JPS6252178B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention provides an electronically controlled automatic transmission that adjusts the input/output torque ratio of a continuously variable transmission according to predetermined speed change control characteristics. This invention relates to a gear transmission.

(Prior art) Recently, as seen in Japanese Patent Publication No. 45-32567, engine speed is transmitted to a speed governor via a continuously variable transmission whose gear ratio changes depending on the accelerator opening. A mechanism has been proposed that mechanically obtains a gear ratio according to a predetermined gear shift control characteristic depending on the operating state of the engine. Further, Japanese Patent Laid-Open No. 57-161346 proposes a continuously variable transmission in which the speed change control is performed electronically based on preset speed change control characteristics. In this device, a shift up zone and a shift down zone are set in advance according to the operating state of the engine, and the shift up or down shift is performed by determining which zone the current engine operating state is in. It's summery. In order to avoid frequent repetition of upshifts and downshifts, a hysteresis zone is provided between the upshift zone and the downshift zone.

In the case of such a device, although it has the advantage that it is possible to perform fuel-efficient operation by setting the above-mentioned speed change control characteristics so as to minimize fuel consumption relative to the engine load, on the other hand, manual stepped speed change The feeling of driving is quite different from that of driving a manual car (hereinafter referred to as a manual car).
This will give the driver a sense of discomfort and dissatisfaction. To elaborate on this point, in the case of the above-mentioned manual car, even with the selected gear ratio of your preference, the vehicle speed can be increased as the engine speed increases in response to changes in the accelerator pedal. Drivers feel a sense of power and smooth engine revving. On the other hand, in the case of the above-mentioned continuously variable transmission, the engine speed is uniformly determined for a given accelerator opening according to the shift control characteristics, so it is not compatible with the above-mentioned manual car. It became impossible for me to feel how fast I was running.

(Objective of the Invention) The present invention has been made in consideration of the above-mentioned circumstances, and uses a continuously variable transmission to provide a driving sensation similar to that of a stepped transmission, in other words, the engine rotation An object of the present invention is to provide an electronically controlled continuously variable transmission device capable of increasing vehicle speed as the vehicle speed increases.

(Structure of the Invention) In order to achieve the above-mentioned object, the present invention electronically controls a continuously variable transmission so that the shift control characteristics include a shift down zone and a shift up zone. A hold zone in which the ratio is fixed is newly provided, and when the vehicle is in the hold zone, the gear ratio is fixed so that the vehicle speed increases in response to the increase in engine speed.

Specifically, as shown in FIG. 1, a continuously variable transmission mechanism that is interposed in an engine drive system and has a continuously variable gear ratio between an input shaft and an output shaft; and the gear ratio of the continuously variable transmission mechanism. a gear ratio variable means for changing the gear ratio; a shift up zone that is determined by a first gear change control characteristic line predetermined according to the operating state of the engine and that reduces the gear ratio; On the other hand, a shift control characteristic line is determined by a second shift control characteristic line spaced apart by a value corresponding to a range of change in engine rotation that causes a predetermined vehicle speed change, and a shift down zone in which the gear ratio is increased, and a shift down zone in which the gear ratio is increased between these two lines. According to the shift control characteristic having a hold zone that fixes the gear ratio, it is determined which zone the actual engine operating state is in, and a shift-up signal for decreasing the gear ratio is sent to the gear ratio variable means, and a shift up signal is sent to the gear ratio variable means to increase the gear ratio. The gear ratio changing means outputs a shift down signal for fixing the gear ratio and a hold signal for fixing the gear ratio.

(Example) In FIG. 2 showing the overall outline, 1 is an engine, and the output (rotation) of the engine 1 is transmitted through a clutch 2, a gearbox 3, a continuously variable transmission 4, and a differential gear 5. The power is transmitted to the drive wheels 6, and the power transmission mechanism from the engine 1 to the drive wheels 6 constitutes an engine drive system.

An intake pipe 8 is connected to the engine 1 via an intake manifold 7, and by adjusting the opening degree of a throttle valve 9 disposed within the intake pipe 8, the output of the engine 1 is adjusted. Further, as described later, the gearbox 3 can be set to R (reverse), N (neutral), or D by manual operation.
(drive) and L (low) ranges. Further, the engagement and disengagement of the clutch 2 and the change of the gear ratio of the continuously variable transmission 4 are automatically performed as will be described later by controlling an actuator using hydraulic pressure.

Next, the clutch 2, gearbox 3, and continuously variable transmission 4 will be sequentially explained based on FIG.

The clutch 2 includes a clutch input shaft 21 which also serves as the crankshaft of the engine 1, and a clutch input shaft 21 which also serves as the crankshaft of the engine 1.
The clutch output shaft 22 is rotatable with respect to the clutch output shaft 22. A clutch disc 23 is spline-fitted to the clutch output shaft 22, and by press-contacting the clutch disc 23 to a flywheel 24 that is integrated with the clutch input shaft 21, both shafts
1 and 22 are connected, and conversely, when the clutch disk 23 and flywheel 24 are separated, the shafts 21 and 22 are disconnected from each other, resulting in a disconnected state. In order to press the clutch disk 23 against and separate from the flywheel 24 in this manner, a sleeve 25 is fitted to the output shaft 22 so as to be slidable and rotatable. One end of a spring member 27 such as a disc spring that can swing freely is connected to the clutch pressure plate 28 , the other end of which is connected to a clutch pressure plate 28 facing the back of the clutch disk 23 .
is connected to. As a result, when the sleeve 25 moves to the right in FIG. 2, the clutch pressure plate 28, that is, the clutch disk 23 is displaced to the left in the figure via the spring member 27, resulting in a connected state, and conversely, from this connected state, the sleeve When 25 moves to the left in FIG. 3, it enters the cutting state.

The displacement position of the sleeve 25 in the left-right direction in FIG. 3 is adjusted by a cylinder device 29. That is, the piston rod 30 of the cylinder device 29 is connected to one end of a swinging arm 32 that is swingable about a fulcrum 31, while the other end of the swinging arm 32 is connected to the sleeve 2.
5 is facing the back. Further, an oil chamber 34 defined by the piston 33 of the cylinder device 29
is connected to a clutch solenoid valve 36 consisting of a three-way electromagnetic switching valve via a pipe 35, and the clutch solenoid valve 36 is connected to a pipe 38 extending from the discharge side of the hydraulic pump 37 and a pipe 40 extending from the reservoir tank 39, respectively. It is connected. The suction side of the hydraulic pump 37 is connected to a pipe 42 that is connected to a filter 41 and extends from the reservoir tank 39.

The clutch solenoid valve 36 has two solenoids 36a and 36b for connection and disconnection, and when the connection solenoid 36a is energized (the disconnection solenoid 36b is demagnetized), the oil chambers of the hydraulic pump 37 and the cylinder device 29 are activated. 34, the piston rod 30 is extended, and the clutch 2 is connected. Clutch 2 at this time of connection
The transmission torque increases as the amount of oil supplied to the oil chamber 34 increases (the clutch disc 23
(The pressing force against the flywheel 24 increases). Furthermore, when the disconnection solenoid 36b is energized (the connection solenoid 36a is demagnetized), the oil chamber 34 is opened to the reservoir tank 39, the piston rod 30 is contracted by the return spring 43, and the clutch 2 is disconnected. be done. moreover,
When both solenoids 36a and 36b are demagnetized, the oil chamber 34 is sealed and the piston rod 30 is maintained as it is.

The input shaft of the gearbox 3 is constituted by a clutch output shaft 22, and a first gear 51 and a second gear 52 having a larger diameter are integrally formed on the clutch output shaft 22. There is. A gearbox output shaft 53 is disposed parallel to this output shaft 22, and both shafts 22 and 5
3, a back gear 54 is disposed which is in constant mesh with the second gear. A large-diameter intermediate gear 55 that constantly meshes with the first gear 51 is rotatably fitted to the gearbox output shaft 53, and a sleeve 56 is integrated therein. A clutch gear 57 is always spline-fitted to this sleeve 56, and as the clutch gear 57 is displaced in the axial direction, as shown in FIG.
Spline fitting is also possible for the intermediate gear 55.

In such a gearbox 3, when the clutch gear 57 is at the rightmost position as shown in FIG.
1. It is transmitted to the gearbox output shaft 53 via the intermediate gear 55, clutch gear 57, and sleeve 56, and the rotating direction of the output shaft 53 at this time corresponds to the forward direction of the automobile. Furthermore, when the clutch gear 57 is displaced to the leftmost position in FIG. , the rotational direction of the output shaft 53 at this time corresponds to the backward direction of the vehicle. Furthermore, when the clutch gear 57 is at the intermediate stroke position in the left-right direction in FIG.
When the clutch output shaft 22 and the gearbox output shaft 53 are in a position where they do not mesh with each other, the clutch output shaft 22 and the gearbox output shaft 53 are in a neutral state in which the interlocking movement is cut off.

The displacement position of the clutch gear 57 is adjusted by a cylinder device 58. That is, the piston rod 59 of the cylinder device 58 is linked to the clutch gear 57 via the interlocking arm 60, so that when the piston rod 59 is extended, the clutch gear 57 is displaced to the left in FIG. This cylinder device 5
8 has two oil chambers 6 by its piston 61.
2 and 63 are defined, and the oil chamber 62 and the oil chamber 63 are respectively connected via a pipe 64 and a pipe 65 to a manual valve 66 consisting of a three-way switching valve. And the manual valve 66 is
It is connected to the hydraulic pump 37 via a pipe 67 and to the reservoir tank 39 via a pipe 68, respectively.

Such a manual valve 66 has a fulcrum 69
The switching is performed by manually operating an operating lever 70 that can swing freely around the R range.As the operating lever 70 is swung clockwise in FIG. , N range, D
Range and L range are available.
In this R range position, the oil chamber 62 is communicated with the hydraulic pump 37, and the oil chamber 63 is opened to the reservoir tank 39, so that the piston rod 59 is extended and the gearbox 3 is in the backward state. In addition, in the N range position, both oil chambers 62 and 63 are opened to the reservoir tank 39, and due to the balancing action of the return spring 71, the piston rod 59, that is, the clutch gear 5
7 is the intermediate stroke position, and the gearbox 3 is in the neutral position described above. moreover,
In the D range position, the oil chamber 62 is opened to the reservoir tank 39, the oil chamber 63 is communicated with the hydraulic pump 37, the piston rod 59 is retracted, and the gearbox 3 is in the forward movement state described above. Note that in the L range position, the manual valve 66 is at the same position as in the D range.

The continuously variable transmission 4 has input shafts 81 parallel to each other.
and an output shaft 82, the input shaft 81 is provided with a primary pulley 83, the output shaft 82 is provided with a secondary pulley 84, and both pulleys 83 and 84 are provided.
A V-belt 85 is wound between the two. The primary pulley 83 is composed of a fixed flange 86 that is integrated with the input shaft 81 and a movable flange 87 that can be slidably displaced with respect to the input shaft 81. The movable flange 87 controls the amount of oil supplied to the hydraulic actuator 88. As the V-belt 85 increases, the V-belt 85 approaches the fixed flange 86, and the winding radius of the V-belt 85 around the primary pulley 83 increases. Similarly to the primary pulley 83, the secondary pulley 84 also includes a fixed flange 89 that is integrated with the output shaft 82, and a movable flange 90 that can be slidably displaced with respect to the output shaft 82. As the amount of oil supplied to the hydraulic actuator 91 increases, the V-belt 85 approaches the fixed flange 89 and the winding radius of the V-belt 85 around the secondary pulley 84 increases.

The hydraulic actuator 88 is connected to a speed change solenoid valve 94, which is a three-way electromagnetic switching valve, through a pipe 92, and the hydraulic actuator 91 is connected to a speed change solenoid valve 94, which is a three-way electromagnetic switching valve, through a pipe 95. hydraulic pump 3
7, and the reservoir tank 39 via piping 96.
are connected to each.

The speed change solenoid valve 94 has two solenoids 94a and 94b for speed increase and deceleration, and when the speed increase solenoid 94a is energized (the deceleration solenoid 94b is demagnetized), the hydraulic actuator 88 activates the hydraulic pump 37. Since the hydraulic actuator 91 is opened to the reservoir tank 39, the winding radius of the V-belt 85 around the primary pulley 83 becomes large, while the winding radius around the secondary pulley 84 becomes small.
The output shaft 82 enters a speed increasing state where its rotational speed increases (speed ratio is small). Furthermore, when the deceleration solenoid 94b is energized (the speed increase solenoid 94a is demagnetized), the hydraulic actuator 91 is connected to the hydraulic pump 37, and the hydraulic actuator 8
8 is released to the reservoir tank 39, the winding radius of the V-belt 85 around the primary pulley 83 becomes smaller, while the winding radius around the secondary pulley 84 becomes larger, causing the output shaft 82 to undergo deceleration where its rotational speed decreases. state (large gear ratio).
Furthermore, when both solenoids 94a and 94b are demagnetized, the winding radius of V-belt 85 around both pulleys 83 and 84 remains unchanged (speed ratio fixed). Of course, the gear ratio is determined by changing the rotation speed of the input shaft 81 to the output shaft 82.
(the winding radius of the V-belt 85 around the secondary pulley 84 divided by the winding radius around the primary pulley 83).

Reference numeral 97 in FIG. 3 is an electromagnetic relief valve that continues to maintain the illustrated position during clutch control and gear ratio control, which will be described later.

In FIGS. 2 and 3, 101 is a control unit, to which the outputs from the respective sensors 102 to 109 are input.
From there, output is made to the clutch solenoid valve 36, the speed change solenoid valve 94, and the relief valve 97. To explain each of the sensors 102 to 109, the sensor 102 is a throttle sensor that detects the opening degree of the throttle valve 9. The sensor 103 detects the rotation speed NE of the engine 1.
This is a rotational speed sensor that detects the rotational speed E of the clutch input shaft 21 (in the embodiment, the same as the rotational speed E of the clutch input shaft 21). sensor 10
4 is a rotation speed sensor that detects the rotation speed C of the clutch output shaft 22. The sensor 105 is a position sensor that detects the R, N, D, and L positions of the operating lever 70. The sensor 106 is a rotation speed sensor that detects the rotation speed NP of the input shaft 81 of the continuously variable transmission 4. The sensor 107 is a vehicle speed sensor that detects the rotational speed of the output shaft 82 of the continuously variable transmission 4, that is, the vehicle speed. The sensor 108 is the accelerator pedal 1
10 is an accelerator sensor for detecting whether or not the accelerator is depressed. Sensor 109 is a brake sensor for detecting whether brake pedal 111 is being operated.

Next, the details of control by the control unit 101 will be explained based on the flowcharts shown in FIGS. 4 to 6.

FIG. 4 shows the entire processing system. First, the system is initialized in step A, various data necessary for control are input in step B, and then clutch control is performed in step C, and gear shifting is performed in step D. Ratio control will be performed (in consideration of responsiveness, some ratios may be read at the time of control in step D). In addition, in the following explanation, the routine for clutch control,
This section will be divided into routines for speed ratio control.

Clutch Control Routine (FIG. 5) First, in step 121, it is determined whether or not the operating lever 70, that is, the gearbox 3, is in the N range. If it is not in the N range, the routine proceeds to step 122. In this step 122,
It is determined whether the vehicle speed is high (for example, 10 km/h or more), and if the vehicle speed is high, step 12 is performed.
After the vehicle speed flag is set in step 3, step 1
Move to 24.

In step 124, the clutch input shaft 2
Find the differential value E' of the rotation speed E of 1, and calculate the differential value
It is determined whether E' is positive indicating an increase in the rotational speed, and if the differential value E' is positive, the process moves to step 125. In this step 125, it is determined whether the rotation speed E of the clutch input shaft 21 is larger than the rotation speed C of the clutch output shaft 22, and if E>C, the process proceeds to step 126.
Move to. In step 126, the connecting solenoid 36a of the clutch solenoid valve 36 is energized, while the disconnecting solenoid 36b is deenergized to connect the clutch 2, thereby increasing its transmitted torque. If it is determined in step 125 that E>C is not true, the process proceeds to step 128, where the clutch solenoid valve 36 is connected and disconnected.
Both a and 36b are demagnetized to maintain the transmission torque of the clutch 2 as it is.

Furthermore, if it is determined in step 124 that E'>0 is not true, the process moves to step 127,
Here, it is determined whether E<C. When E<C, the process moves to step 126, where the clutch 2 is connected, and when E<C, the process moves to step 128, where the connected state of the clutch 2 is maintained.

The flow from step 124 to step 125 described above is based on the assumption that the rotation of the clutch input shaft 21 is increasing.
26 is the rotation speed E of the clutch input shaft 21.
is larger than the rotational speed C of the clutch output shaft 22, it is necessary to increase the transmission torque of the clutch 2, and for this reason, the connection is performed in order to increase the transmission torque of the clutch 2. This case corresponds, for example, to a so-called half-clutch state when starting a car. Further, since the flow from step 125 to step 128 is when the transmitted torque of the clutch 2 is exactly balanced, the clutch 2 is held in that state, which corresponds to, for example, a steady running state. .

Conversely, the flow from step 124 to step 127 is based on the assumption that the rotational speed of the clutch input shaft 21 is decreasing, and the clutch input/output shaft 21 is decreasing in rotation speed.
Since the transfer of torque between steps 1 and 22 is exactly the opposite of the flow from step 124 to step 125,
The determination in step 127 is carried out in step 12.
Contrary to the determination in step 5, it is checked whether E<C. Note that the flow from step 127 to step 126 is, for example, the operation lever 70.
While driving with the set in N range,
This corresponds to the case of changing to the D range, and in this case also a so-called half-clutch state is formed.
Also, the flow from step 127 to 128 is as follows:
For example, this corresponds to a deceleration running state using engine braking.

On the other hand, if it is determined in step 121 that the vehicle is in the N range, the vehicle speed flag is reset in step 129, and then the process proceeds to step 130. In this step 130, the connection solenoid 36a of the clutch solenoid valve 36 is
While demagnetizing the clutch 2, the disconnection solenoid 36b is energized to disconnect the clutch 2. That is, in this case, it is clear that the driver himself requests a neutral state, so the clutch 2 is unconditionally disengaged.

If it is determined in step 122 that the vehicle speed is low, the process moves to step 131, where it is determined whether or not the accelerator pedal 110 is depressed. This accelerator is ON
If not, then the output of engine 1 is not requested, so the process moves to step 132.
It is determined whether the vehicle speed flag is set. When the vehicle speed flag is set, the vehicle speed has not yet decreased sufficiently, and in this case, the process moves to step 133, where it is determined whether or not the brake pedal 111 is depressed. be done. And the brakes
If it is ON, the process moves to step 134, and if it is determined here that the engine speed NE is 1500 rpm or less, the process moves to step 130 via step 129 (clutch 2 is disengaged). In addition, if it is determined in step 133 that the brake is not turned on, step 13
5, and here the engine speed NE is
If it is determined that the rotation speed is 1000 rpm or less, the process of step 130 is performed after passing through step 129 (clutch 2 is disengaged). If it is determined in step 134 that the engine speed NE is not less than 1500 rpm, and in step 135
If it is determined that the speed is not below 1000rpm,
The process moves to step 124 and the above-described processing is performed.

In this way, the reason for varying the magnitude of the engine speed NE as a criterion for determining whether or not clutch 2 should be disengaged when the brake is ON or OFF is that when the brake is ON, the vehicle speed does not decrease. This is to allow more time to avoid the danger of stalling, taking into account that the engine speed is faster than when the brakes are not applied. If it is determined in step 132 that the vehicle speed flag is not set, the process of step 130 is performed via step 129 to prevent the engine from stalling (clutch 2 is disengaged).

Gear ratio control (Fig. 6) In this embodiment, to determine the gear change control characteristic having a hold zone, as shown in Fig. 8, a predetermined basic gear change control characteristic line _X1 is used. , the target input rotation speed TNpA of the continuously variable transmission 4 is set according to the throttle opening (same as the accelerator opening), while the M value ( Set _the target rotational speed TNpB for hold determined _by the shift control characteristic The zone to the right of _X1 is a shift up zone (a zone where the gear ratio is reduced), and the area between _X1 and _X2 is a hold zone (where the gear ratio is fixed).

Based on the above, first, step 1.
At step 41, the opening degree α of the accelerator pedal 110 is read. After this, in step 142,
It is determined whether the operating lever 70 is in the L range, which requires a large engine braking force, and if it is in the L range, step 143 is performed.
After setting a new accelerator opening amount by adding a certain amount A to the actual accelerator opening degree α, the process moves to step 144, and if it is not in the L range, the process moves to step 14.
3, the accelerator opening degree α read in step 141 is set as is, and the process moves to step 144.

In step 144, in comparison with the basic shift control characteristic line _X1 shown in FIG.
Target input rotation speed corresponding to accelerator opening α
TNpA (target rotational speed of the input shaft 81 of the continuously variable transmission 4) is calculated. After that, in step 145, the vehicle speed v is read, and then in step 146
, the vehicle speed v is determined from the map shown in FIG.
The M value corresponding to is set, but this M value is
It is set to become smaller as the vehicle speed v increases. Then, in step 147, the TNpA calculated in step 144 is calculated.
After the hold input rotational speed TNpB is calculated by subtracting the above M value, the current input rotational speed NP of the continuously variable transmission 4 is read in step 148.

After step 148, step 149
, it is determined whether NP is greater than TNpA, and NP, which means the shift up zone, is determined.
> If TNpA, F in step 150.
After (flag) is set to 1, step 1
51. In step 151, a shift up signal is issued, that is, the speed increase solenoid 94a of the speed change solenoid valve 94 is energized, while the speed reduction solenoid 94b is deenergized, thereby reducing the speed ratio and reducing the input rotational speed NP. To go.

Also, in step 149, NP>TNpA
If it is determined that this is not the case, the process moves to step 152, where it is determined whether NP is smaller than TNpB and corresponds to the downshift zone.
When NP<TNpB, the F is set to 0 in step 153, and then step 154 is performed.
Move to. In step 154, a downshift signal is issued, that is, the speed increase solenoid 94a is deenergized, while the deceleration solenoid 94b is energized, thereby increasing the gear ratio and increasing NP.

When it is determined in step 152 that NP<TNpB is not true, TNpB≦NP≦TNpA, which corresponds to the hold zone. In this case, in step 155, the differential value v' of the vehicle speed v is After being calculated, step 156
In the step, it is determined whether or not the differential value v' is positive indicating an increase in vehicle speed. When v'> 0, which indicates an increase in vehicle speed, the process moves to step 157, where F is determined, and when F=0, the process moves to step 158, where the gear ratio is fixed. . If it is determined in step 157 that F=0, then the process moves to step 151 and the gear ratio is reduced.

Further, if it is determined in step 156 that v'>0 is not satisfied, the process proceeds to step 159, where F is determined, and if F=0, the process proceeds to step 154, where the gear ratio is increased. . If it is determined in step 159 that F=0, then the process moves to step 158 and the gear ratio is held.

The processes from step 149 described above are shown in FIG. 8 by arrow lines Y ₁ (below ~) and Y ₂ (below~).
The details are explained below based on the following.

First, the flow of steps 149, 150, and 151 is from the shift up zone until the gear ratio decreases to reach point β (shift up).

Steps 149, 152, 155, 156,
Flows 159 and 158 are from point β to point γ in FIG. 8 (gear ratio hold).

Steps 149, 152, 155, 156,
Flows 159 and 154 are from point γ to point β in FIG. 8 (downshift).

The flow of steps 149, 152, 153, and 154 occurs when the gear ratio increases from the downshift zone until reaching point δ (downshift).

Steps 149, 152, 155, 156,
Flows 157 and 158 are from point δ to point ε in FIG. 8 (hold).

Steps 149, 152, 155, 156,
Flows 157 and 151 are from point ε to point δ in FIG. (shift up).

In this way, in the hold zone (see above,,,), when the vehicle speed decreases (v'<0), the gear ratio is fixed until the input rotational speed NP reaches the lower limit value TNpB. (β → γ), the same driving sensation as when using engine braking with a fixed gear ratio in a manual car is obtained. and,
When NP reaches the lower limit TNpB, the engine is shifted down and the engine speed reaches the upper limit again.
It is increased to TNpA (γ→β). Also, when the vehicle speed increases (v'>0), the gear ratio is fixed until the input rotation speed NP reaches the upper limit value TNpA (δ→
ε), as in the case of a manual car, a driving feeling can be obtained in which the vehicle speed increases in proportion to the engine speed. Then, when NP reaches the upper limit value TNpA, the engine is shifted up and the engine speed is reduced to the lower limit value TNpB again (ε→
δ).

The state of acceleration as described above (corresponding to the arrow line _Y2 in FIG. 8) is shown in FIG. As is clear from this figure, the upward slope line section to the right indicated by Z ₁ to _{Z 4} indicates when the gear ratio is fixed,
It is understood that the operating state is exactly the same as when a four-speed transmission sequentially shifts up and accelerates. Also, as shown in Fig. 7, if the M value is a decreasing function with respect to the vehicle speed v, then the 9th
As is clear from the figure, the gradient of acceleration decreases as it progresses from Z ₁ , Z ₂ , Z ₃ , and Z ₄ , and as a result,
In a stepped transmission, as the gears are shifted up sequentially, the interval between gear ratios between each gear becomes smaller (for example, the interval between gear ratios between 1st and 2nd gears is smaller than that between 2nd gear and 3rd gear). (the gear ratio interval between the two speeds is smaller). Of course, by adjusting the relationship between the M value and the vehicle speed _v shown in _FIG . 4 stages Z ₁ to Z ₄ ) can be changed.

In addition, in step 143, the reason for adding A (A>0) to the accelerator opening α in the L range is to increase the gear ratio in order to increase the target input rotation speed NP by this addition. This is to allow driving in a lower gear compared to driving in the D range if the actual throttle opening is the same (the above addition is based on the shift control characteristic curve).
(This has the same effect as offsetting X ₁ to the side where the engine speed increases).

Although the embodiments have been described above, the present invention is not limited thereto, and includes, for example, the following cases.

The shift control characteristics include engine load such as throttle opening, accelerator opening, and intake negative pressure as one parameter, and other parameters such as engine rotation speed, vehicle speed, and output torque of the continuously variable transmission 4. It is possible to select and create the information indicating the output state of the engine 1 as appropriate.

When the control unit 101 is configured by a microcomputer, it can be configured by either a digital type or an analog type.

In step 156 of FIG. 6, the hold may be made only when v'> 0, that is, only during acceleration where the vehicle speed increases. In this case, the determination in step 159 is omitted, and in step 156, If it is determined that '>0 is not satisfied, the process may proceed to step 154 in all cases.

(Effects of the Invention) As is clear from the above, the present invention has the following advantages:
The driver can enjoy the same driving sensation as a manual car, in which the vehicle speed increases in proportion to the increase in engine speed.In addition, the driver can easily adjust the engine speed according to the vehicle speed using engine sounds, etc. Since it is possible to know this, it is possible to prevent the throttle opening from increasing unnecessarily, which is preferable from the viewpoint of fuel efficiency and noise prevention.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of the present invention. FIG. 2 is an overall schematic diagram showing an embodiment of the present invention. FIG. 3 is an overall system diagram showing one embodiment of the present invention. 4 to 6 are flowcharts showing an example of control contents of the present invention. FIG. 7 is a graph used to set the hold zone. FIG. 8 is a graph showing an example of shift control characteristics. FIG. 9 is a graph schematically showing the effect of the present invention. 1; Engine, 4; Continuously variable transmission, 81; Input shaft of continuously variable transmission, 82; Output shaft of continuously variable transmission, 8
8, 91; actuator; 101; control unit.

Claims (1)

[Scope of Claims] 1. A continuously variable transmission mechanism that is interposed in an engine drive system and has a continuously variable gear ratio between an input shaft and an output shaft; and a variable gear ratio that changes the gear ratio of the continuously variable transmission mechanism. means, a shift up zone that is determined by a first shift control characteristic line predetermined according to the operating state of the engine and reduces the gear ratio, and a predetermined vehicle speed change with respect to the first shift control characteristic line. a shift down zone in which the gear ratio is increased, and a hold zone in which the gear ratio is fixed between these two lines. It determines which zone the actual engine operating state is in according to the speed change control characteristics, and provides the speed ratio variable means with a shift-up signal for decreasing the speed ratio and a shift-down signal for increasing the speed ratio. An electronically controlled continuously variable transmission comprising: 1, a gear ratio changing means for outputting a hold signal for fixing a gear ratio;