 67 is connected to the large sun gear shaft 4.
Combined with 8. A hub 74 of a third clutch 73 is connected to the drum 60 of the fifth clutch. The third clutch 73 is a so-called reverse clutch that operates during reverse travel, and the clutch drum 75 is connected to a small sun gear 78 via a small sun gear shaft 77. Third clutch 73
The drum 75 also serves as a brake drum for the first brake 71, and the first brake 71 is activated in the third and fifth speeds.

The planetary gear unit 180 is a so-called Ravigneau-type planetary gear unit that has two sun gears with different numbers of teeth and shares a carrier and a ring gear. However, in the present invention, a Ravigneaux-type gear train with a ring gear as an output is used. adopt.

A shaft 81 is attached to the carrier 54 which is integrally connected to the intermediate shaft 55.
and one end of the shaft 83 is attached. The shaft 81 supports a long pinion 82 and the shaft 83 supports a short pinion 84. The large sun gear 49 meshes with the long pinion 82, and the small sun gear 78 meshes with the short pinion 84, respectively.

The other ends of the shaft 81 and the shaft 83 are connected to a hub 85 of a third brake 93, and the hub 85 supports a brake disc of a friction plate type brake 93 on its outer periphery, and the brake plate is supported on the case 30 side. Ru. The third brake 93 operates during reverse travel and for engine braking in 1st and 2nd gears.

The inner peripheral portion of the hub 85 forms an outer race 91 of the second one-way clutch 90, and an inner race 92 of the one-way clutch 90 is integrally fixed to the support 35 fixed to the case 30. The second one-sided clutch 90 operates in first and second speeds.

The short pinion 84 meshes with a ring gear 96 formed inside one end of a drum 95, which acts as a high-strength member of the main transmission 4 and as an input member of the sub-transmission 10.

That is, a ring gear 101 is provided inside the other end of the drum 95.
is integrally formed, and a shaft 105 is attached to this ring gear 101.
The pinion 102 supported by the pinion meshes with the pinion 102 . One end of the shaft 105 is supported by a carrier 103, and the carrier 103 is integrated with the output shaft 120. The other end of the shaft 105 is connected to the clutch hub of the fourth clutch 104, and the clutch drum 1.10 of the fourth clutch 104 is connected to the second brake 1.
Also serves as the brake drum for 12.

The fourth clutch 104 operates in the second to fifth speeds, and brings the sub-transmission 10 into a directly connected state. The second brake 112 is a reverse brake that operates during reverse travel and during engine braking in first gear, and employs a band type brake.

The other end of the shaft 108, which has a sun gear 106 meshing with the pinion 102 formed at one end, forms an inner race 109 of a third one-way clutch 113, and fixes an outer race 115 of the - direction clutch 113 to the case 30. drum 1
10 is integrally coupled to shaft 108.

Figure 1 shows a cross section of an automatic transmission, and the whole is denoted by 1.
The automatic transmission shown by is composed of a torque converter 2 and a transmission 3. The torque converter 2 is installed in a case 20, and includes a drum-shaped converter case 21 connected to the engine crankshaft at the frontmost part (hereinafter, the side closest to the engine is referred to as "front side J").Converter case 2
1 connects and drives an engine crankshaft and a pump impeller 22, and the hydraulic oil pressurized by the pump impeller 22 drives a turbine runner 27 and stator 2.
3 to the pump impeller 22. The turbine runner 27 drives a turbine shaft 28 directly connected thereto.

The stator 23 is connected to the fixed part 30 via the one-sided clutch 24.
A lock-up piston 25 is disposed between the turbine runner 27 and the drum-shaped converter case 21, and when necessary, a lock-up clutch 26 between the lock amplifier piston 25 and the converter case 21 is actuated to increase the turbine output. The converter case 21 is directly connected to the shaft 28 which serves as the input shaft of the transmission. An oil pump cover 31, a partition plate 32, and an oil pump housing 33 are arranged at the joint between the case 2o of the torque converter 2 and the case 30 housing the transmission 3.

The oil pump cover 31 consists of a face plate-like portion having an oil passage therein and a boss portion whose center portion protrudes rearward. The partition plate 32 supports the side surface of the rotating body of the oil pump 29 and defines an oil passage, etc., and forms the oil pump 29 within the oil pump housing 33 .

A rear end portion of the pump impeller 22 is coupled to a rotating body of an oil pump 29. The rotating body of the oil pump 29 is driven within the oil pump 29 to generate the necessary hydraulic pressure. The oil pump cover 31 has an oil pump 29 formed inside.
A face plate portion 311 that covers the front opening of the transmission case, and a hollow boss portion 312 that protrudes from the center of the transmission case into the inside of the case.
A hollow tubular support cylinder 34 is press-fitted into 2.

The support cylinder 34 supports the shaft 28 connected to the turbine runner 27 of the torque converter through a sleeve and a bearing inside the front and rear ends. This shaft 28 is an input shaft of the transmission 3, and the rear end of the shaft 28 is provided with a flange portion 281 that expands in the radial direction, and thrust bearings having the same diameter are interposed on both sides of the flange portion 281.

The outer circumference of the flange 281 is connected to the inner cylinder 401 of the clutch drum 4o, and the first clutch 41 is installed inside the clutch drum 4o. The clutch drum 40 has a cylindrical shape with a supported front end and an open rear end, and rotates together with the input shaft 28 . Inner cylinder 401
The inner diameter side of the front support 31 slides and rotates on the outer circumferential surface of a cylindrical oil passage member 315 that forms an oil passage and is fitted to the outer circumference of the boss portion 312 of the front support 31 .

A large diameter piston 42 is provided on the outer circumference of the inner cylinder 401.
and a small diameter piston 56 is inserted in the form of a double piston. The large-diameter piston 42 also serves as a cylinder for the small-diameter piston 56, and the six large-diameter pistons 42 that fit liquid-tight inside the drum 40 are for operating the first clutch 41, and when the piston 42 is operated. Power is transmitted between a clutch plate splined to the inside of the drum 40 and a clutch disc splined to the clutch hub 43. A wall surface 431 extending in the axial direction is formed on the front side of the clutch hub 43.

Thrust bearings are arranged on both sides of this wall surface 431. The inner diameter portion of the clutch hub 43 is connected to the first one-sided clutch 4
The inner race 47 of the -direction clutch 45 is formed integrally with the front end of the large sun gear shaft 48. A large sun gear 49 is attached to the rear end of the large sun gear shaft 48 via serrations. The large sun gear shaft has a cylindrical shape, and the inner peripheral portions of its front and rear ends are supported by an intermediate shaft 55 using bearings.

A second clutch 5 is disposed inside the large diameter piston 42 in the radial direction.
2 and a small-diameter clutch piston 56 that operates the clutch 52. The clutch plate is spline engaged with the inner peripheral surface of the piston 42, and the clutch disk is spline engaged with a clutch hub 53 disposed inside. The small-diameter piston 56 transmits power between the large-diameter piston 42 and the hub 53, which rotate together with the drum 4o. The large diameter piston 42 and the small diameter piston 56 are always urged in the non-operating direction by a return spring 541 stretched between them and the inner cylinder 401.

The clutch hub 53 has a wall surface 5 extending from the rear end side to the shaft center.
31, the intermediate shaft 55 is spline-serrated connected to the vicinity of the distal end thereof. The tip of the intermediate shaft 55 is the input shaft 28
It is supported via a bearing on the inner diameter of the rear end. The rear end of the intermediate shaft 55 is supported by the front end of an output shaft, which will be described later, and a carrier 54 that extends in the radial direction is provided near the rear end of the intermediate shaft 55.

The open rear end of the drum 40 containing the first clutch 41 and the second clutch 52 is connected to a fifth clutch by a spline.
The clutch drum 60 of the clutch is coupled to the clutch drum 60 of the clutch. A fifth clutch 65 is provided inside the clutch drum 60 and includes a clutch plate that is spline-engaged with the clutch drum 60 and a clutch disc that is spline-engaged with a clutch hub 67 located inside the clutch drum.
Deploy. A lower end of a wall surface 671 formed from the front side of the clutch hub 67 toward the axis is coupled to the large sun gear shaft 48 . An inner cylinder 601 is formed on the inner circumferential side of the clutch drum 60, and the outer circumferential side of the inner cylinder 601 supports a piston 66 in a slidable manner. A return spring 661 is provided between the piston 66 and the inner cylinder 601.

The inner peripheral side of the inner cylinder 601 is a stepped cylindrical member 771
It is rotatably supported. A clutch hub 74 is connected to the drum 6 on the opposite side of the clutch drum 60 from the fifth clutch 65.
The clutch hub 74 supports a clutch disk constituting the third clutch 73 via a spline. The clutch plate of the third clutch 73 is supported by a drum 75 that also serves as an outer cylinder, and a belt-type first brake 71 is provided on the outer periphery of the drum 75. An inner cylinder 751 is formed on the inner circumferential side of the drum 75, and a piston 76 that operates the clutch 73 is slidably supported on the outer circumferential side of the inner cylinder 751. A return spring 761 is provided between the inner cylinder 751 and the piston 76.

The distal end of the inner cylinder 751 is spline-engaged with the cylindrical member 771, and the inner periphery of the cylindrical member 771 is coupled to the front end of the small sun gear shaft 77, so that the drum 75 rotates together with the small sun gear shaft 77. The small sun gear shaft 77 is cylindrical and has a small sun gear 78 formed at its rear end. The inner peripheral portions of the front and rear ends of the small sun gear shaft 77 are supported by the large sun gear shaft 48 via bearings.

A central support member 35 is provided at the center inside the case 30. This central support member 35 has a flange portion that engages with the inner peripheral portion of the case, a stepped boss formed in the inner diameter direction of the flange portion that protrudes to the front side, and a short boss that protrudes to the rear side, and protrudes to the front side. A small-diameter ring member 36 and a large-diameter ring member 37 are respectively fitted to the outer periphery of the stepped portion of the boss.

The small diameter ring member 36 rotates and slides on the inner circumference of the cylindrical member 771 at its outer circumference, and the large diameter ring member 37 rotates and slides on the inner circumference of the inner cylinder 751 of the drum 75 at its outer circumference via a bearing. It is rotatably supported by a member 37.

Since the intermediate shaft 55 supports the large sun gear shaft 48 and the large sun gear shaft 48 supports the small sun gear shaft 77, this shaft portion has a triple shaft structure.

The rear side of the flange portion of the central support member 35 forms a cylinder, into which a piston 94 for actuating a third brake 93 is fitted. An iron sleeve 38 is press-fitted into the inner diameter of the central support member 35, and the rear end of the sleeve 38 is formed into a ring shape, into which the inner race 92 of the second one-way clutch 90 is press-fitted. A return spring 941 is interposed between the inner race 92 and the piston 94. The outer race 91 of the second one-sided clutch 90 also serves as the hub of the third brake 93, and a brake disc is spline-engaged with the outer periphery of the outer race 91. The brake plate of the third brake 93 is fitted onto the inner periphery of the case 30 with a spline.

A ring member 911 is fixed to the rear side of the outer race 91 of the second one-sided clutch 90.
1 and the carrier 54 of the intermediate shaft 55.
and supports the pinion shaft 83. These pinion shafts 8
A plurality of pinion shafts 1.83 are provided, and the pinion shaft 81 supports a long pinion 82 and the pinion shaft 83 supports a short pinion 84. The short pinion 84 meshes with the small sun gear 78 and the ring gear 96, and the long pinion 82 meshes with the large sun gear 49.

The ring gear 96 is fixed to the front end of the drum 95,
The inner hole formed in the wall surface 951 of the drum 95 has a gap between it and the intermediate shaft, and both sides of the inner hole are supported by thrust bearings. The ring gear 96 has a ring gear 101 at its rear end on the opposite side with this wall surface 951 in between.

The ring gear 101 provides input to the auxiliary transmission, and as described above, the auxiliary transmission is a reduction gear having one set of planetary gear trains, and is of the type that takes the input of the ring gear from the carrier and outputs it. . A pinion 102 that meshes with a ring gear 101 meshes with a sun gear 106, and the pinion 102 is supported by a shaft 105. The front end of the shaft 105 is supported by a carrier 103 formed at the front end of an output shaft 120, and a hub 107 of a fourth clutch 104 is provided at the rear end of the shaft 105. The clutch hub 107 supports a clutch disk by a spline, and supports a clutch plate by a spline on the inner circumference of an opposing drum 112.

A second brake 112 is arranged on the outer periphery of the drum 110.

A stepped cylindrical rear shaft support member 125 that protrudes toward the front of the case 3o is attached to the rear wall of the transmission case 30, and the inner circumference of the cylindrical sun gear shaft 108 is attached to the outer periphery of the rear shaft support member 125. Support the periphery. The sun gear shaft 108 has a sun gear 106 that meshes with the pinion 105 at its front end, and the rear part of the sun gear shaft 108 is integrated with the drum 110. A piston 116 is fitted inside the drum 110,
A return spring 117 is provided between the piston 116 and the sun gear shaft 108.

An inner race 109 of a third one-way clutch 113 is formed on the rear side of the drum 110 of the sun gear shaft 108, and an outer race 115 of the one-way clutch 113 is spline supported inside the case 30.

A rear case 301 that supports the output shaft 120 is attached to the rear end of the case 30, and the output shaft is supported by bearings arranged inside the front end of the rear shaft support member 125 and inside the rear end of the rear case 301. The outer diameter portion of the rear end of the intermediate shaft 55 is supported by a bearing.

The output shaft 120 is provided with a parking gear 126 and a speedometer drive gear 131.

The parking gear 126 cooperates with a pawl 127 disposed on the fixed side to achieve a parking brake, and the drive gear 131
drives the speedometer.

A flange 129 is integrally provided on the parking gear 126, and the rotation speed of the output shaft 120 is obtained by detecting passage of the flange through the slit with a sensor 130.6 At the rear end of the output shaft 120, a connecting member 135 to the axle shaft is provided.
is inserted and fixed to the output shaft 120 with a nut 136. A hydraulic control device (not shown) is provided at the bottom of the transmission case 30 to control the operation of the clutch and brake of the transmission. The hydraulic control device is covered with a cover 11 that also serves as an oil pan.

The operation of this automatic transmission will be explained below.

This automatic transmission has five forward speeds and one reverse speed. Table 1 shows each speed and the operation of the frictional engagement elements that achieve the speed change.

In Table 1, the O mark indicates that the frictional engagement element is operating, and the mark (○) indicates that it operates during engine braking. Reference numerals 41, 52, 73 and 104.65 respectively indicate the first clutch and the fifth clutch;
112.93 indicates the first to third brakes, and 45.90 and 113 indicate the first to third one-way clutches, respectively.

Figures 3 to 8 show the power transmission paths at each gear stage, and the thick line portion is the path where the power is transmitted.
The shaded area indicates the element to be fixed.

Figure 3 shows the power transmission path at 1st speed, and shows the input shaft 28.
The power is transmitted from the first clutch 41 to the first one-way clutch 45 and drives the large sun gear shaft 48 and the large sun gear 49. Since the shaft 81 of the long binion with which the large sun gear 49 meshes is fixed by the action of the second one-way clutch 90, the rotation of the large sun gear 49 is decelerated and transmitted to the ring gear 96. This rotation is transmitted to ring gear 101 via drum 95. In the 1st speed, the sun gear shaft 108 of the planetary device constituting the sub-reducer is fixed by the action of the third one-way clutch 113, so the rotation input from the ring gear 101 is decelerated and transmitted to the carrier 103 and output shaft 120. Output from.

That is, in the first speed, the rotation that has been decelerated by the main transmission is further decelerated by the sub-transmission and then output.

FIG. 4 shows the power transmission path in 2nd speed, and the same path as in 1st speed is followed up to the drum 95, which also serves as the output shaft of the main transmission and the input shaft of the auxiliary transmission.

The fourth clutch 104 of the auxiliary transmission operates to maintain the auxiliary transmission in a directly coupled state, and the input from the drum 95 is transmitted to the output shaft 120 as is.

Figure 5 shows the power transmission path in 3rd gear.

The first brake 71 operates to fix the small sun gear shaft 77. The power of the large sun gear shaft 48 is decelerated from the large sun gear shaft 49 and transmitted to the ring gear. The reduction ratio at this time is determined by the number of teeth of the small sun gear 78, large sun gear 49, and ring gear 96. The fourth clutch 104 is operated to maintain the direct connection state of the sub-transmission, and the power of the drum 95 is directly transmitted to the output shaft.

FIG. 6 shows the power transmission path at the fourth speed, where both the first clutch 41 and the second clutch 52 operate. Therefore, the power of the input shaft 28 is transferred to the intermediate shaft 55 and the large sun gear shaft 4.
Since the planetary gear train does not move relative to each other, the intermediate shaft 55 and the large sun gear shaft 48 are directly connected to the drum 95. The auxiliary transmission is also maintained in a directly connected state, and eventually the input shaft 28 and output shaft 120 are directly connected.

FIG. 7 shows the power transmission path at the fifth speed, in which the second clutch 52 operates and the power from the input shaft 28 is transmitted to the intermediate shaft 55. The first brake 71 operates and the small sun gear shaft 7
7 is fixed, the rotation of the carrier 54 integrated with the intermediate shaft 55 is accelerated and transmitted to the drum 95. Since the sub-transmission is maintained in a directly connected state, the power of the drum 95 is directly transmitted to the output shaft 120.

The fifth speed is an overdrive in which the rotational speed of the input shaft 28 is increased and transmitted to the output shaft 120.

FIG. 8 shows the power transmission path during reverse movement, in which the third clutch 73 operates to transfer the power from the input shaft 28 to the small sun gear shaft 77.
tell to. Since the third brake 93 operates and fixes the short pinion shaft 83 that meshes with the small sun gear shaft 78,
The rotation of the small sun gear shaft 78 is reversed with deceleration and transmitted to the ring gear 96 and drum 95. Since the second brake 112 of the sub-transmission is also activated and fixes the sun gear shaft 108, the power input to the ring gear 101 is decelerated and transmitted from the carrier 103 to the output shaft 120.

Therefore, when reversing, the auxiliary transmission further decelerates the vehicle.

This speed change state is shown in the speed diagram of FIG.

In the figure, reference numeral 4 indicates a main transmission equipped with a Ravigneau planetary gear mechanism, and reference numeral 10 indicates an auxiliary transmission that achieves deceleration (underdrive).

The gear ratio of each transmission is determined by appropriately selecting the number of gear teeth of the planetary gear train, but in this transmission, the sub-transmission that acts as a speed reducer is activated only during first speed and reverse. The reason for this is to avoid, as much as possible, control to engage and disengage two clutches and brakes at the same time.

In an automatic transmission having five forward speeds and one reverse speed, the present invention operates the auxiliary transmission when shifting to the next lower gear while driving in 4th or 5th gear. By doing so, the gears are changed to gears having different gear ratios.

The automatic transmission of the present invention can achieve various gear ratios by selecting a gear train, and for example, a case will be explained in which a forward gear gear ratio as shown by the solid line in FIG. 10 is selected.

As mentioned above, this automatic transmission includes a sub-reducer 10 for deceleration at the rear of the main transmission 4, which has four forward speeds and one reverse speed.
The auxiliary reducer 10 operates only in 1st gear and reverse, and in other gears it is directly connected and the gear ratio is 1.
becomes.

As the gear ratio of the four forward gears achieved by the main transmission 4, the gear ratio of the second gear is I, :2.3, and the gear ratio of the third gear is I, =
1. The gear ratio of 3rd and 4th gears is I, = 1.0 (direct connection), and the gear ratio of 5th gear is 1. = 0.75 (overdrive) and the gear ratio of the auxiliary transmission 10 is selected as I = 1.5, the gear ratio of the first speed is I = 2.3 x 1.5 = 3.4
5, and the gear ratios of each forward gear stage shown by the solid lines in the diagram of FIG. 10 are obtained.

As shown in FIG. 6, the power transmission line at the time of 4th gear is a direct connection between the main transmission 4 and the auxiliary transmission 10, and the I,
=1.0. If you press the accelerator pedal when you need acceleration while driving in 4th gear, the vehicle will shift down to 3rd gear depending on the situation. The power transmission line at this time is shown in Figure 5, and the gear ratio is 1.

=1.3.

The present invention maintains the state of the main transmission 4 and operates the sub-transmission 10 during this downshift. That is, as shown in the eleventh power transmission line, the main transmission 4 maintains the direct connection state and the sub-transmission 10 operates. Since the gear ratio of the auxiliary transmission 10 is selected to be I=1.5, if the new gear stage is called 3A speed, the gear ratio of 3A speed is 1.5. A is
13A=1.0Xl, 5=1.5, and the 10th
As shown by the dotted line in the figure, the gear ratio is larger than that of the normal 3rd speed, and a larger driving torque can be obtained.

This shift is easy to control because it is only necessary to release the fourth clutch 104.

Next, in the power transmission line for 5th gear, as shown in Fig. 7, the main transmission 4 is in overdrive, the auxiliary transmission 10 is in direct connection, and the transmission ratio is 0.75. When the sub-transmission 10 is operated from this state, the power transmission system becomes as shown in FIG. 12, and the sub-transmission is shifted down to a gear position having a gear ratio of 8!10. If this gear stage is called 4A speed, the gear ratio of 4A speed is 1. A is 1, A=0.75X1.5=1.13, which is the normal 4
Speed ratio 1. = 1.0, and a larger driving torque can be obtained.

This shift is easy to control because it is only necessary to release the fourth clutch 104.

Whether to shift down from 4th gear to 3rd gear or to 3A speed as explained above depends on the vehicle speed.

Control is performed to select a shift pattern according to predetermined conditions such as engine speed and throttle opening.

The same applies to downshift control from 5th speed to 4th speed or 4A speed.

In order to achieve this effect, the gear ratio of the auxiliary transmission and the
The relationship between speed and gear ratio I is I=1.08 to 1.15 I.

It is advisable to determine the gear ratio of each stage so that the relationship is as follows.

〔Effect of the invention〕

As described above, the present invention combines a main transmission with four forward speeds and one reverse speed and an auxiliary transmission which is a reduction gear, and normally operates the auxiliary transmission only in 1st gear to drive 5 forward speeds. In an automatic transmission that achieves a high speed gear, when driving in high speed 4th or 5th gear, when downshifting to the gear one step lower, depending on one condition, the shift speed is changed to the normal gear or, It is possible to selectively downshift to a gear position achieved by operating the sub-transmission.

By appropriately selecting the gear ratio of the auxiliary transmission, it is possible to downshift to a gear position that the main transmission does not have.
It is possible to improve power characteristics, fuel efficiency, etc.

Furthermore, the operation of the sub-transmission can be easily controlled by simply releasing one clutch.

[Brief explanation of drawings]

Fig. 1 is a sectional view of the automatic transmission of the present invention, Fig. 2 is an explanatory diagram showing an overview of the automatic transmission, Fig. 3 is an explanatory diagram showing the power transmission line at 1st speed, and Fig. 4 is An explanatory diagram showing the power transmission line at 2nd speed, FIG. 5 is an explanatory diagram showing the power transmission line at 3rd gear, and FIG. 6 is an explanatory diagram showing the power transmission line at 4th gear.
FIG. 7 is an explanatory diagram showing the power transmission line at 5th speed. FIG. 8 is an explanatory diagram showing a power transmission system during reverse movement, and FIG. 9 is a diagram showing a gear ratio. FIG. 10 is another diagram showing the gear ratio, and FIG. 11 is an explanatory diagram showing the power transmission line at 3A speed. FIG. 12 is an explanatory diagram showing the power transmission line at 4A speed. 1... Automatic transmission, 2... Torque converter, 4...
...Main transmission, 10...Sub-transmission, 28...Input shaft, 30...Transmission case, 35・・・・・・
... Central support member, 48 ...... Large sun gear shaft, 55 ...... Intermediate shaft, 77 ...... Small sun gear shaft, 120・・・・・・
...Output shaft, 104...Fourth clutch, 113...
......Third one-sided clutch. Patent Applicant: Aisin ADA Co., Ltd. Agent: Patent Attorney: 8 Akira Meiki (2 others) Figure Figure Output Figure 10 Figure 11 Figure 12

Claims (1)

[Claims] (1) In an automatic transmission consisting of a main transmission equipped with a starting device and a planetary gear set, and a sub-transmission equipped with a planetary gear set for deceleration connected in series, the main transmission has four forward speeds and one reverse speed. The auxiliary transmission is equipped with a planetary gear device for achieving a reduction gear or a direct-coupling gear by using a ring gear as an input member to achieve a gear shift of the main transmission. , Normally, the auxiliary transmission is selectively operated in the reduction gear or direct gear only when the main transmission is selected in the first or second gear, thereby achieving five forward speeds.
When downshifting from 5th or 5th gear to a lower gear, the auxiliary transmission is operated to a reduction gear according to a preset gear shift pattern, thereby reducing the gear ratio of the main transmission gear. An automatic transmission characterized by downshifting to a gear with a different gear ratio.