JP2000193077A - Shift control device for continuously variable transmission in infinite change gear ratio - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly operate the manual mode of a continuously variable transmission in infinite change gear ratio by preventing the increase of the size of a transmission. SOLUTION: By switching a coupling mode and a power circulation mode, a change gear ratio is continuously varied from a neutral position, where a unit change gear ratio is rendered infinite, to a forward direction or a backward direction. When an automatic shift mode and a manual mode are provided, one of the steps of the manual mode is set to a rotation synchronous point, at which a unit change gear ratio coincides with the same continuously variable transmission change gear ratio, in a direct coupling mode and a power circulation mode. In any shift direction of up shift and down shift, the shift step is set to the rotation synchronous point without fail. During setting of this shift step, engagement and disengagement between a direct coupling mode clutch and a power circulation mode clutch are executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a control device for a continuously variable transmission with an infinite transmission ratio employed in a vehicle or the like.

[0002]

2. Description of the Related Art A belt-type or toroidal-type continuously variable transmission is conventionally known as a vehicle transmission. In order to further expand the shift range of such a continuously variable transmission, a continuously variable transmission is known. There is known a continuously variable transmission having an infinitely variable transmission ratio, which is capable of controlling the transmission ratio to infinity by combining a constant transmission and a planetary gear mechanism. For example, Japanese Unexamined Patent Publication No. 9-210175 proposed by the present applicant and so on.

[0003] This is a planetary gear mechanism in which a continuously variable transmission and a constant transmission (reduction gear) are connected in parallel to a unit input shaft connected to an engine, and their outputs are arranged on a unit output shaft. The output side of the continuously variable transmission is connected to the sun gear of the planetary gear mechanism via the continuously variable transmission output gear train, and the output shaft of the constant transmission is connected to the carrier of the planetary gear mechanism via the power circulation mode clutch. Respectively.

The output shaft of the continuously variable transmission connected to the sun gear is connected to a unit output shaft which is the output shaft of an infinitely variable speed ratio transmission via a direct connection mode clutch.
The ring gear of the planetary gear mechanism is also coupled to the unit output shaft.

In such a continuously variable transmission with an infinite transmission ratio,
As shown in FIG. 4, while the power-circulation mode clutch is connected and the direct-connection mode clutch is disconnected, the unit speed ratio ii (IVT in the diagram) is changed according to the speed ratio difference between the continuously variable transmission and the fixed transmission. From the negative value to the positive value, the unit input shaft rotation speed / unit output shaft rotation speed is infinite (=
(A geared neutral point GNP) and a power circulating mode in which gear shifting control is continuously performed, and a power circulating mode clutch is disengaged, while a direct connection mode clutch is connected to perform gear shifting control in accordance with the gear ratio ic of the continuously variable transmission. The direct connection mode to be performed can be selectively used.

A control device for a continuously variable transmission used in a vehicle includes an automatic transmission mode in which a target transmission ratio is determined in accordance with a vehicle speed and an operation amount of an accelerator pedal, as well as a conventional manual transmission. In addition, there is known a device provided with a manual mode in which an arbitrary shift speed can be set. For example, there is Japanese Patent Application Laid-Open No. Hei 9-196165 proposed by the present applicant.

This is a manual mode in which the speed ratio of the continuously variable transmission is set to an arbitrary speed by operating the shift lever to an upshift or downshift position. Regardless of the amount, the driver can select a desired gear ratio (gear position).

[0008]

However, when the manual mode is added to the conventional infinitely variable speed ratio transmission, the switching between the power circulation mode and the direct connection mode is performed at the rotation synchronization point shown in FIG. When the unit speed ratio ii passes through the rotation synchronization point, it is necessary to quickly engage and disengage the power circulation mode clutch and the direct connection mode clutch. It is necessary to secure the capacity and durability of the clutch in order to perform the engagement and the release of the clutch, and there is a problem that the size of the transmission is increased and the mountability to the vehicle is impaired.

In addition, the engagement and disengagement of the power circulation mode clutch and the direct connection mode clutch at the rotation synchronization point are as follows.
There has been a problem that the shift control has to be performed quickly and smoothly, and the shift control becomes complicated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and prevents the transmission from being enlarged, smoothly operates the manual mode of the infinitely variable transmission, and complicates the control. To suppress.

[0011]

According to a first aspect of the present invention, a continuously variable transmission capable of continuously changing a gear ratio and a constant transmission are connected to a unit input shaft, respectively. Infinite speed ratio continuously variable transmission in which the output shaft of the machine is connected to the unit output shaft via a planetary gear mechanism, a power circulation mode clutch and a direct connection mode clutch, and power circulation by controlling the power circulation mode clutch and the direct connection mode clutch The speed change control means, which switches between the mode and the direct connection mode and controls the speed ratio of the continuously variable transmission to set the unit speed ratio of the continuously variable transmission is infinite, according to the driving state of the vehicle. Based on first target gear ratio setting means for setting the unit gear ratio of the large continuously variable transmission and gear shift command means operated by the driver, the unit of the infinitely variable gear ratio continuously variable transmission is controlled. A second target gear ratio setting means for setting to one of a plurality of gear stages set the gear ratio previously,
Shift mode switching means for selectively switching between the first target gear ratio setting means and the second target gear ratio setting means,
The second target gear ratio setting means sets a gear position at a rotational synchronization point between the power circulation mode and the direct connection mode.

According to a second aspect of the present invention, in the first aspect, the second target speed ratio setting means sets at least the speed ratio of the continuously variable transmission at each forward speed to be different from each other. Set.

In a third aspect based on the first aspect, the second target speed ratio setting means continuously changes the speed ratio from the neutral position in the forward first speed and the reverse first speed. Change.

In a fourth aspect based on the third aspect, the second target gear ratio setting means sets the gear position set at the rotation synchronization point of the power circulation mode and the direct connection mode to a second speed or higher. I do.

[0015]

According to the first invention, in the continuously variable transmission with infinite transmission ratio, the direct connection mode in which the unit transmission ratio is in accordance with the transmission ratio of the continuously variable transmission, and the transmission between the continuously variable transmission and the fixed transmission are performed. By switching the power circulation mode in which the unit gear ratio according to the difference in the ratio is changed, the gear ratio is continuously changed in the forward or backward direction from the neutral position where the unit gear ratio is infinite,
First target gear ratio setting means for automatically setting a unit gear ratio in accordance with an operation state (hereinafter referred to as an automatic gear mode)
And a second target gear ratio setting means (hereinafter referred to as a manual mode) for setting a unit gear ratio at an arbitrary gear position set by the driver, one of the manual mode gear positions is a direct connection mode. And in power circulation mode,
The rotation speed is set to the rotation synchronization point at which the unit speed ratio matches the same continuously variable transmission speed ratio, and is always set to this rotation synchronization point in both upshift and downshift speed directions. By engaging and disengaging the direct connection mode clutch and the power circulation mode clutch during the setting, the durability of each clutch can be easily secured and the size can be prevented, and the control contents can be simplified, and the control contents can be simplified. , And at the same time, the manufacturing cost can be reduced by simplifying the control.

According to a second aspect of the present invention, the second target gear ratio setting means for setting the gear position in the manual mode includes a gear ratio of the continuously variable transmission corresponding to each gear position at least on the forward side used for normal traveling. Are set to be different from each other to prevent the same gear ratio from being used in the power circulation mode and the direct connection mode, and the rotating element of the continuously variable transmission configured by a toroidal or V-belt type, It is possible to prevent an increase in wear at a specific gear ratio, thereby ensuring durability.

According to a third aspect of the invention, in the manual mode, in the first speed on the forward side and the first speed on the reverse side, the speed ratio is continuously changed from the neutral position to smoothly start from the neutral position. It is possible to do.

According to a fourth aspect of the present invention, in the manual mode, the gear position set at the rotation synchronization point of the power circulation mode and the direct connection mode is set to the second speed or higher, so that the first position is shifted from the neutral position to the first position by the power circulation mode. The region where the gear ratio is continuously changed up to the speed can be reduced to improve the fuel efficiency of the vehicle.

[0019]

An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIGS. 1 and 2 show an example in which the present invention is applied to an infinitely variable speed ratio transmission using a toroidal type continuously variable transmission.

As shown in FIGS. 1 and 2, the continuously variable transmission 50 has an infinitely variable speed ratio, which is provided on a unit input shaft 1 a or 1 b connected to a crankshaft of the engine 13. The step transmission 2 and a constant transmission 3 (reduction gear) composed of gears 3a and 3b are connected in parallel, and their output shafts 4 and 3c are arranged coaxially with the unit output shaft 6. The output shaft 4 of the continuously variable transmission 2 is connected to a sun gear 5a of the planetary gear mechanism 5, and the output shaft 3c of the constant transmission 3 is connected to the planetary gear mechanism via a power circulation mode clutch 9. 5 carrier 5b.

The continuously variable transmission output shaft 4 connected to the sun gear 5a receives the driving force of the continuously variable transmission 2 from the sprocket 4a and the chain 40 and receives the infinitely variable transmission 50 through the direct connection mode clutch 10. The ring gear 5c is also connected to the unit output shaft 6, while the ring gear 5c is connected to the unit output shaft 6.

A transmission output gear 7 is provided on the right side of the unit output shaft 6 in the drawing, and the transmission output gear 7 meshes with the final gear 12 of the differential gear 8 and is connected to the drive shaft 11 a connected to the differential gear 8. , 11b
The driving force is transmitted at a predetermined total reduction ratio.

As shown in FIG. 1, the continuously variable transmission 2 is a double-cavity half-toroidal type that sandwiches and presses the power rollers 20, 20 with two sets of input disks 21 and output disks 22, respectively. The output sprocket 2a interposed between the pair of output discs 22 is formed on the continuously variable transmission output shaft 4 of the unit output shaft 6 arranged in parallel with the unit input shafts 1a and 1b via the chain 40. Connects to sprocket 4a.

The unit input shafts 1a and 1b are arranged coaxially and connected in the rotational direction via a loading cam device (not shown). And forms a gear 3a of the fixed transmission 3, and the unit input shaft 1b is connected to two sets of input disks 21, 2
The power rollers 20, 20 are pinched and pressed between the input and output disks by the axial pressing force generated by the loading cam device in accordance with the input torque from the unit input shaft 1a.

In the continuously variable transmission 50 with infinite transmission ratio, the power circulation mode clutch 9 is disengaged, while the direct connection mode clutch 10 is engaged to change the transmission ratio ic of the continuously variable transmission 2 (hereinafter referred to as CVT ratio ic). ) According to the difference between the gear ratios of the continuously variable transmission 2 and the fixed transmission 3 by disengaging the direct coupling mode clutch 10 while engaging the power circulation mode clutch 9 and transmitting the driving force in accordance with the transmission ratio. Thus, the unit speed ratio ii (the speed ratio between the unit input shaft 1a and the unit output shaft 6) of the entire continuously variable transmission is controlled almost continuously from a negative value to a positive value including infinity. The power circulation mode to be performed can be selectively used.

The speed change control is performed by a speed change controller 14 mainly composed of a microcomputer as shown in FIG. 2, and the speed change controller 14 sets an automatic speed change to a unit speed ratio ii according to an operation state. A mode and a manual mode for setting a preset gear position according to the shift lever 18 operated by the driver are provided.

For this reason, the transmission control controller 14
The shift position POS set by the driver is read from the select switch 17 corresponding to the shift lever 18, and
When the shift position POS is in the “D” range or the “R” range in the drawing, the automatic shift mode is determined, and the accelerator pedal operation amount APS detected by the accelerator opening sensor 15 is determined.
Based on the vehicle speed VSP detected by the vehicle speed sensor 16 and the vehicle speed VSP, the power circulation mode clutch 9 and the direct connection mode clutch 10 are engaged and disengaged so as to attain a predetermined unit speed ratio ii, and the continuously variable transmission according to the map of FIG. 2 CVT
Change the ratio ic.

On the other hand, when the shift lever 18 is
When the shift switch 18 is operated to the manual switch 30 side indicated by "-", the shift control controller 14 determines that the mode is the manual mode, and when the shift lever 18 is operated to "+" of the manual switch 30, an upshift is commanded. On the other hand, when it is also operated to "-", a downshift is instructed, and the gears are sequentially set to a preset gear. The shift operation in this case is called a so-called sequential shift. For example, when upshifting from the first speed to the third speed, the shift lever 18 is operated twice to the “+” side to temporarily shift to the second speed. Later, it will be shifted to third gear.

Here, when the gears in the manual mode are, for example, 5 forward speeds (1st to 5th speed) and 1 reverse speed,
Target unit speed ratio ii and CVT of continuously variable transmission 2
The relationship of the ratio ic is set as in the map shown in FIG.

Now, the unit speed ratio at the first speed is ii.
1, 2nd gear is ii2, 3rd gear is ii3, 4th gear is ii
Assuming that the fourth and fifth speeds are ii5 and the reverse is iiR, the magnitude relation of these unit speed ratios ii is set as ii1>ii2>ii3>ii4>ii5> iiR (negative value). In addition, geared neutral GNP
, The unit speed ratio ii = ∞, and the unit speed ratio ii is at the neutral position.

The CVT ratio ic of the continuously variable transmission 2 corresponding to the unit speed ratio ii of each of these speed stages is ic1 for the first speed, ic2 for the second speed, ic3 for the third speed, and ic3 for the third speed.
Assuming that the fourth speed is ic4, the fifth speed is ic5, the reverse is icR, and the geared neutral point GNP is icN, the setting of the CVT ratio ic is performed as follows.

(1) One of the gear positions is set as the rotation synchronization point. Here, it is assumed that the rotation synchronization point is the second speed.

At the rotation synchronization point, as described above, the power circulation mode clutch 9 and the direct connection mode clutch are engaged and released, and when the gear stage is set so as to pass through this rotation synchronization point, In order to ensure the durability of the clutch, the capacity is increased, and furthermore, it is necessary to perform quick and smooth switching control, so that the control content becomes complicated.

Therefore, by setting the rotation synchronization point to one of the shift speeds, the rotation synchronization point is always set in both the upshift and downshift directions, and the engagement and disengagement of each clutch during the set period is performed. By doing this, the durability of the clutch can be easily ensured to prevent an increase in size, and the control contents can be simplified, so that mountability to the vehicle can be ensured, and at the same time, manufacturing costs can be reduced by simplifying the control. be able to.

In addition, if the gear position set at the rotation synchronization point is set to the direct connection mode, the power circulation mode clutch 9 and the fixed transmission 3 only rotate together. As a result, the power transmission efficiency can be improved as compared with the above, and the fuel efficiency of the vehicle can be reduced.

(2) Each shift speed is set so that the CVT ratios ic do not overlap at least on the forward side. For example, ic2>ic1>ic3>icN>ic4>icR> i
Set to c5.

In a continuously variable transmission with an infinite speed ratio, the speed direction of the continuously variable transmission 2 and the speed direction of the unit speed ratio ii are reversed at the rotation synchronization point, and the CVT ratio ic in the direct connection mode.
Increases, the unit speed ratio ii also increases and L
When the CVT ratio ic decreases on the o side, the unit speed ratio ii also decreases on the Hi side.

On the other hand, in the power circulation mode, when the CVT ratio ic increases on the forward side of the geared neutral point GNP, the unit speed ratio ii decreases and Hi
On the other hand, on the reverse side of the geared neutral point GNP, if the CVT ratio ic increases, the absolute value of the unit speed ratio ii increases and becomes Lo.

Then, the geared neutral point G
If the CVT ratio becomes smaller on the forward side than NP, the unit speed ratio ii becomes larger and becomes Lo side. If the CVT ratio becomes smaller on the reverse side than the geared neutral point GNP, the absolute value of the unit speed ratio ii becomes smaller. Becomes smaller and becomes Hi side in retreat.

That is, two unit speed ratios ii of the direct connection mode and the power circulation mode can be set at the same CVT ratio ic.

Here, the same CVT ratio ic on the forward side where the sign of the unit speed ratio ii used for normal running is positive.
In the toroidal type continuously variable transmission 2, the contact radius between the power roller 20 and the input / output disks 21, 22 is the same, and the input / output disks 21, 22 are the same. The wear at a specific turning radius of 22 increases, and the durability of the continuously variable transmission 2 decreases.

Therefore, on the forward side used for normal traveling, by setting the CVT ratios ic of the respective shift speeds to be different as shown in FIG. 3, only the specific turning radii of the input / output disks 21 and 22 are worn. And the durability can be ensured.

The same applies to the case where the V-belt type is employed as the continuously variable transmission 2, whereby the pulley frictionally engaged with the V-belt can be prevented from being worn only at a specific turning radius.

In the reverse position, the time used for normal traveling is extremely smaller than that on the forward side, so that even if the reverse gear and the forward gear are set to the same CVT ratio ic, the endurance position is not changed. Although the effect on the property is small, preferably
CVT set for the reverse and forward gears
The durability of the continuously variable transmission 2 can be improved by changing the ratio ic.

(3) In the first speed and reverse, the vehicle starts smoothly from the geared neutral point GNP.
The T ratio continuously changes from icN corresponding to the geared neutral point GNP to the first speed ic1 or from icN to reverse.

Unlike the conventional automatic transmission, the continuously variable transmission 50 with infinite speed ratio does not have a starting element such as a torque converter and a clutch, so that a geared neutral point GNP at a neutral or parking position is provided.
If the shift is suddenly performed from the CVT ratio icN corresponding to the first speed to ic1 or reverse = icR, problems such as a stall of the engine 13 and a sudden increase in the driving torque to generate a shock occur.

Therefore, the CVT ratio i corresponding to the first forward speed
By setting the cVT and the reverse CVT ratio icR to be continuously changed including the CVT ratio icN corresponding to the geared neutral point GNP, it is possible to prevent a shock at the start and a stall of the engine 13 and prevent the engine 13 from stalling. Can also perform a smooth start.

(4) The rotation synchronization point is set so as to be in the second or higher speed. In other words, at least one shift speed is set in the section from the geared neutral point GNP to the rotation synchronization point.

The section from the geared neutral point GNP to the rotation synchronization point is a region in which the power circulation mode is provided on the forward side. In the power circulation mode, the power circulation mode clutch 9 is engaged so that the speed ratio of the fixed transmission 3 and the continuously variable transmission are obtained. Machine 2 CV
Since the difference of the T ratio ic becomes the unit speed ratio ii, the CVT
The power transmission efficiency is reduced as compared with the direct connection mode in which the ratio ic directly corresponds to the unit speed ratio ii.

Then, the geared neutral point G
When the NP is set in the range of the first speed, as described in (3) above, in order to secure the startability, the shift is continuously performed in a section from the geared neutral point GNP to the rotation synchronization point. Therefore, the entire area of the power circulation mode on the forward side is used, and the fuel efficiency of the vehicle is reduced.

Therefore, as shown in FIG. 3, by setting the second or higher gear at the rotation synchronization point, the shift range of the first gear for continuously shifting is reduced, and the fuel efficiency of the vehicle is improved. Can be improved.

As described above, by setting the gear position in the manual mode, the durability and the mountability to the vehicle can be secured and the control can be performed without increasing the capacity of the power circulation mode clutch 9 and the direct connection mode clutch 10. The simplification makes it possible to add the manual mode to the continuously variable transmission 50 with infinite transmission ratio, thereby improving the drivability of the vehicle including the continuously variable transmission 50 with infinite transmission ratio. It is.

In the above embodiment, the forward side is set to 5
Although an example is shown in which the first speed and the reverse side are configured as the first speed, the forward and reverse sides can be set to any number of gears.

In the above-described embodiment, an example is shown in which the position of the power circulation mode clutch 9 is disposed between the counter gear 3b and the carrier 5b. However, the power circulation mode clutch 9 is moved from the unit input shaft 1a to the unit. Output shaft 6
5, for example, as shown in FIG. 5, between the unit input shaft 1a and the gear 3a of the fixed transmission 3. As shown in FIG. 6, it is interposed in the middle of the continuously variable transmission output shaft 4 connected to the sun gear 5a, or is disposed between the ring gear 5c and the unit output shaft 6 as shown in FIG. These arrangement positions are equivalent to those in the above embodiment.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a continuously variable transmission with an infinite gear ratio showing an embodiment of the present invention.

FIG. 2 is a conceptual diagram of the transmission control device.

FIG. 3 shows a gear position in manual mode and a unit gear ratio i.
It is an example of a map showing the relationship between i and CVT ratio ic.

FIG. 4 shows the unit speed ratio ii and CVT in the automatic speed change mode.
It is an example of a map showing the relationship of the ratio ic.

FIG. 5 is a schematic configuration diagram of an infinitely variable speed ratio continuously variable transmission showing another embodiment.

FIG. 6 is a schematic configuration diagram of a continuously variable transmission with an infinite speed ratio according to another embodiment.

FIG. 7 is a schematic configuration diagram of an infinitely variable speed ratio continuously variable transmission according to another embodiment.

[Explanation of symbols]

 2 Continuously variable transmission 3 Constant transmission 5 Planetary gear mechanism 9 Power circulation mode clutch 10 Direct connection mode clutch 14 Transmission control controller 17 Select switch 30 Manual switch

Claims (4)

[Claims] 1. A continuously variable transmission capable of continuously changing a gear ratio and a constant transmission are respectively connected to a unit input shaft, and an output shaft of the continuously variable transmission and the constant transmission is connected to a planetary gear mechanism and a power source. A continuously variable transmission with an infinite speed ratio connected to a unit output shaft via a circulation mode clutch and a direct connection mode clutch; and a power circulation mode and a direct connection mode controlled by controlling the power circulation mode clutch and the direct connection mode clutch. The speed change control means for setting the unit speed ratio of the continuously variable transmission with an infinitely variable transmission ratio by controlling the speed ratio of the transmission changes the unit speed ratio of the continuously variable transmission with the infinitely variable speed ratio in accordance with the driving state of the vehicle. Based on first target gear ratio setting means to be set and gear shift command means operated by the driver, a plurality of unit gear ratios of a continuously variable transmission with infinite gear ratio are set in advance. A second target gear ratio setting unit for setting one of the gear positions; and a shift mode switching unit for selectively switching between the first target gear ratio setting unit and the second target gear ratio setting unit. 2. The transmission control device for a continuously variable transmission with an infinite transmission ratio, wherein the two target transmission ratio setting means sets a transmission gear at a rotation synchronization point between the power circulation mode and the direct connection mode. 2. The apparatus according to claim 1, wherein the second target gear ratio setting means sets a gear ratio of the continuously variable transmission in each gear at least on the forward side so as to be different from each other. Transmission control device for infinitely variable speed ratio transmission. 3. The system according to claim 1, wherein the second target gear ratio setting means changes the gear ratio continuously from a neutral position at a first speed on a forward side and at a first speed on a reverse side. A shift control device for an infinitely variable speed ratio continuously variable transmission. 4. The transmission according to claim 3, wherein the second target gear ratio setting means sets a gear position set at a rotation synchronization point of the power circulation mode and the direct connection mode to a second speed or higher. Transmission control device for a continuously variable transmission with infinite ratio.