JPS61218441A - Method of changing mode of stepless speed change gear - Google Patents

Abstract

PURPOSE:To reduce the size and weight of a unit by carrying out the change of a mode at the time of changing the mode of a subsidiary speed change gear with steps so as to enable the synchronization of gears in said subsidiary speed change gear with steps by adjusting the speed change ratio of a stepless speed change gear, in a stepless speed change gear to which said subsidiary speed change gear with steps is added. CONSTITUTION:A stepless speed change gear 3 is installed in alignment to the output shaft 1a of an engine 1 and a subsidiary speed change gear 2 with steps is installed in alignment to the output shaft of the stepless speed change gear 3. the fuel regulator 1b of the engine 1 is normally controlled by the operation of an accelerator pedal 1, while it is controlled by a calculator 7 when the mode of the subsidiary speed change gear 2 with steps is changed. At this time of change of control, the fuel supply level in a fuel regulator is lowered to a low level, while the subsidiary speed change gear 2 with steps is set to a neutral position. And, the gear ratio of the subsidiary speed change gear 2 with steps is set to a new gear ratio under a condition that difference between the speed of rotation of a driving shaft connecting both speed change gears 3, 2 and a defined speed of rotation becomes zero.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a mode switching method for a continuously variable transmission used in an automobile.

[Prior Art] Considering the ideal speed change range of a continuously variable automobile transmission, the value obtained by dividing the maximum speed ratio by the minimum speed change ratio is 6.5 to 1O.
degree is required. However, as a practical matter, only about three shift ranges can be used in one mode in the continuously variable transmission.

Conventionally, these continuously variable transmissions for automobiles skillfully utilize the differential motion of differential gears and a combination of multiple clutches to continuously switch between many different so-called modes. By connecting different modes, a wide shifting range was achieved as described above.

[Problems to be Solved by the Invention] However, the above method uses multiple complex differential gears and multi-disc clutches, which not only complicates the structure but also increases both its weight and size. It had the disadvantage of being

It is an object of the present invention to provide a mode switching method for a continuously variable transmission that eliminates the drawbacks mentioned in -I- and makes it possible to provide a lightweight and compact continuously variable transmission with a simple configuration suitable for practical use. There you are.

[Means for solving problems] The present invention has the following configuration.

A transmission installed in the drive system between the engine and the drive wheels,
In controlling the transmission, which is a continuously variable transmission having an auxiliary stepped transmission, when changing the gear 1L of the auxiliary stepped transmission, the computer performing the Mij control performs the following steps: : Switching the control of the fuel regulator in the engine from the normal control from the accelerator pedal to the control by the computer, lowering the fuel supply level in the fuel regulator to a low level, and at the lowering level, the auxiliary stepped transmission. (b) In the neutral position setting state, the rotational speed of the output shaft of the transmission, the rotational speed of the engine, and the relationship between the continuously variable transmission and the auxiliary stepped transmission; C: The auxiliary stepped transmission sets a new gear ratio based on the rotational speed of the output shaft of the transmission or the rotational speed of the engine. Calculate a predetermined rotational speed of the drive shaft at which the gear system constituting the gear ratio has a synchronized rotational speed, and d: the difference between the detected rotational speed of the drive shaft and the predetermined rotational speed. e: in the state where the difference between the rotational speed of the drive shaft and the predetermined rotational speed becomes zero, The gear ratio is set to the new gear ratio, and immediately after that, the fuel supply level of the fuel regulator is switched to normal control using the accelerator pedal.

In this case, the output shaft of the engine is linked to the input shaft of the transmission, the output shaft of the transmission is linked to the drive wheels, and this transmission consists of a continuously variable transmission and an auxiliary stepped transmission, The relationship between the continuously variable transmission and the auxiliary stepped transmission is as follows: 1: The engine output shaft is linked to the input shaft of the continuously variable transmission, and the output shaft of the continuously variable transmission is linked to the input shaft of the auxiliary stepped transmission. 2. When the engine output shaft is interlocked with the input shaft of the auxiliary stepped transmission and the output shaft of the auxiliary stepped transmission is not connected. In some cases, the input shaft of a continuously variable transmission is interlocked with the input shaft, and the output shaft of the continuously variable transmission is interlocked with the drive wheels.

Further, the gear ratio of a continuously variable transmission is a value obtained by dividing the output shaft rotation speed of the continuously variable transmission by the input shaft rotation speed of the continuously variable transmission.

[Function] While the car is running, when the running resistance changes or the amount of pressure on the accelerator pedal changes, the computer changes the gear ratio of the continuously variable transmission in response to these changes. It is being

In controlling the gear ratio in such a continuously variable transmission,
If the gear ratio becomes the maximum or minimum gear ratio in that gear mode, and it is no longer possible to raise or lower the gear ratio in that mode, the calculator will Switch the gear ratio of the auxiliary stepped transmission to a lower gear ratio or higher gear ratio,
Converts continuously variable speed mode.

In this way, when changing the gear ratio of the auxiliary stepped transmission, the computer performing the control described in -4- calculates the control of the fuel regulator in the engine from the normal control from the accelerator pedal. Control the device! -■ and reduce the fuel supply level at that fuel regulator to a low level.

When the fuel supply level in the fuel regulator is lowered to a low level in this way, during the lowering, the torque of the engine output shaft changes from a driving state to an engine braking state with respect to the transmission output shaft. During this change, there is a state in which the torque at the engine output shaft becomes zero. This means that when the torque of the engine output shaft becomes zero, the torque of the drive shaft that connects the continuously variable transmission and the auxiliary step transmission in the transmission also becomes zero.

When the torque on this drive shaft becomes zero, i.e. immediately after reducing the fuel supply level to a low level, the counter sets the auxiliary stepped transmission to a neutral position.

In such a neutral position setting state, the b/q meter measures the rotational speed of the output shaft in the transmission, the rotational speed of the engine, and the drive shaft connecting the continuously variable transmission and the auxiliary stepped transmission. (hereinafter referred to as drive-11), C: Of these detected values, based on the value of the rotational speed of the output shaft in the transmission or the rotational speed of the engine, the metering machine operates at a predetermined speed. Calculate the rotation speed of

Here, the predetermined rotational speed refers to the rotational speed of the drive shaft required for the gear system that makes up the gear ratio to reach a synchronized rotational speed when the auxiliary stepped transmission is set to a new gear ratio. There is.

In addition, the calculation of the specified rotational speed described in -1- is performed when the transmission is operated as described above. If the input shaft of a stepped transmission is interlocked with the output shaft of the auxiliary stepped transmission and the drive wheel is interlocked with the Using a constant corresponding to the gear ratio from the human power shaft to the output shaft in the auxiliary stepped transmission, which is the new gear ratio in the auxiliary stepped transmission that should be set to It is being calculated.

In addition, the transmission configuration is 2.The engine output shaft is linked to the input shaft of the auxiliary stepped transmission, and the output shaft of the auxiliary stepped transmission is linked to the input shaft of the continuously variable transmission. When the output shaft of the engine is linked to the drive wheels, the value of the detected rotational speed of the engine output shaft and the new gear ratio in the auxiliary stepped transmission that should be newly set are , and a constant corresponding to the gear ratio from the input shaft to the output shaft in the auxiliary stepped transmission.

Based on the predetermined rotational speed calculated in this way, the computer adjusts the speed change 1 in the continuously variable transmission so that the difference between the rotational speed of the drive shaft detected in the knee and the predetermined rotational speed becomes zero.
control the heat.

In this case, the reason why the continuously variable transmission can control the rotational speed of the drive shaft to a predetermined rotational speed is as follows.

] - As shown in the description, the transmission operates as follows: 1: The engine output ihl+ is pulsated to the input shaft of the continuously variable transmission, the output shaft of the continuously variable transmission is interlocked with the input shaft of the auxiliary stepped transmission, and the When the output shaft of the auxiliary stepped transmission is linked to the drive shaft, the gear ratio e in only the continuously variable transmission is - From the above definition, e = nd / n 1 or nd = nl * e (1) becomes. However, nd is the rotational speed of the drive shaft, and nl is the rotational speed of the engine output shaft.

Therefore, as is clear from equation (1), when the auxiliary stepped transmission is set at the neutral position, change the gear ratio e in the continuously variable transmission with respect to the rotational speed n1 of the engine output shaft. For example, it is possible to freely adjust the rotational speed nd of the drive shaft.

On the other hand, the transmission configuration is 2: The engine output shaft is linked to the input shaft of the auxiliary stepped transmission, the output shaft of the auxiliary stepped transmission is linked to the input shaft of the continuously variable transmission, and the output shaft of the auxiliary stepped transmission is linked to the input shaft of the continuously variable transmission. When the output shaft of the step-variable transmission is interlocked with the driving wheels, the gear ratio e in only the continuously variable transmission becomes e=n 2 /nd or nd=n2/e (2) from the above definition. However, n2 is the rotational speed of the output shaft in the transmission.

Therefore, as is clear from equation (2), when the auxiliary stepped transmission is set at the neutral position, the gear ratio e in the continuously variable transmission is changed with respect to the rotational speed n2 of the transmission output shaft. By doing so, it becomes possible to freely adjust the rotational speed nd of the drive shaft.

e: When the difference between the rotational speed of the drive shaft and the predetermined rotational speed is zero, that is, when the rotational speed of the driveshaft has been adjusted to the predetermined rotational speed, the gear ratio in the auxiliary stepped transmission is updated. Set the gear ratio accordingly.

In this case, when setting the gear ratio in the auxiliary stepped transmission to a new gear ratio, the setting must be done with the drive shaft set to a predetermined rotational speed as described above, so the new gear ratio must be set to a new gear ratio. Setting to the gear 1L is performed in a completely synchronized state with the auxiliary stepped transmission.

Therefore, the operation of switching to the new gear ratio is completed smoothly and quickly.

In this way, mode switching in the auxiliary stepped transmission (
After the change (to a new gear ratio) is completed, the computer selects: f: The state in which the fuel supply level of the fuel regulator is switched to normal control by the accelerator pedal, and the driving speed of the vehicle is adjusted by the normal operation of the accelerator pedal. to go into.

[Example] Hereinafter, the present invention will be explained based on Examples.

FIG. 1 is a system diagram showing an embodiment of a power transmission device necessary for carrying out the mode switching method of a continuously variable transmission according to the present invention.

The engine output shaft 1a of the engine 1 is a continuously variable transmission 3
The output shaft of the continuously variable transmission 3 becomes the input shaft 2a of the auxiliary stepped transmission 2, and the output shaft 2b of the auxiliary stepped transmission 2 is linked to the drive wheels of an automobile (not shown). However, the fuel regulator 1b in the engine 1 is normally operated by operating an accelerator pedal (not shown), and is used when changing the mode of the auxiliary stepped transmission 2 (when switching the auxiliary stepped transmission 2 to a new gear ratio). The gear ratio of the continuously variable transmission 3 is controlled by the calculator 7, and the gear ratio control in the normal state where power is transmitted from the engine 1 to the drive wheels is controlled by the engine output shaft la. The continuously variable transmission 3 and the auxiliary stepped transmission 2 constitute a transmission.

The auxiliary stepped transmission 2 has a gear 2g fixed to an input shaft 2a,
Gears 2d, 2f, and 2m are each fixed to the subshaft 2e, and each of the gears 2h and 2j is rotatably fitted onto the output shaft 2b, and the hub 21 fitted onto the output shaft 2'b has a Sleeves 2k are spline-fitted to enable sliding in the axial direction, and gears 2g and 2d, gears 2h and 2 are
f, gear 2j, and gear 2m are always in gear engagement.

The calculator 7 is configured to detect the rotational speed of the human power shaft 2a, the rotational speed of the output shaft 2b, and the rotational speed of the engine output shaft 1a using detectors 7a, 7b, and 7C, and detect the movement of an accelerator pedal (not shown). It becomes.

The operation of the configuration of the embodiment of the present invention described below will be explained below.

When the automobile starts, the mode of the auxiliary stepped transmission 2 is set to the low gear ratio shown in the figure, and the gear ratio of the continuously variable transmission 3 is set to zero.

The low gear ratio shown here is set in such a state that the sleeve 2k engages the gear 2j with the /\b21, and the power of the engine l is transmitted through the engine output shaft 1a, the continuously variable transmission 3, and the input shaft 2.
a, it is ready to be transmitted to the drive wheels via the auxiliary stepped transmission 2 and the output shaft 2b.

When the accelerator pedal is depressed in this state, the output of engine 1 increases and at the same time the output of engine 1 increases.
The Q unit 7 controls the gear ratio of the continuously variable transmission 3, and the control always selects the gear ratio so that the operating state of the engine 1 has the best fuel consumption rate.

As a result of this operation, the gear ratio of the continuously variable transmission 3 increases, but eventually the increase in the gear ratio reaches its limit.
The gear ratio will no longer become larger than that. That is, the gear ratio in the continuously variable transmission 3 has reached the maximum gear ratio.

When this state is reached, the calculator 7 switches the auxiliary stepped transmission 2 to the high mode.

Here, switching to the high mode means that the sleeve 2k is moved to the left, the engagement between the hub 21 and the gear 2j is adjusted, and the hub 21 and the gear 2h are switched to be engaged. The flow of power from the engine 1 in the high mode due to the switching is the engine output shaft 1a, the continuously variable transmission 3, the input shaft 2a, the gears 2g and 2d, the subshaft 2e, the gears 2f and 2h, and the sleeve. 2k
, is transmitted to the drive wheels via the hub 21 and the output shaft 2b.

The effect of switching the auxiliary stepped transmission 2 to the high mode will be described below.

When the vehicle is running as described above, the calculator 7 temporarily sets the fuel supply to the engine 1 at a low level while the accelerator pedal is depressed.

In this state where the fuel supply to the engine 1 is being lowered to a low level, the l-lux generated at the engine output shaft 1a changes from the previous state to the state where engine braking begins. As we move on,
During this period, there is a state in which the torque of the engine output shaft 1a becomes zero.

Therefore, in a state where the torque at the engine output shaft 1a is zero, the torque at the human power shaft 2a interlocked with the engine output shaft 1a via the continuously variable transmission 3 also becomes zero, and as a result, in this state The sliding resistance of the sleeve 2 in the axial direction with respect to the hub 21 and the gear 2j is reduced.

In this way, when the torque of the input shaft 2a becomes zero, that is, immediately after the fuel supply to the fuel regulator 1b is lowered to a low level, the calculator 7 moves the sleeve 2k to the position shown in FIG. 2 (low gear ratio). position) to an intermediate position (neutral position) in the axial direction between gear 2h and gear 2j.

In this way, by setting the sleeve 2k to the neutral position, the drive system on the input shaft 2a side (input shaft 2a, gears 2g and 2d, subshaft 2e, gears 2m and 2N, and the drive system on the output shaft 2b side) The system (hub 21 and output shaft 2b) is
/＼It becomes a disconnected state at the position of 21.

In this state, the calculator 7 calculates the rotational speed n of the output shaft 2b.
2 and the signal from the detector 7b detecting the gear 2g,
The number of teeth Z1.2d, 2f and 2h. Z2, Z
Using 3 and z4, the following n d o = (Z4/Z3)X (Z2/Z 1)
Perform the calculation of Xn2 (3).

Here, when the auxiliary stepped transmission 2 is set to the high mode position, the formula (3) is expressed as follows:
The combination of and 2h indicates a relationship in which the rotational speed of the input shaft 2a must be a predetermined rotational speed ndo with respect to the current rotational speed n2 of the output shaft 2b.

Here, the relationship in equation (3) is obtained from the relationship ndoXZ1=ncXZ2 ncXZ3=n2XZ4, where nC is the rotational speed of the subshaft 2e.

” 2, the predetermined rotational speed n obtained from equation (3)
do is the input 1 detected by the detector 7a in the calculator 7.
+d+ 2 compared with the actual rotational speed nd at a,
When n d > n d O, the counter 7 adjusts the gear ratio e of the continuously variable transmission 3 to the side that reduces the rotational speed 1i nd of the input shaft 2a, and conversely, when n d < n d o , the gf calculator 7 inputs the input shaft 2 to the continuously variable transmission 3.
The speed ratio e is adjusted in a direction that increases the rotational speed nd of the motor a, and the calculator 7 finally approaches the state where nd=ndo. That is, the rotational speed of the gear 2h and the rotational speed of the hub 21 are synchronized.

Here, the reason why it is possible to adjust ncl=ndo by adjusting the gear ratio of continuously variable transmission R3.'' - (1)
This is because, from the relationship in the equation, if the gear ratio e is adjusted according to the instructions from the calculator 7, the rotational speed nd of the input shaft 2a can be adjusted.

In this way, when the rotational speed nd of the input shaft 2a is synchronized with the predetermined rotational speed ncro, the calculator 7 moves the sleeve 2k from the neutral position 1 row to the left in FIG. The gear 2h is set to be engaged.

At this time, as mentioned above, the rotational speed of the gear 2h and the hub 21
Since the rotational speeds of the sleeves 2k and the gears 2h are synchronized, the action of the sleeve 2k engaging with the gear 2h causes almost no shock during the engagement, and the mode can be switched smoothly.

Simultaneously with the completion of the gear change in the auxiliary stepped transmission 2, the calculator 7 switches the fuel supply to the engine 1 to a state where it is normally regulated by the accelerator pedal, and thereafter the speed adjustment of the vehicle is controlled by the driver. This is done by operating the accelerator pedal, and while the continuously variable transmission 3 is in its high mode, the calculator 7 shifts to normal gear ratio control that optimizes the fuel consumption rate of the engine 1.

-1- Regarding switching from low mode to high mode,
Switching from high mode to low mode can be done in exactly the same way as above, but in that case, the newly set power transmission path for low mode will be the same as when setting to high mode as described in ``-''. Therefore, the predetermined rotational speed ndo calculated in the calculator 7 is different, and the value of ndo in the low mode is calculated as n do = (Z6/Z5)X (Z2/Z
l) x n 2 (
4).

Here, z6 and z5 are the numbers of teeth of the gears 2j and 2m.

Here, in the second embodiment, the number of convertible modes of the auxiliary stepped transmission 2 is two, but even if the number of modes is even higher,
The mode switching method described above can be used when switching from one mode to another, such as from the low mode to the high mode or from the high mode to the low mode.

In the above embodiment, the auxiliary stepped transmission 2 was provided on the output shaft side of the continuously variable transmission 3 as a transmission configuration.
The structure of the transmission is essentially the same even if the auxiliary stepped transmission 2 is provided on the input shaft side of the continuously variable transmission 3, and the mode switching method is essentially the same. .

However, the rotational speed that is used as a reference for determining the predetermined rotational speed at the time of mode switching is different.

FIG. 2 shows that the configuration of the transmission is such that the auxiliary stepped transmission &! This is an embodiment in which the engine 1 is provided with the engine 1.
The output power is transmitted through the engine output shaft 1a, the auxiliary stepped transmission 2, the output shaft 2b, the continuously variable transmission 3, and the output shaft 3a of the continuously variable transmission 3 to drive drive wheels (not shown). It has become.

Further, in the reference numerals in FIG. 2, the same reference numerals as those in FIG. 1 indicate the same materials as in FIG.

In the configuration shown in FIG. 2, its operation will be explained. The operation at the time of starting is to set the mode of the auxiliary stepped transmission R2 to the low mode as shown in the figure, and to turn the continuously variable transmission 3 on.
The gear ratio of the continuously variable transmission 3 is also set to zero, and when the accelerator pedal is depressed in that state, the gear ratio of the continuously variable transmission 3 changes.
2, the car starts moving, and this action is exactly the same as that shown in Figure 1.

Due to such a starting action, when the mode is changed from the low mode to the high mode as in FIG. 1, the following action occurs.

When switching from the current low mode state to the high mode state, the sleeve 2k is first set to the neutral position, and the operation until setting it to this neutral position is also shown in Figure 1. It is the same as the case.

However, when switching from this neutral state to the high mode, the rotational speed of the hub 21 must be synchronized with the rotational speed of the gear 2h. In this case, gear 2h
is interlocked with the engine output shaft 1a via the gear 2f, countershaft 2e, gears 2d and 2g, and its rotational speed is regulated by the engine output shaft 1a.

Therefore, this synchronization is achieved by the output shaft 2b directly connected to the hub 21.
This must be achieved by adjusting the sides.

From this, the equation corresponding to equation (3) for Figure 1 is ndo-(Zl/Z2)X (Z3/Z4)Xnl
(5) It becomes. In this case, ndo is the output shaft 2b in FIG.
is a predetermined rotational speed that should be set when switching to the high mode, and nl is the actual rotational speed of the engine output shaft 1a detected by the calculator 7.

Further, equation (5) is obtained from the relationship n1XZ1=ncXZ2 n1XZ1=ncXZ2, and the symbols used are the same as in equation (3).

That is, the calculator 7 uses the rotational speed nl of the engine output shaft 1a detected by the detector 7C and equation (5) to calculate
After determining a predetermined rotational speed ndo, the calculator 7 calculates the rotation speed ndo
While comparing the actual rotational speed nd of the output shaft 2b detected by a with the predetermined rotational speed ndo, the gear ratio e in the continuously variable transmission 3 is adjusted so that nd=nd.

Set it to .

In this case, in the state of this neutral position setting, the continuously variable transmission 3 adjusts its gear ratio e so that the output shaft 2b
The reason why the rotational speed nd of the fruit can be adjusted is because of (2)
) is possible from the relationship of the equation.

The operation after the synchronization operation of nd=ndo is achieved in this way is the same as that in FIG. 1.

In addition, with respect to the switching from the low mode to the high mode in Figure 2, the predetermined rotational speed ndo in the case of switching from the high mode to the low mode in Figure 2 is calculated by the formula (4) in Figure 1. Corresponding to, n d o = (Zl/Z2)X (Z5/Z6)Xn
It will be calculated according to the relationship of l (6), and in this case, z5
and z6 are the same as in equation (4).

As can be understood from the explanation of FIGS. 1 and 2 below, regardless of the configuration of the transmission, whether the auxiliary stepped transmission 2 is provided on the output shaft side of the continuously variable transmission R3 or the continuously variable transmission R3 is Even if the auxiliary stepped transmission 2 is provided on the input shaft side of the transmission 3, the parts that are adjusted for synchronization by the continuously variable transmission 3 during mode switching are the same as those of the continuously variable transmission 3. This is the portion of the drive shaft that connects the auxiliary stepped transmission 2 (the input shaft 2a portion in FIG. 1, and the output shaft 2b portion in FIG. 2).

In addition, when calculating the above-mentioned predetermined rotational speed, the reference rotational speed is the rotational speed n2 of the output shaft 2b in the case of FIG. 1, and the rotational speed n2 of the engine output shaft 1a in the case of FIG. The only difference between the two is that the rotation speed n1 is used.

[Effects] As is clear from the following explanation, the mode switching method for a continuously variable transmission according to the present invention has the following effects.

A transmission in which a continuously variable transmission 3 is provided with an auxiliary stepped transmission 2,
The mode switching at the time of mode I switching in the auxiliary stepped transmission 2 enables synchronization of the gears in the auxiliary stepped transmission 49.2 by adjusting the gear ratio of the continuously variable transmission 3.

Therefore, the continuously variable transmission using the present invention enables smooth mode switching that is substantially the same as that of the conventional mode switching system using multiple differential gears and clutches, and also has the same structure. This eliminates the need for a complex differential gear and a plurality of multi-disc clutches as in the past, making the configuration extremely simple.

This not only makes the continuously variable transmission less expensive, but also reduces the weight of the car equipped with the continuously variable transmission, which reduces the fuel consumption rate of the car and improves the acceleration of the car. This will improve the quality of the product.

[Brief explanation of the drawing]

FIG. 1 shows a system diagram of a power transmission device for carrying out the mode switching method of a continuously variable transmission according to the present invention, and FIG. 2 shows a system diagram of a power transmission device as another embodiment of the invention. This is illustrated by the diagram. The main symbols used in the examples are as follows. 1: Engine, 1a: Engine output shaft, 1b:
Fuel regulator, 2: Auxiliary stepped transmission, 2a: Input shaft, 2b: Output shaft, 3: Continuously variable transmission, 3a: Output shaft, 7: Calculator, 7a, 7b, 7C: Detector.

Claims (1)

[Claims] 1. In the control of a transmission interposed in the drive system between the engine and the drive wheels, the transmission is a continuously variable transmission having an auxiliary stepped transmission. When changing the gear ratio of the auxiliary stepped transmission, the computer performing the control: a) switches the control of the fuel regulator in the engine from the normal control from the accelerator pedal to the control of the computer; , lowering the fuel supply level in the fuel regulator to a low level, and setting the auxiliary stepped transmission to a neutral position in the lowering, b: in the neutral position setting, rotation of the output shaft of the transmission c: detecting the rotational speed of the output shaft of the transmission or the rotational speed of the drive shaft connecting the continuously variable transmission and the auxiliary stepped transmission; Based on the value of the rotational speed of the engine, determine a predetermined rotational speed of the drive shaft such that when the auxiliary stepped transmission sets a new gear ratio, the gear systems making up the gear ratio are at a synchronized rotational speed. d: controlling the gear ratio in the continuously variable transmission so that the difference between the detected rotational speed of the drive shaft and the predetermined rotational speed becomes zero; e: the rotational speed of the drive shaft; and the predetermined rotational speed becomes zero, the gear ratio in the auxiliary stepped transmission is set to the new gear ratio, f: Immediately thereafter, the fuel supply level of the fuel regulator is adjusted. A mode switching method for a continuously variable transmission having the above-described operation, in which the mode is switched to normal control using an accelerator pedal.