Transmission

Abstract

To provide a transmission which can perform a forward four-speed gear change without being accompanied by the double-switching of a fastening element at a gear change, by a simple structure.SOLUTION: A transmission comprises: a first planetary gear mechanism having a first sun gear, a first carrier, and a first ring gear; a second planetary gear mechanism having a second sun gear, a second carrier, and a second ring gear; a first fastening element; a second fastening element; a third fastening element; a fourth fastening element; and a transmission case. The first fastening element is located between the second carrier and the transmission case, the second fastening element is located between the first carrier and the second sun gear, the third fastening element is located between the second fastening element and the second carrier, the fourth fastening element is located between the first sun gear and the second carrier, the first ring gear is non-rotatably connected to the transmission case, the first sun gear is connected with an input shaft, and the second ring gear is connected with an output shaft.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a transmission. [Background technology]

[0002] Patent Document 1 discloses a transmission that includes two planetary gear mechanisms and four fastening elements and realizes four forward speeds. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-118218 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the invention described in Patent Document 1, double switching of the engagement elements is required when shifting between first and second gears, making it difficult to synchronize the timing of these switches and resulting in a large shift shock when shifting between first and second gears.

[0005] The present invention has been made in consideration of the above circumstances, and aims to provide a transmission that realizes four forward speed changes with a simple structure without double switching of the fastening elements when changing gears. [Means for solving the problem]

[0006] According to one aspect of the present invention, a transmission includes an input shaft to which rotation is input from a drive source, an output shaft that outputs the rotation of the input shaft to drive wheels, a first planetary gear mechanism, a second planetary gear mechanism, a first engagement element that is engaged in first gear, a second engagement element that is engaged in first, second and third gears, a third engagement element that is engaged in second and fourth gears, a fourth engagement element that is engaged in third and fourth gears, and a transmission case, wherein the first planetary gear mechanism is a single pinion planetary gear mechanism having a first sun gear, a first carrier and a first ring gear, and the second planetary gear mechanism is a single pinion planetary gear mechanism having a second sun gear, a second carrier and a first ring gear. and a second ring gear, wherein the first fastening element is located between the second carrier and the transmission case, the second fastening element is located between the first carrier and the second sun gear, the third fastening element is located between the second fastening element and the second carrier, and the fourth fastening element is located between the first sun gear and the second carrier, the first ring gear is non-rotatably connected to the transmission case, the first sun gear is connected to the input shaft, and the second ring gear is connected to the output shaft.

[0007] According to another aspect of the present invention, a transmission includes an input shaft to which rotation is input from a drive source, an output shaft to which the rotation of the input shaft is output to a drive wheel, a first planetary gear mechanism, a second planetary gear mechanism, a first engagement element that is engaged in first gear, a second engagement element that is engaged in first, second and third gears, a third engagement element that is engaged in second and fourth gears, a fourth engagement element that is engaged in third and fourth gears, and a transmission case, wherein the first planetary gear mechanism is a single pinion planetary gear mechanism having a first sun gear, a first carrier and a first ring gear, and the second planetary gear mechanism is a double pinion planetary gear mechanism having a first fastening element, a second sun gear, a second carrier and a second ring gear, wherein the first fastening element is located between the second carrier and the transmission case, the second fastening element is located between the first ring gear and the transmission case, the third fastening element is located between the first carrier and the second carrier, and the fourth fastening element is located between the first sun gear and the second carrier, the first sun gear is connected to the input shaft, and the second ring gear is connected to the output shaft.

[0008] According to another aspect of the present invention, a transmission includes an input shaft to which rotation is input from a drive source, an output shaft to which the rotation of the input shaft is output to a drive wheel, a first planetary gear mechanism, a second planetary gear mechanism, a first engagement element that is engaged in first gear, a second engagement element that is engaged in first, second and third gears, a third engagement element that is engaged in second and fourth gears, a fourth engagement element that is engaged in third and fourth gears, and a transmission case, wherein the first planetary gear mechanism is a single pinion planetary gear mechanism having a first sun gear, a first carrier and a first ring gear, and the second planetary gear mechanism is a single pinion planetary gear mechanism having a second sun gear, a second carrier and a first ring gear. and a second ring gear, the first fastening element being positioned between the second ring gear and the transmission case, the second fastening element being positioned between the first carrier and the second sun gear, the third fastening element being positioned between the second fastening element and the second ring gear, and the fourth fastening element being positioned between the first sun gear and the second ring gear, the first ring gear non-rotatably connected to the transmission case, the first sun gear being connected to the input shaft, and the second carrier being connected to the output shaft.

[0009] According to another aspect of the present invention, a transmission includes an input shaft to which rotation is input from a drive source, an output shaft to which the rotation of the input shaft is output to drive wheels, a first planetary gear mechanism, a second planetary gear mechanism, a first engagement element that is engaged in first gear, a second engagement element that is engaged in first, second and third gears, a third engagement element that is engaged in second and fourth gears, a fourth engagement element that is engaged in third and fourth gears, and a transmission case, wherein the first planetary gear mechanism is a single pinion planetary gear mechanism having a first sun gear, a first carrier and a first ring gear, and the second planetary gear mechanism is There is provided a transmission comprising a single pinion planetary gear mechanism having a second sun gear, a second carrier and a second ring gear, wherein the first fastening element is located between the second ring gear and the transmission case, the second fastening element is located between the first ring gear and the transmission case, the third fastening element is located between the first carrier and the second ring gear, and the fourth fastening element is located between the first sun gear and the second ring gear, the first sun gear is connected to the input shaft, and the second carrier is connected to the output shaft.

[0010] According to another aspect of the present invention, a transmission includes an input shaft to which rotation is input from a drive source, an output shaft to which the rotation of the input shaft is output to drive wheels, a first planetary gear mechanism, a second planetary gear mechanism, a first engagement element that is engaged in first gear, a second engagement element that is engaged in first, second and third gears, a third engagement element that is engaged in second and fourth gears, a fourth engagement element that is engaged in third and fourth gears, and a transmission case, wherein the first planetary gear mechanism is a double pinion planetary gear mechanism having a first sun gear, a first carrier and a first ring gear, and the second planetary gear mechanism is a double pinion planetary gear mechanism having a second sun gear, a second carrier and a first ring gear. There is provided a transmission comprising a single pinion planetary gear mechanism having a second ring gear, the first fastening element being positioned between the second ring gear and the transmission case, the second fastening element being positioned between the first ring gear and the second sun gear, the third fastening element being positioned between the second fastening element and the second ring gear, and the fourth fastening element being positioned between the first carrier and the second ring gear, the first sun gear being non-rotatably connected to the transmission case, the first carrier being connected to the input shaft, and the second carrier being connected to the output shaft.

[0011] According to another aspect of the present invention, a transmission includes an input shaft to which rotation is input from a drive source, an output shaft to which the rotation of the input shaft is output to a drive wheel, a first planetary gear mechanism, a second planetary gear mechanism, a first engagement element that is engaged in first gear, a second engagement element that is engaged in first, second and third gears, a third engagement element that is engaged in second and fourth gears, a fourth engagement element that is engaged in third and fourth gears, and a transmission case, wherein the first planetary gear mechanism is a double pinion planetary gear mechanism having a first sun gear, a first carrier and a first ring gear, and the second planetary gear mechanism is a There is provided a transmission comprising a single pinion planetary gear mechanism having a second sun gear, a second carrier, and a second ring gear, wherein the first fastening element is located between the second ring gear and the transmission case, the second fastening element is located between the first sun gear and the transmission case, the third fastening element is located between the first ring gear and the second ring gear, and the fourth fastening element is located between the first carrier and the second ring gear, the first carrier is connected to the input shaft, and the second carrier is connected to the output shaft.

[0012] According to another aspect of the present invention, a transmission includes an input shaft to which rotation is input from a drive source, an output shaft to which the rotation of the input shaft is output to a drive wheel, a first planetary gear mechanism, a second planetary gear mechanism, a first engagement element that is engaged in first gear, a second engagement element that is engaged in first, second and third gears, a third engagement element that is engaged in second and fourth gears, a fourth engagement element that is engaged in third and fourth gears, and a transmission case, wherein the first planetary gear mechanism is a double pinion planetary gear mechanism having a first sun gear, a first carrier and a first ring gear, and the second planetary gear mechanism is a double pinion planetary gear mechanism having a second sun gear, a second carrier and a first ring gear. and a second ring gear, the first fastening element being located between the second carrier and the transmission case, the second fastening element being located between the first ring gear and the second sun gear, the third fastening element being located between the second fastening element and the second carrier, and the fourth fastening element being located between the first sun gear and the second carrier, the first carrier non-rotatably connected to the transmission case, the first sun gear being connected to the input shaft, and the second ring gear being connected to the output shaft.

[0013] According to another aspect of the present invention, a transmission includes an input shaft to which rotation is input from a drive source, an output shaft to which the rotation of the input shaft is output to a drive wheel, a first planetary gear mechanism, a second planetary gear mechanism, a first engagement element that is engaged in first gear, a second engagement element that is engaged in first, second and third gears, a third engagement element that is engaged in second and fourth gears, a fourth engagement element that is engaged in third and fourth gears, and a transmission case, wherein the first planetary gear mechanism is a double pinion planetary gear mechanism having a first sun gear, a first carrier and a first ring gear, and the second planetary gear mechanism is a double pinion planetary gear mechanism having a first fastening element, a second sun gear, a second carrier and a second ring gear, wherein the first fastening element is located between the second carrier and the transmission case, the second fastening element is located between the first carrier and the transmission case, the third fastening element is located between the first ring gear and the second carrier, and the fourth fastening element is located between the first sun gear and the second carrier, the first sun gear is connected to the input shaft, and the second ring gear is connected to the output shaft. Effect of the Invention

[0014] According to the aspects of the present invention, four forward speeds can be achieved with a simple structure without double switching of the engagement elements during gear shifting. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a skeleton diagram of a transmission according to a first embodiment. [Diagram 2] FIG. 2 is a table showing, as an example, the proportional values ​​between the number of sun gear teeth and the number of ring gear teeth of a single pinion planetary gear mechanism and a double pinion planetary gear mechanism. [Diagram 3] FIG. 3 is a table showing whether or not the fastening elements according to the first embodiment are engaged, and shows gear ratios and step differences as examples. [Figure 4A] FIG. 4A is a collinear diagram of the first speed of the transmission according to the first embodiment. [Figure 4B] FIG. 4B is a collinear diagram of the second speed of the transmission according to the first embodiment. [Figure 4C] FIG. 4C is a collinear diagram of the three speeds of the transmission according to the first embodiment. [Figure 4D] FIG. 4D is a collinear diagram of the fourth speed of the transmission according to the first embodiment. [Diagram 5] FIG. 5 is a skeleton diagram of a transmission according to the second embodiment. [Figure 6] FIG. 6 is a table showing whether or not the fastening elements are engaged according to the second embodiment. [Figure 7A] FIG. 7A is a collinear diagram of the first speed of the transmission according to the second embodiment. [Figure 7B] FIG. 7B is a collinear diagram of the second speed of the transmission according to the second embodiment. [Figure 7C] FIG. 7C is a collinear diagram of the third gear of the transmission according to the second embodiment. [Figure 7D] FIG. 7D is a collinear diagram of the fourth speed of the transmission according to the second embodiment. [Figure 8] FIG. 8 is a skeleton diagram of a transmission according to the third embodiment. [Figure 9] FIG. 9 is a table showing whether or not the fastening elements are fastened according to the third embodiment. [Figure 10A] FIG. 10A is a collinear diagram of the first speed of the transmission according to the third embodiment. [Figure 10B] FIG. 10B is a collinear diagram of the second speed of the transmission according to the third embodiment. [Figure 10C] FIG. 10C is a collinear diagram of the third speed of the transmission according to the third embodiment. [Figure 10D] FIG. 10D is a collinear diagram of the fourth speed of the transmission according to the third embodiment. [Figure 11] FIG. 11 is a skeleton diagram of a transmission according to a fourth embodiment. [Figure 12] FIG. 12 is a table showing whether or not the fastening elements according to the fourth embodiment are engaged. [Figure 13A] FIG. 13A is a collinear diagram of the first speed of the transmission according to the fourth embodiment. [Figure 13B] FIG. 13B is a collinear diagram of the second speed of the transmission according to the fourth embodiment. [Figure 13C] FIG. 13C is a collinear diagram of the third speed of the transmission according to the fourth embodiment. [Figure 13D] FIG. 13D is a collinear diagram of the fourth speed of the transmission according to the fourth embodiment. [Figure 14] FIG. 14 is a skeleton diagram of a transmission according to a fifth embodiment. [Figure 15] FIG. 15 is a table showing whether or not the fastening elements are engaged according to the fifth embodiment. [Figure 16A] FIG. 16A is a collinear diagram of the first speed of the transmission according to the fifth embodiment. [Figure 16B] FIG. 16B is a collinear diagram of the second speed of the transmission according to the fifth embodiment. [Figure 16C] FIG. 16C is a collinear diagram of the third gear of the transmission according to the fifth embodiment. [Figure 16D] FIG. 16D is a collinear diagram of the fourth speed of the transmission according to the fifth embodiment. [Figure 17] FIG. 17 is a skeleton diagram of a transmission according to the sixth embodiment. [Figure 18] FIG. 18 is a table showing whether or not the fastening elements are fastened according to the sixth embodiment. [Figure 19A] FIG. 19A is a collinear diagram of the first speed of the transmission according to the sixth embodiment. [Figure 19B] FIG. 19B is a collinear diagram of the second speed of the transmission according to the sixth embodiment. [Figure 19C] FIG. 19C is a collinear diagram of the third gear of the transmission according to the sixth embodiment. [Figure 19D] FIG. 19D is a collinear diagram of the fourth speed of the transmission according to the sixth embodiment. [Figure 20] FIG. 20 is a skeleton diagram of a transmission according to the seventh embodiment. [Figure 21] FIG. 21 is a table showing whether or not the fastening elements according to the seventh embodiment are engaged. [Figure 22A] FIG. 22A is a collinear diagram of the first speed of the transmission according to the seventh embodiment. [Figure 22B] FIG. 22B is a collinear diagram of the second speed of the transmission according to the seventh embodiment. [Figure 22C] FIG. 22C is a collinear diagram of the third speed of the transmission according to the seventh embodiment. [Figure 22D] FIG. 22D is a collinear diagram of the fourth speed of the transmission according to the seventh embodiment. [Figure 23] FIG. 23 is a skeleton diagram of a transmission according to the eighth embodiment. [Figure 24] FIG. 24 is a table showing whether or not the fastening elements are fastened according to the eighth embodiment. [Figure 25A] FIG. 25A is a collinear diagram of the first speed of the transmission according to the eighth embodiment. [Figure 25B] FIG. 25B is a collinear diagram of the second speed of the transmission according to the eighth embodiment. [Figure 25C] FIG. 25C is a collinear diagram of the third speed of the transmission according to the eighth embodiment. [Figure 25D] FIG. 25D is a collinear diagram of the fourth speed of the transmission according to the eighth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In this specification, the same elements are denoted by the same reference numerals throughout.

[0017] (First embodiment) First, a transmission 1 according to a first embodiment will be described with reference to Figs. 1 to 4D.

[0018] FIG. 1 is a skeleton diagram of the transmission 1 according to the first embodiment. FIG. 2 is a table showing, as an example, the proportional value (i.e., λ value) between the number of sun gear teeth and the number of ring gear teeth of the first planetary gear mechanism 13 and the second planetary gear mechanism 14. FIG. 3 is a table showing the engagement / non-engagement of the engagement elements according to the first embodiment, and shows the gear ratio and the step difference as an example. In FIG. 3, "◯" indicates an engagement state, and no mark indicates a release state. In addition, in FIG. 3, "gear ratio" indicates the gear ratio between the input shaft 11 and the output shaft 12, and "step difference" is a proportional value between the high-speed gear ratio and the low-speed gear ratio. FIG. 4A is a nomogram of the first speed of the transmission 1 according to the first embodiment. FIG. 4B is a nomogram of the second speed of the transmission 1 according to the first embodiment. FIG. 4C is a nomogram of the third speed of the transmission 1 according to the first embodiment. FIG. 4D is a nomogram of the fourth speed of the transmission 1 according to the first embodiment.

[0019] 1, the transmission 1 according to the first embodiment is, for example, an automatic transmission used in a vehicle (not shown). The transmission 1 includes a transmission case 10, an input shaft 11, an output shaft 12, a first planetary gear mechanism 13, a second planetary gear mechanism 14, a first engagement element 15, a second engagement element 16, a third engagement element 17, and a fourth engagement element 18.

[0020] The transmission case 10 is a housing for housing a first planetary gear mechanism 13, a second planetary gear mechanism 14, a first engagement element 15, a second engagement element 16, a third engagement element 17, and a fourth engagement element 18. The transmission case 10 is non-rotatably mounted on the vehicle.

[0021] The input shaft 11 rotates by power from a motor (not shown) serving as a drive source. The motor has a function as an electric motor that receives power from a battery (not shown) to rotate and a function as a generator that rotates with an external force to generate electricity. When regenerative control is performed, the motor functions as an electric motor.

[0022] The output shaft 12 outputs the rotation of the input shaft 11 to driving wheels (not shown).

[0023] Between the input shaft 11 and the output shaft 12, a first planetary gear mechanism 13, a second planetary gear mechanism 14, a first engagement element 15, a second engagement element 16, a third engagement element 17, and a fourth engagement element 18 are provided.

[0024] The first planetary gear mechanism 13 is a single pinion planetary gear mechanism having a first sun gear 13a, a first carrier 13b, and a first ring gear 13c. A first pinion gear group 13d is provided between the first sun gear 13a and the first ring gear 13c, and meshes with both the first sun gear 13a and the first ring gear 13c. The first ring gear 13c is non-rotatably connected to the transmission case 10. The first pinion gear group 13d is rotatably supported by the first carrier 13b. The first pinion gear group 13d is also made of a single first pinion gear (not shown) that meshes with both the first sun gear 13a and the first ring gear 13c. The first sun gear 13a is connected to the input shaft 11.

[0025] The second planetary gear mechanism 14 is a double pinion planetary gear mechanism having a second sun gear 14a, a second carrier 14b, and a second ring gear 14c. Between the second sun gear 14a and the second ring gear 14c, a second pinion gear group 14d is provided, which meshes with both the second sun gear 14a and the second ring gear 14c. The second pinion gear group 14d is rotatably supported by the second carrier 14b. The second pinion gear group 14d is also composed of one second pinion gear (not shown) which meshes with the second sun gear 14a, and the other second pinion gear (not shown) which meshes with both the second ring gear 14c and the one second pinion gear. The second ring gear 14c is connected to the output shaft 12.

[0026] The power transmission path from the input shaft 11 to the output shaft 12 is switched by switching the states of the first engagement element 15, the second engagement element 16, the third engagement element 17, and the fourth engagement element 18 between an engaged state and a released state. Since the rotation input to the input shaft 11 can be output to the output shaft 12 at a gear ratio according to the switching of these engagement elements, a plurality of gear stages can be realized.

[0027] The first engagement element 15 is a brake located between the second carrier 14b and the transmission case 10. The second engagement element 16 is a clutch located between the first carrier 13b and the second sun gear 14a. The third engagement element 17 is a clutch located between the second engagement element 16 and the second carrier 14b, and between the fourth engagement element 18 and the second sun gear 14a. The fourth engagement element 18 is a clutch located between the first sun gear 13a and the second carrier 14b, and between the first sun gear 13a and the third engagement element 17.

[0028] 2, in the first planetary gear mechanism 13 according to the present embodiment, the number of teeth of the first sun gear 13a is 39, and the number of teeth of the first ring gear 13c is 79. The λ value of the first planetary gear mechanism 13 is 39 / 79=0.493671.

[0029] On the other hand, in the second planetary gear mechanism 14, the number of teeth of the second sun gear 14a is 43, and the number of teeth of the second ring gear 14c is 103. The λ value of the second planetary gear mechanism 14 is 43 / 103=0.417476.

[0030] As shown in FIG. 3, in the transmission 1, four forward gears can be achieved by engaging two of the first engagement element 15, the second engagement element 16, the third engagement element 17, and the fourth engagement element 18 at each gear stage.

[0031] Specifically, in first gear, the transmission 1 has the first engagement element 15 and the second engagement element 16 in an engaged state, and the third engagement element 17 and the fourth engagement element 18 in a disengaged state. In addition, in first gear, the gear ratio is 7.247466.

[0032] In the first gear, the first sun gear 13a and the first carrier 13b are rotatable, and the first ring gear 13c is non-rotatable. The first carrier 13b is connected to the second sun gear 14a by the engagement of the second fastening element 16. The second sun gear 14a and the second ring gear 14c are rotatable, and the second carrier 14b is non-rotatable by the engagement of the first fastening element 15. Thus, the rotation of the first carrier 13b caused by the rotation of the input shaft 11, the first sun gear 13a, and the first pinion gear group 13d is transmitted to the second sun gear 14a through the second fastening element 16. The rotation of the second sun gear 14a is transmitted to the output shaft 12 through the second pinion gear group 14d and the second ring gear 14c.

[0033] According to this, as shown in the collinear diagram of Figure 4A, when rotation is input from the motor to the input shaft 11, the rotation transmitted from the input shaft 11 to the first sun gear 13a is reduced to the rotation of the second ring gear 14c that is between the rotation of the first ring gear 13c (second carrier 14b) (i.e., non-rotatable) and the rotation of the first carrier 13b (second sun gear 14a) which is smaller than the rotation of the first sun gear 13a, and is output from the output shaft 12 connected to the second ring gear 14c.

[0034] In second gear, the transmission 1 has the second engagement element 16 and the third engagement element 17 in an engaged state, and the first engagement element 15 and the fourth engagement element 18 in a disengaged state. In second gear, the gear ratio is 3.025641. The difference in gear ratio between first gear and second gear is 7.247466 / 3.025641=2.395349.

[0035] In the second gear, the first sun gear 13a and the first carrier 13b are rotatable, and the first ring gear 13c is non-rotatable. The first carrier 13b is connected to the second sun gear 14a and the second carrier 14b by the engagement of the second fastening element 16 and the third fastening element 17. The second sun gear 14a and the second ring gear 14c are rotatable, and the second carrier 14b is rotatable by the release of the first fastening element 15. Thus, the rotation of the first carrier 13b caused by the rotation of the input shaft 11, the first sun gear 13a, and the first pinion gear group 13d is transmitted to the second sun gear 14a and the second carrier 14b through the second fastening element 16 and the third fastening element 17, respectively. The rotation of the second sun gear 14a and the rotation of the second carrier 14b are transmitted to the output shaft 12 through the second pinion gear group 14d and the second ring gear 14c.

[0036] According to this, as shown in the collinear diagram of Figure 4B, when rotation is input from the motor to the input shaft 11, the rotation transmitted from the input shaft 11 to the first sun gear 13a is reduced to the rotation of the first carrier 13b (second sun gear 14a, second carrier 14b and second ring gear 14c) and output from the output shaft 12 connected to the second ring gear 14c.

[0037] In the third gear, the transmission 1 has the second engagement element 16 and the fourth engagement element 18 in an engaged state, and the first engagement element 15 and the third engagement element 17 in a disengaged state. In addition, in the third gear, the gear ratio is 1.387918. The difference in gear ratio between the second gear and the third gear is 3.025641 / 1.387918=2.179985.

[0038] In the third gear, the first sun gear 13a and the first carrier 13b are rotatable, and the first ring gear 13c is non-rotatable. The first sun gear 13a is connected to the second carrier 14b by the engagement of the fourth fastening element 18, and the first carrier 13b is connected to the second sun gear 14a by the engagement of the second fastening element 16. The second sun gear 14a and the second ring gear 14c are rotatable, and the second carrier 14b is rotatable by the release of the first fastening element 15. Thus, the rotation of the first sun gear 13a caused by the rotation of the input shaft 11 is transmitted to the second carrier 14b through the fourth fastening element 18, and the rotation of the first carrier 13b caused by the rotation of the input shaft 11, the first sun gear 13a, and the first pinion gear group 13d is transmitted to the second sun gear 14a through the second fastening element 16. The rotation of the second sun gear 14a and the rotation of the second carrier 14b are transmitted to the output shaft 12 via the second pinion gear group 14d and the second ring gear 14c.

[0039] According to this, as shown in the collinear diagram of Figure 4C, when rotation is input from the motor to the input shaft 11, the rotation transmitted from the input shaft 11 to the first sun gear 13a is reduced to the rotation of the second ring gear 14c which is between the rotation of the first carrier 13b (second sun gear 14a) which is smaller than the rotation of the first sun gear 13a (second carrier 14b) and the rotation of the first sun gear 13a (second carrier 14b), and is output from the output shaft 12 connected to the second ring gear 14c.

[0040] In the fourth gear, the transmission 1 has the third engagement element 17 and the fourth engagement element 18 in an engagement state, and the first engagement element 15 and the second engagement element 16 in a disengaged state. In addition, in the fourth gear, the gear ratio is 1. The difference in gear between the third gear and the fourth gear is 1.387918 / 1=1.387918.

[0041] In the fourth gear, the first sun gear 13a and the first carrier 13b are rotatable, and the first ring gear 13c is non-rotatable. The first sun gear 13a is connected to the second sun gear 14a by the engagement of the fourth fastening element 18 and the third fastening element 17, and the first sun gear 13a is connected to the second carrier 14b by the engagement of the fourth fastening element 18. The second sun gear 14a and the second ring gear 14c are rotatable, and the second carrier 14b is rotatable by the release of the first fastening element 15. Thus, the rotation of the first sun gear 13a caused by the rotation of the input shaft 11 is transmitted to the second sun gear 14a through the fourth fastening element 18 and the third fastening element 17, and is transmitted to the second carrier 14b through the fourth fastening element 18. The rotation of the second sun gear 14a and the rotation of the second carrier 14b are transmitted to the output shaft 12 via the second pinion gear group 14d and the second ring gear 14c.

[0042] According to this, as shown in the collinear diagram of Figure 4D, when rotation is input from the motor to the input shaft 11, the rotation transmitted from the input shaft 11 to the first sun gear 13a (rotation of the second sun gear 14a, the second carrier 14b and the second ring gear 14c) is output at a constant speed from the output shaft 12 connected to the second ring gear 14c.

[0043] In this embodiment, the drive source is constituted by a motor, and therefore the transmission 1 does not have a reverse (Rvs) gear.

[0044] 3, when shifting between first and second gears, the transmission 1 keeps the second engagement element 16 in an engaged state, puts the first engagement element 15 in either an engaged state or a released state, and puts the third engagement element 17 in either an engaged state or a released state. In other words, when shifting between first and second gears, the transmission 1 only switches the first engagement element 15 and the third engagement element 17, without switching the second engagement element 16. This makes it possible to achieve a shift between first and second gears with a simple structure without double switching of the engagement elements.

[0045] 3, when shifting between second and third gears, the transmission 1 keeps the second engagement element 16 in an engaged state, puts the third engagement element 17 in either an engaged state or a released state, and puts the fourth engagement element 18 in either the engaged state or a released state. In other words, when shifting between second and third gears, the transmission 1 does not switch the second engagement element 16, but only switches the third engagement element 17 and the fourth engagement element 18. This makes it possible to achieve a shift between second and third gears with a simple structure without double switching of the engagement elements.

[0046] 3, the transmission 1 keeps the fourth engagement element 18 in an engaged state when shifting between third and fourth gears, puts the second engagement element 16 in either an engaged state or a released state, and puts the third engagement element 17 in either the engaged state or a released state. In other words, the transmission 1 does not switch the fourth engagement element 18 when shifting between third and fourth gears, but only switches the second engagement element 16 and the third engagement element 17. This makes it possible to achieve a simple structure for shifting between third and fourth gears without double switching of the engagement elements.

[0047] This makes it possible to realize four forward speeds without double switching of the engagement elements during gear shifting with a simple structure, thereby suppressing the occurrence of large gear shift shocks caused by double switching of the engagement elements during gear shifting.

[0048] According to the transmission 1 of the first embodiment, the gear ratio in first speed can be secured to be 7 or more (actually, it is 7.247466), so that a wide gear ratio of four forward speeds can be realized.

[0049] Second embodiment First, a transmission 1 according to a second embodiment will be described with reference to Fig. 5 to Fig. 7D. Note that in the second embodiment, the same points as in the first embodiment will be omitted, and differences from the first embodiment will be mainly described.

[0050] FIG. 5 is a skeleton diagram of the transmission 1 according to the second embodiment. FIG. 6 is a table showing whether the engagement elements according to the second embodiment are engaged. In FIG. 6, "◯" indicates an engaged state, and no mark indicates a disengaged state. FIG. 7A is a collinear diagram of the first gear of the transmission 1 according to the second embodiment. FIG. 7B is a collinear diagram of the second gear of the transmission 1 according to the second embodiment. FIG. 7C is a collinear diagram of the third gear of the transmission 1 according to the second embodiment. FIG. 7D is a collinear diagram of the fourth gear of the transmission 1 according to the second embodiment.

[0051] As shown in FIG. 5, the transmission 1 according to the second embodiment includes a transmission case 10, an input shaft 11, an output shaft 12, a first planetary gear mechanism 13, a second planetary gear mechanism 14, a first clutch element 15, a second clutch element 16, a third clutch element 17, and a fourth clutch element 18.

[0052] The transmission case 10, the input shaft 11 and the output shaft 12 of the second embodiment are similar to the transmission case 10, the input shaft 11 and the output shaft 12 of the first embodiment, and therefore a description thereof will be omitted.

[0053] The first planetary gear mechanism 13 is a single pinion planetary gear mechanism having a first sun gear 13a, a first carrier 13b, and a first ring gear 13c. A first pinion gear group 13d is provided between the first sun gear 13a and the first ring gear 13c, and meshes with both the first sun gear 13a and the first ring gear 13c. The first pinion gear group 13d is rotatably supported by the first carrier 13b. The first pinion gear group 13d is also made of a single first pinion gear (not shown) that meshes with both the first sun gear 13a and the first ring gear 13c. The first sun gear 13a is connected to the input shaft 11.

[0054] The second planetary gear mechanism 14 is a double pinion planetary gear mechanism having a second sun gear 14a, a second carrier 14b, and a second ring gear 14c. Between the second sun gear 14a and the second ring gear 14c, a second pinion gear group 14d is provided, which meshes with both the second sun gear 14a and the second ring gear 14c. The second pinion gear group 14d is rotatably supported by the second carrier 14b. The second pinion gear group 14d is also composed of one second pinion gear (not shown) which meshes with the second sun gear 14a, and the other second pinion gear (not shown) which meshes with both the second ring gear 14c and the one second pinion gear. The second ring gear 14c is connected to the output shaft 12.

[0055] The power transmission path from the input shaft 11 to the output shaft 12 is switched by switching the states of the first engagement element 15, the second engagement element 16, the third engagement element 17, and the fourth engagement element 18 between an engaged state and a released state. Since the rotation input to the input shaft 11 can be output to the output shaft 12 at a gear ratio according to the switching of these engagement elements, a plurality of gear stages can be realized.

[0056] The first fastening element 15 is a brake located between the second carrier 14b and the transmission case 10. The second fastening element 16 is a brake located between the first ring gear 13c and the transmission case 10. The third fastening element 17 is a clutch located between the first carrier 13b and the second carrier 14b, and between the fourth fastening element 18 and the second sun gear 14a. The fourth fastening element 18 is a clutch located between the first sun gear 13a and the second carrier 14b, and between the first sun gear 13a and the third fastening element 17.

[0057] As shown in FIG. 6, in the transmission 1, four forward gears can be achieved by engaging two of the first engagement element 15, the second engagement element 16, the third engagement element 17, and the fourth engagement element 18 at each gear stage.

[0058] Specifically, in first gear, the transmission 1 places the first engagement element 15 and the second engagement element 16 in an engaged state, and places the third engagement element 17 and the fourth engagement element 18 in a disengaged state.

[0059] In the first gear, the first sun gear 13a and the first carrier 13b are rotatable, and the first ring gear 13c is rendered non-rotatable by the engagement of the second engagement element 16. The first carrier 13b is directly connected to the second sun gear 14a. The second sun gear 14a and the second ring gear 14c are rotatable, and the second carrier 14b is rendered non-rotatable by the engagement of the first engagement element 15. Thus, the rotation of the first carrier 13b caused by the rotation of the input shaft 11, the first sun gear 13a, and the first pinion gear group 13d is directly transmitted to the second sun gear 14a. The rotation of the second sun gear 14a is transmitted to the output shaft 12 via the second pinion gear group 14d and the second ring gear 14c.

[0060] According to this, as shown in the collinear diagram of Figure 7A, when rotation is input from the motor to the input shaft 11, the rotation transmitted from the input shaft 11 to the first sun gear 13a is reduced in speed to the rotation of the second ring gear 14c that is between the rotation of the first ring gear 13c (i.e., non-rotatable) and the rotation of the first carrier 13b (second sun gear 14a), which is smaller than the rotation of the first sun gear 13a (second carrier 14b), and is output from the output shaft 12 connected to the second ring gear 14c.

[0061] In second gear, the transmission 1 places the second engagement element 16 and the third engagement element 17 in an engaged state, and places the first engagement element 15 and the fourth engagement element 18 in a disengaged state.

[0062] In the second gear, the first sun gear 13a and the first carrier 13b are rotatable, and the first ring gear 13c is made non-rotatable by the engagement of the second fastening element 16. The first carrier 13b is directly connected to the second sun gear 14a, and the first carrier 13b is connected to the second carrier 14b by the engagement of the third fastening element 17. The second sun gear 14a and the second ring gear 14c are rotatable, and the second carrier 14b is rotatable by the release of the first fastening element 15. Thus, the rotation of the first carrier 13b caused by the rotation of the input shaft 11, the first sun gear 13a, and the first pinion gear group 13d is directly transmitted to the second sun gear 14a, and is then transmitted to the second carrier 14b through the third fastening element 17. The rotation of the second sun gear 14a and the rotation of the second carrier 14b are transmitted to the output shaft 12 through the second pinion gear group 14d and the second ring gear 14c.

[0063] According to this, as shown in the collinear diagram of Figure 7B, when rotation is input from the motor to the input shaft 11, the rotation transmitted from the input shaft 11 to the first sun gear 13a is reduced in speed to the rotation of the first carrier 13b (second sun gear 14a, second carrier 14b and second ring gear 14c) and output from the output shaft 12 connected to the second ring gear 14c.

[0064] In the third gear, the transmission 1 places the second engagement element 16 and the fourth engagement element 18 in an engaged state, and places the first engagement element 15 and the third engagement element 17 in a disengaged state.

[0065] In third gear, the first sun gear 13a and the first carrier 13b are rotatable, and the first ring gear 13c is non-rotatable due to the engagement of the second engagement element 16. The first sun gear 13a is connected to the second carrier 14b due to the engagement of the fourth engagement element 18, and the first carrier 13b is directly connected to the second sun gear 14a. The second sun gear 14a and the second ring gear 14c are rotatable, and the second carrier 14b is rotatable due to the release of the first engagement element 15. Thus, the rotation of the first sun gear 13a caused by the rotation of the input shaft 11 is transmitted to the second carrier 14b through the fourth engagement element 18, and the rotation of the first carrier 13b caused by the rotation of the input shaft 11, the first sun gear 13a, and the first pinion gear group 13d is transmitted directly to the second sun gear 14a. The rotation of the second sun gear 14a and the rotation of the second carrier 14b are transmitted to the output shaft 12 via the second pinion gear group 14d and the second ring gear 14c.

[0066] According to this, as shown in the collinear diagram of Figure 7C, when rotation is input from the motor to the input shaft 11, the rotation transmitted from the input shaft 11 to the first sun gear 13a is reduced in speed to the rotation of the second ring gear 14c which is between the rotation of the first carrier 13b (second sun gear 14a) which is smaller than the rotation of the first sun gear 13a (second carrier 14b) and the rotation of the first sun gear 13a (second carrier 14b), and is output from the output shaft 12 connected to the second ring gear 14c.

[0067] In the fourth gear, the transmission 1 places the third engagement element 17 and the fourth engagement element 18 in an engaged state, and the first engagement element 15 and the second engagement element 16 in a disengaged state.

[0068] In the fourth gear, the first sun gear 13a and the first carrier 13b are rotatable, and the first ring gear 13c is rotatable due to the release of the second fastening element 16. Therefore, the first carrier 13b and the first ring gear 13c are directly connected to the first sun gear 13a via the first pinion gear group 13d. That is, when the first sun gear 13a rotates, the first carrier 13b and the first ring gear 13c also rotate integrally with the first sun gear 13a. In addition, the first sun gear 13a is connected to the second sun gear 14a due to the fastening of the fourth fastening element 18 and the third fastening element 17, the first sun gear 13a is connected to the second carrier 14b due to the fastening of the fourth fastening element 18, and the first carrier 13b is directly connected to the second sun gear 14a. Then, the second sun gear 14a and the second ring gear 14c become rotatable, and the second carrier 14b becomes rotatable due to the release of the first fastening element 15. Therefore, the second carrier 14b and the second ring gear 14c are directly connected to the second sun gear 14a via the second pinion gear group 14d. That is, when the second sun gear 14a rotates, the second carrier 14b and the second ring gear 14c also rotate integrally with the second sun gear 14a. Therefore, the rotation of the first sun gear 13a caused by the rotation of the input shaft 11 is transmitted to the second carrier 14b through the fourth fastening element 18, and the rotation of the first carrier 13b caused by the rotation of the input shaft 11, the first sun gear 13a, and the first pinion gear group 13d is directly transmitted to the second sun gear 14a. The rotation of the second sun gear 14a and the rotation of the second carrier 14b are transmitted to the output shaft 12 via the second pinion gear group 14d and the second ring gear 14c.

[0069] According to this, as shown in the collinear diagram of Figure 7D, when rotation is input from the motor to the input shaft 11, the rotation (rotation of the second carrier 14b) transmitted from the input shaft 11 to the first sun gear 13a is output at a constant speed from the output shaft 12 connected to the second ring gear 14c.

[0070] 6, when shifting between first and second gears, the transmission 1 keeps the second engagement element 16 in an engaged state, puts the first engagement element 15 in either an engaged state or a released state, and puts the third engagement element 17 in either an engaged state or a released state. In other words, when shifting between first and second gears, the transmission 1 only switches the first engagement element 15 and the third engagement element 17, without switching the second engagement element 16. This makes it possible to achieve a shift between first and second gears with a simple structure without double switching of the engagement elements.

[0071] 6, when shifting between second and third gears, the transmission 1 keeps the second engagement element 16 in an engaged state, puts the third engagement element 17 in either an engaged state or a released state, and puts the fourth engagement element 18 in either the engaged state or a released state. In other words, when shifting between second and third gears, the transmission 1 does not switch the second engagement element 16, but only switches the third engagement element 17 and the fourth engagement element 18. This makes it possible to achieve a simple structure for shifting between second and third gears without double switching of the engagement elements.

[0072] 6, the transmission 1 keeps the fourth engagement element 18 in an engaged state when shifting between third and fourth gears, puts the second engagement element 16 in either an engaged state or a released state, and puts the third engagement element 17 in either the engaged state or a released state. In other words, the transmission 1 does not switch the fourth engagement element 18 when shifting between third and fourth gears, but only switches the second engagement element 16 and the third engagement element 17. This makes it possible to achieve a simple structure for shifting between third and fourth gears without double switching of the engagement elements.

[0073] This makes it possible to realize four forward speeds without double switching of the engagement elements during gear shifting with a simple structure, thereby suppressing the occurrence of large gear shift shocks caused by double switching of the engagement elements during gear shifting.

[0074] Third embodiment First, a transmission 1 according to a third embodiment will be described with reference to Fig. 8 to Fig. 10D. Note that in the third embodiment, the same points as in the first and second embodiments will be omitted, and the differences from the first and second embodiments will be mainly described.

[0075] FIG. 8 is a skeleton diagram of the transmission 1 according to the third embodiment. FIG. 9 is a table showing whether the engagement elements according to the third embodiment are engaged. In FIG. 9, "◯" indicates an engaged state, and no mark indicates a disengaged state. FIG. 10A is a collinear diagram of the first gear of the transmission 1 according to the third embodiment. FIG. 10B is a collinear diagram of the second gear of the transmission 1 according to the third embodiment. FIG. 10C is a collinear diagram of the third gear of the transmission 1 according to the third embodiment. FIG. 10D is a collinear diagram of the fourth gear of the transmission 1 according to the third embodiment.

[0076] As shown in FIG. 8, the transmission 1 according to the third embodiment includes a transmission case 10, an input shaft 11, an output shaft 12, a first planetary gear mechanism 13, a second planetary gear mechanism 14, a first clutch element 15, a second clutch element 16, a third clutch element 17, and a fourth clutch element 18.

[0077] The transmission case 10, the input shaft 11 and the output shaft 12 of the third embodiment are similar to the transmission case 10, the input shaft 11 and the output shaft 12 of the first and second embodiments, and therefore description thereof will be omitted.

[0078] The first planetary gear mechanism 13 is a single pinion planetary gear mechanism having a first sun gear 13a, a first carrier 13b, and a first ring gear 13c. A first pinion gear group 13d is provided between the first sun gear 13a and the first ring gear 13c, and meshes with both the first sun gear 13a and the first ring gear 13c. The first ring gear 13c is non-rotatably connected to the transmission case 10. The first pinion gear group 13d is rotatably supported by the first carrier 13b. The first pinion gear group 13d is also made of a single first pinion gear (not shown) that meshes with both the first sun gear 13a and the first ring gear 13c. The first sun gear 13a is connected to the input shaft 11.

[0079] The second planetary gear mechanism 14 is a single pinion planetary gear mechanism having a second sun gear 14a, a second carrier 14b, and a second ring gear 14c. Between the second sun gear 14a and the second ring gear 14c, a second pinion gear group 14d is provided, which meshes with both the second sun gear 14a and the second ring gear 14c. The second pinion gear group 14d is rotatably supported by the second carrier 14b. The second pinion gear group 14d is also made of a single first pinion gear (not shown) which meshes with both the second sun gear 14a and the second ring gear 14c. The second carrier 14b is connected to the output shaft 12.

[0080] The power transmission path from the input shaft 11 to the output shaft 12 is switched by switching the states of the first engagement element 15, the second engagement element 16, the third engagement element 17, and the fourth engagement element 18 between an engaged state and a released state. Since the rotation input to the input shaft 11 can be output to the output shaft 12 at a gear ratio according to the switching of these engagement elements, a plurality of gear stages can be realized.

[0081] The first fastening element 15 is a brake located between the second ring gear 14c and the transmission case 10. The second fastening element 16 is a clutch located between the first carrier 13b and the second sun gear 14a. The third fastening element 17 is a clutch located between the second fastening element 16 and the second ring gear 14c, and between the fourth fastening element 18 and the second sun gear 14a. The fourth fastening element 18 is a clutch located between the first sun gear 13a and the second ring gear 14c, and between the first sun gear 13a and the third fastening element 17.

[0082] As shown in FIG. 9, in the transmission 1, four forward gears can be achieved by engaging two of the first engagement element 15, the second engagement element 16, the third engagement element 17, and the fourth engagement element 18 in each gear position.

[0083] Specifically, in first gear, the transmission 1 places the first engagement element 15 and the second engagement element 16 in an engaged state, and places the third engagement element 17 and the fourth engagement element 18 in a disengaged state.

[0084] In the first gear, the first sun gear 13a and the first carrier 13b are rotatable, and the first ring gear 13c is non-rotatable. The first carrier 13b is connected to the second sun gear 14a by the engagement of the second fastening element 16. The second sun gear 14a and the second carrier 14b are rotatable, and the second ring gear 14c is non-rotatable by the engagement of the first fastening element 15. Thus, the rotation of the first carrier 13b caused by the rotation of the input shaft 11, the first sun gear 13a, and the first pinion gear group 13d is transmitted to the second sun gear 14a through the second fastening element 16. The rotation of the second sun gear 14a is transmitted to the output shaft 12 through the second pinion gear group 14d and the second carrier 14b.

[0085] According to this, as shown in the collinear diagram of Figure 10A, when rotation is input from the motor to the input shaft 11, the rotation transmitted from the input shaft 11 to the first sun gear 13a is reduced to the rotation of the second carrier 14b that is between the rotation of the first ring gear 13c (second ring gear 14c) (i.e., non-rotatable) and the rotation of the first carrier 13b (second sun gear 14a), which is smaller than the rotation of the first sun gear 13a, and is output from the output shaft 12 connected to the second carrier 14b.

[0086] In second gear, the transmission 1 places the second engagement element 16 and the third engagement element 17 in an engaged state, and places the first engagement element 15 and the fourth engagement element 18 in a disengaged state.

[0087] In the second gear, the first sun gear 13a and the first carrier 13b are rotatable, and the first ring gear 13c is non-rotatable. The first carrier 13b is connected to the second sun gear 14a by the engagement of the second fastening element 16, and the first carrier 13b is connected to the second ring gear 14c by the engagement of the second fastening element 16 and the third fastening element 17. The second sun gear 14a and the second carrier 14b are rotatable, and the second ring gear 14c is rotatable by the release of the first fastening element 15. Thus, the rotation of the first carrier 13b caused by the rotation of the input shaft 11, the first sun gear 13a, and the first pinion gear group 13d is transmitted to the second sun gear 14a through the second fastening element 16, and is transmitted to the second ring gear 14c through the second fastening element 16 and the third fastening element 17. The rotation of the second sun gear 14a and the rotation of the second ring gear 14c are transmitted to the output shaft 12 via the second pinion gear group 14d and the second carrier 14b.

[0088] According to this, as shown in the collinear diagram of Figure 10B, when rotation is input from the motor to the input shaft 11, the rotation transmitted from the input shaft 11 to the first sun gear 13a is reduced to the rotation of the first carrier 13b (the second sun gear 14a, the second carrier 14b and the second ring gear 14c) and output from the output shaft 12 connected to the second carrier 14b.

[0089] In the third gear, the transmission 1 places the second engagement element 16 and the fourth engagement element 18 in an engaged state, and places the first engagement element 15 and the third engagement element 17 in a disengaged state.

[0090] In the third gear, the first sun gear 13a and the first carrier 13b are rotatable, and the first ring gear 13c is non-rotatable. The first sun gear 13a is connected to the second ring gear 14c by the engagement of the fourth fastening element 18, and the first carrier 13b is connected to the second sun gear 14a by the engagement of the second fastening element 16. The second sun gear 14a and the second carrier 14b are rotatable, and the second ring gear 14c is rotatable by the release of the first fastening element 15. Thus, the rotation of the first sun gear 13a caused by the rotation of the input shaft 11 is transmitted to the second ring gear 14c through the fourth fastening element 18, and the rotation of the first carrier 13b caused by the rotation of the input shaft 11, the first sun gear 13a, and the first pinion gear group 13d is transmitted to the second sun gear 14a through the second fastening element 16. The rotation of the second sun gear 14a and the rotation of the second ring gear 14c are transmitted to the output shaft 12 via the second pinion gear group 14d and the second carrier 14b.

[0091] According to this, as shown in the collinear diagram of Figure 10C, when rotation is input from the motor to the input shaft 11, the rotation transmitted from the input shaft 11 to the first sun gear 13a is reduced to the rotation of the second carrier 14b that is between the rotation of the first carrier 13b (second sun gear 14a) which is smaller than the rotation of the first sun gear 13a (second ring gear 14c) and the rotation of the first sun gear 13a (second ring gear 14c), and is output from the output shaft 12 connected to the second carrier 14b.

[0092] In the fourth gear, the transmission 1 places the third engagement element 17 and the fourth engagement element 18 in an engaged state, and the first engagement element 15 and the second engagement element 16 in a disengaged state.

[0093] In the fourth gear, the first sun gear 13a and the first carrier 13b are rotatable, and the first ring gear 13c is non-rotatable. The first sun gear 13a is connected to the second sun gear 14a by the engagement of the fourth fastening element 18 and the third fastening element 17, and the first sun gear 13a is connected to the second ring gear 14c by the engagement of the fourth fastening element 18. The second sun gear 14a and the second carrier 14b are rotatable, and the second ring gear 14c is rotatable by the release of the first fastening element 15. Thus, the rotation of the first sun gear 13a caused by the rotation of the input shaft 11 is transmitted to the second sun gear 14a through the fourth fastening element 18 and the third fastening element 17, and is transmitted to the second ring gear 14c through the fourth fastening element 18. The rotation of the second sun gear 14a and the rotation of the second ring gear 14c are transmitted to the output shaft 12 via the second pinion gear group 14d and the second carrier 14b.

[0094] According to this, as shown in the collinear diagram of Figure 10D, when rotation is input from the motor to the input shaft 11, the rotation (rotation of the second sun gear 14a, the second carrier 14b and the second ring gear 14c) transmitted from the input shaft 11 to the first sun gear 13a is output at a constant speed from the output shaft 12 connected to the second carrier 14b.

[0095] 9, the transmission 1 keeps the second engagement element 16 in an engaged state when shifting between first and second gears, puts the first engagement element 15 in either an engaged state or a released state, and puts the third engagement element 17 in either the engaged state or a released state. In other words, the transmission 1 does not switch the second engagement element 16 when shifting between first and second gears, but only switches the first engagement element 15 and the third engagement element 17. This makes it possible to achieve a simple structure for shifting between first and second gears without double switching of the engagement elements.

[0096] 9, the transmission 1 keeps the second engagement element 16 in an engaged state when shifting between second and third gears, puts the third engagement element 17 in either an engaged state or a released state, and puts the fourth engagement element 18 in either the engaged state or a released state. In other words, the transmission 1 does not switch the second engagement element 16 when shifting between second and third gears, but only switches the third engagement element 17 and the fourth engagement element 18. This makes it possible to achieve a simple structure for shifting between second and third gears without double switching of the engagement elements.

[0097] 9, the transmission 1 keeps the fourth engagement element 18 in an engaged state when shifting between third and fourth gears, puts the second engagement element 16 in either an engaged state or a released state, and puts the third engagement element 17 in either the engaged state or a released state. In other words, the transmission 1 does not switch the fourth engagement element 18 when shifting between third and fourth gears, but only switches the second engagement element 16 and the third engagement element 17. This makes it possible to achieve a simple structure for shifting between third and fourth gears without double switching of the engagement elements.

[0098] This makes it possible to realize four forward speeds without double switching of the engagement elements during gear shifting with a simple structure, thereby suppressing the occurrence of large gear shift shocks caused by double switching of the engagement elements during gear shifting.

[0099] (Fourth embodiment) First, a transmission 1 according to a fourth embodiment will be described with reference to Fig. 11 to Fig. 13D. Note that in the fourth embodiment, the same points as those in the first to third embodiments will be omitted, and the differences from the first to third embodiments will be mainly described.

[0100] FIG. 11 is a skeleton diagram of the transmission 1 according to the fourth embodiment. FIG. 12 is a table showing whether the engagement elements according to the fourth embodiment are engaged or not. In FIG. 12, "◯" indicates an engaged state, and no mark indicates a disengaged state. FIG. 13A is a collinear diagram of the first gear of the transmission 1 according to the fourth embodiment. FIG. 13B is a collinear diagram of the second gear of the transmission 1 according to the fourth embodiment. FIG. 13C is a collinear diagram of the third gear of the transmission 1 according to the fourth embodiment. FIG. 13D is a collinear diagram of the fourth gear of the transmission 1 according to the fourth embodiment.

[0101] As shown in FIG. 11, the transmission 1 according to the fourth embodiment includes a transmission case 10, an input shaft 11, an output shaft 12, a first planetary gear mechanism 13, a second planetary gear mechanism 14, a first clutch element 15, a second clutch element 16, a third clutch element 17, and a fourth clutch element 18.

[0102] The transmission case 10, the input shaft 11 and the output shaft 12 of the fourth embodiment are similar to the transmission case 10, the input shaft 11 and the output shaft 12 of the first to third embodiments, and therefore description thereof will be omitted.

[0103] The first planetary gear mechanism 13 is a single pinion planetary gear mechanism having a first sun gear 13a, a first carrier 13b, and a first ring gear 13c. A first pinion gear group 13d is provided between the first sun gear 13a and the first ring gear 13c, and meshes with both the first sun gear 13a and the first ring gear 13c. The first pinion gear group 13d is rotatably supported by the first carrier 13b. The first pinion gear group 13d is also made of a single first pinion gear (not shown) that meshes with both the first sun gear 13a and the first ring gear 13c. The first sun gear 13a is connected to the input shaft 11.

[0104] The second planetary gear mechanism 14 is a single pinion planetary gear mechanism having a second sun gear 14a, a second carrier 14b, and a second ring gear 14c. Between the second sun gear 14a and the second ring gear 14c, a second pinion gear group 14d is provided which meshes with both the second sun gear 14a and the second ring gear 14c. The second pinion gear group 14d is rotatably supported by the second carrier 14b. The second pinion gear group 14d is also made of a single second pinion gear (not shown) which meshes with both the second sun gear 14a and the second ring gear 14c. The second carrier 14b is connected to the output shaft 12.

[0105] The power transmission path from the input shaft 11 to the output shaft 12 is switched by switching the states of the first engagement element 15, the second engagement element 16, the third engagement element 17, and the fourth engagement element 18 between an engaged state and a released state. Since the rotation input to the input shaft 11 can be output to the output shaft 12 at a gear ratio according to the switching of these engagement elements, a plurality of gear stages can be realized.

[0106] The first fastening element 15 is a brake located between the second ring gear 14c and the transmission case 10. The second fastening element 16 is a brake located between the first ring gear 13c and the transmission case 10. The third fastening element 17 is a clutch located between the first carrier 13b and the second ring gear 14c, and between the fourth fastening element 18 and the second sun gear 14a. The fourth fastening element 18 is a clutch located between the first sun gear 13a and the second ring gear 14c, and between the first sun gear 13a and the third fastening element 17.

[0107] As shown in FIG. 9, in the transmission 1, four forward gears can be achieved by engaging two of the first engagement element 15, the second engagement element 16, the third engagement element 17, and the fourth engagement element 18 in each gear position.

[0108] Specifically, in first gear, the transmission 1 places the first engagement element 15 and the second engagement element 16 in an engaged state, and places the third engagement element 17 and the fourth engagement element 18 in a disengaged state.

[0109] In the first gear, the first sun gear 13a and the first carrier 13b are rotatable, and the first ring gear 13c is rendered non-rotatable by the engagement of the second engagement element 16. The first carrier 13b is directly connected to the second sun gear 14a. The second sun gear 14a and the second carrier 14b are rotatable, and the second ring gear 14c is rendered non-rotatable by the engagement of the first engagement element 15. Thus, the rotation of the first carrier 13b caused by the rotation of the input shaft 11, the first sun gear 13a, and the first pinion gear group 13d is directly transmitted to the second sun gear 14a. The rotation of the second sun gear 14a is transmitted to the output shaft 12 via the second pinion gear group 14d and the second carrier 14b.

[0110] According to this, as shown in the collinear diagram of Figure 13A, when rotation is input from the motor to the input shaft 11, the rotation transmitted from the input shaft 11 to the first sun gear 13a is reduced in speed to the rotation of the second carrier 14b which is between the rotation of the first ring gear 13c (second ring gear 14c) (i.e., non-rotatable) and the rotation of the first carrier 13b (second sun gear 14a), which is smaller than the rotation of the first sun gear 13a, and is output from the output shaft 12 connected to the second carrier 14b.

[0111] In second gear, the transmission 1 places the second engagement element 16 and the third engagement element 17 in an engaged state, and places the first engagement element 15 and the fourth engagement element 18 in a disengaged state.

[0112] In second gear, the first sun gear 13a and the first carrier 13b are rotatable, and the first ring gear 13c is rendered non-rotatable by the engagement of the second fastening element 16. The first carrier 13b is directly connected to the second sun gear 14a, and the first carrier 13b is connected to the second ring gear 14c by the engagement of the third fastening element 17. The second sun gear 14a and the second carrier 14b are rotatable, and the second ring gear 14c is rotatable by the release of the first fastening element 15. Thus, the rotation of the first carrier 13b caused by the rotation of the input shaft 11, the first sun gear 13a, and the first pinion gear group 13d is directly transmitted to the second sun gear 14a, and then transmitted to the second ring gear 14c via the third fastening element 17. The rotation of the second sun gear 14a and the rotation of the second ring gear 14c are transmitted to the output shaft 12 via the second pinion gear group 14d and the second carrier 14b.

[0113] According to this, as shown in the collinear diagram of Figure 13B, when rotation is input from the motor to the input shaft 11, the rotation transmitted from the input shaft 11 to the first sun gear 13a is reduced to the rotation of the first carrier 13b (second sun gear 14a, second carrier 14b and second ring gear 14c) and output from the output shaft 12 connected to the second carrier 14b.

[0114] In the third gear, the transmission 1 places the second engagement element 16 and the fourth engagement element 18 in an engaged state, and places the first engagement element 15 and the third engagement element 17 in a disengaged state.

[0115] In third gear, the first sun gear 13a and the first carrier 13b are rotatable, and the first ring gear 13c is non-rotatable due to the engagement of the second fastening element 16. The first sun gear 13a is connected to the second ring gear 14c due to the engagement of the fourth fastening element 18, and the first carrier 13b is directly connected to the second sun gear 14a. The second sun gear 14a and the second carrier 14b are rotatable, and the second ring gear 14c is rotatable due to the release of the first fastening element 15. Thus, the rotation of the first sun gear 13a caused by the rotation of the input shaft 11 is transmitted to the second ring gear 14c through the fourth fastening element 18, and the rotation of the first carrier 13b caused by the rotation of the input shaft 11, the first sun gear 13a, and the first pinion gear group 13d is directly transmitted to the second sun gear 14a. The rotation of the second sun gear 14a and the rotation of the second ring gear 14c are transmitted to the output shaft 12 via the second pinion gear group 14d and the second carrier 14b.

[0116] According to this, as shown in the collinear diagram of Figure 13C, when rotation is input from the motor to the input shaft 11, the rotation transmitted from the input shaft 11 to the first sun gear 13a is reduced to the rotation of the second carrier 14b that is between the rotation of the first carrier 13b (second sun gear 14a) which is smaller than the rotation of the first sun gear 13a (second ring gear 14c) and the rotation of the first sun gear 13a (second ring gear 14c), and is output from the output shaft 12 connected to the second carrier 14b.

[0117] In the fourth gear, the transmission 1 places the third engagement element 17 and the fourth engagement element 18 in an engaged state, and the first engagement element 15 and the second engagement element 16 in a disengaged state.

[0118] In the fourth gear, the first sun gear 13a and the first carrier 13b are rotatable, and the first ring gear 13c is rotatable due to the release of the second fastening element 16. Therefore, the first carrier 13b and the first ring gear 13c are directly connected to the first sun gear 13a via the first pinion gear group 13d. That is, when the first sun gear 13a rotates, the first carrier 13b and the first ring gear 13c also rotate integrally with the first sun gear 13a. In addition, the first sun gear 13a is connected to the second sun gear 14a due to the fastening of the fourth fastening element 18 and the third fastening element 17, the first sun gear 13a is connected to the second ring gear 14c due to the fastening of the fourth fastening element 18, and the first carrier 13b is directly connected to the second sun gear 14a. Then, the second sun gear 14a and the second carrier 14b become rotatable, and the second ring gear 14c becomes rotatable due to the release of the first fastening element 15. Therefore, the second sun gear 14a and the second carrier 14b are directly connected to the second ring gear 14c via the second pinion gear group 14d. That is, when the second sun gear 14a rotates, the second carrier 14b and the second ring gear 14c also rotate integrally with the second sun gear 14a. Therefore, the rotation of the first sun gear 13a caused by the rotation of the input shaft 11 is transmitted to the second ring gear 14c through the fourth fastening element 18, and the rotation of the first carrier 13b caused by the rotation of the input shaft 11, the first sun gear 13a, and the first pinion gear group 13d is directly transmitted to the second sun gear 14a. The rotation of the second sun gear 14a and the rotation of the second ring gear 14c are transmitted to the output shaft 12 via the second pinion gear group 14d and the second carrier 14b.

[0119] According to this, as shown in the collinear diagram of Figure 13D, when rotation is input from the motor to the input shaft 11, the rotation (rotation of the second ring gear 14c) transmitted from the input shaft 11 to the first sun gear 13a is output at a constant speed from the output shaft 12 connected to the second carrier 14b.

[0120] 12, when shifting between first and second gears, the transmission 1 keeps the second engagement element 16 in an engaged state, puts the first engagement element 15 in either an engaged state or a released state, and puts the third engagement element 17 in either the engaged state or a released state. In other words, when shifting between first and second gears, the transmission 1 only switches the first engagement element 15 and the third engagement element 17, without switching the second engagement element 16. This makes it possible to achieve a shift between first and second gears with a simple structure without double switching of the engagement elements.

[0121] 12, when shifting between second and third gears, the transmission 1 keeps the second engagement element 16 in an engaged state, puts the third engagement element 17 in either an engaged state or a released state, and puts the fourth engagement element 18 in either the engaged state or a released state. In other words, when shifting between second and third gears, the transmission 1 does not switch the second engagement element 16, but only switches the third engagement element 17 and the fourth engagement element 18. This makes it possible to achieve a simple structure for shifting between second and third gears without double switching of the engagement elements.

[0122] 12, when shifting between third and fourth gears, the transmission 1 keeps the fourth engagement element 18 in an engaged state, puts the second engagement element 16 in either an engaged state or a released state, and puts the third engagement element 17 in either the engaged state or a released state. In other words, when shifting between third and fourth gears, the transmission 1 only switches the second engagement element 16 and the third engagement element 17, without switching the fourth engagement element 18. This makes it possible to achieve a simple structure for shifting between third and fourth gears without double switching of the engagement elements.

[0123] This makes it possible to realize four forward speeds without double switching of the engagement elements during gear shifting with a simple structure, thereby suppressing the occurrence of large gear shift shocks caused by double switching of the engagement elements during gear shifting.

[0124] Fifth embodiment First, a transmission 1 according to a fifth embodiment will be described with reference to Fig. 14 to Fig. 16D. Note that in the fifth embodiment, the same points as those in the first to fourth embodiments will be omitted, and the differences from the first to fourth embodiments will be mainly described.

[0125] FIG. 14 is a skeleton diagram of the transmission 1 according to the fifth embodiment. FIG. 15 is a table showing whether the engagement elements according to the fifth embodiment are engaged or not. In FIG. 15, "◯" indicates an engaged state, and no mark indicates a disengaged state. FIG. 16A is a collinear diagram of the first gear of the transmission 1 according to the fifth embodiment. FIG. 16B is a collinear diagram of the second gear of the transmission 1 according to the fifth embodiment. FIG. 16C is a collinear diagram of the third gear of the transmission 1 according to the fifth embodiment. FIG. 16D is a collinear diagram of the fourth gear of the transmission 1 according to the fifth embodiment.

[0126] As shown in FIG. 14, the transmission 1 according to the fifth embodiment includes a transmission case 10, an input shaft 11, an output shaft 12, a first planetary gear mechanism 13, a second planetary gear mechanism 14, a first clutch element 15, a second clutch element 16, a third clutch element 17, and a fourth clutch element 18.

[0127] The transmission case 10, the input shaft 11 and the output shaft 12 of the fifth embodiment are similar to the transmission case 10, the input shaft 11 and the output shaft 12 of the first to fourth embodiments, and therefore description thereof will be omitted.

[0128] The first planetary gear mechanism 13 is a double pinion planetary gear mechanism having a first sun gear 13a, a first carrier 13b, and a first ring gear 13c. A first pinion gear group 13d meshing with both the first sun gear 13a and the first ring gear 13c is provided between the first sun gear 13a and the first ring gear 13c. The first sun gear 13a is non-rotatably connected to the transmission case 10. The first pinion gear group 13d is rotatably supported by the first carrier 13b. The first pinion gear group 13d is made up of one first pinion gear (not shown) meshing with the first sun gear 13a, and the other first pinion gear (not shown) meshing with both the first ring gear 13c and the one first pinion gear. The first carrier 13b is connected to the input shaft 11.

[0129] The second planetary gear mechanism 14 is a single pinion planetary gear mechanism having a second sun gear 14a, a second carrier 14b, and a second ring gear 14c. Between the second sun gear 14a and the second ring gear 14c, a second pinion gear group 14d is provided which meshes with both the second sun gear 14a and the second ring gear 14c. The second pinion gear group 14d is rotatably supported by the second carrier 14b. The second pinion gear group 14d is also made of a single second pinion gear (not shown) which meshes with both the second sun gear 14a and the second ring gear 14c. The second carrier 14b is connected to the output shaft 12.

[0130] The power transmission path from the input shaft 11 to the output shaft 12 is switched by switching the states of the first engagement element 15, the second engagement element 16, the third engagement element 17, and the fourth engagement element 18 between an engaged state and a released state. Since the rotation input to the input shaft 11 can be output to the output shaft 12 at a gear ratio according to the switching of these engagement elements, a plurality of gear stages can be realized.

[0131] The first fastening element 15 is a brake located between the second ring gear 14c and the transmission case 10. The second fastening element 16 is a clutch located between the first ring gear 13c and the second sun gear 14a. The third fastening element 17 is a clutch located between the second fastening element 16 and the second ring gear 14c, and between the fourth fastening element 18 and the second sun gear 14a. The fourth fastening element 18 is a clutch located between the first carrier 13b and the second ring gear 14c, and between the first carrier 13b and the third fastening element 17.

[0132] As shown in FIG. 9, in the transmission 1, four forward gears can be achieved by engaging two of the first engagement element 15, the second engagement element 16, the third engagement element 17, and the fourth engagement element 18 in each gear position.

[0133] Specifically, in first gear, the transmission 1 places the first engagement element 15 and the second engagement element 16 in an engaged state, and places the third engagement element 17 and the fourth engagement element 18 in a disengaged state.

[0134] In the first gear, the first carrier 13b and the first ring gear 13c are rotatable, and the first sun gear 13a is non-rotatable. The first ring gear 13c is connected to the second sun gear 14a by the engagement of the second fastening element 16. The second sun gear 14a and the second carrier 14b are rotatable, and the second ring gear 14c is non-rotatable by the engagement of the first fastening element 15. Thus, the rotation of the first ring gear 13c caused by the rotation of the input shaft 11, the first carrier 13b, and the first pinion gear group 13d is transmitted to the second sun gear 14a through the second fastening element 16. The rotation of the second sun gear 14a is transmitted to the output shaft 12 through the second pinion gear group 14d and the second carrier 14b.

[0135] According to this, as shown in the collinear diagram of Figure 16A, when rotation is input from the motor to the input shaft 11, the rotation transmitted from the input shaft 11 to the first carrier 13b is reduced to the rotation of the second carrier 14b that is between the rotation of the first sun gear 13a (second ring gear 14c) (i.e., non-rotatable) and the rotation of the first ring gear 13c (second sun gear 14a) which is smaller than the rotation of the first carrier 13b, and is output from the output shaft 12 connected to the second carrier 14b.

[0136] In second gear, the transmission 1 places the second engagement element 16 and the third engagement element 17 in an engaged state, and places the first engagement element 15 and the fourth engagement element 18 in a disengaged state.

[0137] In the second gear, the first carrier 13b and the first ring gear 13c are rotatable, and the first sun gear 13a is non-rotatable. The first ring gear 13c is connected to the second sun gear 14a by the engagement of the second fastening element 16, and the first ring gear 13c is connected to the second ring gear 14c by the engagement of the second fastening element 16 and the third fastening element 17. The second sun gear 14a and the second carrier 14b are rotatable, and the second ring gear 14c is rotatable by the release of the first fastening element 15. Thus, the rotation of the first ring gear 13c caused by the rotation of the input shaft 11, the first carrier 13b, and the first pinion gear group 13d is transmitted to the second sun gear 14a through the second fastening element 16, and is transmitted to the second ring gear 14c through the second fastening element 16 and the third fastening element 17. The rotation of the second sun gear 14a and the rotation of the second ring gear 14c are transmitted to the output shaft 12 via the second pinion gear group 14d and the second carrier 14b.

[0138] According to this, as shown in the collinear diagram of Figure 16B, when rotation is input from the motor to the input shaft 11, the rotation transmitted from the input shaft 11 to the first carrier 13b is reduced in speed to the rotation of the first ring gear 13c (second sun gear 14a, second carrier 14b and second ring gear 14c) and output from the output shaft 12 connected to the second carrier 14b.

[0139] In the third gear, the transmission 1 places the second engagement element 16 and the fourth engagement element 18 in an engaged state, and places the first engagement element 15 and the third engagement element 17 in a disengaged state.

[0140] In the third gear, the first carrier 13b and the first ring gear 13c are rotatable, and the first sun gear 13a is non-rotatable. The first carrier 13b is connected to the second ring gear 14c by the engagement of the fourth fastening element 18, and the first ring gear 13c is connected to the second sun gear 14a by the engagement of the second fastening element 16. The second sun gear 14a and the second carrier 14b are rotatable, and the second ring gear 14c is rotatable by the release of the first fastening element 15. Thus, the rotation of the first carrier 13b caused by the rotation of the input shaft 11 is transmitted to the second ring gear 14c through the fourth fastening element 18, and the rotation of the first ring gear 13c caused by the rotation of the input shaft 11, the first carrier 13b, and the first pinion gear group 13d is transmitted to the second sun gear 14a through the second fastening element 16. The rotation of the second sun gear 14a and the rotation of the second ring gear 14c are transmitted to the output shaft 12 via the second pinion gear group 14d and the second carrier 14b.

[0141] According to this, as shown in the collinear diagram of Figure 16C, when rotation is input from the motor to the input shaft 11, the rotation transmitted from the input shaft 11 to the first carrier 13b is reduced to the rotation of the second carrier 14b that is between the rotation of the first ring gear 13c (second sun gear 14a) which is smaller than the rotation of the first carrier 13b (second ring gear 14c) and the rotation of the first carrier 13b (second ring gear 14c), and is then output from the output shaft 12 connected to the second carrier 14b.

[0142] In the fourth gear, the transmission 1 places the third engagement element 17 and the fourth engagement element 18 in an engaged state, and the first engagement element 15 and the second engagement element 16 in a disengaged state.

[0143] In the fourth gear, the first carrier 13b and the first ring gear 13c are rotatable, and the first sun gear 13a is non-rotatable. The first carrier 13b is connected to the second sun gear 14a by the engagement of the fourth fastening element 18 and the third fastening element 17, and the first carrier 13b is connected to the second ring gear 14c by the engagement of the fourth fastening element 18. The second sun gear 14a and the second carrier 14b are rotatable, and the second ring gear 14c is rotatable by the release of the first fastening element 15. Thus, the rotation of the first carrier 13b caused by the rotation of the input shaft 11 is transmitted to the second sun gear 14a through the fourth fastening element 18 and the third fastening element 17, and is transmitted to the second ring gear 14c through the fourth fastening element 18. The rotation of the second sun gear 14a and the rotation of the second ring gear 14c are transmitted to the output shaft 12 via the second pinion gear group 14d and the second carrier 14b.

[0144] According to this, as shown in the collinear diagram of Figure 16D, when rotation is input from the motor to the input shaft 11, the rotation (rotation of the second sun gear 14a, the second carrier 14b and the second ring gear 14c) transmitted from the input shaft 11 to the first carrier 13b is output at a constant speed from the output shaft 12 connected to the second carrier 14b.

[0145] 15, when shifting between first and second gears, the transmission 1 keeps the second engagement element 16 in an engaged state, puts the first engagement element 15 in either an engaged state or a released state, and puts the third engagement element 17 in either the engaged state or a released state. In other words, when shifting between first and second gears, the transmission 1 only switches the first engagement element 15 and the third engagement element 17, without switching the second engagement element 16. This makes it possible to achieve a shift between first and second gears with a simple structure without double switching of the engagement elements.

[0146] 15, when shifting between second and third gears, the transmission 1 keeps the second engagement element 16 in an engaged state, puts the third engagement element 17 in either an engaged state or a released state, and puts the fourth engagement element 18 in either the engaged state or a released state. In other words, when shifting between second and third gears, the transmission 1 does not switch the second engagement element 16, but only switches the third engagement element 17 and the fourth engagement element 18. This makes it possible to achieve a shift between second and third gears with a simple structure without double switching of the engagement elements.

[0147] 15, when shifting between third and fourth gears, the transmission 1 keeps the fourth engagement element 18 in an engaged state, puts the second engagement element 16 in either an engaged state or a released state, and puts the third engagement element 17 in either the engaged state or a released state. In other words, when shifting between third and fourth gears, the transmission 1 only switches the second engagement element 16 and the third engagement element 17, without switching the fourth engagement element 18. This makes it possible to achieve a simple structure for shifting between third and fourth gears without double switching of the engagement elements.

[0148] This makes it possible to realize four forward speeds without double switching of the engagement elements during gear shifting with a simple structure, thereby suppressing the occurrence of large gear shift shocks caused by double switching of the engagement elements during gear shifting.

[0149] Sixth embodiment First, a transmission 1 according to a sixth embodiment will be described with reference to Fig. 17 to Fig. 19D. Note that in the sixth embodiment, the same points as those in the first to fifth embodiments will be omitted, and the differences from the first to fifth embodiments will be mainly described.

[0150] FIG. 17 is a skeleton diagram of the transmission 1 according to the sixth embodiment. FIG. 18 is a table showing whether the engagement elements according to the sixth embodiment are engaged or not. In FIG. 18, "◯" indicates an engaged state, and no mark indicates a disengaged state. FIG. 19A is a collinear diagram of the first gear of the transmission 1 according to the sixth embodiment. FIG. 19B is a collinear diagram of the second gear of the transmission 1 according to the sixth embodiment. FIG. 19C is a collinear diagram of the third gear of the transmission 1 according to the sixth embodiment. FIG. 19D is a collinear diagram of the fourth gear of the transmission 1 according to the sixth embodiment.

[0151] As shown in FIG. 17, the transmission 1 according to the sixth embodiment includes a transmission case 10, an input shaft 11, an output shaft 12, a first planetary gear mechanism 13, a second planetary gear mechanism 14, a first clutch element 15, a second clutch element 16, a third clutch element 17, and a fourth clutch element 18.

[0152] The transmission case 10, the input shaft 11 and the output shaft 12 of the sixth embodiment are similar to the transmission case 10, the input shaft 11 and the output shaft 12 of the first to fifth embodiments, and therefore description thereof will be omitted.

[0153] The first planetary gear mechanism 13 is a double pinion planetary gear mechanism having a first sun gear 13a, a first carrier 13b, and a first ring gear 13c. A first pinion gear group 13d is provided between the first sun gear 13a and the first ring gear 13c, and meshes with both the first sun gear 13a and the first ring gear 13c. The first pinion gear group 13d is rotatably supported by the first carrier 13b. The first pinion gear group 13d is made up of one first pinion gear (not shown) that meshes with the first sun gear 13a, and the other first pinion gear (not shown) that meshes with both the first ring gear 13c and the one first pinion gear. The first carrier 13b is connected to the input shaft 11.

[0154] The second planetary gear mechanism 14 is a single pinion planetary gear mechanism having a second sun gear 14a, a second carrier 14b, and a second ring gear 14c. Between the second sun gear 14a and the second ring gear 14c, a second pinion gear group 14d is provided which meshes with both the second sun gear 14a and the second ring gear 14c. The second pinion gear group 14d is rotatably supported by the second carrier 14b. The second pinion gear group 14d is also made of a single second pinion gear (not shown) which meshes with both the second sun gear 14a and the second ring gear 14c. The second carrier 14b is connected to the output shaft 12.

[0155] The power transmission path from the input shaft 11 to the output shaft 12 is switched by switching the states of the first engagement element 15, the second engagement element 16, the third engagement element 17, and the fourth engagement element 18 between an engaged state and a released state. Since the rotation input to the input shaft 11 can be output to the output shaft 12 at a gear ratio according to the switching of these engagement elements, a plurality of gear stages can be realized.

[0156] The first fastening element 15 is a brake located between the second ring gear 14c and the transmission case 10. The second fastening element 16 is a brake located between the first sun gear 13a and the transmission case 10. The third fastening element 17 is a clutch located between the first ring gear 13c and the second ring gear 14c, and between the fourth fastening element 18 and the second sun gear 14a. The fourth fastening element 18 is a clutch located between the first carrier 13b and the second ring gear 14c, and between the first carrier 13b and the third fastening element 17.

[0157] As shown in FIG. 18, in the transmission 1, four forward gears can be achieved by engaging two of the first engagement element 15, the second engagement element 16, the third engagement element 17, and the fourth engagement element 18 in each gear position.

[0158] Specifically, in first gear, the transmission 1 places the first engagement element 15 and the second engagement element 16 in an engaged state, and places the third engagement element 17 and the fourth engagement element 18 in a disengaged state.

[0159] In the first gear, the first carrier 13b and the first ring gear 13c are rotatable, and the first sun gear 13a is rendered non-rotatable by the engagement of the second fastening element 16. The first ring gear 13c is directly connected to the second sun gear 14a. The second sun gear 14a and the second carrier 14b are rotatable, and the second ring gear 14c is rendered non-rotatable by the engagement of the first fastening element 15. Thus, the rotation of the first ring gear 13c caused by the rotation of the input shaft 11, the first carrier 13b, and the first pinion gear group 13d is directly transmitted to the second sun gear 14a. The rotation of the second sun gear 14a is transmitted to the output shaft 12 via the second pinion gear group 14d and the second carrier 14b.

[0160] According to this, as shown in the collinear diagram of Figure 19A, when rotation is input from the motor to the input shaft 11, the rotation transmitted from the input shaft 11 to the first carrier 13b is reduced to the rotation of the second carrier 14b that is between the rotation of the first sun gear 13a (second ring gear 14c) (i.e., non-rotatable) and the rotation of the first ring gear 13c (second sun gear 14a) which is smaller than the rotation of the first carrier 13b, and is output from the output shaft 12 connected to the second carrier 14b.

[0161] In second gear, the transmission 1 places the second engagement element 16 and the third engagement element 17 in an engaged state, and places the first engagement element 15 and the fourth engagement element 18 in a disengaged state.

[0162] In second gear, the first carrier 13b and the first ring gear 13c are rotatable, and the first sun gear 13a is rendered non-rotatable by the engagement of the second fastening element 16. The first ring gear 13c is directly connected to the second sun gear 14a, and the first ring gear 13c is connected to the second ring gear 14c by the engagement of the third fastening element 17. The second sun gear 14a and the second carrier 14b are rotatable, and the second ring gear 14c is rotatable by the release of the first fastening element 15. Thus, the rotation of the first ring gear 13c caused by the rotation of the input shaft 11, the first carrier 13b, and the first pinion gear group 13d is directly transmitted to the second sun gear 14a, and then transmitted to the second ring gear 14c via the third fastening element 17. The rotation of the second sun gear 14a and the rotation of the second ring gear 14c are transmitted to the output shaft 12 via the second pinion gear group 14d and the second carrier 14b.

[0163] According to this, as shown in the collinear diagram of Figure 19B, when rotation is input from the motor to the input shaft 11, the rotation transmitted from the input shaft 11 to the first carrier 13b is reduced in speed to the rotation of the first ring gear 13c (second sun gear 14a, second carrier 14b and second ring gear 14c) and output from the output shaft 12 connected to the second carrier 14b.

[0164] In the third gear, the transmission 1 places the second engagement element 16 and the fourth engagement element 18 in an engaged state, and places the first engagement element 15 and the third engagement element 17 in a disengaged state.

[0165] In third gear, the first carrier 13b and the first ring gear 13c are rotatable, and the first sun gear 13a is made non-rotatable by the engagement of the second fastening element 16. The first carrier 13b is connected to the second ring gear 14c by the engagement of the fourth fastening element 18, and the first ring gear 13c is directly connected to the second sun gear 14a. The second sun gear 14a and the second carrier 14b are rotatable, and the second ring gear 14c is rotatable by the release of the first fastening element 15. Thus, the rotation of the first carrier 13b caused by the rotation of the input shaft 11 is transmitted to the second ring gear 14c through the fourth fastening element 18, and the rotation of the first ring gear 13c caused by the rotation of the input shaft 11, the first carrier 13b, and the first pinion gear group 13d is transmitted directly to the second sun gear 14a. The rotation of the second sun gear 14a and the rotation of the second ring gear 14c are transmitted to the output shaft 12 via the second pinion gear group 14d and the second carrier 14b.

[0166] According to this, as shown in the nomographic diagram of Figure 19C, when rotation is input from the motor to the input shaft 11, the rotation transmitted from the input shaft 11 to the first carrier 13b is reduced to the rotation of the second carrier 14b that is between the rotation of the first ring gear 13c (second sun gear 14a) which is smaller than the rotation of the first carrier 13b (second ring gear 14c) and the rotation of the first carrier 13b (second ring gear 14c), and is then output from the output shaft 12 connected to the second carrier 14b.

[0167] In the fourth gear, the transmission 1 places the third engagement element 17 and the fourth engagement element 18 in an engaged state, and the first engagement element 15 and the second engagement element 16 in a disengaged state.

[0168] In the fourth gear, the first carrier 13b and the first ring gear 13c are rotatable, and the first sun gear 13a is rotatable due to the release of the second fastening element 16. Therefore, the first carrier 13b and the first ring gear 13c are directly connected to the first sun gear 13a via the first pinion gear group 13d. That is, when the first carrier 13b rotates, the first sun gear 13a and the first ring gear 13c also rotate integrally with the first carrier 13b. In addition, the first carrier 13b is connected to the second sun gear 14a due to the fastening of the fourth fastening element 18 and the third fastening element 17, the first carrier 13b is connected to the second ring gear 14c due to the fastening of the fourth fastening element 18, and the first ring gear 13c is directly connected to the second sun gear 14a. Then, the second sun gear 14a and the second carrier 14b become rotatable, and the second ring gear 14c becomes rotatable due to the release of the first fastening element 15. Therefore, the second sun gear 14a and the second carrier 14b are directly connected to the second ring gear 14c via the second pinion gear group 14d. That is, when the second sun gear 14a rotates, the second carrier 14b and the second ring gear 14c also rotate integrally with the second sun gear 14a. Therefore, the rotation of the first carrier 13b caused by the rotation of the input shaft 11 is transmitted to the second ring gear 14c through the fourth fastening element 18, and the rotation of the first ring gear 13c caused by the rotation of the input shaft 11, the first carrier 13b, and the first pinion gear group 13d is directly transmitted to the second sun gear 14a. The rotation of the second sun gear 14a and the rotation of the second ring gear 14c are transmitted to the output shaft 12 via the second pinion gear group 14d and the second carrier 14b.

[0169] According to this, as shown in the collinear diagram of Figure 19D, when rotation is input from the motor to the input shaft 11, the rotation (rotation of the second ring gear 14c) transmitted from the input shaft 11 to the first carrier 13b is output at a constant speed from the output shaft 12 connected to the second carrier 14b.

[0170] 18, when shifting between first and second gears, the transmission 1 keeps the second engagement element 16 in an engaged state, puts the first engagement element 15 in either an engaged state or a released state, and puts the third engagement element 17 in either the engaged state or a released state. In other words, when shifting between first and second gears, the transmission 1 only switches the first engagement element 15 and the third engagement element 17, without switching the second engagement element 16. This makes it possible to achieve a shift between first and second gears with a simple structure without double switching of the engagement elements.

[0171] 18, when shifting between second and third gears, the transmission 1 keeps the second engagement element 16 in an engaged state, puts the third engagement element 17 in either an engaged state or a released state, and puts the fourth engagement element 18 in either the engaged state or a released state. In other words, when shifting between second and third gears, the transmission 1 does not switch the second engagement element 16, but only switches the third engagement element 17 and the fourth engagement element 18. This makes it possible to achieve a simple structure for shifting between second and third gears without double switching of the engagement elements.

[0172] 18, the transmission 1 keeps the fourth engagement element 18 in an engaged state when shifting between third and fourth gears, puts the second engagement element 16 in either an engaged state or a released state, and puts the third engagement element 17 in either the engaged state or a released state. In other words, the transmission 1 does not switch the fourth engagement element 18 when shifting between third and fourth gears, but only switches the second engagement element 16 and the third engagement element 17. This makes it possible to achieve a simple structure for shifting between third and fourth gears without double switching of the engagement elements.

[0173] This makes it possible to realize four forward speeds without double switching of the engagement elements during gear shifting with a simple structure, thereby suppressing the occurrence of large gear shift shocks caused by double switching of the engagement elements during gear shifting.

[0174] Seventh embodiment First, a transmission 1 according to the seventh embodiment will be described with reference to Fig. 20 to Fig. 22D. Note that in the seventh embodiment, the same points as those in the first to sixth embodiments will be omitted, and the differences from the first to sixth embodiments will be mainly described.

[0175] FIG. 20 is a skeleton diagram of the transmission 1 according to the seventh embodiment. FIG. 21 is a table showing whether the engagement elements according to the seventh embodiment are engaged or not. In FIG. 21, "◯" indicates an engaged state, and no mark indicates a disengaged state. FIG. 22A is a collinear diagram of the first gear of the transmission 1 according to the seventh embodiment. FIG. 22B is a collinear diagram of the second gear of the transmission 1 according to the seventh embodiment. FIG. 22C is a collinear diagram of the third gear of the transmission 1 according to the seventh embodiment. FIG. 22D is a collinear diagram of the fourth gear of the transmission 1 according to the seventh embodiment.

[0176] As shown in FIG. 20, the transmission 1 according to the seventh embodiment includes a transmission case 10, an input shaft 11, an output shaft 12, a first planetary gear mechanism 13, a second planetary gear mechanism 14, a first clutch element 15, a second clutch element 16, a third clutch element 17, and a fourth clutch element 18.

[0177] The transmission case 10, the input shaft 11 and the output shaft 12 of the seventh embodiment are similar to the transmission case 10, the input shaft 11 and the output shaft 12 of the first to sixth embodiments, and therefore description thereof will be omitted.

[0178] The first planetary gear mechanism 13 is a double pinion planetary gear mechanism having a first sun gear 13a, a first carrier 13b, and a first ring gear 13c. A first pinion gear group 13d meshing with both the first sun gear 13a and the first ring gear 13c is provided between the first sun gear 13a and the first ring gear 13c. The first carrier 13b is non-rotatably connected to the transmission case 10. The first pinion gear group 13d is rotatably supported by the first carrier 13b. The first pinion gear group 13d is composed of one first pinion gear (not shown) meshing with the first sun gear 13a, and the other first pinion gear (not shown) meshing with both the first ring gear 13c and the one first pinion gear. The first sun gear 13a is connected to the input shaft 11.

[0179] The second planetary gear mechanism 14 is a double pinion planetary gear mechanism having a second sun gear 14a, a second carrier 14b, and a second ring gear 14c. Between the second sun gear 14a and the second ring gear 14c, a second pinion gear group 14d is provided, which meshes with both the second sun gear 14a and the second ring gear 14c. The second pinion gear group 14d is rotatably supported by the second carrier 14b. The second pinion gear group 14d is also composed of one second pinion gear (not shown) which meshes with the second sun gear 14a, and the other second pinion gear (not shown) which meshes with both the second ring gear 14c and the one second pinion gear. The second ring gear 14c is connected to the output shaft 12.

[0180] The power transmission path from the input shaft 11 to the output shaft 12 is switched by switching the states of the first engagement element 15, the second engagement element 16, the third engagement element 17, and the fourth engagement element 18 between an engaged state and a released state. Since the rotation input to the input shaft 11 can be output to the output shaft 12 at a gear ratio according to the switching of these engagement elements, a plurality of gear stages can be realized.

[0181] The first engagement element 15 is a brake located between the second carrier 14b and the transmission case 10. The second engagement element 16 is a clutch located between the first ring gear 13c and the second sun gear 14a. The third engagement element 17 is a clutch located between the second engagement element 16 and the second carrier 14b, and between the fourth engagement element 18 and the second sun gear 14a. The fourth engagement element 18 is a clutch located between the first sun gear 13a and the second carrier 14b, and between the first sun gear 13a and the third engagement element 17.

[0182] As shown in FIG. 9, in the transmission 1, four forward gears can be achieved by engaging two of the first engagement element 15, the second engagement element 16, the third engagement element 17, and the fourth engagement element 18 in each gear position.

[0183] Specifically, in first gear, the transmission 1 places the first engagement element 15 and the second engagement element 16 in an engaged state, and places the third engagement element 17 and the fourth engagement element 18 in a disengaged state.

[0184] In the first gear, the first sun gear 13a and the first ring gear 13c are rotatable, and the first carrier 13b is non-rotatable. The first ring gear 13c is connected to the second sun gear 14a by the engagement of the second fastening element 16. The second sun gear 14a and the second ring gear 14c are rotatable, and the second carrier 14b is non-rotatable by the engagement of the first fastening element 15. Thus, the rotation of the first ring gear 13c caused by the rotation of the input shaft 11, the first sun gear 13a, and the first pinion gear group 13d is transmitted to the second sun gear 14a through the second fastening element 16. The rotation of the second sun gear 14a is transmitted to the output shaft 12 through the second pinion gear group 14d and the second ring gear 14c.

[0185] According to this, as shown in the collinear diagram of Figure 22A, when rotation is input from the motor to the input shaft 11, the rotation transmitted from the input shaft 11 to the first sun gear 13a is reduced in speed to the rotation of the second ring gear 14c which is between the rotation of the first carrier 13b (second carrier 14b) (i.e., non-rotatable) and the rotation of the first ring gear 13c (second sun gear 14a), which is smaller than the rotation of the first sun gear 13a, and is output from the output shaft 12 connected to the second ring gear 14c.

[0186] In second gear, the transmission 1 places the second engagement element 16 and the third engagement element 17 in an engaged state, and places the first engagement element 15 and the fourth engagement element 18 in a disengaged state.

[0187] In the second gear, the first sun gear 13a and the first ring gear 13c are rotatable, and the first carrier 13b is non-rotatable. The first ring gear 13c is connected to the second sun gear 14a by the engagement of the second fastening element 16, and the first ring gear 13c is connected to the second carrier 14b by the engagement of the second fastening element 16 and the third fastening element 17. The second sun gear 14a and the second ring gear 14c are rotatable, and the second carrier 14b is rotatable by the release of the first fastening element 15. Thus, the rotation of the first ring gear 13c caused by the rotation of the input shaft 11, the first sun gear 13a, and the first pinion gear group 13d is transmitted to the second sun gear 14a through the second fastening element 16, and is transmitted to the second carrier 14b through the second fastening element 16 and the third fastening element 17. The rotation of the second sun gear 14a and the rotation of the second carrier 14b are transmitted to the output shaft 12 via the second pinion gear group 14d and the second ring gear 14c.

[0188] According to this, as shown in the collinear diagram of Figure 22B, when rotation is input from the motor to the input shaft 11, the rotation transmitted from the input shaft 11 to the first sun gear 13a is reduced in speed to the rotation of the first ring gear 13c (second sun gear 14a, second carrier 14b and second ring gear 14c) and output from the output shaft 12 connected to the second ring gear 14c.

[0189] In the third gear, the transmission 1 places the second engagement element 16 and the fourth engagement element 18 in an engaged state, and places the first engagement element 15 and the third engagement element 17 in a disengaged state.

[0190] In the third gear, the first sun gear 13a and the first ring gear 13c are rotatable, and the first carrier 13b is non-rotatable. The first sun gear 13a is connected to the second carrier 14b by the engagement of the fourth fastening element 18, and the first ring gear 13c is connected to the second sun gear 14a by the engagement of the second fastening element 16. The second sun gear 14a and the second ring gear 14c are rotatable, and the second carrier 14b is rotatable by the release of the first fastening element 15. Thus, the rotation of the first sun gear 13a caused by the rotation of the input shaft 11 is transmitted to the second carrier 14b through the fourth fastening element 18, and the rotation of the first ring gear 13c caused by the rotation of the input shaft 11, the first sun gear 13a, and the first pinion gear group 13d is transmitted to the second sun gear 14a through the second fastening element 16. The rotation of the second sun gear 14a and the rotation of the second carrier 14b are transmitted to the output shaft 12 via the second pinion gear group 14d and the second ring gear 14c.

[0191] According to this, as shown in the collinear diagram of Figure 22C, when rotation is input from the motor to the input shaft 11, the rotation transmitted from the input shaft 11 to the first sun gear 13a is reduced to the rotation of the second ring gear 14c which is between the rotation of the first ring gear 13c (second sun gear 14a) which is smaller than the rotation of the first sun gear 13a (second carrier 14b) and the rotation of the first sun gear 13a (second carrier 14b), and is output from the output shaft 12 connected to the second ring gear 14c.

[0192] In the fourth gear, the transmission 1 places the third engagement element 17 and the fourth engagement element 18 in an engaged state, and the first engagement element 15 and the second engagement element 16 in a disengaged state.

[0193] In the fourth gear, the first sun gear 13a and the first ring gear 13c are rotatable, and the first carrier 13b is non-rotatable. The first sun gear 13a is connected to the second sun gear 14a by the engagement of the fourth fastening element 18 and the third fastening element 17, and the first sun gear 13a is connected to the second carrier 14b by the engagement of the fourth fastening element 18. The second sun gear 14a and the second ring gear 14c are rotatable, and the second carrier 14b is rotatable by the release of the first fastening element 15. Thus, the rotation of the first sun gear 13a caused by the rotation of the input shaft 11 is transmitted to the second sun gear 14a through the fourth fastening element 18 and the third fastening element 17, and is transmitted to the second carrier 14b through the fourth fastening element 18. The rotation of the second sun gear 14a and the rotation of the second carrier 14b are transmitted to the output shaft 12 via the second pinion gear group 14d and the second ring gear 14c.

[0194] According to this, as shown in the collinear diagram of Figure 22D, when rotation is input from the motor to the input shaft 11, the rotation (rotation of the second sun gear 14a, the second carrier 14b and the second ring gear 14c) transmitted from the input shaft 11 to the first sun gear 13a is output at a constant speed from the output shaft 12 connected to the second ring gear 14c.

[0195] 21, when shifting between first and second gears, the transmission 1 keeps the second engagement element 16 in an engaged state, puts the first engagement element 15 in either an engaged state or a released state, and puts the third engagement element 17 in either the engaged state or a released state. In other words, when shifting between first and second gears, the transmission 1 only switches the first engagement element 15 and the third engagement element 17, without switching the second engagement element 16. This makes it possible to achieve a simple structure for shifting between first and second gears without double switching of the engagement elements.

[0196] 21, when shifting between second and third gears, the transmission 1 keeps the second engagement element 16 in an engaged state, puts the third engagement element 17 in either an engaged state or a released state, and puts the fourth engagement element 18 in either the engaged state or a released state. In other words, when shifting between second and third gears, the transmission 1 does not switch the second engagement element 16, but only switches the third engagement element 17 and the fourth engagement element 18. This makes it possible to achieve a simple structure for shifting between second and third gears without double switching of the engagement elements.

[0197] 21, when shifting between third and fourth gears, the transmission 1 keeps the fourth engagement element 18 in an engaged state, puts the second engagement element 16 in either an engaged state or a released state, and puts the third engagement element 17 in either an engaged state or a released state. In other words, when shifting between third and fourth gears, the transmission 1 only switches the second engagement element 16 and the third engagement element 17, without switching the fourth engagement element 18. This makes it possible to achieve a simple structure for shifting between third and fourth gears without double switching of the engagement elements.

[0198] This makes it possible to realize four forward speeds without double switching of the engagement elements during gear shifting with a simple structure, thereby suppressing the occurrence of large gear shift shocks caused by double switching of the engagement elements during gear shifting.

[0199] Eighth embodiment First, a transmission 1 according to an eighth embodiment will be described with reference to Fig. 23 to Fig. 25D. Note that in the eighth embodiment, the same points as those in the first to seventh embodiments will be omitted, and the differences from the first to seventh embodiments will be mainly described.

[0200] FIG. 23 is a skeleton diagram of the transmission 1 according to the eighth embodiment. FIG. 24 is a table showing whether the engagement elements according to the eighth embodiment are engaged or not. In FIG. 24, "◯" indicates an engaged state, and no mark indicates a disengaged state. FIG. 25A is a collinear diagram of the first gear of the transmission 1 according to the eighth embodiment. FIG. 25B is a collinear diagram of the second gear of the transmission 1 according to the eighth embodiment. FIG. 25C is a collinear diagram of the third gear of the transmission 1 according to the eighth embodiment. FIG. 25D is a collinear diagram of the fourth gear of the transmission 1 according to the eighth embodiment.

[0201] As shown in FIG. 23, the transmission 1 of the eighth embodiment includes a transmission case 10, an input shaft 11, an output shaft 12, a first planetary gear mechanism 13, a second planetary gear mechanism 14, a first clutch element 15, a second clutch element 16, a third clutch element 17, and a fourth clutch element 18.

[0202] The transmission case 10, the input shaft 11 and the output shaft 12 of the eighth embodiment are similar to the transmission case 10, the input shaft 11 and the output shaft 12 of the first to seventh embodiments, and therefore description thereof will be omitted.

[0203] The first planetary gear mechanism 13 is a double pinion planetary gear mechanism having a first sun gear 13a, a first carrier 13b, and a first ring gear 13c. A first pinion gear group 13d is provided between the first sun gear 13a and the first ring gear 13c, and meshes with both the first sun gear 13a and the first ring gear 13c. The first pinion gear group 13d is rotatably supported by the first carrier 13b. The first pinion gear group 13d is made up of one first pinion gear (not shown) that meshes with the first sun gear 13a, and the other first pinion gear (not shown) that meshes with both the first ring gear 13c and the one first pinion gear. The first sun gear 13a is connected to the input shaft 11.

[0204] The second planetary gear mechanism 14 is a double pinion planetary gear mechanism having a second sun gear 14a, a second carrier 14b, and a second ring gear 14c. Between the second sun gear 14a and the second ring gear 14c, a second pinion gear group 14d is provided, which meshes with both the second sun gear 14a and the second ring gear 14c. The second pinion gear group 14d is rotatably supported by the second carrier 14b. The second pinion gear group 14d is also composed of one second pinion gear (not shown) which meshes with the second sun gear 14a, and the other second pinion gear (not shown) which meshes with both the second ring gear 14c and the one second pinion gear. The second ring gear 14c is connected to the output shaft 12.

[0205] The power transmission path from the input shaft 11 to the output shaft 12 is switched by switching the states of the first engagement element 15, the second engagement element 16, the third engagement element 17, and the fourth engagement element 18 between an engaged state and a released state. Since the rotation input to the input shaft 11 can be output to the output shaft 12 at a gear ratio according to the switching of these engagement elements, a plurality of gear stages can be realized.

[0206] The first fastening element 15 is a brake located between the second carrier 14b and the transmission case 10. The second fastening element 16 is a brake located between the first carrier 13b and the transmission case 10. The third fastening element 17 is a clutch located between the first ring gear 13c and the second carrier 14b, and between the fourth fastening element 18 and the second sun gear 14a. The fourth fastening element 18 is a clutch located between the first sun gear 13a and the second carrier 14b, and between the first sun gear 13a and the third fastening element 17.

[0207] As shown in FIG. 24, in the transmission 1, four forward gears can be achieved by engaging two of the first engagement element 15, the second engagement element 16, the third engagement element 17, and the fourth engagement element 18 in each gear position.

[0208] Specifically, in first gear, the transmission 1 places the first engagement element 15 and the second engagement element 16 in an engaged state, and places the third engagement element 17 and the fourth engagement element 18 in a disengaged state.

[0209] In the first gear, the first sun gear 13a and the first ring gear 13c are rotatable, and the first carrier 13b is rendered non-rotatable by the engagement of the second fastening element 16. The first ring gear 13c is directly connected to the second sun gear 14a. The second sun gear 14a and the second ring gear 14c are rotatable, and the second carrier 14b is rendered non-rotatable by the engagement of the first fastening element 15. Thus, the rotation of the first ring gear 13c caused by the rotation of the input shaft 11, the first sun gear 13a, and the first pinion gear group 13d is directly transmitted to the second sun gear 14a. The rotation of the second sun gear 14a is transmitted to the output shaft 12 via the second pinion gear group 14d and the second ring gear 14c.

[0210] According to this, as shown in the collinear diagram of Figure 25A, when rotation is input from the motor to the input shaft 11, the rotation transmitted from the input shaft 11 to the first sun gear 13a is reduced to the rotation of the second ring gear 14c which is between the rotation of the first carrier 13b (second carrier 14b) (i.e., non-rotatable) and the rotation of the first ring gear 13c (second sun gear 14a), which is smaller than the rotation of the first sun gear 13a, and is output from the output shaft 12 connected to the second ring gear 14c.

[0211] In second gear, the transmission 1 places the second engagement element 16 and the third engagement element 17 in an engaged state, and places the first engagement element 15 and the fourth engagement element 18 in a disengaged state.

[0212] In second gear, the first sun gear 13a and the first ring gear 13c are rotatable, and the first carrier 13b is rendered non-rotatable by the engagement of the second fastening element 16. The first ring gear 13c is directly connected to the second sun gear 14a, and the first ring gear 13c is connected to the second carrier 14b by the engagement of the third fastening element 17. The second sun gear 14a and the second ring gear 14c are rotatable, and the second carrier 14b is rotatable by the release of the first fastening element 15. Thus, the rotation of the first ring gear 13c caused by the rotation of the input shaft 11, the first sun gear 13a, and the first pinion gear group 13d is directly transmitted to the second sun gear 14a, and then transmitted to the second carrier 14b via the third fastening element 17. The rotation of the second sun gear 14a and the rotation of the second ring gear 14c are transmitted to the output shaft 12 via the second pinion gear group 14d and the second ring gear 14c.

[0213] According to this, as shown in the collinear diagram of Figure 25B, when rotation is input from the motor to the input shaft 11, the rotation transmitted from the input shaft 11 to the first sun gear 13a is reduced in speed to the rotation of the first ring gear 13c (second sun gear 14a, second carrier 14b and second ring gear 14c) and output from the output shaft 12 connected to the second ring gear 14c.

[0214] In the third gear, the transmission 1 places the second engagement element 16 and the fourth engagement element 18 in an engaged state, and places the first engagement element 15 and the third engagement element 17 in a disengaged state.

[0215] In third gear, the first sun gear 13a and the first ring gear 13c are rotatable, and the first carrier 13b is made non-rotatable by the engagement of the second fastening element 16. The first sun gear 13a is connected to the second carrier 14b by the engagement of the fourth fastening element 18, and the first ring gear 13c is directly connected to the second sun gear 14a. The second sun gear 14a and the second ring gear 14c are rotatable, and the second carrier 14b is rotatable by the release of the first fastening element 15. Thus, the rotation of the first sun gear 13a caused by the rotation of the input shaft 11 is transmitted to the second carrier 14b through the fourth fastening element 18, and the rotation of the first ring gear 13c caused by the rotation of the input shaft 11, the first sun gear 13a, and the first pinion gear group 13d is transmitted directly to the second sun gear 14a. The rotation of the second sun gear 14a and the rotation of the second carrier 14b are transmitted to the output shaft 12 via the second pinion gear group 14d and the second ring gear 14c.

[0216] According to this, as shown in the collinear diagram of Figure 25C, when rotation is input from the motor to the input shaft 11, the rotation transmitted from the input shaft 11 to the first sun gear 13a is reduced to the rotation of the second ring gear 14c that is between the rotation of the first ring gear 13c (second sun gear 14a) which is smaller than the rotation of the first sun gear 13a (second carrier 14b) and the rotation of the first sun gear 13a (second carrier 14b), and is output from the output shaft 12 connected to the second ring gear 14c.

[0217] In the fourth gear, the transmission 1 places the third engagement element 17 and the fourth engagement element 18 in an engaged state, and the first engagement element 15 and the second engagement element 16 in a disengaged state.

[0218] In the fourth gear, the first sun gear 13a and the first ring gear 13c are rotatable, and the first carrier 13b is rotatable due to the release of the second fastening element 16. Therefore, the first sun gear 13a and the first ring gear 13c are directly connected to the first carrier 13b via the first pinion gear group 13d. That is, when the first sun gear 13a rotates, the first carrier 13b and the first ring gear 13c also rotate integrally with the first sun gear 13a. In addition, the first sun gear 13a is connected to the second sun gear 14a due to the fastening of the fourth fastening element 18 and the third fastening element 17, the first sun gear 13a is connected to the second carrier 14b due to the fastening of the fourth fastening element 18, and the first ring gear 13c is directly connected to the second sun gear 14a. Then, the second sun gear 14a and the second ring gear 14c become rotatable, and the second carrier 14b becomes rotatable due to the release of the first fastening element 15. Therefore, the second sun gear 14a and the second ring gear 14c are directly connected to the second carrier 14b via the second pinion gear group 14d. That is, when the second sun gear 14a rotates, the second carrier 14b and the second ring gear 14c also rotate integrally with the second sun gear 14a. Therefore, the rotation of the first sun gear 13a caused by the rotation of the input shaft 11 is transmitted to the second carrier 14b through the fourth fastening element 18, and the rotation of the first ring gear 13c caused by the rotation of the input shaft 11, the first sun gear 13a, and the first pinion gear group 13d is directly transmitted to the second sun gear 14a. The rotation of the second sun gear 14a and the rotation of the second carrier 14b are transmitted to the output shaft 12 via the second pinion gear group 14d and the second ring gear 14c.

[0219] According to this, as shown in the collinear diagram of Figure 25D, when rotation is input from the motor to the input shaft 11, the rotation (rotation of the second carrier 14b) transmitted from the input shaft 11 to the first sun gear 13a is output at a constant speed from the output shaft 12 connected to the second ring gear 14c.

[0220] 24, the transmission 1 keeps the second engagement element 16 in an engaged state when shifting between first and second gears, puts the first engagement element 15 in either an engaged state or a released state, and puts the third engagement element 17 in either the engaged state or a released state. In other words, the transmission 1 does not switch the second engagement element 16 when shifting between first and second gears, but only switches the first engagement element 15 and the third engagement element 17. This makes it possible to achieve a simple structure for shifting between first and second gears without double switching of the engagement elements.

[0221] 24, when shifting between second and third gears, the transmission 1 keeps the second engagement element 16 in an engaged state, puts the third engagement element 17 in either an engaged state or a released state, and puts the fourth engagement element 18 in either the engaged state or a released state. In other words, when shifting between second and third gears, the transmission 1 does not switch the second engagement element 16, but only switches the third engagement element 17 and the fourth engagement element 18. This makes it possible to achieve a simple structure for shifting between second and third gears without double switching of the engagement elements.

[0222] 24, the transmission 1 keeps the fourth engagement element 18 in an engaged state when shifting between third and fourth gears, puts the second engagement element 16 in either an engaged state or a released state, and puts the third engagement element 17 in either the engaged state or a released state. In other words, the transmission 1 does not switch the fourth engagement element 18 when shifting between third and fourth gears, but only switches the second engagement element 16 and the third engagement element 17. This makes it possible to achieve a simple structure for shifting between third and fourth gears without double switching of the engagement elements.

[0223] This makes it possible to realize four forward speeds without double switching of the engagement elements during gear shifting with a simple structure, thereby suppressing the occurrence of large gear shift shocks caused by double switching of the engagement elements during gear shifting.

[0224] (Action and effect) Next, main effects of each embodiment will be described.

[0225] (1) The transmission 1 includes an input shaft 11 to which rotation is input from a drive source, an output shaft 12 that outputs the rotation of the input shaft 11 to drive wheels, a first planetary gear mechanism 13, a second planetary gear mechanism 14, a first engagement element 15 that is engaged in first gear, a second engagement element 16 that is engaged in first gear, second gear, and third gear, a third engagement element 17 that is engaged in second gear and fourth gear, a fourth engagement element 18 that is engaged in third gear and fourth gear, and a transmission case 10. The first planetary gear mechanism 13 is a single-pinion planetary gear mechanism having a first sun gear 13a, a first carrier 13b, and a first ring gear 13c. The second planetary gear mechanism 14 is a single-pinion planetary gear mechanism having a second sun gear 13a, a first carrier 13b, and a first ring gear 13c. The transmission comprises a double pinion planetary gear mechanism having a first fastening element 15 located between the second carrier 14b and the transmission case 10, a second fastening element 16 located between the first carrier 13b and the second sun gear 14a, a third fastening element 17 located between the second fastening element 16 and the second carrier 14b, and a fourth fastening element 18 located between the first sun gear 13a and the second carrier 14b. The first ring gear 13c is supported by the transmission case 10 so as not to rotate, the first sun gear 13a is connected to the input shaft 11, and the second ring gear 14c is connected to the output shaft 12.

[0226] (2) The transmission 1 includes an input shaft 11 to which rotation is input from a drive source, an output shaft 12 that outputs the rotation of the input shaft 11 to drive wheels, a first planetary gear mechanism 13, a second planetary gear mechanism 14, a first engagement element 15 that is engaged in first gear, a second engagement element 16 that is engaged in first gear, second gear, and third gear, a third engagement element 17 that is engaged in second gear and fourth gear, a fourth engagement element 18 that is engaged in third gear and fourth gear, and a transmission case 10. The first planetary gear mechanism 13 is a single-pinion planetary gear mechanism having a first sun gear 13a, a first carrier 13b, and a first ring gear 13c, and the second planetary gear mechanism 14 is a single-pinion planetary gear mechanism having a first sun gear 13a, a first carrier 13b, and a first ring gear 13c. The star gear mechanism 14 is composed of a double pinion planetary gear mechanism having a second sun gear 14a, a second carrier 14b and a second ring gear 14c, a first fastening element 15 is located between the second carrier 14b and the transmission case 10, a second fastening element 16 is located between the first ring gear 13c and the transmission case 10, a third fastening element 17 is located between the first carrier 13b and the second carrier 14b, and a fourth fastening element 18 is located between the first sun gear 13a and the second carrier 14b, the first sun gear 13a is connected to the input shaft 11, and the second ring gear 14c is connected to the output shaft 12.

[0227] (3) The transmission 1 includes an input shaft 11 to which rotation is input from a drive source, an output shaft 12 that outputs the rotation of the input shaft 11 to drive wheels, a first planetary gear mechanism 13, a second planetary gear mechanism 14, a first engagement element 15 that is engaged in first gear, a second engagement element 16 that is engaged in first gear, second gear, and third gear, a third engagement element 17 that is engaged in second gear and fourth gear, a fourth engagement element 18 that is engaged in third gear and fourth gear, and a transmission case 10. The first planetary gear mechanism 13 is a single-pinion planetary gear mechanism having a first sun gear 13a, a first carrier 13b, and a first ring gear 13c. The second planetary gear mechanism 14 is a single-pinion planetary gear mechanism having a second sun gear 14a, a first carrier 13b, and a first ring gear 13c. The transmission comprises a single-pinion planetary gear mechanism having a first fastening element 15, a second carrier 14b and a second ring gear 14c, a first fastening element 15 is located between the second ring gear 14c and the transmission case 10, a second fastening element 16 is located between the first carrier 13b and the second sun gear 14a, a third fastening element 17 is located between the second fastening element 16 and the second ring gear 14c, and a fourth fastening element 18 is located between the first sun gear 13a and the second ring gear 14c, the first ring gear 13c is supported by the transmission case 10 so as to be non-rotatable, the first sun gear 13a is connected to the input shaft 11, and the second carrier 14b is connected to the output shaft 12.

[0228] (4) The transmission 1 includes an input shaft 11 to which rotation is input from a drive source, an output shaft 12 that outputs the rotation of the input shaft 11 to drive wheels, a first planetary gear mechanism 13, a second planetary gear mechanism 14, a first engagement element 15 that is engaged in first gear, a second engagement element 16 that is engaged in first gear, second gear, and third gear, a third engagement element 17 that is engaged in second gear and fourth gear, a fourth engagement element 18 that is engaged in third gear and fourth gear, and a transmission case 10. The first planetary gear mechanism 13 is a single-pinion planetary gear mechanism having a first sun gear 13a, a first carrier 13b, and a first ring gear 13c, and a second planetary gear The gear mechanism 14 consists of a single pinion planetary gear mechanism having a second sun gear 14a, a second carrier 14b and a second ring gear 14c, a first fastening element 15 is located between the second ring gear 14c and the transmission case 10, a second fastening element 16 is located between the first ring gear 13c and the transmission case 10, a third fastening element 17 is located between the first carrier 13b and the second ring gear 14c, and a fourth fastening element 18 is located between the first sun gear 13a and the second ring gear 14c, the first sun gear 13a is connected to the input shaft 11 and the second carrier 14b is connected to the output shaft 12.

[0229] (5) The transmission 1 includes an input shaft 11 to which rotation is input from a drive source, an output shaft 12 that outputs the rotation of the input shaft 11 to drive wheels, a first planetary gear mechanism 13, a second planetary gear mechanism 14, a first engagement element 15 that is engaged in first gear, a second engagement element 16 that is engaged in first gear, second gear, and third gear, a third engagement element 17 that is engaged in second gear and fourth gear, a fourth engagement element 18 that is engaged in third gear and fourth gear, and a transmission case 10. The first planetary gear mechanism 13 is a double pinion planetary gear mechanism having a first sun gear 13a, a first carrier 13b, and a first ring gear 13c. The second planetary gear mechanism 14 is a double pinion planetary gear mechanism having a second sun gear 14a, a first carrier 13b, and a first ring gear 13c. The transmission case 10 includes a single-pinion planetary gear mechanism having a first fastening element 15, a second carrier 14b, and a second ring gear 14c, a first fastening element 15 being located between the second ring gear 14c and the transmission case 10, a second fastening element 16 being located between the first ring gear 13c and the second sun gear 14a, a third fastening element 17 being located between the second fastening element 16 and the second ring gear 14c, and a fourth fastening element 18 being located between the first carrier 13b and the second ring gear 14c, the first sun gear 13a is supported by the transmission case 10 so as to be non-rotatable, the first carrier 13b is connected to the input shaft 11, and the second carrier 14b is connected to the output shaft 12.

[0230] (6) The transmission 1 includes an input shaft 11 to which rotation is input from a drive source, an output shaft 12 that outputs the rotation of the input shaft 11 to drive wheels, a first planetary gear mechanism 13, a second planetary gear mechanism 14, a first engagement element 15 that is engaged in first gear, a second engagement element 16 that is engaged in first gear, second gear, and third gear, a third engagement element 17 that is engaged in second gear and fourth gear, a fourth engagement element 18 that is engaged in third gear and fourth gear, and a transmission case 10. The first planetary gear mechanism 13 is a double pinion planetary gear mechanism having a first sun gear 13a, a first carrier 13b, and a first ring gear 13c, and a second planetary gear The gear mechanism 14 consists of a single pinion planetary gear mechanism having a second sun gear 14a, a second carrier 14b and a second ring gear 14c, a first fastening element 15 is located between the second ring gear 14c and the transmission case 10, a second fastening element 16 is located between the first sun gear 13a and the transmission case 10, a third fastening element 17 is located between the first ring gear 13c and the second ring gear 14c, and a fourth fastening element 18 is located between the first carrier 13b and the second ring gear 14c, the first carrier 13b is connected to the input shaft 11 and the second carrier 14b is connected to the output shaft 12.

[0231] (7) The transmission 1 includes an input shaft 11 to which rotation is input from a drive source, an output shaft 12 that outputs the rotation of the input shaft 11 to drive wheels, a first planetary gear mechanism 13, a second planetary gear mechanism 14, a first engagement element 15 that is engaged in first gear, a second engagement element 16 that is engaged in first gear, second gear, and third gear, a third engagement element 17 that is engaged in second gear and fourth gear, a fourth engagement element 18 that is engaged in third gear and fourth gear, and a transmission case 10. The first planetary gear mechanism 13 is a double pinion planetary gear mechanism having a first sun gear 13a, a first carrier 13b, and a first ring gear 13c. The second planetary gear mechanism 14 is a double pinion planetary gear mechanism having a second sun gear 13a, a first carrier 13b, and a first ring gear 13c. The transmission comprises a double pinion planetary gear mechanism having a first fastening element 15 and a second carrier 14b, and a second ring gear 14c, a first fastening element 15 being located between the second carrier 14b and the transmission case 10, a second fastening element 16 being located between the first ring gear 13c and the second sun gear 14a, a third fastening element 17 being located between the second fastening element 16 and the second carrier 14b, and a fourth fastening element 18 being located between the first sun gear 13a and the second carrier 14b, the first carrier 13b being supported by the transmission case 10 so as not to rotate, the first sun gear 13a being connected to the input shaft 11, and the second ring gear 14c being connected to the output shaft 12.

[0232] (8) The transmission 1 includes an input shaft 11 to which rotation is input from a drive source, an output shaft 12 that outputs the rotation of the input shaft 11 to drive wheels, a first planetary gear mechanism 13, a second planetary gear mechanism 14, a first engagement element 15 that is engaged in first gear, a second engagement element 16 that is engaged in first gear, second gear, and third gear, a third engagement element 17 that is engaged in second gear and fourth gear, a fourth engagement element 18 that is engaged in third gear and fourth gear, and a transmission case 10. The first planetary gear mechanism 13 is a double pinion planetary gear mechanism having a first sun gear 13a, a first carrier 13b, and a first ring gear 13c, and the second planetary gear mechanism 14 is a double pinion planetary gear mechanism having a first sun gear 13a, a first carrier 13b, and a first ring gear 13c. The gear mechanism 14 consists of a double pinion planetary gear mechanism having a second sun gear 14a, a second carrier 14b and a second ring gear 14c, a first fastening element 15 is located between the second carrier 14b and the transmission case 10, a second fastening element 16 is located between the first carrier 13b and the transmission case 10, a third fastening element 17 is located between the first ring gear 13c and the second carrier 14b, and a fourth fastening element 18 is located between the first sun gear 13a and the second carrier 14b, the first sun gear 13a is connected to the input shaft 11, and the second ring gear 14c is connected to the output shaft 12.

[0233] According to these configurations, the transmission 1 keeps the second engagement element 16 in an engaged state when shifting between first and second gears, puts the first engagement element 15 in either an engaged state or a released state, and puts the third engagement element 17 in either the other of an engaged state or a released state. In other words, the transmission 1 does not switch the second engagement element 16 when shifting between first and second gears, but only switches the first engagement element 15 and the third engagement element 17. This makes it possible to achieve a shift between first and second gears with a simple structure without double switching of the engagement elements.

[0234] Furthermore, when shifting between second and third gears, the transmission 1 keeps the second engagement element 16 in an engaged state, puts the third engagement element 17 in either an engaged state or a released state, and puts the fourth engagement element 18 in either the engaged state or a released state. In other words, when shifting between second and third gears, the transmission 1 does not switch the second engagement element 16, but only switches the third engagement element 17 and the fourth engagement element 18. This makes it possible to achieve a shift between second and third gears with a simple structure without double switching of the engagement elements.

[0235] Furthermore, when shifting between third and fourth gears, the transmission 1 keeps the fourth engagement element 18 in an engaged state, puts the second engagement element 16 in either an engaged state or a released state, and puts the third engagement element 17 in either the engaged state or a released state. In other words, when shifting between third and fourth gears, the transmission 1 only switches the second engagement element 16 and the third engagement element 17, without switching the fourth engagement element 18. This makes it possible to achieve a shift between third and fourth gears with a simple structure without double switching of the engagement elements.

[0236] This makes it possible to realize four forward speeds without double switching of the engagement elements during gear shifting with a simple structure, thereby suppressing the occurrence of large gear shift shocks caused by double switching of the engagement elements during gear shifting.

[0237] Although the embodiments of the present invention have been described above, the above-mentioned embodiments merely show some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above-mentioned embodiments. [Explanation of symbols]

[0238] 1. Transmission 10. Gearbox case 11 Input shaft 12 Output shaft 13 First planetary gear mechanism 13a 1st sun gear 13b First Carrier 13c 1st ring gear 14 Second planetary gear mechanism 14a 2nd Sun Gear 14b Second Career 14c 2nd ring gear 15 First fastening element 16 Secondary fastening element 17 Third fastening element 18 Fourth fastening element

Claims

1. an input shaft to which rotation is input from a drive source; an output shaft that outputs the rotation of the input shaft to a drive wheel; A first planetary gear mechanism; A second planetary gear mechanism; a first clutch element that is engaged in first gear; a second clutch element that is engaged in first, second, and third gears; a third clutch element that is engaged in second and fourth gears; a fourth clutch element which is engaged in third and fourth gears; A transmission case; the first planetary gear mechanism is a single pinion planetary gear mechanism having a first sun gear, a first carrier, and a first ring gear; the second planetary gear mechanism is a double pinion planetary gear mechanism having a second sun gear, a second carrier, and a second ring gear; the first fastening element is located between the second carrier and the transmission case, the second fastening element is located between the first carrier and the second sun gear, the third fastening element is located between the second fastening element and the second carrier; the fourth fastening element is located between the first sun gear and the second carrier, the first ring gear is non-rotatably connected to the transmission case, the first sun gear is connected to the input shaft, The second ring gear is connected to the output shaft. Transmission.

2. an input shaft to which rotation is input from a drive source; an output shaft that outputs the rotation of the input shaft to a drive wheel; A first planetary gear mechanism; A second planetary gear mechanism; a first clutch element that is engaged in first gear; a second clutch element that is engaged in first, second, and third gears; a third clutch element that is engaged in second and fourth gears; a fourth clutch element which is engaged in third and fourth gears; A transmission case; the first planetary gear mechanism is a single pinion planetary gear mechanism having a first sun gear, a first carrier, and a first ring gear; the second planetary gear mechanism is a double pinion planetary gear mechanism having a second sun gear, a second carrier, and a second ring gear; the first fastening element is located between the second carrier and the transmission case, the second fastening element is located between the first ring gear and the transmission case, the third fastening element is located between the first carrier and the second carrier, the fourth fastening element is located between the first sun gear and the second carrier, the first sun gear is connected to the input shaft, The second ring gear is connected to the output shaft. Transmission.

3. an input shaft to which rotation is input from a drive source; an output shaft that outputs the rotation of the input shaft to a drive wheel; A first planetary gear mechanism; A second planetary gear mechanism; a first clutch element that is engaged in first gear; a second clutch element that is engaged in first, second, and third gears; a third clutch element that is engaged in second and fourth gears; a fourth clutch element which is engaged in third and fourth gears; A transmission case; the first planetary gear mechanism is a single pinion planetary gear mechanism having a first sun gear, a first carrier, and a first ring gear; the second planetary gear mechanism is a single pinion planetary gear mechanism having a second sun gear, a second carrier, and a second ring gear; the first fastening element is located between the second ring gear and the transmission case, the second fastening element is located between the first carrier and the second sun gear, the third fastening element is located between the second fastening element and the second ring gear, the fourth fastening element is located between the first sun gear and the second ring gear, the first ring gear is non-rotatably connected to the transmission case, the first sun gear is connected to the input shaft, The second carrier is connected to the output shaft. Transmission.

4. an input shaft to which rotation is input from a drive source; an output shaft that outputs the rotation of the input shaft to a drive wheel; A first planetary gear mechanism; A second planetary gear mechanism; a first clutch element that is engaged in first gear; a second clutch element that is engaged in first, second, and third gears; a third clutch element that is engaged in second and fourth gears; a fourth clutch element which is engaged in third and fourth gears; A transmission case; the first planetary gear mechanism is a single pinion planetary gear mechanism having a first sun gear, a first carrier, and a first ring gear; the second planetary gear mechanism is a single pinion planetary gear mechanism having a second sun gear, a second carrier, and a second ring gear; the first fastening element is located between the second ring gear and the transmission case, the second fastening element is located between the first ring gear and the transmission case, the third fastening element is located between the first carrier and the second ring gear, the fourth fastening element is located between the first sun gear and the second ring gear, the first sun gear is connected to the input shaft, The second carrier is connected to the output shaft. Transmission.

5. an input shaft to which rotation is input from a drive source; an output shaft that outputs the rotation of the input shaft to a drive wheel; A first planetary gear mechanism; A second planetary gear mechanism; a first clutch element that is engaged in first gear; a second clutch element that is engaged in first, second, and third gears; a third clutch element that is engaged in second and fourth gears; a fourth clutch element which is engaged in third and fourth gears; A transmission case; the first planetary gear mechanism is a double pinion planetary gear mechanism having a first sun gear, a first carrier, and a first ring gear; the second planetary gear mechanism is a single pinion planetary gear mechanism having a second sun gear, a second carrier, and a second ring gear; the first fastening element is located between the second ring gear and the transmission case, the second fastening element is located between the first ring gear and the second sun gear, the third fastening element is located between the second fastening element and the second ring gear, the fourth fastening element is located between the first carrier and the second ring gear, the first sun gear is non-rotatably connected to the transmission case, The first carrier is connected to the input shaft, The second carrier is connected to the output shaft. Transmission.

6. an input shaft to which rotation is input from a drive source; an output shaft that outputs the rotation of the input shaft to a drive wheel; A first planetary gear mechanism; A second planetary gear mechanism; a first clutch element that is engaged in first gear; a second clutch element that is engaged in first, second, and third gears; a third clutch element that is engaged in second and fourth gears; a fourth clutch element which is engaged in third and fourth gears; A transmission case; the first planetary gear mechanism is a double pinion planetary gear mechanism having a first sun gear, a first carrier, and a first ring gear; the second planetary gear mechanism is a single pinion planetary gear mechanism having a second sun gear, a second carrier, and a second ring gear; the first fastening element is located between the second ring gear and the transmission case, the second fastening element is located between the first sun gear and the transmission case, the third fastening element is located between the first ring gear and the second ring gear, the fourth fastening element is located between the first carrier and the second ring gear, The first carrier is connected to the input shaft, The second carrier is connected to the output shaft. Transmission.

7. an input shaft to which rotation is input from a drive source; an output shaft that outputs the rotation of the input shaft to a drive wheel; A first planetary gear mechanism; A second planetary gear mechanism; a first clutch element that is engaged in first gear; a second clutch element that is engaged in first, second, and third gears; a third clutch element that is engaged in second and fourth gears; a fourth clutch element which is engaged in third and fourth gears; A transmission case; the first planetary gear mechanism is a double pinion planetary gear mechanism having a first sun gear, a first carrier, and a first ring gear; the second planetary gear mechanism is a double pinion planetary gear mechanism having a second sun gear, a second carrier, and a second ring gear; the first fastening element is located between the second carrier and the transmission case, the second fastening element is located between the first ring gear and the second sun gear, the third fastening element is located between the second fastening element and the second carrier; the fourth fastening element is located between the first sun gear and the second carrier, the first carrier is non-rotatably connected to the transmission case, the first sun gear is connected to the input shaft, The second ring gear is connected to the output shaft. Transmission.

8. an input shaft to which rotation is input from a drive source; an output shaft that outputs the rotation of the input shaft to a drive wheel; A first planetary gear mechanism; A second planetary gear mechanism; a first clutch element that is engaged in first gear; a second clutch element that is engaged in first, second, and third gears; a third clutch element that is engaged in second and fourth gears; a fourth clutch element which is engaged in third and fourth gears; A transmission case; the first planetary gear mechanism is a double pinion planetary gear mechanism having a first sun gear, a first carrier, and a first ring gear; the second planetary gear mechanism is a double pinion planetary gear mechanism having a second sun gear, a second carrier, and a second ring gear; the first fastening element is located between the second carrier and the transmission case, the second fastening element is located between the first carrier and the transmission case, the third fastening element is located between the first ring gear and the second carrier, the fourth fastening element is located between the first sun gear and the second carrier, the first sun gear is connected to the input shaft, The second ring gear is connected to the output shaft. Transmission.

Images