JP2009133384A - Automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic transmission which achieves forward 7 gear shifts by using three sets of simple planetary gears and five friction elements, wherein members passing through an outer diameter side of a planetary gear are minimized in number. <P>SOLUTION: In an automatic transmission, a third sun gear S3 is normally locked. A first rotary member is formed by connecting a first sun gear S1 and second ring gear R2. A second rotary member is formed by connecting a first carrier PC1 and a third ring gear R3. An input shaft is normally connected to a first ring gear R1. An output shaft is normally connected to a second sun gear S2. At least forward 7 gear shifts and reverse 1 gear shift are achieved through combinations of simultaneously fastened two of five friction elements. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a stepped automatic transmission applied as a transmission of a vehicle.

Conventionally, as an automatic transmission that achieves the seventh forward speed using three sets of planetary gears, for example, techniques described in Patent Document 1 and Patent Document 2 are known. Patent Document 1 describes an automatic transmission that achieves 7 forward speeds by using three sets of single pinion type planetary gears that are advantageous in terms of transmission efficiency and gear noise and that are advantageous in terms of durability because the pinion gear does not have a small diameter and that uses six friction elements. A machine is disclosed. Similarly, Patent Document 2 discloses an automatic transmission that achieves 6 to 8 forward speeds using three sets of single pinion planetary gears and five friction elements.
JP 2004-176765 A USP 6648791, Fig. 23, 24, 25, 26

  In Patent Document 1, since at least six friction elements are required to achieve the seventh forward speed, there is a problem in that the number of friction elements is large and the number of parts and axial dimensions are increased.

With respect to Patent Document 2, there are five friction elements to achieve the seventh forward speed, and there is an effect that the number of friction elements is smaller than that of Patent Document 1 and the number of parts can be reduced.
However, the automatic transmission described in FIGS. 23 and 24 of Patent Document 2 has a problem that there are many connecting members passing through the outer diameter side of the planetary gear, leading to deterioration of fuel consumption. For example, in Fig. 23, the member passing through the outer diameter side of the ring gear of the central planetary gear has a three-layer structure. For this reason, in general, in an automatic transmission, lubricating oil is discharged from the shaft center side using centrifugal force, and is collected in an oil pan provided at a lower portion of the automatic transmission via a lubrication required portion. However, if a connecting member such as a drum member has a multilayer structure on the outer diameter side of the planetary gear, the lubricating oil tends to stay inside the member, and these are members that rotate during traveling. In many cases, there is a problem that friction increases and fuel consumption deteriorates.

  On the other hand, in the invention described in Fig. 25 of Patent Document 2, the member passing through the outer diameter side of the planetary gear has two layers, and the structure is less likely to stay than Fig. 23. The inner diameter side of the sun gear of the planetary gear on the shaft side has a multi-axis structure, specifically, a maximum three-axis structure. For this reason, there is a problem that the size of the sun gear is restricted and the degree of freedom of the gear ratio of the planetary gear on the input shaft side is small. In order to secure the gear ratio of the planetary gear, there is a problem that the size of the planetary gear is increased and the outer dimension of the automatic transmission is increased.

  An object of the present invention is an automatic transmission capable of achieving seven forward speeds with three sets of simple planetary gears and five friction elements. The first object is to change the outer diameter side of the planetary gears. A second object is to provide an automatic transmission capable of reducing the number of shafts passing through the inner diameter side of the planetary gear as much as possible. is there.

  To achieve the above object, in the first invention, a first sun gear, a first carrier that supports a first pinion that meshes with the first sun gear, and a first ring gear that meshes with the first pinion. A first planetary gear comprising: a second sun gear; a second carrier that supports a second pinion that meshes with the second sun gear; and a second ring gear that meshes with the second pinion. A third planetary gear comprising a second planetary gear, a third sun gear, a third carrier supporting a third pinion meshing with the third sun gear, and a third ring gear meshing with the third pinion An automatic transmission comprising a planetary gear and five friction elements, and by appropriately fastening and releasing the five friction elements, the gear shifts to at least a forward seventh speed to output torque from the input shaft to the output shaft. In machine The third sun gear is always locked, and the first sun gear and the second ring gear are connected to form a first rotating member, and the first carrier and the second gear are connected to each other. 3 is connected to the third ring gear to form a second rotating member, the input shaft is always connected to the first ring gear, and the output shaft is always connected to the second sun gear. The five friction elements include a first friction element that selectively connects the second sun gear and the third carrier, and a second friction element that can lock the rotation of the second carrier. A friction element; a third friction element that selectively couples between the first rotating member and the third carrier; and a gap between the first ring gear and the second carrier. A fourth friction element to be coupled, the second rotary member, and the second A fifth friction element that selectively couples the carrier to the other carrier, and at least 7 forward speeds and 1 reverse speed are achieved by combining two of the five friction elements at the same time. And

  To achieve the above object, in the second invention, a first sun gear, a first carrier that supports a first pinion that meshes with the first sun gear, and a first ring gear that meshes with the first pinion. A first planetary gear comprising: a second sun gear; a second carrier that supports a second pinion that meshes with the second sun gear; and a second ring gear that meshes with the second pinion. A third planetary gear comprising a second planetary gear, a third sun gear, a third carrier supporting a third pinion meshing with the third sun gear, and a third ring gear meshing with the third pinion An automatic transmission comprising a planetary gear and five friction elements, and by appropriately fastening and releasing the five friction elements, the gear shifts to at least a forward seventh speed to output torque from the input shaft to the output shaft. In machine The first sun gear is always locked, and the first ring gear and the third carrier are connected to form a first rotating member, and the second carrier and the first carrier are connected to each other. 3 is connected to the ring gear 3 to form a second rotating member, the input shaft is always connected to the second sun gear, and the output shaft is always connected to the second rotating member. The five friction elements include a first friction element that selectively connects between the first carrier and the second ring gear, and a second that can lock the rotation of the first carrier. A friction element, a third friction element selectively connecting the first carrier and the third sun gear, and selectively between the second sun gear and the third sun gear. A fourth friction element to be coupled, the second sun gear and the first rotation. A fifth friction element that selectively connects the members, and at least 7 forward speeds and 1 reverse speed are achieved by a combination of two of the five friction elements that are simultaneously engaged. To do.

Therefore, the effects listed below can be obtained in the automatic transmissions of the first and second inventions.
(1) Since seven simple planetary gears and five friction elements can achieve forward seven speeds and reverse first speeds, transmission efficiency and gear noise can be improved, and gear durability is improved.
(2) The seven forward planetary gears and the first reverse gear can be achieved with three sets of simple planetary gears and five friction elements, without the connecting member having three layers on the outer diameter side of the three sets of planetary gears. As a result, the lubricating oil is less likely to stay and fuel consumption is improved by reducing friction while preventing deterioration in durability due to an increase in oil temperature.
(3) Since the members passing through the inner diameter side of the three sets of planetary gears have a maximum biaxial structure, three sets of simple planetary gears and five friction elements can achieve seven forward speeds and one reverse speed. The degree of freedom of the gear ratio of the planetary gear is large. Therefore, the degree of freedom in design for reducing the diameter of the sun gear can be improved as compared with Patent Document 2.

  Hereinafter, the best mode for realizing a transmission mechanism of a stepped automatic transmission according to the present invention will be described based on an embodiment shown in the drawings.

First, the configuration will be described.
FIG. 1 is a skeleton diagram showing a transmission mechanism of a stepped automatic transmission according to a first embodiment, and FIG. 2 is a diagram showing a specific example of a friction element coupling table and a reduction ratio in the automatic transmission according to the first embodiment.

  As shown in FIG. 1, the automatic transmission according to the first embodiment includes, as gear trains, a first planetary gear set PG1, a second planetary gear set PG2, and a third planetary gear set, which are three single-pinion type planetary gear sets. It has PG3. The first planetary gear set PG1 includes a first sun gear S1, a first ring gear R1, and a first pinion P1 that meshes with the first sun gear S1 and the first ring gear R1. The second planetary gear set PG2 includes a second sun gear S2, a second ring gear R2, and a second pinion P2 that meshes with the second sun gear S2 and the second ring gear R2. The third planetary gear set PG3 has a third sun gear S3, a third ring gear R3, and a third pinion P3 that meshes with the third sun gear S3 and the third ring gear R3. The first, second, and third pinions P1, P2, and P3 are rotatably supported with respect to the first, second, and third carriers PC1, PC2, and PC3, respectively.

  The input shaft IN is always connected to the first ring gear R1. The output shaft OUT is always connected to the second sun gear S2. The first sun gear S1 and the second ring gear R2 are always connected to form a first rotating member M1. The first carrier PC1 and the third ring gear R3 are always connected to form a second rotating member M2. The third sun gear S3 is always locked to the transmission case 1.

  The automatic transmission is provided with a second friction element B which is one brake and first, third, fourth and fifth friction elements A, C, D and E which are four clutches. The first friction element A is provided between the second sun gear S2 and the third carrier PC3, and selectively connects the second sun gear S2 and the third carrier PC3. The second friction element B is provided between the second carrier PC2 and the transmission case 1, and selectively locks the rotation of the second carrier PC2. The third friction element C is provided between the second ring gear R2 integral with the first rotating member M1 and the third carrier PC3, and selects the second ring gear R2 (first rotating member M1) and the third carrier PC3. Are connected. The fourth friction element D is provided between the first ring gear R1 and the second carrier PC2, and selectively connects the first ring gear R1 and the second carrier PC2. The fifth friction element E is provided between the first carrier PC1 and the second carrier PC2 integrated with the second rotating member M2, and selectively selects the first carrier PC1 (second rotating member) and the second carrier PC2. Connect to

  The output shaft OUT is provided with an output gear or the like, and rotational driving force is transmitted to the drive wheels via a differential gear and a drive shaft (not shown). In the case of the first embodiment, the output shaft OUT is blocked by other members and is applicable to the FF vehicle.

  The relationship of coupling (fastening) of the friction elements at each gear stage will be described with reference to the coupling table of FIG. 2 (shift control means). In the table, a circle indicates fastening and a blank indicates release.

  First, the time of advance will be described. The first speed is achieved by fastening the first friction element A and the second friction element B. The second speed is achieved by fastening the first friction element A and the third friction element C. The third speed is achieved by fastening the first friction element A and the fourth friction element D. The fourth speed is achieved by fastening the first friction element A and the fifth friction element E. The fifth speed is achieved by fastening the fourth friction element D and the fifth friction element E. The sixth speed is achieved by fastening the third friction element C and the fifth friction element E. The seventh speed is achieved by fastening the third friction element C and the fourth friction element D. The reverse speed is achieved by fastening the second friction element B and the third friction element C.

Next, a specific example of the reduction ratio in the first embodiment will be described with reference to FIG. Here, the gear ratio of the first planetary gear set PG1 ρ ₁ = Z _S1 / Z _R1 = 0.65, the gear ratio of the second planetary gear set PG2 ρ ₂ = Z _S2 / Z _R2 = 0.65, the third planetary gear set This will be explained by an example in which the tooth ratio of PG3 is ρ ₃ = Z _S3 / Z _R3 = 0.65. Z _S1 , Z _S2 , Z _S3 , Z _R1 , Z _R2 , and Z _R3 represent the number of teeth of each gear.

The reduction ratio i ₁ of the _first forward speed is
i ₁ = ρ ₁ ρ ₂ + (1 + ρ ₁ ) (1 + ρ ₃ )
When a specific numerical value is substituted,
The reduction ratio i ₁ of the _first forward speed is i ₁ = 3.145, and the reciprocal of the reduction ratio is 0.318.

The reduction ratio i ₂ of the _second forward speed is
i ₂ = (1 + ρ ₁ ) (1 + ρ ₃ ) −ρ ₁
When a specific numerical value is substituted,
The reduction ratio i ₂ of the _second forward speed is i ₂ = 2.073, and the reciprocal of the reduction ratio is 0.482.

The reduction ratio i ₃ of the _3rd forward speed is
i ₃ = ((1 + ρ ₁ ) (1 + ρ ₃ ) + ρ ₁ ρ ₂ ) / (1 + ρ ₁ (1 + ρ ₂ ))
When a specific numerical value is substituted,
The reduction ratio i ₃ for the _third forward speed is i ₃ = 1.517, and the reciprocal of the reduction ratio is 0.659.

The reduction ratio i ₄ of the forward 4th speed is
i ₄ = 1 + ρ ₃ −ρ ₁ ρ ₂ ρ ₃
When a specific numerical value is substituted,
The reduction ratio i ₄ for the _fourth forward speed is i ₄ = 1.375, and the reciprocal of the reduction ratio is 0.727.

The reduction ratio i ₅ of the _5th forward speed is
i ₅ = 1.0
Without needing to substitute a specific numerical value,
The reduction ratio i ₅ for the _fifth forward speed is i ₅ = 1.000, and the reciprocal of the reduction ratio is 1.000.

The reduction ratio i ₆ for the _6th forward speed is
i ₆ = ρ ₂ (1 + ρ ₃ + ρ ₁ ρ ₃ ) / (ρ ₂ + ρ ₃ + ρ ₂ ρ ₃ )
When a specific numerical value is substituted,
The reduction ratio i ₆ for the _sixth forward speed is i ₆ = 0.782, and the reciprocal of the reduction ratio is 1.279.

The reduction ratio i _{7 for} forward 7 speed is
i ₇ = ρ ₂ (1 + ρ ₃ + ρ ₁ ρ ₃ ) / ((1 + ρ ₂ ) (1 + ρ ₃ + ρ ₁ ρ ₃ ) -1)
When a specific numerical value is substituted,
The reduction ratio i ₇ for the _seventh forward speed is i ₇ = 0.557, and the reciprocal of the reduction ratio is 1.789.

The reverse speed reduction ratio i _R is
i _R = − ((1 + ρ ₁ ) (1 + ρ ₃ ) −ρ ₁ ) ρ ₂
When a specific numerical value is substituted,
The reverse speed reduction ratio i _R is i _R = -1.347, and the reciprocal of the reduction ratio is −0.742.

[Effect of Example 1]
-Effects of the entire skeleton In the first embodiment, an automatic transmission with seven forward speeds and one reverse speed capable of ensuring an appropriate reduction ratio is realized, although it is a simple and few component elements of three simple planets and five friction elements. be able to.

・ Effects of using three simple planetary pairs By using three simple planetary sets, transmission efficiency and gear noise are improved compared to the case of using a double pinion, and it is not necessary to reduce the pinion diameter. Improves durability.

・ Effects based on forward ratio coverage Forward ratio coverage (gear ratio width) refers to the lowest gear ratio / highest gear ratio. It can be said that it is excellent in compatibility with fuel efficiency in high-speed cruising, and the gear ratio setting freedom at each forward gear is increased. The specific numerical value in Example 1 is that the reduction ratio of the first forward speed is 3.145, and the reduction ratio of the seventh forward speed is 0.557, so the 1-7 speed ratio coverage is 5.65, and sufficient ratio coverage is achieved. It can be secured. Therefore, for example, it is useful as a transmission of a vehicle in which a diesel engine having a narrower engine speed range as a power source than a gasoline engine and having a large torque when compared with the same displacement is used as a power source.

  Further, if the gear ratio on the low speed side is large for the ratio coverage, the torque transmitted to the final gear becomes large. For this reason, the strength of the automatic transmission and the propeller shaft is required, and the entire vehicle becomes large. That is, if the ratio coverage is the same, it is preferable that the minimum speed gear ratio is not so large. Since the automatic transmission shown in Fig. 23 of the prior art USP 6648791 has a maximum gear ratio of 1, when trying to increase the ratio coverage, the gear ratio of the minimum gear must be increased. Transmissions and propeller shafts will become larger. On the other hand, the automatic transmission according to the first embodiment can ensure a sufficient ratio coverage without increasing the gear ratio of the lowest gear stage so much.

.Effects based on the number of friction element changes during shifting
(i) During shifting, if one or more friction elements are released and two or more friction elements are engaged, or if two or more friction elements are released and one or more friction elements are engaged, friction will occur. The timing of element fastening / release and the control of torque become complicated. Therefore, from the viewpoint of avoiding complicated shift control, it is preferable to release one friction element and fasten the other friction element. This is prevention of so-called double change. In the first embodiment, the first friction element A is shifted from the first forward speed to the fourth forward speed while the first friction element A is engaged, and the fifth friction element E is maintained from the fourth forward speed to the sixth forward speed. The speed is changed from the sixth forward speed to the seventh forward speed while the third friction element C remains engaged. That is, the shift from the first forward speed to the seventh forward speed can be achieved by a change gear shift in which one friction element is released and the other friction element is fastened. Therefore, complication of control at the time of shifting can be avoided.

  (ii) As shown in (i) above, the shift to the adjacent gear stage can be achieved by a reshuffling shift that releases one friction element and fastens one friction element. Even in the case of a one-step jump shift such as the forward three speed, it can be achieved by a replacement shift that releases one friction element and fastens one friction element in the same manner. Therefore, controllability can be improved.

・ Effect based on layout
(i) In the automatic transmission according to the first embodiment, as shown in the skeleton diagram of FIG. 1, the connecting members do not have three layers on the outer diameter side of the three planetary gears. As a result, the lubricating oil is less likely to stay and fuel consumption can be improved by reducing friction.

  (ii) Further, as shown in the skeleton diagram of FIG. 1, the rotating member passing through the outer peripheral side of the planetary gear set has a single layer structure. The automatic transmission constantly supplies lubricating oil to gears, bearings, and the like that are rotating elements for the purpose of cooling and lubrication. Further, this lubrication is generally supplied by centrifugal force from the axial center side. At this time, if the discharge performance of the lubricating oil deteriorates on the outer peripheral side, the oil temperature of the lubricating oil rises, and the durability of the friction elements and the bearing members (not shown) decreases. In the first embodiment, as described above, since the rotating member passing through the outer peripheral side of the planetary gear set has a single layer structure, the lubricating oil discharge performance is not deteriorated, the oil temperature rise is suppressed, and the durability is improved. improves.

  (iii) While the members passing through the inner diameter side of the three sets of planetary gears have a maximum biaxial structure, three forward planetary gears and five friction elements can achieve the seventh forward speed and the first reverse speed. Therefore, the size of the sun gear is not restricted as compared with Patent Document 2, and the degree of freedom in the gear ratio of the planetary gear is large, so the degree of freedom in design can be improved.

-Effect based on the number of friction elements The second friction element B is used as a brake in the first embodiment. In other words, the provision of a brake makes it possible to suppress the increase in the number of rotating seal rings and the centrifugal cancellation mechanism compared to the case where the number of clutches is large, and the number of parts and axial dimensions are reduced while improving fuel efficiency. To do.

(Modification 1-1)
Next, a modified example 1-1 of the first embodiment will be described. Since the basic configuration is the same as that of the first embodiment, only different points will be described.

  FIG. 3 is a skeleton diagram showing the modified example 1-1. In Modification 1-1, a one-way clutch is arranged in parallel with the second friction element B. When shifting from forward 1st speed to forward 2nd speed, one-way for 1st speed to simplify control from 1st speed to 2nd speed with large torque step and to eliminate excessive engine braking feeling during normal driving A clutch OWC is preferably provided.

  For this purpose, the one-speed one-way clutch OWC is provided in parallel with a friction element that is released when upshifting from the first forward speed to the second forward speed. In the case of Example 1, this friction element corresponds to the second friction element B. The second friction element B is a brake that selectively locks the second carrier PC2 to the transmission case 1. When shifting from the first speed to the second speed, the second carrier PC2 rotates in the forward direction (forward rotation in the engine rotation direction). Therefore, in order to dispose the one-way clutch on the second friction element B, the rotation direction of the second carrier PC2 needs to be normal rotation at all the gear speeds where the second friction element B is released. There is.

  If a negative rotation occurs at any of the gear positions, another friction element that can switch the operation / non-operation of this one-way clutch OWC must be added in series with the one-way clutch OWC. This is not very useful. Therefore, considering the rotational speed of the second carrier PC2 at all the gear positions in the first embodiment, the second carrier PC2 is rotating forward at all the gear speeds. Therefore, by simply configuring the one-way clutch OWC in parallel with the second friction element B, it is possible to simplify the control logic while avoiding a significant increase in parts, resulting in excessive engine braking during normal driving. Can be suppressed.

(Modification 1-2)
Next, a modified example 1-2 of the first embodiment will be described. Since the basic configuration is the same as that of the first embodiment, only different points will be described. In Example 1, the seventh forward speed was achieved by simultaneous engagement of the third friction element C and the fourth friction element D. On the other hand, in the modified example 1-2, the second friction element B and the fifth friction element E are achieved simultaneously as the seventh forward speed. Select a reduction ratio based on the following relational expression.

The reduction ratio i _{7 for} forward 7 speed is
i ₇ = ρ ₁ ρ ₂
When a specific numerical value is substituted,
The reduction ratio i ₇ for the _seventh forward speed is i ₇ = 0.423, and the reciprocal of the reduction ratio is 2.364.

  According to this modified example 1-2, it is possible to set the seventh forward speed, which is a reduction ratio smaller than that of the first embodiment, and the ratio coverage can also take a large value of 7.44. Since the step difference between the sixth forward speed and the seventh forward speed is slightly large, the seventh speed can also be used as a dedicated fuel efficiency improvement gear stage during high-speed cruising, for example, on a highway.

(Modification 1-3)
Next, a modified example 1-3 of the first embodiment will be described. Since the basic configuration is the same as that of the first embodiment, only different points will be described. In the first embodiment, up to the seventh forward speed is set, but in the modification 1-3, the forward eight speed is set. In this 8th speed, in addition to the 7th speed of the first embodiment, the 7th speed set in the modified example 1-2 is set as a new 8th speed. Incidentally, in the change gear shift between the 7th speed and the 8th speed, although it is necessary to carry out the double change, the shift shock is not a problem because it is basically a shift in a state where the acting torque is small. That is, it is possible to provide an automatic transmission with 8 forward speeds and 1 reverse speed with a small number of parts of three planetary five friction elements.

First, the configuration will be described.
FIG. 6 is a skeleton diagram showing the speed change mechanism of the stepped automatic transmission according to the second embodiment, and FIG. 7 is a diagram showing a specific example of a friction element coupling table and a reduction ratio in the automatic transmission according to the second embodiment.

  As shown in FIG. 6, the automatic transmission according to the second embodiment includes a first planetary gear set PG1, a second planetary gear set PG2, and a third planetary gear set, which are three single-pinion type planetary gear sets, as gear trains. It has PG3. The first planetary gear set PG1 includes a first sun gear S1, a first ring gear R1, and a first pinion P1 that meshes with the first sun gear S1 and the first ring gear R1. The second planetary gear set PG2 includes a second sun gear S2, a second ring gear R2, and a second pinion P2 that meshes with the second sun gear S2 and the second ring gear R2. The third planetary gear set PG3 has a third sun gear S3, a third ring gear R3, and a third pinion P3 that meshes with the third sun gear S3 and the third ring gear R3. The first, second, and third pinions P1, P2, and P3 are rotatably supported with respect to the first, second, and third carriers PC1, PC2, and PC3, respectively.

  The input shaft IN is always connected to the second sun gear S2. The first ring gear R1 and the third carrier PC3 are always connected to form a first rotating member M1. The second carrier PC2 and the third ring gear R3 are always connected to form a second rotating member M2. The output shaft OUT is always connected to a second carrier PC2 integrated with the second rotating member M2. The first sun gear S1 is always locked to the transmission case 1.

  The automatic transmission is provided with a second friction element B which is one brake and first, third, fourth and fifth friction elements A, C, D and E which are four clutches. The first friction element A is provided between the first carrier PC1 and the second ring gear R2, and selectively connects the first carrier PC1 and the second ring gear R2. The second friction element B is provided between the first carrier PC1 and the transmission case 1, and selectively locks the rotation of the first carrier PC1. The third friction element C is provided between the first carrier PC1 and the third sun gear S3, and selectively connects the first carrier PC1 and the third sun gear S3. The fourth friction element D is provided between the second sun gear S2 and the third sun gear S3, and selectively connects the second sun gear S2 and the third sun gear S3. The fifth friction element E is provided between the second sun gear S2 and the third carrier PC3 integrated with the first rotating member M1, and selectively connects the second sun gear S2 and the first rotating member M1.

  The output shaft OUT is provided with an output gear or the like, and rotational driving force is transmitted to the drive wheels via a differential gear and a drive shaft (not shown). In the case of the second embodiment, the output shaft OUT is not blocked by other members or the like, so that it can be applied to both FF vehicles and FR vehicles.

  The relationship of the coupling (fastening) of the friction elements at each gear stage will be described with reference to the coupling table of FIG. 7 (transmission control means). In the table, a circle indicates fastening and a blank indicates release.

  First, the time of advance will be described. The first speed is achieved by fastening the first friction element A and the second friction element B. The second speed is achieved by fastening the first friction element A and the third friction element C. The third speed is achieved by fastening the first friction element A and the fourth friction element D. The fourth speed is achieved by fastening the first friction element A and the fifth friction element E. The fifth speed is achieved by fastening the fourth friction element D and the fifth friction element E. The sixth speed is achieved by fastening the third friction element C and the fifth friction element E. The seventh speed is achieved by fastening the third friction element C and the fourth friction element D. The reverse speed is achieved by fastening the second friction element B and the fourth friction element D.

Next, a specific example of the reduction ratio in the second embodiment will be described with reference to FIG. Here, the gear ratio of the first planetary gear set PG1 ρ ₁ = Z _S1 / Z _R1 = 0.40, the gear ratio of the second planetary gear set PG2 ρ ₂ = Z _S2 / Z _R2 = 0.30, the third planetary gear set This will be explained using an example in which the PG3 tooth number ratio ρ ₃ = Z _S3 / Z _R3 = 0.30. Z _S1 , Z _S2 , Z _S3 , Z _R1 , Z _R2 , and Z _R3 represent the number of teeth of each gear.

The reduction ratio i ₁ of the _first forward speed is
i ₁ = (1 + ρ ₂ ) / ρ ₂
When a specific numerical value is substituted,
The reduction ratio i ₁ of the _first forward speed is i ₁ = 4.333, and the reciprocal of the reduction ratio is 0.231.

The reduction ratio i ₂ of the _second forward speed is
i ₂ = 1 + (ρ ₁ (1 + ρ ₃ )) / (ρ ₁ (1 + ρ ₁ + ρ ₁ ρ ₃ ))
When a specific numerical value is substituted,
The reduction ratio i ₂ of the _second forward speed is i ₂ = 2.140, and the reciprocal of the reduction ratio is 0.467.

The reduction ratio i ₃ of the _3rd forward speed is
i ₃ = ((1 + ρ ₁ ) (1 + ρ ₂ ) (1 + ρ ₃ ) −1) / (ρ ₃ + ρ ₂ (1 + ρ ₁ ) (1 + ρ ₃ ))
When a specific numerical value is substituted,
The reduction ratio i ₃ of the _third forward speed is i ₃ = 1.615, and the reciprocal of the reduction ratio is 0.619.

The reduction ratio i ₄ of the forward 4th speed is
i ₄ = (1 + ρ ₁ ) (1 + ρ ₂ ) / ((1 + ρ ₁ ) ρ ₂ +1)
When a specific numerical value is substituted,
The reduction ratio i ₄ of the _fourth forward speed is i ₄ = 1.282, and the reciprocal of the reduction ratio is 0.780.

The reduction ratio i ₅ of the _5th forward speed is
i ₅ = 1.0
Without needing to substitute a specific numerical value,
The reduction ratio i ₅ for the _fifth forward speed is i ₅ = 1.000, and the reciprocal of the reduction ratio is 1.000.

The reduction ratio i ₆ for the _6th forward speed is
i ₆ = (1 + ρ ₁ ) / ((1 + ρ ₁ ) (1 + ρ ₃ ) −ρ ₃ )
When a specific numerical value is substituted,
The reduction ratio i ₆ for the _sixth forward speed is i ₆ = 0.921, and the reciprocal of the reduction ratio is 1.086.

The reduction ratio i _{7 for} forward 7 speed is
i ₇ = 1 / ((1 + ρ ₁ ) (1 + ρ ₃ ) −ρ ₃ )
When a specific numerical value is substituted,
The reduction ratio i ₇ for the _seventh forward speed is i ₇ = 0.658, and the reciprocal of the reduction ratio is 1.520.

The reverse speed reduction ratio i _R is
i _R = -1 / ρ ₃
When a specific numerical value is substituted,
The reverse speed reduction ratio i _R is i _R = −3.333, and the reciprocal of the reduction ratio is −0.300.

[Effect of Example 2]
-Effects of the entire skeleton In the second embodiment, an automatic transmission with 7 forward speeds and 1 reverse speed capable of securing an appropriate reduction ratio is realized, although it is a simple and few constituent elements of 3 sets of simple planets and 5 friction elements. be able to.

・ Effects of using three simple planetary sets By using three simple planetary sets, the transmission efficiency and gear noise are improved compared to the case of using a double pinion, and the pinion does not need to have a small diameter. Gear durability is improved.

・ Effects based on forward ratio coverage Forward ratio coverage (gear ratio width) refers to the lowest gear ratio / highest gear ratio. It can be said that it is excellent in compatibility with fuel efficiency in high-speed cruising, and the gear ratio setting freedom at each forward gear is increased. The specific numerical value in the second embodiment is that the reduction ratio of the first forward speed is 4.333 and the reduction ratio of the seventh forward speed is 0.658, so the 1-7 speed ratio coverage is 6.59, and sufficient ratio coverage is obtained. It can be secured. Therefore, for example, it is useful as a transmission of a vehicle in which a diesel engine having a narrower engine speed range as a power source than a gasoline engine and having a large torque when compared with the same displacement is used as a power source.

  Further, if the gear ratio on the low speed side is large for the ratio coverage, the torque transmitted to the final gear becomes large. For this reason, the strength of the automatic transmission and the propeller shaft is required, and the entire vehicle becomes large. That is, if the ratio coverage is the same, it is preferable that the minimum speed gear ratio is not so large. Since the automatic transmission shown in Fig. 23 of the prior art USP 6648791 has a maximum gear ratio of 1, when trying to increase the ratio coverage, the gear ratio of the minimum gear must be increased. Transmissions and propeller shafts will become larger. On the other hand, the automatic transmission according to the second embodiment can ensure a sufficient ratio coverage without increasing the gear ratio of the lowest gear stage so much.

.Effects based on the number of friction element changes during shifting
(i) During shifting, if one or more friction elements are released and two or more friction elements are engaged, or if two or more friction elements are released and one or more friction elements are engaged, friction will occur. The timing of element fastening / release and the control of torque become complicated. Therefore, from the viewpoint of avoiding complicated shift control, it is preferable to release one friction element and fasten the other friction element. This is prevention of so-called double change. In Example 2, the first friction element A is shifted from the first forward speed to the fourth forward speed while the first friction element A is engaged, and the fifth friction element E is maintained from the fourth forward speed to the sixth forward speed. The speed is changed from the sixth forward speed to the seventh forward speed while the third friction element C remains engaged. That is, the shift from the first forward speed to the seventh forward speed can be achieved by a change gear shift in which one friction element is released and the other friction element is fastened. Therefore, complication of control at the time of shifting can be avoided.

  (ii) As shown in (i) above, the shift to the adjacent gear stage can be achieved by a reshuffling shift that releases one friction element and fastens one friction element. Even in the case of a one-step jump shift such as the forward three speed, it can be achieved by a replacement shift that releases one friction element and fastens one friction element in the same manner. Therefore, controllability can be improved.

・ Effect based on layout
(i) In the automatic transmission according to the second embodiment, as shown in the skeleton diagram of FIG. 6, the connecting members do not have three layers on the outer diameter side of the three planetary gears. As a result, the lubricating oil is less likely to stay and fuel consumption can be improved by reducing friction.

  (ii) Further, as shown in the skeleton diagram of FIG. 6, the rotating member passing through the outer peripheral side of the planetary gear set has a two-layer structure. The automatic transmission constantly supplies lubricating oil to gears, bearings, and the like that are rotating elements for the purpose of cooling and lubrication. Further, this lubrication is generally supplied by centrifugal force from the axial center side. At this time, if the discharge performance of the lubricating oil deteriorates on the outer peripheral side, the oil temperature of the lubricating oil rises, and the durability of the friction elements and the bearing members (not shown) decreases. In the second embodiment, as described above, since the rotating member passing through the outer peripheral side of the planetary gear set has a two-layer structure, the discharge performance of the lubricating oil is not deteriorated and the durability is improved.

  (iii) The member passing through the inner diameter side of the three sets of planetary gears has a uniaxial structure. Therefore, the size of the sun gear is not restricted as compared with Patent Document 2, and the degree of freedom in the gear ratio of the planetary gear is large, so the degree of freedom in design can be improved.

  (iv) Since the automatic transmission according to the second embodiment is an automatic transmission that can input from one side of the planetary gear set and output from the other side, either a front-wheel drive vehicle or a rear-wheel drive vehicle can be used. The application range of the automatic transmission can be widened.

(Modification 2-1)
Next, a modified example 2-1 of the second embodiment will be described. Since the basic configuration is the same as that of the second embodiment, only different points will be described.

  FIG. 8 is a skeleton diagram showing the modified example 2-1. In Modification 2-1, a one-way clutch is arranged in parallel with the second friction element B. When shifting from forward 1st speed to forward 2nd speed, one-way for 1st speed to simplify control from 1st speed to 2nd speed with large torque step and to eliminate excessive engine braking feeling during normal driving A clutch OWC is preferably provided.

  For this purpose, the one-speed one-way clutch OWC is provided in parallel with a friction element that is released when upshifting from the first forward speed to the second forward speed. In the case of Example 2, this friction element corresponds to the second friction element B. The second friction element B is a brake that selectively locks the first carrier PC1 to the transmission case 1, and the first carrier PC1 rotates forward (forward rotation in the engine rotation direction) when shifting from the first speed to the second speed. Therefore, in order to dispose the one-way clutch on the second friction element B, the rotation direction of the first carrier PC1 needs to be normal rotation at all the gear speeds where the second friction element B is released. There is.

  If a negative rotation occurs at any of the gear positions, another friction element that can switch the operation / non-operation of this one-way clutch OWC must be added in series with the one-way clutch OWC. This is not very useful. Therefore, when the rotational speed of the first carrier PC1 at all the gear speeds is examined in the second embodiment, the first carrier PC1 is normally rotated at all the gear speeds. Therefore, by simply configuring the one-way clutch OWC in parallel with the second friction element B, it is possible to simplify the control logic while avoiding a significant increase in parts, resulting in excessive engine braking during normal driving. Can be suppressed.

(Modification 2-2)
Next, a modification 2-2 of the second embodiment will be described. Since the basic configuration is the same as that of the second embodiment, only different points will be described. FIG. 9 is a skeleton diagram showing the configuration of Modification 2-2. In the second embodiment, the first planetary gear set PG1, the second planetary gear set PG2, and the third planetary gear set PG3, which are three single-pinion type planetary gear sets, are used as the gear train in order from the output side. The set PG1 → the second planetary gear set PG2 → the third planetary gear set PG3. On the other hand, the modification 2-2 is different in that the second planetary gear set PG2 → the first planetary gear set PG1 → the third planetary gear set PG3 is arranged in this order. In the modification 2-2, the first planetary gear set PG1 → the second planetary gear set PG2 → the third planetary gear set PG3 is described in order from the left in FIG. Then
The first planetary gear set PG1 of Modification 2-2 corresponds to the second planetary gear set PG2 of Example 2,
The second planetary gear set PG2 of Modification 2-2 corresponds to the first planetary gear set PG1 of Example 2,
The third planetary gear set PG3 of the modification 2-2 corresponds to the third planetary gear set PG3 of the second embodiment.

  It should be noted that the positional relationship of the friction elements, the connection relationship of the rotating members, and the engagement relationship of the friction elements at each gear are all the same.

  In the second embodiment, since the first sun gear S1 of the first planetary gear set PG1 arranged at the right end is always locked to the transmission case 1, the output rotational speed from the second carrier PC2 of the second planetary gear set PG2. It was possible to pass the inner diameter side of the first sun gear S1 when removing the first sun gear S1. On the other hand, in the modified example 2-2, since the sun gear that is always locked is the second sun gear S2, the first planetary gear set PG1 is surrounded by a member that locks the second sun gear S2 on the inner diameter side. It will be. Therefore, in the modification 2-2, it becomes a structure applicable to a front-wheel drive vehicle.

  However, since the fixing member for locking the second sun gear S2 extends to the second planetary gear set PG2 side, this extended portion as well as the second friction element B as a brake is provided. Therefore, oil can be easily supplied to the first friction element A and the third friction element C which are clutches. That is, when oil is supplied to the first friction element A and the third friction element C, it is not necessary to go through a rotating member that is not related to these fastening elements, and can be supplied directly. Thereby, the number of seal rings and the like can be reduced, and the frictional resistance can be reduced.

  As described above, the second embodiment and the modification example 2-2 have been described. However, the one-way clutch can be provided in parallel with the second friction element B in the second embodiment and the modification example 2-2. As a result, the one-speed one-way clutch can be arranged without significantly increasing the number of parts, and the controllability can be improved.

1 is a skeleton diagram illustrating an automatic transmission according to a first embodiment. It is a figure which shows the specific example of the coupling | bonding table | surface of the friction element in the automatic transmission of Example 1, and a reduction ratio. It is a skeleton figure which shows the automatic transmission of the modification 1-1 of Example 1. FIG. It is a figure which shows the specific example of the coupling | bonding table of a friction element and the reduction ratio in the automatic transmission of the modification 1-2. It is a figure which shows the specific example of the coupling | bonding table | surface of a friction element and the reduction ratio in the automatic transmission of the modification 1-3. It is a skeleton figure which shows the automatic transmission of Example 2. FIG. It is a figure which shows the specific example of the coupling | bonding table | surface of the friction element in the automatic transmission of Example 2, and a reduction ratio. It is a skeleton figure which shows the automatic transmission of the modification 2-1. It is a skeleton figure which shows the automatic transmission of modification 2-2.

Explanation of symbols

1 Transmission case
PG1 1st planetary gear set
S1 1st sun gear
R1 1st ring gear
P1 first pinion
PC1 first carrier
PG2 2nd planetary gear set
S2 2nd sun gear
R2 2nd ring gear
P2 Second pinion
PC2 2nd carrier
PG3 3rd planetary gear set
S3 3rd sun gear
R3 3rd ring gear
P3 3rd pinion
PC3 3rd carrier
IN input shaft
OUT output shaft
A First friction element
B Second friction element
C Third friction element
D Fourth friction element
E Fifth friction element

Claims (5)

A first planetary gear comprising a first sun gear, a first carrier that supports a first pinion that meshes with the first sun gear, and a first ring gear that meshes with the first pinion;
A second planetary gear comprising a second sun gear, a second carrier that supports a second pinion that meshes with the second sun gear, and a second ring gear that meshes with the second pinion;
A third planetary gear comprising a third sun gear, a third carrier that supports a third pinion that meshes with the third sun gear, and a third ring gear that meshes with the third pinion;
5 friction elements,
With
In an automatic transmission capable of shifting to at least a forward speed of seven speeds by appropriately fastening and releasing the five friction elements and outputting torque from the input shaft to the output shaft,
The third sun gear is always locked,
The first sun gear and the second ring gear are connected to form a first rotating member;
The first carrier and the third ring gear are connected to form a second rotating member;
The input shaft is always connected to the first ring gear,
The output shaft is always connected to the second sun gear,
The five friction elements are:
A first friction element that selectively couples between the second sun gear and the third carrier;
A second friction element capable of locking the rotation of the second carrier;
A third friction element that selectively couples between the first rotating member and the third carrier;
A fourth friction element that selectively couples between the first ring gear and the second carrier;
A fifth friction element that selectively couples between the second rotating member and the second carrier;
Consisting of
An automatic transmission characterized in that at least 7 forward speeds and 1 reverse speed are achieved by a combination of two simultaneous engagements among the five friction elements. A first planetary gear comprising a first sun gear, a first carrier that supports a first pinion that meshes with the first sun gear, and a first ring gear that meshes with the first pinion;
A second planetary gear comprising a second sun gear, a second carrier that supports a second pinion that meshes with the second sun gear, and a second ring gear that meshes with the second pinion;
A third planetary gear comprising a third sun gear, a third carrier that supports a third pinion that meshes with the third sun gear, and a third ring gear that meshes with the third pinion;
5 friction elements,
With
In an automatic transmission capable of shifting to at least a forward speed of seven speeds by appropriately fastening and releasing the five friction elements and outputting torque from the input shaft to the output shaft,
The first sun gear is always locked,
The first ring gear and the third carrier are connected to form a first rotating member;
The second carrier and the third ring gear are connected to form a second rotating member;
The input shaft is always connected to the second sun gear,
The output shaft is always connected to the second rotating member,
The five friction elements are:
A first friction element that selectively couples between the first carrier and the second ring gear;
A second friction element capable of locking the rotation of the first carrier;
A third friction element for selectively connecting between the first carrier and the third sun gear;
A fourth friction element that selectively couples between the second sun gear and the third sun gear;
A fifth friction element for selectively connecting the second sun gear and the first rotating member;
Consisting of
An automatic transmission characterized in that at least 7 forward speeds and 1 reverse speed are achieved by a combination of two simultaneous engagements among the five friction elements. The automatic transmission according to claim 1 or 2,
The combination of two simultaneous engagements of the first to fifth friction elements that achieve the seventh forward speed is the simultaneous engagement of the first friction element and the second friction element, the first friction element And the third friction element, the first friction element and the fourth friction element, the first friction element and the fifth friction element, and the fourth friction. 7 combinations of simultaneous fastening of an element and the fifth friction element, simultaneous fastening of the third friction element and the fifth friction element, and simultaneous fastening of the third friction element and the fourth friction element An automatic transmission characterized by being. The automatic transmission according to claim 1, wherein
The combination of two simultaneous engagements of the first to fifth friction elements that achieve the seventh forward speed is the simultaneous engagement of the first friction element and the second friction element, the first friction element And the third friction element, the first friction element and the fourth friction element, the first friction element and the fifth friction element, and the fourth friction. Simultaneous fastening of an element and the fifth friction element, simultaneous fastening of the third friction element and the fifth friction element, simultaneous fastening of the third friction element and the fourth friction element, the second An automatic transmission comprising a combination of seven friction elements and a fifth friction element that are simultaneously engaged. The automatic transmission according to claim 3 or 4,
Two simultaneous engagements of the first to fifth friction elements that achieve the first reverse speed are the simultaneous engagement of the second friction element and the third friction element, or the second friction element An automatic transmission comprising simultaneous engagement of the fourth friction elements.

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