JP6533084B2 - Power split type continuously variable transmission - Google Patents

Description

The present invention relates to a power split continuously variable transmission employed in a motor vehicle, and more particularly, to improvement of a reduction gear ratio at reverse.

A power split type continuously variable transmission for an automobile includes a continuously variable transmission mechanism, a constant transmission mechanism, and a planetary gear type synthesis mechanism that synthesizes the power transmitted from both mechanisms, and the power is the continuously variable transmission. Switching to the power split mode in which the power is split and transmitted to the continuously variable transmission mechanism and the constant transmission mechanism and is combined by the combining mechanism and transmitted to the drive wheels It is comprised possible (for example, refer patent document 1).

JP, 2015-10645, A

By the way, in the above-mentioned power split type conventional device, various configurations are adopted to realize the reverse drive mode. For example, the apparatus shown in FIG. 4 includes a CVT (continuously variable transmission mechanism) 20, a constant transmission mechanism 30 including a planetary gear mechanism 120, and a combining mechanism 40 of a planetary gear type, and constant in the reverse drive mode. By fixing the fixed transmission gear 130 connected to the sun gear 120a of the transmission mechanism 30 with the reverse brake B2, the composite carrier 40c of the combining mechanism 40 is fixed, and the ring gear 40d is reversely rotated by forward rotation from the CVT 20. (See the straight line A indicated by a broken line in FIG. 3).

However, when the ring gear 40d is configured to be reversely rotated by fixing the synthetic carrier 40c of the planetary gear type synthesis mechanism 40, the lowest gear ratio at reverse is the ring gear and the sun gear as compared with the lowest gear ratio γmax at forward. The gear ratio is further lowered by the ratio of the number of gear teeth, the reverse rotation speed decreases, and the reverse torque becomes excessive.

In order to avoid this problem, there is a method of shifting the CVT 20 to the high side during reverse. However, for this purpose, CVT pulley shift control and reverse brake braking will be simultaneously executed in an idle state with a low engine speed, and the required pump displacement will increase, resulting in an increase in loss torque and vehicle weight. The problem arises.

The present invention has been made in view of the above-mentioned conventional situation, and it is possible to suppress a power split type continuously variable transmission which can suppress that the lowest gear ratio at the time of reverse traveling becomes excessively lower than the lowest gear ratio at the time of forward traveling. It is an issue to provide.

The present invention comprises a continuously variable transmission mechanism, a constant transmission mechanism, a planetary gear type combining mechanism that combines the outputs of both transmission mechanisms, and a wheel drive mechanism that transmits power from the combining mechanism to the drive wheels. Switchable between a continuously variable transmission mode in which power is transmitted only to the continuously variable transmission mechanism and a power split mode in which the power is divided and transmitted to both the continuously variable transmission mechanism and the constant transmission mechanism In the configured power split type continuously variable transmission,
The synthesis mechanism includes a ring gear, wherein a sun gear fixed to the output shaft of the continuously variable transmission mechanism, a carrier for supporting the pinion Oh Ngiya meshing with said sun gear, is coupled to the wheel drive mechanism while meshed with the pinion has the door, the fixed speed change mechanism includes a fixed speed ratio drive gear which is connected to the input shaft to the power split mode, it meshed through a fixed speed ratio idler gear to the fixed speed ratio drive gear, formed on the carrier and a fixed speed ratio driven gear has a reverse drive gear that is connected to the input shaft upon reverse, a reverse idler gear meshing with the rear advancing drive gear, said predetermined speed change idler gear while meshing with the rear proceeds idler gear is fixed And a reverse driven mechanism having a reverse driven gear fixed to the idler shaft.

  According to the first aspect of the invention, during reverse, in the combining mechanism, the sun gear fixed to the output shaft of the continuously variable transmission mechanism rotates forward according to the lowest speed ratio of the continuously variable transmission mechanism. On the other hand, in the reverse drive mechanism, the reverse driven gear rotates forward through the reverse idler gear by the forward rotation of the reverse drive gear, whereby the constant-speed idler gear reversely rotates the carrier. As a result, the ring gear is reversely rotated via the pinin gear pivotally supported by the carrier, the wheels are reversely rotated via the rear wheel drive mechanism, and the vehicle reverses.

As described above, at the time of reverse travel, in the combining mechanism, the carrier is reversely rotated with respect to the forward rotation of the sun gear, so the output rotation number (ring gear rotation number) becomes higher than when the carrier is fixed. As a result, the lowest gear ratio at reverse is higher than when the carrier is fixed, and the reverse rotation speed is increased to prevent the reverse torque from becoming excessive.

BRIEF DESCRIPTION OF THE DRAWINGS It is a skeleton block diagram of the power split-type continuously variable transmission which concerns on Example 1 of this invention. It is a figure which shows each mode of the said continuously variable transmission, and each brake and the working state of a clutch at the time of reverse gear. It is an alignment chart which shows the rotational speed of the sun gear of the synthetic | combination mechanism at the time of reverse movement of the said stepless transmission, carrier, and a ring gear. It is a skeleton block diagram of the conventional power split type continuously variable transmission.

Hereinafter, embodiments of the present invention will be described with reference to the attached drawings.

1 to 3 are views for explaining a power split-type continuously variable transmission according to a first embodiment of the present invention.

In the figure, reference numeral 1 denotes a power split type continuously variable transmission for an automobile. The continuously variable transmission 1 comprises a CVT (continuously variable transmission mechanism) 2 that shifts and outputs engine rotation at a stepless ratio, a constant transmission mechanism 3 that shifts and outputs engine rotation at a constant ratio, the CVT 2 and A planetary gear type combining mechanism 4 which combines and outputs the output from the constant speed change mechanism 3, a reverse movement mechanism 5 which reversely rotates the engine and transmits it to the combining mechanism 4 via the constant speed change mechanism 3; And a wheel drive mechanism 6 for transmitting the output from the combining mechanism 4 to the drive wheels.

The CVT 2 has a structure in which a metal belt 11 is wound around a primary shaft 7 and a primary pulley 9 fixed to a secondary shaft 8 and a secondary pulley 10 fixed in parallel to each other. By changing the belt winding diameter, the input rotation is shifted from the lowest speed ratio (γmax) to the highest speed ratio (γmin). The primary shaft 7 is connected to an input shaft 17 connected to a torque converter (not shown).

The CVT 2 has, for example, the lowest gear ratio γmax when the primary pulley 9 has the smallest diameter and the secondary pulley 10 has the largest diameter, and conversely, the highest gear ratio when the primary pulley 9 has the largest diameter and the secondary pulley 10 has the smallest diameter. It becomes γmin.

The constant transmission mechanism 3 meshes with a constant transmission planetary gear mechanism 12 disposed on the input shaft 7, a constant transmission drive gear 13 fixed to a sun gear 12 a of the mechanism 12, and the drive gear 13. It has a constant-speed idler gear 14 and a constant-speed driven gear 4e formed on a composite carrier 4c described later. The constant-speed idler gear 14 is fixed to a constant-speed idler shaft 15 axially supported by the transmission case.

The constant-speed planetary gear mechanism 12 supports a sun gear 12a axially supported by the input shaft 17, an idler gear 12b meshed with the sun gear 12a, a carrier 12c fixed to the input shaft 17, and the idler gear 12b. And a split brake B1 formed to be capable of braking the ring gear 12d.

Here, the transmission ratio of the constant transmission mechanism 3 is set to the same value as the highest transmission ratio γmin of the CVT 2. The constant-speed idler gear 14 does not contribute to the transmission ratio.

The combining mechanism 4 supports a combining sun gear 4a fixed to the secondary shaft 8 and a plurality of combining idler gears 4b meshing with the combining sun gear 4a, and a combining carrier 4c supported by the secondary 8; And a synthetic ring gear 4d engaged with the idler gear 4b. The constant speed driven gear 4e is formed to rotate with the synthetic carrier 4c.

Further, a forward clutch C2 is formed between the combined ring gear 4d and the secondary shaft 8. The wheel drive mechanism 6, which directly connects the secondary shaft 8 and the output shaft 6a connected to the combined ring gear 4d when the forward clutch C2 is turned on, includes an output gear 6b fixed to the output shaft 6a. It has an output idler gear 6c meshing with the output gear 6b, and a differential drive gear 6e fixed to the output idler shaft 6d to which the output idler gear 6c is fixed and meshing with the ring gear 16a of the differential mechanism 16.

The reverse drive mechanism 5 includes a reverse drive gear 5a configured to be connectable to the input shaft 17 via a reverse clutch C1, a reverse idler gear 5b meshing with the reverse drive gear 5a, and a reverse gear meshing with the reverse idler gear 5b. And a driven gear 5c. The reverse driven gear 5 c is fixed to the constant speed shift idler shaft 15.

In the first embodiment, the engine rotation is transmitted to both the CVT 2 and the constant transmission mechanism 3, and the engine rotation is transmitted to both the CVT 2 and the constant transmission mechanism 3. It is configured to be switchable to the power split mode transmitted to the drive wheel.

In the continuously variable transmission mode, the reverse clutch C1 of the reverse mechanism 5 and the split brake B1 of the constant speed planetary gear mechanism 12 are turned off (released), and the forward clutch C2 of the combining mechanism 4 is turned on (engaged).

Then, since the reverse rotation clutch C1 and the split brake B1 are both off, the engine rotation is not transmitted to the reverse rotation mechanism 5 and the constant speed change mechanism 3 but is transmitted only to the CVT 2 and is shifted by the CVT 2 at a predetermined gear ratio. , And transmitted to the output shaft 8. Then, the rotation of the output shaft 8 is transmitted to the output shaft 6a of the wheel drive mechanism 6 via the forward clutch C2 that is turned on, and transmitted to the drive wheels via the differential mechanism 16 from there to drive the vehicle forward. .

When the CVT 2 reaches the highest gear ratio γmin, the mode is switched to the power split mode. In this case, the reverse clutch C1 of the reverse mechanism 5 and the forward clutch C2 of the combining mechanism 4 are turned off (released), and the split brake B1 of the constant speed planetary gear mechanism 12 is turned on (braking).

In this power split mode, the rotation transmitted to the CVT 2 is shifted by the CVT 2 at the highest gear ratio γmin, transmitted to the output shaft 8, and causes the synthetic sun gear 4a to rotate. On the other hand, since the split brake B1 fixes the ring gear 12d, the sun gear 12b is rotated forward via the pinion gear 12b by the rotation transmitted to the carrier 12c of the constant speed change mechanism 3.

This rotation causes the composite carrier 4c to rotate forward via the constant transmission drive gear 13 and the constant transmission idler gear 14. Since the transmission gear ratio of the constant transmission mechanism 3 is the same as the highest transmission gear ratio γmin of the CVT 2, the rotations of the synthetic carrier 4c, the synthetic sun gear 4a and the synthetic ring gear 4d and hence the output shaft 6a become the same. In this state, when the transmission ratio of the CVT 2 is changed to the low side, the rotation of the combined ring gear 4 d and hence the output shaft 6 a is increased. That is, in the power split type continuously variable transmission 1 according to the present embodiment, the transmission ratio width can be expanded.

  Then, during reverse, the reverse clutch C1 is turned on, and the split brake B1 and the forward clutch C2 are turned off. At this time, the CVT 2 is in the lowest gear ratio state, and the engine rotation is decelerated at the lowest gear ratio by the CVT 2 and transmitted from the output shaft 8 to the synthetic sun gear 4 a. The engine rotation rotates the composite carrier 4c in the reverse direction via the reverse drive clutch C1, the reverse drive gear 5a, the reverse idler gear 5b, the reverse driven gear 5c, the constant speed change idler gear 14 and the constant speed driven gear 4e. As a result, the synthetic ring gear 4d and hence the output shaft 6a of the wheel drive mechanism 6 rotate in the reverse direction.

As described above, in the present embodiment, since the synthetic carrier 4c is reversely rotated, the transmission gear ratio of the synthetic mechanism 4 becomes larger as compared with the case where the carrier is not rotated (indicated by the dashed straight line A in FIG. 3). The ring gear 4d is accelerated (indicated by a solid line B in FIG. 3), the reverse torque is reduced, the reverse operation can be made gentle, and the safety can be improved.

Here, it is conceivable to shift the CVT to the high side at the time of reverse travel in order to avoid that the gear ratio at the time of reverse travel becomes excessively low while the carrier of the planetary gear mechanism is fixed. However, in order to do this, it is necessary to increase the pump displacement to simultaneously enable CVT shift and reverse brake braking in an idle state with low engine speed when switching the shift lever to reverse. It is feared that the loss torque increases, the vehicle weight and cost increase. Such a problem can be avoided in the present embodiment.

  In the embodiment described above, the case where the continuously variable transmission mechanism is a CVT and the constant transmission mechanism is a planetary gear mechanism has been described. However, the continuously variable transmission mechanism and the constant transmission mechanism of the present invention It is not limited. For example, the continuously variable transmission mechanism may of course be a toroidal system or a hydraulic system.

1 Power split type continuously variable transmission 2 CVT (continuously variable transmission mechanism)
3 constant speed change mechanism 4 synthetic mechanism 4a synthetic sun gear 4b synthetic pinin gear 4c synthetic carrier 4d synthetic ring gear 4e constant speed transmission driven gear 5 reverse mechanism 5a reverse drive gear 5b reverse idler gear 5c reverse driven gear 6 wheel drive mechanism 7 primary shaft (input shaft)
8 Secondary axis (output axis)
13 constant speed drive gear 14 constant speed idler gear 15 idler shaft

Claims (1)

A continuously variable transmission mechanism, a constant transmission mechanism, a planetary gear type combining mechanism that combines outputs of the both transmission mechanisms, and a wheel drive mechanism that transmits power from the combining mechanism to drive wheels,
It is configured to be switchable between a continuously variable transmission mode in which power is transmitted only to the continuously variable transmission mechanism and a power split mode in which the power is divided and transmitted to both the continuously variable transmission mechanism and a constant transmission mechanism. Power split type continuously variable transmission,
The synthesis mechanism includes a ring gear, wherein a sun gear fixed to the output shaft of the continuously variable transmission mechanism, a carrier for supporting the pinion Oh Ngiya meshing with said sun gear, is coupled to the wheel drive mechanism while meshed with the pinion Have and
The certain speed change mechanism includes a fixed speed ratio drive gear which is connected to the input shaft to the power split mode, the fixed speed ratio engaged through a fixed speed ratio idler gear to the drive gear, the fixed speed ratio driven gear formed on the carrier Have and
A reverse drive gear that is connected to the input shaft upon reverse, a reverse idler gear meshing with the rear advancing drive gear, the reverse driven gear is the fixed speed change idler gear while meshing with the rear proceeds idler gear fixed to the idler shaft fixed What is claimed is: 1. A power split type continuously variable transmission, comprising: a reverse gear mechanism having:

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