JPH0631241Y2 - Continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is a vehicle for automobiles (four wheels or more) that can continuously change the gear ratio with a width equal to or larger than the gear ratio of the continuously variable transmission. More particularly, it relates to a transmission having an input shaft connected to an engine mounted on a front-wheel drive vehicle or a four-wheel drive vehicle.

[Prior Art] As a typical continuously variable transmission of this type (corresponding to a continuously variable transmission portion in the present invention), there is one using a variable pulley. In this continuously variable transmission, variable pulleys are mounted on parallel shafts, and belts are wound around both pulleys. The gear ratio is continuously changed by changing the diameter of the pulleys in contact with the belts. Others use friction discs and conical wheels.

A transmission mechanism using this typical continuously variable transmission as a variable ratio belt driving means is disclosed in JP-A-57-29845.
In the disclosed transmission mechanism, one of a pair of interconnected simple planetary gear means is continuously drive-coupled with the variable ratio belt drive means by one member, but the variable ratio width that can be continuously changed. Does not exceed the range of the gear ratio of the variable ratio belt drive means. When a variable ratio belt is used,
There is a general need to overcome the problem of poor durability. Furthermore, corresponding to various vehicles and engines,
There is a general need to be able to change and set the range of gear ratios without changing the basic structure. In addition, it is also required to ensure the compatibility of the arrangement of the front-wheel drive vehicle (including four-wheel drive) in the engine room.

[Problems to be Solved by the Invention] In the conventional continuously variable transmission, the width of the gear ratio is determined by the effective dimensions of the main elements constituting the continuously variable transmission, such as the variable pulley, the friction disk, and the conical wheel. The width of the gear ratio cannot be widened beyond that. When the width of the gear ratio is widened, the size of the main element of the continuously variable transmission is inevitably increased.
In order to solve this drawback, the present inventor has disclosed a continuously variable transmission in which the size of the main element is kept unchanged and the range of the transmission ratio is widened, in Japanese Patent Application No. 58-038235, which is the prior application of this application.

The present invention has been made to further improve this continuously variable transmission, and the purpose thereof is to widen the transmission ratio as much as possible while keeping the effective dimensions of the main elements as they are, and to force them into the engine room in a front-wheel drive vehicle or the like. (EN) Provided is a continuously variable transmission that can be installed without any change, that is, that the durability is improved and that the gear ratio and its width can be changed without changing the basic structure.

[Technical Means for Solving Problems] In order to achieve the above object, the present invention includes a continuously variable transmission unit, a power transmission unit, and a power split unit between parallel input shafts and output shafts. In the continuously variable transmission, (i) the drive side of the continuously variable transmission unit, the power split unit, and the power transmission unit are sequentially arranged on the input axis connected to the engine mounted on the four-wheeled vehicle from the engine side. A drive side is provided, (ii) a continuously variable transmission section and a driven side of the power transmission section are provided on the output axis, and (iii) the power split section includes a sun gear, a carrier, and a ring gear, The sun gear is connected to the drive side of the power transmission unit, the carrier is connected to the drive side of the continuously variable transmission unit, and the ring gear is connected to the input shaft, respectively, and (iv) the continuously variable transmission unit and the power transmission unit. The driven side of the section to the output shaft, (v) An intermediate shaft having two transmission wheels is disposed between the drive side and the driven side disposed adjacent to the continuously variable transmission section to configure the power transmission section in two stages, and (vi) the power transmission section The drive side of the intermediate shaft is connected to one transmission wheel of the intermediate shaft to form a first-stage transmission section, and the driven side of the power transmission section is connected to the other transmission wheel of the intermediate shaft to form a second-stage transmission section. It is characterized by that.

A continuously variable transmission typically uses a variable pulley type, but a device that achieves the same purpose is also used.
The power transmission part may be a chain type or a belt type, but the gear type is most suitable for downsizing, and two transmission wheels (gear, sprocket or pulley) are provided between the input shaft and the output shaft. Etc.) and the second stage transmission portion is adjacent to the continuously variable transmission portion, a space can be secured around one output shaft (right in FIG. 1), and a front-wheel drive vehicle or The arrangement in the engine room, which is suitable for a four-wheel drive vehicle, is performed without difficulty, and the basis for equalizing the left and right output shafts is provided.

In the above structure, the sun gear of the power transmission unit is connected to the drive side of the power transmission unit, the carrier is connected to the drive side of the continuously variable transmission unit, and the ring gear is connected to the input shaft. The range of the transmission ratio of the continuously variable transmission can be increased sufficiently as necessary for a four-wheel vehicle without increasing it so much.

Furthermore, by arranging the intermediate shaft via two transmission wheels as in the front wheel features (v) and (vi), the reduction ratio of the power transmission part can be made variable, and the transmission ratio of the continuously variable transmission as a whole can be changed. The width of can be adjusted, and when changing the gear ratio, it suffices to change the two transmission wheels without changing the position of the intermediate shaft. Therefore, the basic structure can be made common to various vehicles.

Furthermore, it is preferable to take the following aspects (a) to (c).

(A) The continuously variable transmission unit includes a drive unit disposed on the input shaft side and penetrating the center of the input shaft so as to be relatively rotatable, and a driven unit connected to the output shaft. ) The power split unit is disposed on the side opposite to the input shaft with respect to the continuously variable transmission unit, and is connected to the input shaft to divide the input torque from the input shaft into a positive value torque and a negative value torque. A first distributed torque output shaft that outputs a positive torque and a second distributed torque output shaft that outputs a negative torque, and the first distributed torque output shaft serves as a drive unit of the continuously variable transmission unit. (C) The first-stage transmission portion of the power transmission portion is disposed on the opposite side of the power split portion from the continuously variable transmission portion and is coupled to the second distributed torque output shaft of the power split portion. The second-stage transmission section should be arranged between the power split section and the continuously variable transmission section in the axial direction.

Further, according to the present invention, the power split unit is configured in two stages, and the power transmission unit and the first stage transmission unit and the second stage transmission unit of the power split unit are as described in the above (a) to (c). By having a preferable arrangement and configuration, the degree of freedom in arranging the continuously variable transmission with respect to the engine is increased.

That is, when the continuously variable transmission according to this embodiment is applied as a front-wheel drive transmission, the continuously variable transmission is located at the side portion of the engine with respect to the engine arranged substantially in the center of the engine room. However, since it becomes possible to arrange the output side of the continuously variable transmission such as the second stage transmission section of the power transmission section at the center side of the vehicle, the degree of freedom in the layout of the engine room increases dramatically, In addition, the output side of the continuously variable transmission can be placed in the center of the vehicle, making it possible to make the left and right drive shafts equal in length, which reduces torque steer and greatly improves vehicle performance. It will be possible.

[Operation] When the gear ratio of the power split unit is ρ, the torque T ₁ input to the power split unit from the input shaft is T ₂ = (1 + ρ) T ₁ and T
₃ = −ρT ₁ . The torque T ₂ is transmitted to the drive unit of the continuously variable transmission via the first distribution torque output shaft of the power split unit, and is further transmitted from the drive unit to the driven unit at the variable speed ratio ρ ₁ of the continuously variable transmission unit. As a result, a torque of (1 + ρ) T ₁ ρ ₁ is transmitted from the input shaft to the output shaft via the continuously variable transmission. The torque T ₃ distributed by the power split unit is transmitted to the power transmission unit via the second split torque output shaft of the power split unit. The power transmission unit transmits the torque from the power split unit to the intermediate shaft at the first stage transmission unit, and transmits the torque from the intermediate shaft to the driven unit, specifically to the output shaft via the second stage transmission unit. in this case,
The torque T ₃ from the power split unit is the transmission ratio ρ _{2 of the} power transmission unit.
Is transmitted to the output shaft. As a result, the output shaft
Torque of ρT ₁ ρ ₂ is transmitted. The total torque T ₀ of the output shaft is {(1 + ρ) T ₁ ρ ₁ −ρT ₁ ρ ₂ }.

The gear ratio T ₀ / T ₁ of the continuously variable transmission is {(1 + ρ) ρ ₁ −ρρ ₂ }. When the maximum speed ratio of the continuously variable transmission unit and .rho.max, and .rho.min the minimum speed ratio, the width of the gear ratio of the continuously variable transmission, {(1 + ρ) ρmaxρρ 2} / {(1 + ρ) ρmin-ρρ
₂ }. It is desirable that the gear ratio ρ ₂ be 1 or more.

[Embodiment] An embodiment of the present invention will be specifically described below with reference to the drawings. FIG. 1 shows an example in which the continuously variable transmission according to the present invention is used in a vehicle, particularly an automobile. Engine crankshaft 1 which is the power source
Is connected to the input shaft 4 of the continuously variable transmission 3 via the clutch 2. The continuously variable transmission 3 is arranged and configured along the input shaft 4 in the order of a continuously variable transmission portion A, a power split portion B, and a power transmission portion C.

The continuously variable transmission unit A is of a variable pulley type, the drive unit 5 is located on the input shaft 4 side, and the driven unit 6 is fixed to the output shaft 7 parallel to the input shaft 4. The diameters of the driving portion 5 and the driven portion 6 with which the belt 10 contacts are changed by the servo pistons 8 and 9. The input shaft 4 penetrates the drive unit 5 and is connected to the power split unit B.

The power split unit B is composed of a planetary gear device, and includes a ring gear 11 connected to the input shaft 4, a pinion 12 that meshes with the ring gear 1, a carrier 13 that supports the pinion 12, and a sun gear 14 that is centrally arranged and meshes with the pinion 12. Composed.

The power transmission portion C is of a gear type and is configured in two stages with an intermediate shaft 15 positioned in parallel between the input shaft 4 and the output shaft 7. The first stage (first stage transmission unit) is located adjacent to the power split unit B, and is connected to the sun gear 14 with the gear 16 and the intermediate shaft 1.
5 and a gear 17 fixed to the gear 5.
The final stage (second stage transmission unit) is located adjacent to the driven unit 6 of the continuously variable transmission unit A, and the gear 18 and the gear 1 fixed to the output shaft 7 are provided.
7 and a gear 19 fixed to the intermediate shaft 15 so as to oppose to each other. Since the final stage is adjacent to the driven portion 6, size reduction is achieved and a space is created so that the position of the drive shaft can be relaxed.

The output shaft 7 is provided with three planetary gear units D, E and F and a differential gear G following the driven unit 6 of the continuously variable transmission unit C. The first planetary gear set D is equipped with a brake 20 for overdrive and a clutch 21 for low and high speeds. The last planetary gear unit F is equipped with a reverse brake 22.

The power transmission may be a compound type of chain and belt as shown in FIG. The first stage is a chain type, which is constructed by chaining a chain 27 between a sprocket 25 connected to the sun gear 14 and a sprocket 26 fixed to the intermediate shaft 15. The final stage is a belt type pulley 28 fixed to the output shaft 7 and a pulley 2 fixed to the intermediate shaft 15.
A belt 30 is hung between the belt 9 and the belt 9.

In FIG. 1, the power from the engine, which is the power source, is converted into rotational force by the crankshaft 1. The rotational force (torque T ₁ ) of the crankshaft 1 is transmitted via the clutch 2 to the input shaft 4
Be transmitted to. This torque T ₁ is distributed by the power split unit B to the drive unit 5 of the continuously variable transmission unit A and the gear 16 of the power transmission unit C. Assuming that the gear ratio of the ring gear 11 and the sun gear 14 of the power split section B is ρ, the drive section 5 has a carrier 13
The torque T _{2 of} (1 + ρ) T ₁ is distributed via the sun gear 14, and the torque T _{3 of} −ρT ₁ is distributed to the gear 16 via the sun gear 14.

The torque T ₂ of the drive unit 5 is transmitted via the belt 10 to the gear ratio ρ ₁
Is transmitted to the driven unit 6. Torque T appearing on the output shaft 7
₀ becomes {(1 + ρ) T ₁ ρ ₁ }. The torque T ₃ distributed to the gear 16 of the power transmission unit C is transmitted to the gear 17 meshing with the gear 16, to the gear 19 via the intermediate shaft 15, and from the gear 18 meshing with the gear 19 to the output shaft 7. To be done. In this case, the torque T ₀ that appears on the output shaft 7 is T ₀ = {− ρT ₁ ρ ₂ } when the gear ratio of the power transmission unit C is ρ ₂ . As a result, the total sum T ₀ of the torques appearing on the output shaft 7 is {(1 + ρ) T ₁ ρ ₁ −ρT ₁ ρ ₂ }. Since the gear ratio is T ₀ / T ₁ , it becomes {(1 + ρ) ρ ₁ −ρρ ₂ }. The range of the gear ratio as a whole is such that the maximum gear ratio of the continuously variable transmission unit A is ρ ₁ = ρmax,
Assuming that the minimum gear ratio is ρ ₁ = ρmin, {(1 + ρ) ρmax−ρρ ₂ } / {(1 + ρ) ρmin−ρ
ρ ₂ }. This width is the width ρmax / ρm of the gear ratio of the continuously variable transmission A.
much larger than in. The sun gear 14 of the power split unit B rotates at ρ ₂ n, where n is the number of rotations of the output shaft 7.

Explaining with a specific example, when ρ = 0.326, the belt input torque can be as small as 1.326 × input torque, while the gear ratio width can be as large as 7.596. That is, ρmax to ρm of the belt gear ratio
As in, 2.0 to 0.525 is a reasonable range, and assuming that the gear ratio ρ ₂ of the power transmission section is 1.2258,
The above mentioned gear ratio range is achieved, which can be easily changed by changing the gear ratio via the power transmission (and thus the intermediate shaft).

The torque T ₀ of the output shaft 7 is generated by the clutch 2 of the planetary gear device D.
1 is engaged and the brake 22 of the planetary gear unit F is not operating, the differential gear G is set as a low speed region.
To be forwarded to. When the clutch 21 of the planetary gear device D is released and the brake 20 is actuated, the torque T ₀ of the output shaft 7 is transmitted to the differential gear G as an overdrive. When the brake 22 of the planetary gear device F acts, the torque T ₀ of the output shaft 7 is transmitted to the differential gear G as reverse.

FIG. 3 is a diagram showing a layout in an engine room when the continuously variable transmission according to the present invention is applied as a transmission of an automobile, and is an input of the continuously variable transmission 30 arranged at a side portion of the engine 20. It is possible to arrange the output side 30B in the substantially central portion of the vehicle with respect to the side 30A, and as a result, the lengths d ₁ and d ₂ of the drive shafts 33 and 34 connected to the left and right wheels 31 and 32 are almost the same. Can be taken equally. The space in which the length of d ₂ is secured is due to the contribution of the intermediate shaft having two transmission wheels.

In FIGS. 1 and 2, the intermediate shaft is arranged in parallel between the input shaft and the output shaft in plan view on the skeleton diagram, but the position of the intermediate shaft is orthogonal to the plane of the drawing in order to fit the engine room. Can be shifted in the direction.

[Effects] As described above, according to the present invention, the width of the transmission ratio of the continuously variable transmission is changed to the width (ρ of the transmission ratio of the continuously variable transmission portion.
max / ρmin), the torque of the input portion of the continuously variable transmission required for a four-wheeled vehicle is small, and the power transmission portion is configured in two stages. Since it is located adjacent to the continuously variable transmission, the device can be made compact and lightweight. This continuously variable transmission is
In particular, the structure (shape) has been reduced to a structure (shape) suitable for being placed in the engine room of a front-wheel drive vehicle, increasing the degree of freedom in layout in the engine room, and increasing the basic structure of the transmission without increasing the size of the device. The gear ratio as a whole can be easily changed by changing the two transmission wheels of the power transmission unit without changing. This makes it easy to change the gear ratio (and its width) for various vehicles having various engine specifications under the same basic structure or external dimensions. Further, since the left and right drive shafts can be made substantially equal to each other, torque steer can be reduced.

In addition, the reduction in weight can be expected to improve fuel efficiency and acceleration, and reduce oil in the transmission case.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of the present invention, FIG. 2 is a schematic view showing another embodiment of the present invention, and FIG. 3 is an engine room when the present invention is applied as an automobile transmission. It is explanatory drawing which shows the internal layout. A: continuously variable transmission section, B: power split section, C: power transmission section, 4
... input shaft, 5 ... drive unit, 6 ... driven unit, 7 ... output shaft, 10
... belt, 11 ... ring gear, 12 ... pinion, 13 ...
Carrier, 14 ... Sun gear, 15 ... Intermediate shaft, 16, 1
7, 18, 19 ... Gears.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-58-166164 (JP, A) JP-A-52-79172 (JP, A) JP-B-39-14454 (JP, B1)

Claims (1)

[Scope of utility model registration request] 1. A continuously variable transmission having a continuously variable transmission portion, a power transmission portion, and a power split portion between parallel input and output shafts, comprising: (i) an engine mounted on a four-wheeled vehicle. The drive side of the continuously variable transmission section, the drive side of the power split section, and the drive side of the power transmission section are sequentially arranged from the engine side on the input axis to be connected, and (ii) the continuously variable transmission on the output axis line. Section and the driven side of the power transmission section are provided, and (iii) the power split section is composed of a sun gear, a carrier, and a ring gear, the sun gear is on the drive side of the power transmission section, and the carrier is the continuously variable transmission. A drive side of the section, the ring gear is connected to the input shaft, respectively, (iv) the driven side of the continuously variable transmission section and the power transmission section is connected to the output shaft, (v) the power transmission section Two drive wheels between the drive side of the vehicle and the driven side that is adjacent to the continuously variable transmission. A power transmission section is configured in two stages by disposing an intermediate shaft having the above, and (vi) a drive side of the power transmission section is connected to one transmission wheel of the intermediate shaft to form a first stage transmission section, and A continuously variable transmission characterized in that the driven side of the power transmission section is connected to the other transmission wheel of the intermediate shaft to form a second-stage transmission section.