JP2517958B2 - Control device for vehicle transmission - Google Patents

Description

TECHNICAL FIELD The present invention relates to a control device for a vehicle transmission, and more particularly,
Due to the control of the continuously variable transmission that constitutes the transmission,
The present invention relates to a technique for eliminating a feeling of strangeness that occurs after a brake operation during low speed traveling.

2. Description of the Related Art A continuously variable transmission in which a gear ratio is continuously changed, and a sub-transmission having a plurality of types of gear stages and selectively switching to one of these gear stages or a neutral state are provided. There is a vehicle transmission of a type in which the continuously variable transmission and an auxiliary transmission are inserted in series in a power transmission path to drive wheels. For example, the transmission described in JP-A-60-37455 is that.

Then, the gear ratio of the continuously variable transmission is usually controlled so that the target engine speed determined based on the throttle valve opening and the vehicle speed from the relationship obtained in advance matches the actual engine speed. It As a result, when the throttle valve is further opened while traveling at a predetermined speed, the gear ratio is changed in the downshift direction more than before, and conversely,
When the throttle valve is closed, the gear ratio is changed in the upshift direction more than before, and when the throttle valve is at a constant opening and the vehicle speed decreases, the gear ratio is changed in the downshift direction. On the contrary, when the vehicle speed increases, the gear ratio can be changed in the upshift direction more than before.

Problems to be Solved by the Invention By the way, if the brake for further deceleration is operated while the vehicle is traveling at a relatively low speed, the vehicle speed will decrease with the throttle valve opening being at a minimum. The gear ratio is changed in the downshift direction according to the various gear ratio control. Therefore, even after the required deceleration is obtained and the brake pedal is released, the feeling of deceleration is maintained due to the engine braking action due to the downshift, and there is a drawback that the driver feels uncomfortable. That is, in the conventional vehicle with an automatic transmission that does not have a continuously variable transmission, the gear stage having a relatively small gear ratio is maintained at a low speed, and
In a gear stage having a relatively large gear ratio such as the first speed gear stage or the second speed gear stage, the one-way clutch acts so that the engine brake does not act. After the brake operation, the feeling of deceleration does not occur.

On the other hand, as shown in FIG. 12 of JP-A-61-290269, when the vehicle speed is lower than a predetermined value when the brake is operated, the auxiliary transmission is set to the neutral state,
It has been proposed to keep the neutral position of the sub-transmission until the accelerator pedal is depressed again or the gear ratio of the continuously variable transmission reaches its maximum value.

However, according to the conventional control device described above, since the vehicle speed is not equal to or higher than the predetermined value as a condition for maintaining the neutral state of the auxiliary transmission, after the auxiliary transmission is in the neutral state, When the vehicle speed is increased again in connection with the downhill traveling, there is a disadvantage that the engine braking action cannot be obtained at all.

Means for Solving the Problems The present invention has been made in view of the above circumstances, and an object of the present invention is to eliminate the feeling of low speed after the brake operation during the low speed traveling, and at the same time to temporarily change the sub-shift. An object of the present invention is to provide a control device that can obtain the engine braking action again when the vehicle speed increases after the machine is set to the neutral state.

In order to achieve such an object, the gist of the present invention is to have a continuously variable transmission in which a gear ratio is continuously changed and a plurality of types of gear stages, and one of these gear stages or a neutral state. And an auxiliary transmission that can be selectively switched to
A control device for a vehicle transmission of a type in which the continuously variable transmission and an auxiliary transmission are inserted in series in a power transmission path from an engine to driving wheels, wherein (a) a vehicle brake operation is detected. Brake operation detecting means, (b) speed detecting means for detecting a traveling speed of the vehicle, (c) accelerator pedal operating amount detecting means for detecting an accelerator pedal operating amount of the vehicle,
(D) When the brake operation of the vehicle is detected by the brake operation detecting means, the traveling speed of the vehicle is lower than a predetermined value and the accelerator pedal operation amount is less than a predetermined value. The condition is to include a control unit that continuously brings the auxiliary transmission into a neutral state.

With this configuration, when the vehicle brake operation 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 number is reduced, the auxiliary transmission is brought into the neutral state by the control means. Therefore, while the vehicle is traveling at a relatively low speed, when the brake for further deceleration is operated,
Since the power transmission path is cut off by the neutral state of the auxiliary transmission, a feeling of deceleration due to the engine braking action occurs after the brake pedal is released, even though the gear ratio is changed in the downshift direction by the gear ratio control. This and the fact that the driver feels uncomfortable due to this are eliminated. In addition, even after the auxiliary transmission is once in the neutral state, if the vehicle speed becomes equal to or higher than a predetermined value, the neutral state of the auxiliary transmission is stopped and the power transmission path is connected. A braking action is obtained. Therefore, even after the auxiliary transmission is once brought into the neutral state by the brake operation, for example, when the vehicle speed is recovered to the predetermined value or more in association with traveling on a downhill road, the auxiliary transmission is changed. Since the neutral state of the machine is stopped and the power transmission path is connected, the engine braking action can be enjoyed again.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

In FIG. 1, an engine 10 of a vehicle is connected to an input shaft 16 of a continuously variable transmission 14 via a fluid coupling 12 with a lockup clutch and an auxiliary transmission 30. In this embodiment, the continuously variable transmission 14 and the auxiliary transmission 30 constitute a vehicle transmission.

The input shaft 16 has a variable pulley 22 whose V groove width, that is, a hanging diameter of the transmission belt 20, is changed by a hydraulic cylinder 18.
Is provided, and the output shaft 24 has a hydraulic cylinder 26
A variable pulley 28 whose V-groove width is changed by is provided. Therefore, the rotational force transmitted to the input shaft 16 is transmitted to the output shaft 24 via the transmission belt 20 wound around the variable pulleys 22 and 28. The input hydraulic cylinder 18 is of a double-piston type so that a thrust larger than the thrust of the hydraulic cylinder 26 can be output.

The auxiliary transmission 30 is a well-known planetary gear mechanism,
A sun gear that is fixed to the input shaft 16 and meshes with the planetary gear 35.
32, a pair of planet gears 35 and 36 that are rotatably supported by a carrier 34 fixed to the output shaft 33 of the fluid coupling 12 and mesh with each other, a ring gear 37 that meshes with an outer peripheral planet gear 36, and a ring gear. A reverse brake 38 for stopping the rotation of 37 and a forward clutch 40 connecting the carrier 34 and the variable pulley 22 are provided. The reverse brake 38 and the forward clutch 40 are frictional engagement devices that are hydraulically actuated, and when they are not engaged together, the auxiliary transmission 30 is placed in a neutral state and power transmission is cut off. But the forward clutch
When 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 to each other, and the power in the vehicle forward direction is transmitted. When the reverse brake 38 is engaged, the output shaft 33 of the fluid coupling 12 is
Since the rotation direction is reversed between the input shaft 16 of the continuously variable transmission 12 and the input shaft 16, the 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 the pair of vehicles via the intermediate gears 46 and 48 and the final reduction gear 50.

The brake pedal 56 provided in the driver's seat of the vehicle is provided with a brake operation sensor 57, and the brake operation sensor 57 supplies a brake operation signal SB to the controller 54. In the vicinity of the variable pulleys 22 and 28, pulse signals SP1 and SP2 having a frequency corresponding to the rotation speeds of the variable pulleys 22 and 28 are controlled.
An input shaft rotation sensor 58 and an output shaft rotation sensor 60 for outputting to 54 are provided. Further, in the vicinity of the intermediate gear 48, a vehicle speed sensor 62 for outputting a pulse signal SV having a frequency corresponding to the rotation speed of the intermediate gear 48 to the controller 54.
Is provided. In addition, a throttle sensor provided in an intake pipe (not shown) of the engine 10 includes a throttle sensor.
64 is provided, and the throttle sensor 64 supplies a throttle signal Sθ indicating the throttle valve opening θ to the controller 54. It should be noted that the throttle sensor 64 has a built-in idle switch that is turned on when the throttle valve opening becomes substantially zero, and the output signal of the idle switch is also supplied to the controller 54. Also,
A shift lever 66 is used as a shift switching device, and a shift operation position P _sh of the shift lever 66 is detected from an operation position sensor 68 that detects the operation position of the shift lever 66.
Is supplied to the controller 54. In this embodiment, the brake operation sensor 57 functions as a brake operation detecting means, the vehicle speed sensor 62 functions as a vehicle speed detecting means, and the throttle sensor 64 functions as an accelerator pedal operation amount detecting means.

The shift lever 66 is mechanically associated with a manual valve in the hydraulic circuit 70, and when operated in the neutral range, hydraulic pressure is supplied to both the forward clutch 40 and the reverse brake 38. The auxiliary transmission 30 is blocked to bring the auxiliary transmission 30 into the neutral state. However, when the auxiliary transmission 30 is operated in the reverse range, hydraulic oil is supplied only to the reverse brake 38 to switch the auxiliary transmission 30 to the reverse gear stage. Also,
When the shift lever 66 is operated to the forward range, the hydraulic oil is allowed to be supplied only to the forward clutch 40, and the auxiliary transmission 30 is switched to the forward gear stage.

Further, the hydraulic circuit 70 supplies a line hydraulic pressure adjusted according to 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 for transmission. The tension of the belt 20 is controlled as necessary and sufficient.
The hydraulic circuit 70 supplies or discharges hydraulic oil to the hydraulic cylinder 18 provided on the input shaft 16 in response to the operation of the shift direction switching valve 74, and operates the shift speed switching valve 76. In response, the hydraulic oil inflow speed to the hydraulic cylinder 18 or the hydraulic oil discharge speed from the hydraulic cylinder 18 is changed. As a result, the gear ratio of the continuously variable transmission 14 is continuously changed at a desired change speed. The hydraulic pump 78
Is driven by the engine 10 or the like to pump the hydraulic oil in the oil tank 80 to the hydraulic circuit 70, and functions as a hydraulic source of the hydraulic circuit 70.

Oil passages 82 and 84 for supplying hydraulic oil to the reverse brake 38 and the forward clutch 40 are provided between the hydraulic circuit 70 and the auxiliary transmission 30, and one oil passage 84 is provided.
Is provided with a release valve 86 for forcibly releasing the hydraulic pressure in the forward clutch 40 to the drain.

The controller 54 is a so-called microcomputer including a CPU, a ROM, and a RAM, and functions as the control means of this embodiment. The above CPU uses the memory function of RAM while RO
The input signal is processed according to the program stored in M in advance, and the operation of the shift direction switching valve 74 and the shift speed switching valve 76 is controlled in order to change the gear ratio of the continuously variable transmission 14 to the optimum value.

The main part of the operation of this embodiment will be described below with reference to the flowchart of FIG.

In FIG. 2, first, step S1 is executed to read the pulse signals SP1, SP2, SV, the throttle signal Sθ, and the signal SP representing the shift operation position P _sh , respectively, and at the same time, the actual input shaft rotational speed N _in , output shaft rotation speed N _out , vehicle speed v, throttle valve opening θ, shift operation position P _sh , and gear ratio γ (= N _in / N _out ) are calculated. In the following step S2, the target rotational speed N _in ^* is determined based on the actual throttle valve opening θ and the vehicle speed v from the relationship obtained in advance as shown in FIG. 3, for example. The above relationship is determined in advance so as to operate the engine 10 in the vicinity of the minimum fuel consumption rate curve and obtain suitable drivability, and is stored in advance in the form of a data map or a functional formula. Note that FIG. 3 shows the relationship between the target rotational speed N _in ^* and the vehicle speed v with the throttle valve opening θ as a parameter, and γ _max is the maximum gear ratio of the continuously variable transmission 14 and γ _min
Indicates the minimum gear ratio.

By executing the gear ratio control routine in step S3, the target rotation speed N _in ^* and the actual input rotation speed N _in
The gear ratio is changed so as to match with. In this gear ratio control routine, the operating state of the shift direction switching valve 74 is determined in accordance with the sign of the deviation (= N _in ^* -N _in ) between the target rotational speed N _in ^* and the actual input rotational speed N _in. Depending on the magnitude of the deviation, the operating state of the shift speed switching valve 76, that is, the operating oil flow permitting state, the operating oil flow restraining state, or the duty control state that 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 state determined as described above, thereby changing the gear ratio γ and eliminating the deviation. It

As described above, the target rotation speed N determined based on the throttle valve opening θ and the vehicle speed v from the relationship shown in FIG.
_{When in} ^* and the actual engine speed N _in are controlled so that they match, the throttle valve opening θ
Is further increased, the gear ratio γ is changed in the downshift (increase) direction, and conversely, when the throttle valve opening θ is decreased, the gear ratio γ is upshifted (decreased). ) Direction. Further, when the throttle valve opening θ is a constant value, the vehicle speed v
When the vehicle speed v decreases, the gear ratio γ is changed in the downshift (increase) direction, and conversely, when the vehicle speed v is increased, the gear ratio γ is changed in the upshift (decrease) direction. Become.

Then, by executing step S4, the neutral control of the low vehicle speed brake is executed. That is,
As shown in FIG. 4, first, at step SS1, the flag F indicating the neutral control state by the low vehicle speed brake is set.
It is determined whether the content of 1 is 1. Initially flag F
Since the content of 1 is not 1, it is determined whether step SS2 is executed and the brake pedal 56 is operated, in other words, whether the service brake is in operation. If the determination in step SS2 is negative, step SS7 described later is executed to reset the content of the flag F to 0, but if the brake operation is determined in step SS2, the following step SS3 is executed. To be executed. Even when the determination in step SS1 is positive, step SS2 is skipped and step SS3 is directly executed. this is,
When the neutral control by the low vehicle speed brake is once started based on the brake operation, the step SS3 and subsequent steps are executed regardless of the operation state of the brake.

In step SS3, the engine 10 turns on the idle switch.
It is determined whether or not (θ = 0%). Step SS3
If θ = 0% is not determined in step SS7, the content of the flag F is reset to 0 in step SS7, but if θ = 0% is determined, step SS
At 4, it is determined whether the vehicle speed v is smaller than a predetermined constant value a. This value a is, for example, a vehicle speed value at which a feeling of deceleration is slightly generated after a low vehicle speed braking operation.

If the determination in step SS4 is negative, the content of the flag F is reset to 0 in step SS7, but if the determination is positive, step SS5 is executed and the release valve 86 is set to the first position. It is actuated to the release position shown. As a result, when the brake operation is performed while the vehicle is traveling forward at a relatively low vehicle speed and the engine 10 is in the no-load state, the forward clutch of the auxiliary transmission 30 is used.
The hydraulic oil supplied to 40 is discharged to the drain by the release valve 86, so that the auxiliary transmission 30 is brought into the neutral state and the power transmission is cut off. Then, in step SS6, the content of the flag F is set to 1.

As described above, according to the present embodiment, when the brake is operated and the throttle valve opening θ = 0 and the vehicle speed v is smaller than the predetermined constant value, the auxiliary transmission
Since 30 is set to the neutral state and power transmission is cut off, even if the brake for further deceleration is operated while the vehicle is traveling at a relatively low speed, the power transmission path is cut off by the neutral state of the auxiliary transmission. Therefore, although the gear ratio is changed in the downshift direction by the gear ratio control, a feeling of deceleration due to the engine braking action occurs after releasing the brake pedal 56, or a driver feels uncomfortable due to the feeling. What you give is eliminated. Incidentally, when the brake for further decelerating the vehicle while the vehicle is traveling at a relatively low speed is operated as described above, the gear is downshifted along the broken line in FIG. 3, so deceleration is obtained and the brake pedal is obtained. Even when the 56 is released, in the past, the driver feels uncomfortable due to the feeling of deceleration due to the downshift.

Further, according to the present embodiment, even after the auxiliary transmission 30 is once in the neutral state, if it is determined in step SS4 that the vehicle speed V has become equal to or higher than the predetermined constant value a, the auxiliary transmission 30 Since the neutral state is stopped and the power transmission path is connected, the engine braking action is obtained again. Therefore, even after the auxiliary transmission 30 is once brought into the neutral state by the operation of the brake, for example, when the vehicle speed V recovers to the predetermined value a or more in association with traveling on a downhill road, Since the neutral state of the auxiliary transmission 30 is stopped and the power transmission path is connected, there is an advantage that the engine braking action can be enjoyed again.

Although one embodiment of the present invention has been described above, the present invention can be applied to other aspects.

For example, in the above-described embodiment, the auxiliary transmission 30 is provided between the fluid coupling 12 and the continuously variable transmission 14, but it is provided between the continuously variable transmission 14 and the final reduction gear 50. May be. In short, continuously variable transmission 14 and auxiliary transmission 30
It suffices that and are inserted in series in the power transmission path from the engine 10 to the drive wheels 52.

Further, in the above-described embodiment, the gear ratio γ is controlled so that the target rotation speed N _in ^* determined from the relationship shown in FIG. 3 and the actual input shaft rotation speed N _in match. Determine the target speed ratio γ ^* (= N _in ^* / N _out ) from the target speed N _in ^* and the actual output speed N _{out so} that the actual speed ratio matches the target speed ratio γ ^*. It may be controlled.

Further, although the auxiliary transmission 30 in the above-described embodiment can be switched to the forward gear stage and the reverse gear stage,
It does not matter even if the forward gear is of a type having a plurality of types.

Further, although the throttle valve opening θ is used as a parameter in the above-mentioned embodiment, the accelerator pedal operation amount,
Alternatively, an amount that changes with this may be used.

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

The above is merely an application example of the present invention, and the present invention can be variously modified without departing from the spirit thereof.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the configuration of an embodiment of the present invention.
FIG. 2 is a flow chart for explaining the operation of the embodiment shown in FIG. FIG. 3 is a diagram used in the description of the operation of FIG. 2, and is a diagram showing a relationship for determining a target rotation speed from a vehicle speed and a throttle valve opening. FIG. 4 is a diagram for explaining the operation of the neutral control routine for the low vehicle speed brake of FIG. 14: continuously variable transmission 30: auxiliary 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)

Claims (1)

(57) [Claims] 1. A continuously variable transmission having a continuously variable speed ratio, and a sub transmission having a plurality of types of gears and selectively switching to any one of the gears or a neutral state. A control device for a vehicle transmission of a type in which the continuously variable transmission and an auxiliary transmission are inserted in series in a power transmission path from an engine to driving wheels, the brake operation detecting a brake operation of the vehicle. Detecting means, speed detecting means for detecting a traveling speed of the vehicle, accelerator pedal operation amount detecting means for detecting an accelerator pedal operation amount of the vehicle, and when the brake operation of the vehicle is detected by the brake operation detecting means, The auxiliary transmission is continuously set to a neutral state on condition that the traveling speed of the vehicle is lower than a predetermined value and the accelerator pedal operation amount is smaller than a predetermined value. A control device for a transmission for a vehicle, comprising: