JPH0434271Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a continuously variable transmission that can continuously change the gear ratio by a width greater than the width of the gear ratio of the continuously variable transmission section.

[Prior Art] A typical continuously variable transmission of this type uses a variable pulley. This continuously variable transmission has variable pulleys attached to parallel shafts and a belt wrapped around both pulleys, and the gear ratio is continuously changed by changing the diameter of the pulley that the belt comes into contact with. Others use friction disks or conical pulleys. This type of device is used as a continuously variable transmission section in this application.

A transmission mechanism using this typical continuously variable transmission as a variable ratio belt drive means is disclosed in Japanese Patent Laid-Open No. 57-29845. The disclosed transmission mechanism includes a pair of interconnected simple planetary gear means, one of which is continuously drivingly connected in one member to a variable ratio belt drive means, which provides a continuously variable range of transmission ratios. is only the width of the gear ratio of the variable ratio belt drive means.

[Problems to be solved by the invention] In conventional continuously variable transmissions, the width of the gear ratio is determined by the effective dimensions of the main elements that make up the continuously variable transmission, such as the variable pulley, friction disk, and conical pulley. It is not possible to widen the range of the gear ratio beyond the specified dimensions. Increasing the range of gear ratios inevitably increases the dimensions of the main elements of the continuously variable transmission. In order to overcome this drawback, the inventor of the present invention disclosed in Japanese Patent Application No. 58-038235, which is an earlier application of this application, a continuously variable transmission in which the width of the gear ratio is widened while keeping the dimensions of the main elements unchanged. The present invention has been made to further improve the transmission, and its purpose is to provide a continuously variable transmission that has a wider range of gear ratios and is smaller in size while keeping the effective dimensions of the main elements unchanged.

[Technical means for solving the problem] In order to achieve the above object, the present invention includes a continuously variable transmission section, a power transmission section, and a power division section between parallel input shafts and output shafts. In a continuously variable transmission,
The continuously variable transmission section, the drive side of the power transmission section, and the power division section are disposed on the input axis connected to an engine mounted on a front-wheel drive vehicle or a four-wheel drive vehicle, and the drive side of the power transmission section and the power division section are disposed on the output axis. The continuously variable transmission section and the driven side of the power transmission section are arranged, and the power division 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 on the drive side of the power transmission section. The ring gears are connected to the input shaft on the drive side of the step-change transmission section, and the driven sides of the step-change transmission section and the power transmission section are connected to the output shaft, and the input shaft and the step-less The drive side of the transmission section, the drive side of the power transmission section, and the power division section are arranged in this order.

In addition to the variable pulley type, a device that achieves the same purpose depending on the purpose is used in the continuously variable transmission section.
The power transmission unit is a gear, chain, belt, or other device that can transmit power. It is desirable that the power transmission section transmits torque to the output shaft at a gear ratio of 1 or more. Furthermore, although a planetary gear device having the above-mentioned functions is optimal for the power dividing section, other known devices may be used.

[Operation] Torque T ₁ is transmitted from the power source to the power dividing section via an input shaft coaxially engaged with the drive section and the power transmission section of the continuously variable transmission section. If the gear ratio of the power split section is ρ, then the torque T ₁ at the power split section is T ₂ =
(1+ρ)T ₁ and T ₃ = −ρT ₁ . torque
T ₂ is transmitted to the drive unit of the continuously variable transmission via the first distributed torque output shaft of the power dividing unit, and 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 section.
On the other hand, the torque _T3 distributed by the power dividing section is transmitted to the power transmitting section disposed between the continuously variable transmission section and the power dividing section via the second distributed torque output shaft of the power dividing section. When the gear ratio of the power transmission section is ρ ₂ , a torque of −ρ ₁ ρ ₂ T ₁ is transmitted to the output shaft. The total torque T ₀ of the output shaft is {(1+ρ)ρ ₁ T ₁ −ρρ ₂ T ₁ }
becomes. Since the gear ratio is T ₁ /T ₀ , {(1+ρ)
ρ ₁ −ρρ ₂ ).

Since the gear ratio _ρ1 of the continuously variable transmission is variable, if the maximum gear ratio is ρmax and the minimum gear ratio is ρmin, the width of the gear ratio of the continuously variable transmission is ρmax/ρmin, and the gear ratio of the continuously variable transmission is ρmax/ρmin. The width of the ratio is {(1+ρ)ρmax−
ρρ ₂ }/{(1+ρ) ρmin−ρρ ₂ }.

[Examples] Examples of the present invention will be specifically described below with reference to the drawings. Figure 1 shows the continuously variable transmission of the present invention in a vehicle.
This is particularly an example of use in automobiles. A crankshaft 1 of an engine, which is a power source, is connected to an input shaft 4 of a continuously variable transmission 3 via a clutch 2. The continuously variable transmission 3 includes a continuously variable transmission section A, a power transmission section B, and a power division section C arranged and configured in this order along the input shaft 4.

The continuously variable transmission section A is of a variable pulley type, with a drive section 5 located on the input shaft 4 side, and a driven section 6 fixed to an output shaft 7 parallel to the input shaft 4. The driving part 5 and the driven part 6 are configured so that the diameters with which the belt 10 contacts can be changed by servo pistons 8 and 9.

The power transmission section B is located between the continuously variable transmission section A and the power division section C, and is composed of a drive gear 11, an idler gear 12, and a driven gear 13. The drive gear 11 is connected to a member constituting the power splitting section C, and the driven gear 13 is fixed to the output shaft 7. The gear ratio of this power transmission section B is 1
It is desirable to take more than that.

The power dividing section C is composed of a planetary gear device, and includes a ring gear 14 connected to the input shaft 4, a pinion 15 that meshes with the ring gear 14, a carrier 16 that supports the pinion 15, and a sun gear 17 that is arranged at the center and meshes with the pinion 15. configured. The input shaft 4 is concentrically engaged with the drive section 5 and the drive gear 11, and is connected to a ring gear 14. The carrier 16 is formed into a cylindrical shape, and is connected to the drive unit 5 by passing through the drive gear 11 . The sun gear 17 is connected to the drive 11 by a cylindrical member that surrounds the power splitting portion C.

Three planetary gear devices D, E, F and a differential gear G are arranged on the output shaft 7 following the driven part 6. The first planetary gear set D is equipped with a brake 18 for overdrive and a clutch 19 for low and high speeds. The last planetary gear device F is equipped with a reverse brake 20.

The power transmission section can be constructed of a chain device as shown in FIG. Drive side sprocket 21
is concentrically engaged with the input shaft 4 and connected to the sun gear 17 of the power splitting section C. The driven side sprocket 22 is fixed to the output shaft 7. A chain 23 is wound between the sprockets 21 and 22.

In FIG. 1, power from an engine, which is a power source, is converted into rotational force by a crankshaft 1.
The rotational force (torque T ₁ ) of the crankshaft 1 is transmitted to the input shaft 4 via the clutch 2. This torque
T ₁ is distributed by the power division section C to the drive section 5 of the continuously variable transmission section A and the drive gear 11 of the power transmission section B into torques T ₂ and T ₃ . The gear ratio of the ring gear 14 and sun gear 17 of the power splitter C is ρ
Assuming that, a torque T ₂ of (1+ρ)T ₁ is applied to the drive unit 5 via the carrier 16, and a torque _{T 3 of} -ρT 1 is applied to the drive gear 11 via the sun gear 17.
will be distributed.

Torque T ₂ of the drive unit 5 is transmitted to the driven unit 6 via the belt 10 at a gear ratio ρ ₁ . The gear ratio ρ ₁ can be changed using servo pistons 8 and 9. The torque T ₀ appearing on the output shaft 7 is {(1+ρ)T ₁ ρ ₁ }. Torque T ₃ distributed to the drive gear 11 of the power transmission section B is transmitted to the output shaft 7 via the idler gear 12. When the gear ratio of the power transmission section B is ρ ₂ , a torque of T ₀ ={−ρT ₁ ρ ₂ } is transmitted to the output shaft 7. Total torque appearing on output shaft 7
T ₀ becomes {(1+ρ)T ₁ ρ ₁ −ρT ₁ ρ ₂ }. Since the gear ratio is expressed as T ₁ /T ₀ , this continuously variable transmission 3
The gear ratio is {(1+ρ)ρ ₁ −ρρ ₂ }. Here, if the minimum gear ratio of the continuously variable transmission part A is ρmax and the minimum gear ratio is ρmin, the width of the gear ratio of the continuously variable transmission part A is ρmax/ρmin, and the continuously variable transmission 3 corresponding to this becomes ρmax/ρmin.
The width of the gear ratio is {(1+ρ)ρmax−ρρ ₂ }/{(1
+ρ)ρmin− _ρρ2 }. This width is larger than the width of the gear ratio of the continuously variable transmission section A. In addition, the sun gear 14 of the power splitting part C has ρ ₂ n when the output shaft has n rotations.
Rotate.

The coupling torque T ₀ of the output shaft 7 is the planetary gear device F
When the brake 20 is not acting, it acts as a forward, and when the clutch 19 of the planetary gear set D is engaged in this state, the brake 1 is in the low-high speed region.
8 is activated, it is transmitted to the differential gear G as an overdrive.

FIG. 3 is a diagram showing the layout inside the engine room when the continuously variable transmission according to the present invention is applied as a transmission of an automobile, in which the continuously variable transmission 30 is disposed on the side of the engine 20.
It is possible to arrange the output side 30B in the almost central part of the vehicle interior with respect to the input shaft 30A, and as a result,
The lengths d1 and d2 of the drive shafts 33 and 34 connected to the left and right wheels 31 and 32 can be approximately equal.

[Effect] As explained above, according to the present invention, the width of the gear ratio of the continuously variable transmission can be made larger than the width of the continuously variable transmission section, and the power transmission section is connected to the continuously variable transmission section and the power transmission section. Since it is located in the middle of the divided parts, the entire device can be made compact and lightweight. When this continuously variable transmission is applied as an automobile transmission, the degree of freedom in layout within the engine room will increase, and weight reduction can be expected to improve fuel efficiency and acceleration, and the amount of oil in the transmission case will increase. It is possible to reduce the torque stemmer and make the drive shafts almost equal.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing one embodiment of the invention, Fig. 2 is a schematic diagram showing another embodiment of the invention, and Fig. 3 is a schematic diagram showing another embodiment of the invention.
The figure is an explanatory diagram showing the layout inside the engine room when the present invention is applied as a transmission of an automobile. A...Continuously variable transmission section, B...Power transmission section, C...
Power division section, 4... Input shaft, 5... Drive section, 6...
...Followed part, 7...Output shaft, 10...Belt, 11
... Drive gear, 12 ... Idler gear, 13
...Driven gear, 14...Ring gear, 15...
...pinion, 16...carrier, 17...sun gear, 21, 22...sprocket, 23...chain.

Claims (1)

[Scope of utility model registration request] A continuously variable transmission that includes a continuously variable transmission section, a power transmission section, and a power division section between parallel input shafts and output shafts, and is connected to an engine mounted on a front-wheel drive vehicle or a four-wheel drive vehicle. The continuously variable transmission section and the drive side of the power transmission section and the power division section are disposed on the input axis, and the continuously variable transmission section and the driven side of the power transmission section are disposed on the output axis. , the power dividing 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, the carrier is on the drive side of the continuously variable transmission section, and the ring gear is on the input shaft, and the driven sides of the continuously variable transmission section and the power transmission section are connected to the output shaft, and the input shaft, the drive side of the continuously variable transmission section, the drive side of the power transmission section, and the power division A continuously variable transmission characterized in that parts are arranged in order.