JPS63258235A - Control device for vehicle gear shifter - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a feeling of physical disorder due to engine brake by connecting CVT to a sub gear shifter of gear type in series, and making the sub-gear shifter neutral for interrupting power transmission when a vehicle speed and an accelerator operation amount at the time of brake operation are equal to or less than the predetermined values. CONSTITUTION:An engine 10 is connected to the input shaft 16 of a belt type continuously variable transmission (CVT) 14 via a lockup type fluid coupling 12 and a sub-gear shifter 30 comprising a planetary gear mechanism. The sub- gear shifter 30 is free to operate hydraulically the brake 38 of a reverse ring gear 37 and an advance clutch 40. When a vehicle speed and an accelerator operation amount respectively detected by a vehicle speed sensor 62 and a throttle sensor 64 are equal to or less than the predetermined values at the time of detecting brake operation with a brake pedal sensor 57, a relief valve 86 operates for discharging a hydraulic fluid to the advance clutch 40, thereby causing the sub-gear shifter 30 to be neutral for interrupting power transmission. According to the aforesaid constitution, it becomes possible to eliminate a feeling of physical disorder in deceleration via engine brake.

Description

Detailed Description of the Invention Technical Field The present invention relates to a control device for a vehicular transmission, and in particular, the present invention relates to a control device for a vehicle transmission, and in particular, a control device for controlling a continuously variable transmission constituting the transmission, which prevents a problem from occurring after a brake operation while driving at a low speed. This article relates to technology that eliminates the discomfort caused by

Prior Art A continuously variable transmission in which the gear ratio can be changed steplessly, and an auxiliary transmission that has multiple types of gears and can be selectively switched to one of these gears or to a neutral state, There is a vehicular transmission device in which a continuously variable transmission and an auxiliary transmission are inserted in series in a power transmission path leading to drive wheels. For example, the transmission described in Japanese Patent Application Laid-Open No. 60-37455 is one such example.

The gear ratio of the continuously variable transmission is usually controlled so that the actual engine rotation speed matches the target rotation speed determined from a predetermined relationship based on the throttle valve opening and the vehicle speed. Ru.

As a result, when the throttle valve is further opened while driving at a predetermined speed, the gear ratio is changed more in the downshift direction than before, and conversely, when the throttle valve is closed, the gear ratio is changed more in the amp shift direction than before. At the same time, when the throttle valve is at a constant opening and the vehicle speed decreases, the gear ratio is changed to a more downshift direction than before, and conversely, when the vehicle speed increases, the gear ratio is changed more than before. A knob can be shifted in the direction of shift.

Problems to be Solved by the Invention By the way, if the brake is operated to further decelerate the vehicle while the vehicle is running at a relatively low speed, the vehicle speed will decrease with the throttle valve opening at its minimum. The gear ratio is changed in the downshift direction according to the gear ratio control. Therefore, even after the necessary deceleration is achieved and the brake pedal is released, the feeling of deceleration continues due to the engine braking effect caused by the downshift, which has the disadvantage of giving the driver a sense of discomfort. That is, in conventional automatic transmission vehicles that do not have a continuously variable transmission, a gear with a relatively small gear ratio is maintained until low speed, and a gear such as a first gear or a second gear is At gears with relatively large ratios, the one-way clutch is configured so that engine braking is not applied, so there is no feeling of deceleration after a brake operation during low-speed driving as described above.

Means for Solving the Problems The present invention has been made against the background of the above circumstances.
The purpose is to provide a control device that eliminates the feeling of deceleration after a brake operation during low-speed driving.

In order to achieve such an object, the gist of the present invention is to provide a continuously variable transmission in which the gear ratio can be changed steplessly, and a continuously variable transmission having a plurality of types of gear stages, and to provide a continuously variable transmission in which the gear ratio can be changed steplessly, and which has a plurality of types of gear stages. A control device for a vehicle transmission in which the continuously variable transmission and the auxiliary transmission are inserted in series in a power transmission path from the engine to the driving wheels. (a) Brake operation detection means for detecting the brake operation of the vehicle; (b) Speed detection means for detecting the traveling speed of the vehicle; and (Accelerator pedal operation amount detection means for detecting the accelerator pedal operation amount of the C1 vehicle) means and f
d) When the brake operation of the vehicle is detected by the brake operation detection means, if the traveling speed of the vehicle is lower than a predetermined value and the accelerator pedal operation amount is less than a predetermined value; , and control means for bringing the sub-transmission into a neutral state.

Operation and Effect of the Invention With this arrangement, when the brake operation of the vehicle is performed, the traveling speed of the vehicle becomes lower than a predetermined value and the accelerator pedal operation amount is lower than a predetermined value. When the amount decreases, the control means puts the sub-transmission into a neutral state. Therefore, while the vehicle is running at relatively low speed,
When the brake is operated to further decelerate, the power transmission path is cut off due to the neutral state of the sub-transmission.
Eliminates the feeling of deceleration caused by engine braking after the brake pedal is released, even though the gear ratio is changed in the downshift direction by gear ratio control, and the discomfort that this causes the driver. be done.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

In FIG. 1, a vehicle engine 10 includes a fluid coupling 12 with a lock-up clutch and an auxiliary transmission 3.
0 to the input shaft 16 of the continuously variable transmission 14. In this embodiment, the continuously variable transmission 14 and the sub-transmission 30
constitutes a vehicle transmission.

The input shaft 16 is provided with a variable boob 922 whose groove width, that is, the diameter of the transmission belt 20 is changed by the hydraulic cylinder 18, and the output shaft 24 is provided with a variable boob 922 whose groove width is changed by the hydraulic cylinder 26. variable pulley 28
is provided.

Therefore, the rotational force transmitted to the human power shaft 16 is transmitted to the output shaft 24 via the transmission belt 20 wrapped around the variable pulleys 22 and 28. Note that the hydraulic cylinder 18 on the input side is configured in a multi-piston type, and is capable of outputting a thrust larger than the thrust of the hydraulic cylinder 26.

The sub-transmission 30 is a well-known planetary gear mechanism,
A sun gear 32 fixed to the input shaft 16 and meshing with the planetary gear 35; a pair of planetary gears 35 and 36 rotatably supported by the gear rear 34 fixed to the output shaft 33 of the fluid coupling 12 and meshing with each other; a ring gear 37 that meshes with the planetary gear 36; and a reverse brake 38 for stopping the rotation of the ring gear 37.
and a forward clutch 40 that connects the carrier 34 and the variable boob IJ22. The reverse brake 3 and the forward clutch 40 are hydraulically operated friction engagement devices, and when they are not engaged, the auxiliary transmission 30 is placed in a neutral state and power transmission is cut off. .

However, when the forward clutch 40 is engaged, the output shaft 33 of the fluid coupling 12 and the input shaft 16 of the continuously variable transmission 12 are directly connected, and power in the forward direction of the vehicle is transmitted. When the reverse brake 38 is engaged, the direction of rotation is reversed between the output shaft 33 of the fluid coupling 12 and the input shaft 16 of the continuously variable transmission 12.
Power in the backward direction of the vehicle is transmitted.

The power transmitted to the output shaft 24 of the continuously variable transmission 14 is transmitted to the drive wheels 52 of a pair of vehicles via intermediate gears 46, 48 and a final reduction gear 50, respectively.

A brake operation sensor 57 is provided on a brake pedal 56 provided at the driver's seat of the vehicle, and a brake operation signal SB is supplied from the brake operation sensor 57 to the controller 54. Variable pulley 22
and 28, variable pulleys 22 and 2
An input shaft rotation sensor 58 and an output shaft rotation sensor 60 are provided for outputting pulse signals SPI and SF3 having a frequency corresponding to a rotation speed of 8 to the controller 54. Further, a vehicle speed sensor 62 is provided near the intermediate gear 48 for outputting a pulse signal S■ of a frequency corresponding to the rotational speed of the intermediate gear 48 to the controller 54. Further, a throttle sensor 64 is provided in a throttle valve provided in an intake pipe (not shown) of the engine 10, and a throttle signal Sθ representing the throttle valve opening degree θ is sent from the throttle sensor 64 to the controller 5.
4. The throttle sensor 64 includes an idle switch that is turned on when the throttle valve opening becomes approximately zero, and an output signal from the idle switch is also supplied to the controller 54. Further, a shift lever 66 is used as a shift switching device, and a signal SP representing a shift operation position Pth of the shift lever 66 is supplied to the controller 54 from an operation position sensor 68 that detects the operation position of the shift lever 66. Ru. Note that in this embodiment, the brake operation sensor 5
7 functions as a brake operation detection means, the vehicle speed sensor 62 functions as a vehicle speed detection means, and the throttle sensor 64 functions as an accelerator pedal operation amount detection means.

The shift lever 66 is mechanically connected to a manual valve in the hydraulic circuit 70, and when operated to the neutral range, hydraulic pressure is supplied to both the forward clutch 40 and the reverse brake 38. This is prevented and the auxiliary transmission 30 is placed in a neutral state, but when the reverse range is operated, hydraulic oil is supplied only to the reverse brake 38 and the auxiliary transmission 30 is switched to the reverse gear. Further, when the shift lever 66 is operated to the forward range, hydraulic oil is allowed to be supplied only to the forward clutch 40, and the sub-transmission 30 is switched to the forward gear stage.

Further, the hydraulic circuit 70 supplies line hydraulic pressure regulated in accordance with the actual gear ratio of the continuously variable transmission 14 and the output torque of the engine 10 to the hydraulic cylinder 26 provided on the output shaft 24, thereby transmitting power. The tension in the belt 20 is controlled as necessary and fully. The hydraulic circuit 70 then operates a shift direction switching valve 7 with respect to the hydraulic cylinder 18 provided on the human power shaft 16.
supplying or discharging hydraulic oil in response to the operation of step 4;
In addition, in response to the operation of the shift speed switching valve 76, the hydraulic oil inflow speed to the hydraulic cylinder 18 or the hydraulic cylinder 18
Change the hydraulic oil discharge speed from the

Thereby, the gear ratio of the continuously variable transmission 14 is continuously changed at a desired rate of change. The hydraulic pump 78 is driven by the engine 10 or the like to force-feed the hydraulic oil in the oil tank 80 to the hydraulic circuit 70, and functions as a hydraulic source for the hydraulic circuit 70.

Between the hydraulic circuit 70 and the sub-transmission 30, oil passages 82 and 84 are provided for supplying hydraulic oil to the reverse brake 38 and the forward clutch 40. is provided with a release valve 86 that forcibly releases the hydraulic pressure within the forward clutch 40 to a drain.

The controller 54 is a so-called microcomputer including a CPU and ROMSRAM, and functions as a control means of this embodiment. The CPU processes the input signal according to a program stored in advance in the ROM while utilizing the storage function of the RAM, and controls the shift direction switching valve 74 and the shift speed in order to change the gear ratio of the continuously variable transmission 14 to an optimal value. Controls the operation of the switching valve 76.

Hereinafter, the main part of the operation of this embodiment will be explained according to the flowchart shown in FIG.

In FIG. 2, step S1 is first executed, thereby generating pulse signals SPI, SP2 . S.V.

The throttle signal Sθ and the signal SP representing the shift operation position P5 are read, and the actual input shaft rotational speed N i n and output shaft rotational speed N are read. ut, vehicle speed V, throttle valve opening θ, shift operation position Plk, and gear ratio r (=N+n/Nout) are calculated.

In the subsequent step S2, a target rotational speed N in is determined based on the actual throttle valve opening θ and vehicle speed ■ from a predetermined relationship shown in FIG. 3, for example.

The above relationships are predetermined so as to operate the engine 10 near its minimum fuel efficiency curve and provide suitable drivability, and are stored in advance in the form of a data map or a functional equation. Note that FIG. 3 shows the relationship between the target rotation speed Ni2 and the vehicle speed V using the throttle valve opening degree θ as a parameter, and γ1. ．． l is continuously variable transmission 1
4 indicates the maximum gear ratio, and TIIIM indicates the minimum gear ratio.

By executing the gear ratio control routine in step S3, the gear ratio is changed so that the target rotational speed N ifi'' and the actual input rotational speed N i n match. In this gear ratio control routine, Target rotation speed N
The operating state of the shift direction switching valve 74 is determined according to the sign of the deviation (=Nt--N+, .) between the actual input rotational speed N in and the actual input rotational speed N i n , and the shift speed is switched according to the magnitude of the deviation. The operating state of the valve 76, that is, a hydraulic oil flow permitting state, a hydraulic oil circulating inhibiting state, or a duty control state in which the valve 76 is repeatedly reciprocated between these states is determined. Then, in a control value output step (not shown), the shift direction switching valve 74 and the shift speed switching valve 76 are brought into the operating states determined as described above, thereby changing the gear ratio γ and eliminating the deviation. Ru.

As mentioned above, the target rotational speed N is determined based on the throttle valve opening θ and the vehicle speed V from the relationship shown in FIG.
When L n is controlled so that it matches the actual engine speed N50, the throttle valve opening θ becomes wider (and the gear ratio T becomes lower than before) while driving at a predetermined speed. When the throttle valve opening θ is changed in the shift (increase) direction, and conversely, the throttle valve opening θ is decreased, the gear ratio γ is changed in the upshift (decrease) direction. When the vehicle speed V decreases at a constant value, the gear ratio γ is changed to a more downshift (increase) direction than before, and conversely, when the vehicle speed V increases, the gear ratio γ is changed to an upshift (increase) more than before. :$
i) direction.

Then, by executing step S4, neutral control of the low vehicle speed brake is executed.

That is, as shown in FIG. 4, first, in step SS1, it is determined whether the content of a flag F indicating a neutral control state due to low vehicle speed braking is 1 or not. Initially, the content of flag F is not 1, so step SS2
is executed to determine whether the brake pedal 56 is being operated, in other words, whether or not the service brake is in operation. If the determination in step SS2 is negative, step SS7, which will be described later, is executed and the contents of the flag F are reset to O. However, if the brake operation is determined in step 332, the following step SS
3 is executed. If this judgment in step SSI is affirmative, step SS2 is also skipped and step SS3 is directly executed. This is for the purpose of executing step S83 and subsequent steps regardless of the operating state of the brake once neutral control using the low vehicle speed brake is started based on the operating state of the brake.

In step SS3, it is determined whether the idle switch of the engine 10 is ON (θ=O%). If it is determined in step SS3 that θ=0%, the content of the flag F is reset to O in step SS7, but if it is determined that θ=0%, the vehicle speed is determined in step SS4. It is determined whether V is smaller than a predetermined constant value a. This value a is, for example, a vehicle speed value at which a slight sense of deceleration occurs after a low vehicle speed brake operation.

If the determination in step SS4 is negative, the content of the flag F is reset to 0 in step SS7; however, if the determination is affirmative, step SS5 is executed so that the release valve 86 is It is actuated to the released position shown in the figure.

As a result, when a brake operation is performed while the vehicle is traveling forward at a relatively low speed and the engine 10 is in a no-load state, the hydraulic fluid that has been supplied to the forward clutch 40 of the sub-transmission 30 is transferred to the release valve. Since it is discharged to the drain by 8G, the sub-transmission 30 is brought into a neutral state and power transmission is cut off. Then, in step SS6, the contents of flag F are set to 1.

As described above, according to this embodiment, when the brake is operated, the throttle valve opening θ=0, and the vehicle speed V is smaller than a predetermined constant value, the auxiliary transmission 3
0 is considered a neutral state and power transmission is cut off, so even if the brake is operated to further decelerate while the vehicle is running at a relatively low speed, the power transmission path will be interrupted due to the neutral state of the auxiliary transmission. Even though the gear ratio is changed in the downshift direction by the gear ratio control, a feeling of deceleration due to engine braking occurs after releasing the brake pedal 56, or due to this, the driver feels This eliminates the feeling of discomfort. Incidentally,
As described above, when the brake is operated to further decelerate the vehicle while the vehicle is traveling at a relatively low speed, the downshift occurs along the broken line in FIG. 3, so deceleration is achieved and the brake pedal 56 is released. Conventionally, even when the vehicle is shifted down, a sense of deceleration occurs due to the downshift, giving the driver a sense of discomfort.

Although one embodiment of the present invention has been described above, the present invention is also applicable to other aspects.

For example, in the embodiment described above, the sub-transmission 30 was provided between the fluid coupling 12 and the continuously variable transmission 14, but the sub-transmission 30 was not provided between the continuously variable transmission 14 and the final reduction gear 50. It is okay to do so.

In short, it is sufficient that the continuously variable transmission I4 and the sub-transmission 30 are inserted in series in the power transmission path from the engine 10 to the drive wheels 52.

In addition, in the above embodiment, the target rotation speed N, 78 determined from the relationship shown in FIG. 3 and the actual human power shaft rotation speed N
The gear ratio T was controlled so that the gear ratio T matched with the target gear ratio γ*(=N1..
''/NuL) may be determined and the actual gear ratio may be controlled to match the target gear ratio T''.

Further, although the sub-transmission 30 in the above-described embodiment was capable of switching between a forward gear stage and a reverse gear stage,
There is no problem even if it is of a type in which multiple types of forward gear stages are prepared.

Further, although the throttle valve opening degree θ was used as a parameter in the above-described embodiment, the accelerator pedal operation amount or an amount that changes together with the accelerator pedal operation amount may also be used.

Further, the brake operation sensor 57 may be of a type that detects brake operation by detecting brake fluid pressure.

It should be noted that the above description is merely an example of application of the present invention, and various modifications may be made to the present invention without departing from the spirit thereof.

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating the configuration of an embodiment of the present invention. FIG. 2 is a flowchart illustrating the operation of the embodiment shown in FIG. FIG. 3 is a diagram used in explaining the operation of FIG. 2, and is a diagram showing the relationship for determining the target rotational speed from the vehicle speed and the throttle valve opening. FIG. 4 is a diagram illustrating the operation of the low vehicle speed brake neutral control routine shown in FIG. 14: Continuously variable transmission 30: Sub-transmission 54: Controller (control means) 57: Brake operation sensor (brake operation detection means) 62: Vehicle speed sensor (vehicle speed detection means) 64: Throttle sensor (accelerator pedal operation amount detection means) Applicant: Toyota Motor Corporation Figure 2 Figure 4 Figure 3 Vehicle speed V

Claims (1)

[Claims] A continuously variable transmission whose gear ratio can be changed steplessly, and an auxiliary transmission which has multiple types of gear stages and can be selectively switched to one of these gear stages or to a neutral state. A control device for a vehicle transmission in which the continuously variable transmission and the sub-transmission are inserted in series in a power transmission path from the engine to the drive wheels, the control device detecting brake operation of the vehicle. operation detection means; speed detection means for detecting the traveling speed of the vehicle; accelerator pedal operation amount detection means for detecting the amount of accelerator pedal operation of the vehicle; and when a brake operation of the vehicle is detected by the brake operation detection means; , a control means for bringing the sub-transmission into a neutral state when the traveling speed of the vehicle is lower than a predetermined value and the accelerator pedal operation amount is less than a predetermined value. Characteristic control device for vehicle transmission.