JP4945790B2 - Automatic transmission - Google Patents

Description

  The present invention relates to an automatic transmission that shifts the rotation of an input member to a plurality of stages and transmits it to an output member.

  Conventionally, according to Japanese Patent Application Laid-Open No. 2004-318, a forward planetary gear for decelerating the output of the input shaft, a dual planetary gear for gear shifting, and six engaging elements are used to perform a shift of 7 forward speeds and 1 reverse speed. Automatic transmissions that can be used are known. In this structure, the double planetary gear has four rotating elements configured by connecting parts of the sun gear, the carrier, and the ring gear of the two planetary gears to each other. For example, a first rotating element composed of a sun gear of one planetary gear, a second rotating element configured by connecting a carrier of one planetary gear and a ring gear of the other planetary gear, a ring gear of one planetary gear, and the other planetary gear A third rotating element constituted by connecting the other carrier and a fourth rotating element comprising a sun gear of the other planetary gear. These first to fourth rotating elements are arranged in order at intervals corresponding to the gear ratio in the velocity diagram. The third rotating element is coupled to the output member.

  In addition, as an engagement element, a first clutch that connects the fourth rotating element to the input shaft, a second clutch that connects the first element to the output element of the speed reduction planetary gear, and an output element of the speed reduction planetary gear A third clutch coupled to the input shaft, a fourth clutch coupling the second rotating element to the input shaft, a first brake for fixing the second rotating element to the transmission case, and a fourth rotating element fixed to the transmission case. And a second brake.

According to the above configuration, the first gear is established by engaging the second clutch and the second brake, the second gear is established by engaging the third clutch and the second brake, The third gear is established by engaging the second and third clutches, the fourth gear is established by engaging the first and third clutches, and the first and second clutches are engaged. The fifth gear is established by engaging, the sixth gear is established by engaging the first clutch and the fourth clutch, and the seventh gear is established by engaging the second and fourth clutches. Is established, and the reverse gear is established by engaging the second clutch and the first brake.
Japanese translation of PCT publication No. 2004-524485 (FIG. 10)

  In the above-mentioned conventional example, a total of six engaging elements including three planetary gears, that is, a planetary gear for reduction and two planetary gears constituting a double planetary gear, four clutches, and two brakes are used. ing.

  By the way, in the automatic transmission for FF vehicles, in order to improve the mounting property to a vehicle, it is desired to shorten the shaft length of the transmission. Here, since the planetary gears and clutches are arranged in the axial direction around the input shaft, if the total number of planetary gears and clutches increases, it becomes difficult to shorten the shaft length of the transmission. In the above conventional example, since three planetary gears and four clutches are used, the total number of planetary gears and clutches is as large as seven, and the shaft length of the transmission becomes long, so that it can be mounted on an FF vehicle. There is a problem that gets worse.

  SUMMARY OF THE INVENTION In view of the above, the present invention provides an automatic transmission capable of shifting forward 7 steps and reverse 1 step and reducing the total number of planetary gears and clutches to shorten the shaft length. That is the issue.

  In order to solve the above problems, the present invention includes first and second planetary gears for input, a double planetary gear for shifting, and a plurality of engaging elements, which are arranged in a transmission case. An automatic transmission that shifts the rotation of an input shaft to a plurality of stages and transmits it to an output member, wherein each of the first and second planetary gears can be fixed to an input element coupled to the input shaft and a transmission case The fixed planetary gear has a fixed element and an output element, and is configured to decelerate the rotation of the input shaft and output from the output element when the fixed element is fixed to the transmission case. The four rotating elements are arranged at intervals corresponding to the first rotating element as the first rotating element, the second rotating element, the third rotating element, and the fourth rotating element in the order of arrangement in the velocity diagram. Is the first planetary gear An output element, a second rotation element are connected to the output element of the second planetary gear, and a third rotation element is connected to the output member, respectively, and a first clutch that connects the fourth rotation element to the input shaft as an engagement element, and a second rotation A second clutch that connects the element to the input shaft, a first brake that fixes the fourth rotating element to the transmission case, a second brake that fixes the fixing element of the second planetary gear to the transmission case, and a first planetary gear A third brake for fixing the fixing element to the transmission case and a fourth brake for fixing the second rotating element to the transmission case are provided.

  According to the present invention, the first speed is established by engaging the first brake and the third brake, the second speed is established by engaging the first brake and the second brake, and the second speed is established. The third speed is established by engaging the brake and the third brake, the fourth speed is established by engaging the first clutch and the second brake, and the first clutch and the third brake are engaged. The fifth gear is established by engaging, the sixth gear is established by engaging the first clutch and the second clutch, and the seventh gear is established by engaging the second clutch and the third brake. The reverse gear is established by engaging the third brake and the fourth brake. Therefore, it is possible to perform a shift of 7 forward speeds and 1 reverse speed.

  In the present invention, a total of four planetary gears are used as the planetary gears, ie, the first planetary gear, the second planetary gear, and the two planetary gears constituting the double planetary gear, but only two clutches are used. The total number of planetary gears and clutches is six, which is one less than that in the conventional example. Therefore, the shaft length of the transmission can be shortened compared to the conventional example, and the mountability to the FF vehicle is improved.

  In the present invention, if the gear ratio of the first planetary gear and the gear ratio of the second planetary gear are made different from each other, the degree of freedom in setting the public ratio (ratio ratio between the respective gears) is increased, and the ratio of the first orange (first speed) is increased. The ratio of the stage ratio / the ratio of the seventh speed stage) and the common ratio can both be set to suitable values.

  FIG. 1 (a) shows an embodiment of the automatic transmission of the present invention. This embodiment is a transmission for an FF vehicle, which is rotatably supported in a transmission case 1 and connected to a power source such as an engine (not shown) and concentric with the input shaft 2. And an output gear 3 serving as an output member. The rotation of the output gear 3 is transmitted to the left and right front wheels of the vehicle via a differential gear (not shown).

  Also, in the transmission case 1, two first and second planetary gears 4 and 5 for input and a double planetary gear 6 for shifting are arranged around the input shaft 2.

  The first planetary gear 4 is a carrier Cf1 that supports a pair of pinions Pf1 and Pf1 'that mesh with the sun gear Sf1 and the ring gear Rf1 and that mesh with the sun gear Sf1 and the other mesh with the ring gear Rf1 in a freely rotating and revolving manner. It consists of a double planetary single planetary gear consisting of The second planetary gear 5 also supports a pair of pinions Pf2 and Pf2 ′ that mesh with the sun gear Sf2 and the ring gear Rf2, and one meshes with the sun gear Sf2, and the other meshes with the ring gear Rf2. It is composed of a single planetary gear of double planetary type comprising the carrier Cf2.

  The carrier Cf1 of the first planetary gear 4 and the carrier Cf2 of the second planetary gear 5 are coupled to each other and connected to the input shaft 2, and the carriers Cf1 and Cf2 serve as input elements for the planetary gears 4 and 5, respectively. The ring gear Rf1 serves as an output element as a fixed element for fixing the sun gear Sf1 of the first planetary gear 4 to the transmission case 1 via the third brake B3. The ring gear Rf2 serves as an output element as a fixed element for fixing the sun gear Sf2 of the second planetary gear 5 to the transmission case 1 via the second brake B2.

  As is apparent from the speed diagram of the first planetary gear 4 shown in the upper part of FIG. 2 (the figure in which the rotational speeds of the three elements of the sun gear, the carrier, and the ring gear can be represented by straight lines), the third brake B3 is engaged. When the rotational speed of the sun gear Sf1 is set to “0”, the rotation of the input shaft 2 is decelerated and output from the ring gear Rf1. In the velocity diagram, the lower horizontal line and the upper horizontal line indicate that the rotational speeds are “0” and “1” (the same rotational speed as the input shaft 2), respectively. Each vertical line represents the sun gear Sf1, the ring gear Rf1, and the carrier Cf1 in this order from the left side, and the distance between them is determined according to the gear ratio i of the first planetary gear 4 (the number of teeth of the ring gear / the number of teeth of the sun gear). ing. That is, the ratio between the distance between the sun gear Sf1 and the ring gear Rf1 and the distance between the ring gear Rf1 and the carrier Cf1 is set to be i−1: 1. The output speed of the first planetary gear 4 (the rotational speed of the ring gear Rf1) N1 is (i-1) / i.

  As is apparent from the speed diagram of the second planetary gear 5 shown in the middle stage of FIG. 2, when the second brake B2 is engaged and the rotational speed of the sun gear Sf2 is set to “0”, the rotation of the input shaft 2 is decelerated. And output from the ring gear Rf2. That is, assuming that the gear ratio of the second planetary gear 5 is j, the output speed of the second planetary gear 5 (the rotational speed of the ring gear Rf2) N2 is j−1 / j.

  The compound planetary gear 6 includes a third planetary gear 7 and a fourth planetary gear 8. The third planetary gear 7 is composed of a single-pinion type single planetary gear that includes a sun gear Sm, a ring gear Rm, and a carrier Cm that supports the pinion Pm that meshes with the sun gear Sm and the ring gear Rm so as to rotate and revolve. The fourth planetary gear 8 is also composed of a single-pinion type single planetary gear comprising a sun gear Sr, a ring gear Rr, and a carrier Cr that supports the pinion Pr meshing with the sun gear Sr and the ring gear Rr so as to rotate and revolve. The carrier Cm of the third planetary gear 7 and the ring gear Rr of the fourth planetary gear 8 are coupled, and the ring gear Rm of the third planetary gear 7 and the carrier Cr of the fourth planetary gear 8 are coupled. Accordingly, a coupling body (first coupling body) of the sun gear Sm of the third planetary gear 7, the sun gear Sr of the fourth planetary gear 8, the carrier Cm of the third planetary gear 7 and the ring gear Rr of the fourth planetary gear 8, and the third A compound planetary gear 6 having four rotating elements composed of a coupling body (second coupling body) of the ring gear Rm of the planetary gear 7 and the carrier Cr of the fourth planetary gear 8 is constituted.

  These four rotating elements of the compound planetary gear 6 are respectively arranged in the order of arrangement at intervals corresponding to the gear ratio in the speed diagram of the compound planetary gear 6 shown in the lower part of FIG. Assuming that the rotating element and the fourth rotating element are used, the first rotating element is the sun gear Sm of the third planetary gear 7, the second rotating element is the first connecting body Cm, Rr, the third rotating element is the second connecting body Rm, Cr, the second rotating element. The four rotation elements become the sun gear Sr of the fourth planetary gear 8. The distance between the sun gear Sm of the third planetary gear 7 and the first coupling bodies Cm, Rr, the spacing between the first coupling bodies Cm, Rr and the second coupling bodies Rm, Cr, and the second coupling bodies Rm, Cr The ratio of the fourth planetary gear 8 to the distance between the sun gears Sr is set to k: 1: m, where k is the gear ratio of the third planetary gear 7 and m is the gear ratio of the fourth planetary gear 8.

  Here, in the present embodiment, the sun gear Sm (first rotating element) of the third planetary gear 7 is connected to the ring gear Rf1 that is the output element of the first planetary gear 4, and the first connecting bodies Cm, Rr (second rotating element). Are connected to a ring gear Rf2 which is an output element of the second planetary gear 5, and second connecting bodies Rm, Cr (third rotating element) are connected to the output gear 3. In addition to the second and third brakes B2 and B3 described above, the first clutch C1 that connects the sun gear Sr (fourth rotating element) of the fourth planetary gear 8 to the input shaft 2 as the engaging element, A second clutch C2 for connecting the connecting bodies Cm, Rr (second rotating element) to the input shaft 2; a first brake B1 for fixing the sun gear Sr (fourth rotating element) of the fourth planetary gear 8 to the transmission case 1; And a fourth brake B4 for fixing the first coupling bodies Cm, Rr (second rotating elements) to the transmission case 1. In the present embodiment, the second clutch C2 is interposed between the carriers Cf1 and Cf2 of the first and second planetary gears 4 and 5 connected to the input shaft 2 and the first coupling bodies Cm and Rr. The first coupling bodies Cm, Rr are coupled to the input shaft 2 via the first clutch C1 and the carriers Cf1, Cf2.

  In the present embodiment, the first clutch C1, the fourth planetary gear 8, the third planetary gear 7, the output gear 3, the second clutch C2, and the first clutch are sequentially arranged around the input shaft 2 from the power source side. A planetary gear 4 and a second planetary gear 5 are arranged. By the way, the brake can be arranged outside the planetary gear and the clutch while being overlapped with each other, but the planetary gear and the clutch cannot be arranged so as to overlap each other. Therefore, when the total number of planetary gears and clutches increases, the shaft length of the transmission increases. Here, in the present embodiment, the first to fourth planetary gears C1 to C4 are used, but only two clutches, the first clutch C1 and the second clutch C2, are used. The total number of clutches is six, which is one less than that in the conventional example. The individual shaft lengths of the planetary gear and the clutch are about 35 mm. Therefore, the shaft length of the transmission can be shortened by about 35 mm as compared with the conventional example, and the mountability to the FF vehicle is improved.

  Next, the shift operation by the transmission of this embodiment will be described with reference to FIG. When the first brake B1 and the third brake B3 are engaged, the rotational speed of the sun gear Sr of the fourth planetary gear 8 is “0”, and the rotational speed of the sun gear Sm of the third planetary gear 7 is the output speed N1 of the first planetary gear 4. Thus, the rotation speed of the second coupling bodies Rm, Cr coupled to the output gear 3 is “1st”. That is, the first gear is established.

  When the first brake B1 and the second brake B2 are engaged, the rotational speed of the sun gear Sr of the fourth planetary gear 8 is “0”, and the rotational speed of the first coupling bodies Cm and Rr is the output speed N2 of the second planetary gear 5. Thus, the rotation speed of the second coupling bodies Rm and Cr is “2nd”. That is, the second gear is established.

  When the second brake B2 and the third brake B3 are engaged, the rotation speed of the first coupling bodies Cm, Rr is the output speed N2 of the second planetary gear 5, and the rotation speed of the sun gear Sm of the third planetary gear 7 is the first planetary gear. 4 and the rotation speed of the second coupling bodies Rm, Cr is “3rd”. That is, the third gear is established.

  When the first clutch C1 and the second brake B2 are engaged, the rotational speed of the sun gear Sr of the fourth planetary gear 8 is "1", and the rotational speed of the first coupling bodies Cm, Rr is the output speed N2 of the second planetary gear 5. Thus, the rotation speed of the second coupling bodies Rm, Cr is “4th”. That is, the fourth gear is established.

  When the first clutch C1 and the third brake B3 are engaged, the rotational speed of the sun gear Sr of the fourth planetary gear 8 is "1", and the rotational speed of the sun gear Sm of the third planetary gear 7 is the output speed N1 of the first planetary gear 4. Thus, the rotation speed of the second coupling bodies Rm, Cr is “5th”. That is, the fifth gear is established.

  When the first clutch C1 and the second clutch C2 are engaged, the rotational speed of the sun gear Sr of the fourth planetary gear 8 and the rotational speed of the first coupling bodies Cm, Rr both become “1”, and the second coupling body The rotational speeds of Rm and Cr are also “1”, “6th”. That is, the sixth gear is established.

  When the second clutch C <b> 2 and the third brake B <b> 3 are engaged, the rotational speed of the first coupling bodies Cm and Rr is “1”, and the rotational speed of the sun gear Sm of the third planetary gear 7 is that of the first planetary gear 4. The output speed is N1, and the rotation speed of the second coupling bodies Rm and Cr is “7th”. That is, the seventh gear is established.

  When the third brake B3 and the fourth brake B4 are engaged, the rotation speed of the sun gear Sm of the third planetary gear 7 is the output speed N1 of the first planetary gear 4, and the rotation speed of the rotation speed of the first coupling bodies Cm and Rr is It becomes “0”, and the rotation speed of the second coupling bodies Rm, Cr becomes minus “Rev”. That is, the reverse gear is established.

  FIG. 1B is a diagram collectively showing the relationship between the above-described shift speeds and the engagement states of the clutches C1 and C2 and the brakes B1 to B4, where “◯” represents engagement.

  Here, if the gear ratio i of the first planetary gear 4 and the gear ratio j of the second planetary gear 5 are made different, the output speed N1 of the first planetary gear 4 and the output speed N2 of the second planetary gear 5 become different speeds, The speed line at the third speed is an inclined line. As a result, the degree of freedom for setting the common ratio (ratio of ratios between the respective gears) is increased. In FIG. 1B, the gear ratio i of the first planetary gear 4 and the gear ratio j of the second planetary gear 5 are made different so that i = 2.2 and j = 2.1, and the third planetary gear 7 The ratio of each gear stage (the rotational speed of the input shaft 2 / the rotational speed of the output gear 3) when the gear ratio k is 2.5 and the gear ratio m of the fourth planetary gear 8 is 2.0 is also entered. . As is apparent from this, the ratio orange (1st speed ratio / 7th speed ratio) is a practical value in the vicinity of 6.0. Further, as is apparent from FIG. 3 showing the change in the common ratio, the good common ratio is large on the low speed stage side and small on the high speed stage side.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to this. For example, in the above-described embodiment, the compound planetary gear 6 is configured by combining the third and fourth planetary gears 7 and 8 formed of a single planetary gear, but two sun gears, one ring gear, one sun gear, and a ring gear It is also possible to form the double planetary gear 6 by a Ravigneaux type planetary gear having a pinion that meshes with the pinion and a carrier that supports the pinion and the pinion meshed with the other sun gear so as to rotate and revolve.

(A) Skeleton diagram of embodiment of transmission of this invention, (b) The figure which showed collectively the engagement state of each engagement element in each gear stage. The speed diagram of the 1st, 2nd planetary gear and double type planetary gear of embodiment. The line graph which shows the change of the common ratio in embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Transmission case, 2 ... Input shaft, 3 ... Output gear (output member), 4 ... 1st planetary gear, Sf1 ... Sun gear (fixed element) of 1st planetary gear, Cf1 ... Carrier (input element) of 1st planetary gear, Rf1 ... ring gear (output element) of the first planetary gear, 5 ... second planetary gear, Sf2 ... sun gear (fixed element) of the second planetary gear, Cf2 ... carrier (input element) of the second planetary gear, Rf2 ... ring gear of the second planetary gear ( Output element), 6 ... double planetary gear, Sm ... third gear sun gear (first rotating element), Cm, Rr ... third planetary gear carrier and fourth planetary gear ring gear (second rotating element), Rm, Cr ... first 3 planetary gear ring gear and 4th planetary gear carrier (third rotating element), S ... fourth planetary sun gear Sr (fourth rotating element), C1 ... first clutch, C2 ... second clutch, B1 ... first brake, B2 ... second brake, B3 ... third brake, B4 ... fourth brake.

Claims (2)

Provided with first and second planetary gears for input, a double planetary gear for shifting, and a plurality of engaging elements arranged in the transmission case, and the output of the input shaft is shifted in multiple stages and output. An automatic transmission for transmitting to a member,
Each of the first and second planetary gears has an input element coupled to the input shaft, a fixing element that can be fixed to the transmission case, and an output element, and is input when the fixing element is fixed to the transmission case. It is configured to decelerate the rotation of the shaft and output from the output element,
The compound planetary gear has four rotating elements arranged at intervals corresponding to the gear ratio in the velocity diagram, and these rotating elements are arranged in the order of arrangement in the velocity diagram, respectively, a first rotating element, a second rotating element, a third rotating element, and As the fourth rotating element, the first rotating element is connected to the output element of the first planetary gear, the second rotating element is connected to the output element of the second planetary gear, and the third rotating element is connected to the output member,
As an engagement element, a first clutch that connects the fourth rotating element to the input shaft, a second clutch that connects the second rotating element to the input shaft, and a first brake that fixes the fourth rotating element to the transmission case; A second brake for fixing the fixing element of the second planetary gear to the transmission case, a third brake for fixing the fixing element of the first planetary gear to the transmission case, and a fourth brake for fixing the second rotating element to the transmission case. An automatic transmission comprising a brake.   The automatic transmission according to claim 1, wherein a gear ratio of the first planetary gear and a gear ratio of the second planetary gear are different from each other.

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