JP3810810B2 - Shift control device for continuously variable transmission - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a transmission control device for a continuously variable transmission that continuously controls a transmission ratio according to an operation amount of a transmission ratio actuator.
[0002]
[Prior art]
Conventionally, as a transmission control device for a continuously variable transmission, for example, Japanese Patent Application Laid-Open No. 58-180864 (Conventional Example 1), Japanese Patent Application Laid-Open No. 54-72360 (Conventional Example 2), and Japanese Patent Application Laid-Open No. 1-112067. What is described in (Conventional Example 3) is known.
[0003]
The conventional example 1 aims at obtaining a good acceleration feeling. When the actual acceleration is smaller than a predetermined comparison reference acceleration, a large correction gear ratio is commanded, and the engine is operated in an exercise state where the acceleration is insufficient. A configuration for increasing the output horsepower by increasing the rotation speed is described.
[0004]
The above-mentioned conventional example 2 aims to bring the engine operation to a predetermined desired state in accordance with the running load of the vehicle, and uses the engine operating state, the vehicle running load, the vehicle characteristic, and the engine characteristic as signals. A configuration for controlling the gear ratio is described.
[0005]
The conventional example 3 aims at reducing the storage capacity and facilitating the change of the shift pattern. In the case of the engine brake travel range, a limiter is applied to the shift pattern of the normal travel range to set the target engine. A configuration for increasing the rotational speed is described.
[0006]
[Problems to be solved by the invention]
However, in the transmission control devices for continuously variable transmissions of the above-described conventional example 1 and conventional example 2, the engine speed fluctuates even when there is no accelerator operation or change in vehicle speed when the vehicle is traveling at a high gradient. Therefore, although the acceleration performance is improved, if the gear ratio changes during traveling at a constant speed, the engine feels as if it has blown, and the traveling feeling is impaired.
[0007]
In the transmission control device for the continuously variable transmission of the above-described Conventional Example 3, when it is desired to perform acceleration traveling while increasing the target engine speed, a manual operation for switching from the normal traveling range to the engine braking traveling range is performed. Cost.
[0008]
The present invention has been made paying attention to the above-mentioned problems, and a first object is to provide a transmission control device for a continuously variable transmission that continuously controls the transmission ratio according to the operation amount of the transmission ratio actuator. When driving uphill, there is no need for manual operation and the road surface slope And vehicle speed Regardless of the acceleration performance.
[0009]
The second purpose is in addition to the first purpose. Appropriately set the minimum target engine speed to be limited according to the driving load to ensure good driving feeling when climbing There is.
[0010]
The third purpose is: In a continuously variable transmission speed change control device that controls the speed ratio in a stepless manner according to the operation amount of the speed ratio actuator, the acceleration performance during re-acceleration is not required during climbing, and no manual operation is required regardless of the road gradient. Improve response There is.
[0011]
[Means for Solving the Problems]
In order to achieve the first object, in the transmission control device for a continuously variable transmission according to the first aspect of the invention, as shown in the claim correspondence diagram of FIG. A continuously variable transmission b whose speed ratio is controlled in a stepless manner according to the operation amount of the ratio actuator a, a travel load detecting means c for detecting a travel load, and a target engine speed according to a predetermined vehicle state detected The target engine speed setting means d for setting the number, and the detected traveling load is larger And the higher the vehicle speed, Limiting the minimum target engine speed to be higher (or larger) and if the current target engine speed is lower (or smaller) than the minimum target engine speed, the current target engine speed is set to the lowest target engine speed. A target engine speed limiting means e to be set, and a gear ratio control means f to output a control command for obtaining the set target engine speed to the speed ratio actuator a while receiving a restriction on the minimum target engine speed. It is characterized by having.
[0012]
In order to achieve the second object, in the transmission control device for a continuously variable transmission according to the second invention, in the transmission control device for a continuously variable transmission according to claim 1, The target engine speed setting means is a means for setting the target engine speed according to at least the accelerator opening and the vehicle speed, The target engine speed limiting means is Rotational speed lower than the load / load speed calculated from the driving load And a means for limiting the engine speed to a target engine speed equal to or higher than the normal minimum engine speed.
[0013]
In order to achieve the third object, in the transmission control device for a continuously variable transmission according to the third aspect of the present invention, the transmission ratio actuator a operated by an external command and the stepless operation according to the operation amount of the transmission ratio actuator a. A continuously variable transmission b whose gear ratio is controlled, traveling load detection means c for detecting a traveling load, and target engine speed setting means d for setting a target engine speed according to a detected predetermined vehicle state. In order to increase (or increase) the minimum target engine speed as the detected traveling load increases, a rotational speed reduction allowable value that decreases as the traveling load increases from the actual engine speed. Subtraction The target engine speed is set to the minimum target engine speed when the current target engine speed is lower (or smaller) than the minimum target engine speed. A speed ratio limiting means e, and a gear ratio control means f for outputting to the speed ratio actuator a a control command for obtaining a set target engine speed while being limited by the minimum target engine speed. It is characterized by.
[0014]
[Action]
The operation of the first invention will be described.
[0015]
When the vehicle travels, the travel load is detected by the travel load detection means c, and the target engine speed setting means d sets the target engine speed according to the predetermined vehicle state detected. Then, in the target engine speed limit means e, the target engine speed setting means d for setting the target engine speed according to the detected predetermined vehicle state, and the detected traveling load is larger. And the higher the vehicle speed, Limiting the minimum target engine speed to be higher (or larger) and if the current target engine speed is lower (or smaller) than the minimum target engine speed, the current target engine speed is set to the lowest target engine speed. The transmission ratio control means f outputs a control command for obtaining the set target engine speed while receiving the restriction on the minimum target engine speed, to the speed ratio actuator a, and according to the operation amount of the speed ratio actuator a. Thus, the gear ratio is controlled steplessly by the continuously variable transmission b.
[0016]
Therefore, when traveling on an uphill, for example, when controlling the gear ratio so as to obtain a target engine speed set according to a predetermined vehicle state, the target engine speed is set with reference to flat road travel, The target engine speed becomes too low and the gear ratio is not sufficiently changed to the deceleration side, the engine driving force against the running resistance is insufficient and the running performance is inferior, and the driver sets the target engine speed in advance from the running range. It is necessary to select the low range that is set high. On the other hand, in the first invention, a traveling load including a road surface gradient is detected. And the higher the vehicle speed, If the minimum target engine speed is automatically limited to the higher one, that is, if the current target engine speed is lower (or smaller) than the minimum target engine speed, the current target engine speed is set to the minimum target engine speed As a result, the decrease in engine driving force is suppressed, so manual switching of the range position is not required, and the road surface gradient And vehicle speed Regardless of the acceleration performance will be ensured.
[0017]
The operation of the second invention will be described.
[0018]
When the vehicle is traveling, the target engine speed setting means d sets the target engine speed according to at least the accelerator opening and the vehicle speed, and the target engine speed limit means e uses the load / load speed calculated by the travel load. Is limited to a target engine speed that is lower than the normal minimum engine speed. .
[0019]
Therefore, By limiting the target engine speed with the load load speed that balances the driving load including the road surface gradient and the output torque as the upper limit, there is no acceleration even if the accelerator is not operated, Good driving feeling is secured .
[0020]
The operation of the third invention will be described.
[0021]
In the third aspect of the invention, a traveling load including a road surface gradient is detected, and the rotation that becomes a smaller value as the traveling load is increased from the actual engine rotational speed so that the minimum target engine rotational speed is increased (or increased) as the traveling load increases. Number reduction tolerance Subtraction Is set to the minimum target engine speed. If the current target engine speed is lower (or smaller) than the minimum target engine speed, the current target engine speed is set to the minimum target engine speed. That is, when the target engine speed limiting means e limits the target engine speed according to the travel load, the limit is a value that does not exceed the actual engine speed and is equal to or higher than the normal minimum engine speed. It will be limited to the number of revolutions.
[0022]
Therefore, The target engine speed does not drop significantly even when the driver who has stepped on the accelerator performs the accelerator return operation, so the acceleration performance and response can be improved when the accelerator is re-accelerated after that. .
[0023]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0024]
(First embodiment)
First, the configuration will be described.
[0025]
2 and 3 show claims 1 and Claim 2 1 is a cross-sectional view showing a half-toroidal continuously variable transmission (corresponding to a continuously variable transmission b) to which a transmission control device according to a first embodiment corresponding to the invention described in FIG.
[0026]
2 and 3, 1 is an input shaft, 2 is a loading cam, 3 is a cam roller, 4 is an input disk, 5 is a power roller, 6 is an output disk, 7 is an output gear, 8 and 9 are bearings, 10 and 11 Is a trunnion, 12 is a control valve, 13 is a stepping motor (corresponding to gear ratio actuator a), 14 is a sensor rod, 15 is a link, 16 is a precess cam, 17 is a spool, 18 is a sleeve, 19 is a first cylinder, 20 is The second cylinder, 21 is a third cylinder, and 22 is a fourth cylinder.
[0027]
The input torque from the input shaft 1 is transmitted to the loading cam 2 → cam roller 3 → input disk 4 → power roller 5 → output disk 6 → output gear 7.
[0028]
The bearing 8 supports the thrust force of the power roller 5. The bearing 9 supports the axial force of the input / output disks 4 and 6.
[0029]
The reaction force of the driving force acting on the trunnions 10 and 11 is received by the oil pressure in the four hydraulic cylinders 19, 20 and 21.
[0030]
When power is transmitted between the input / output disks 4 and 6 and the power roller 5 and all the rotation axes of the power rollers 5 and the rotation axes of the input / output disks 4 and 6 have intersections, FIG. The balance of force in the y-axis direction is expressed by the following equation.
[0031]
2Ft = PH, S-PL, S
Here, PH is the hydraulic pressure of the first and third cylinders 19 and 21, PL is the hydraulic pressure of the second and fourth cylinders 20 and 22, and S is the pressure receiving area of the cylinder. The 1st, 3rd cylinders 19 and 21 and the 2nd and 4th cylinders 20 and 22 are each connected by piping. The hydraulic pressures PH and PL are controlled by the control valve 12.
[0032]
FIG. 4 is a block diagram showing an electronic control system of the shift control device.
[0033]
In FIG. 4, 13 is a stepping motor, 30 is a CVT control unit, 31 is a throttle opening sensor, 32 is a vehicle speed sensor, 33 is an engine speed sensor, 34 is a turbine speed sensor, 35 is a select position switch, and 36 is others. Sensor switches.
[0034]
The CVT control unit 13 is an electronic control circuit centered on a microcomputer, and an actuator operation amount is calculated from various control input information, and a step pulse command is output to the stepping motor 13 to obtain the actuator operation amount.
[0035]
The throttle opening sensor 31 detects the throttle opening TVO.
[0036]
The vehicle speed sensor 32 detects a vehicle speed VSP.
[0037]
The engine speed sensor 33 detects the engine speed Ne.
[0038]
The turbine rotation speed sensor 34 detects a turbine rotation speed Nt (input shaft rotation speed) of a torque converter provided between an engine output shaft (not shown) and the input shaft 1 of the continuously variable transmission.
[0039]
The select position switch 35 detects a range position (for example, P range, R range, N range, D range, Ds range) selected by a select lever (not shown) by a switch signal.
[0040]
Next, the operation will be described.
[0041]
[Shift operation]
Shifting in the half toroidal type continuously variable transmission is performed by tilt angle control of the power roller 5. The force for tilting the power roller 5 is obtained by utilizing a side slip generated by moving the central axis of the power roller 5 in the y-axis direction of FIG. As shown in FIG. 3, when the rotation axis of the power roller 5 and the rotation axis of the input / output disks 4 and 6 cross each other to balance the force and transmit power, the stepping motor 13 controls the control valve 12. When the sleeve 18 is moved in the x-axis direction, the pressures PH and PL change, and the trunnions 10 and 11 move in the y-axis direction (opposite directions), and the power roller 5 and the input / output disks 4 and 6 The point of contact changes. As a result, a tilting force is generated, and the trunnions 10 and 11 tilt in directions symmetrical to each other.
[0042]
A sensor rod 14 is attached to the trunnions 10 and 11, and the tilt amount is changed to the movement of the spool 17 of the control valve 12 in the x-axis direction (opposite to the sleeve 18) via the link 15 at the tip thereof. A precess cam 16 is attached.
[0043]
The precess cam 16 moves the spool 17 so as to correct the displacement of the first sleeve 18 to change the pressure. When the force is balanced, the tilting is stopped.
[0044]
[Shift control operation]
FIG. 5 is a flowchart showing the flow of the shift control processing operation performed by the CVT control unit 30, and each step will be described below.
[0045]
In step 50, the throttle opening TVO, the vehicle speed VSP, and the turbine speed Nt are input.
[0046]
In step 51, the target turbine speed TNt is calculated (corresponding to the target engine speed setting means d) from the throttle opening degree TVO and the vehicle speed VSP indicating the vehicle operating state and the D range shift pattern shown in the step frame.
[0047]
In step 52, the running resistance is calculated by the following calculation process (corresponding to the running load detecting means c).
[0048]
Running resistance ≒ F-mα
F: Transmission output torque (F = Tt * i)
Tt: Turbine torque (retrieval from turbine torque map not shown using throttle opening TVO, turbine speed Nt, etc.)
i: Actual gear ratio (i = K1 · Nt / VSP)
m: Constant (vehicle weight)
α: Vehicle acceleration (differential calculation of vehicle speed VSP)
In step 53, the target turbine speed limit value TNt.LIM is set using the target turbine speed limit value characteristic set in advance using the travel resistance as a parameter, and the travel resistance and vehicle speed VSP obtained in step 52. .
[0049]
In step 54, it is determined whether the target turbine speed TNt set in step 51 is less than the target turbine speed limit value TNt.LIM set in step 53.
[0050]
In step 55, when TNt <TNt.LIM, the target turbine speed TNt is set to TNt = TNt.LIM. Here, Step 53 to Step 55 correspond to the target engine speed limiting means e.
[0051]
In step 56, a control command for controlling the gear ratio is output so that the actual turbine speed Nt matches the target turbine speed TNt set in step 51 or step 55 (corresponding to the gear ratio control means f).
[0052]
In this gear ratio control, when the target turbine speed TNt is given, the target gear speed TNt (= input shaft speed), the vehicle speed VSP (= output shaft speed), and the coefficient K1, The ratio TRATIO is calculated, and a step pulse command for obtaining this target speed ratio TRATIO is sent to the stepping motor 13.
[0053]
TRATIO = K1 * (TNt / VSP)
[Setting method of target turbine speed limit value characteristics]
A method for setting the target turbine speed limit value characteristic used in step 53 will be described.
[0054]
First, on the travel performance diagram in which the output torque characteristic with respect to the vehicle speed shown in FIG. 6 is expressed with the throttle opening as a parameter, the travel resistance characteristics at each gradient (for example, 0%, 3%, 6%, 10%) are shown. The road load vehicle speed is obtained from the intersection of the throttle openings.
[0055]
Here, taking the case of a 6% gradient as an example, the intersection of each throttle opening of the 6% running resistance characteristic and the transmission output torque characteristic becomes a point indicated by a circle in FIG. 6, and the vehicle speed read at each point. Is the road load vehicle speed at each throttle opening. The road load vehicle speed is the vehicle speed that keeps the balance between the running resistance and the transmission output torque and keeps the accelerator constant, and the vehicle accelerates without the accelerator being depressed. It is the limit vehicle speed that never happens.
[0056]
Then, the load turbine speed and the throttle opening point are plotted on the D-range shift pattern for each gradient, and the target turbine rotation speed limit value characteristic is set by smoothly connecting the plotted points.
[0057]
Here, taking the case of a 6% gradient as an example, as shown in FIG. 7, a black dot is determined on the D-range shift pattern according to the road load vehicle speed and each throttle opening, and the black dot is smoothly connected. This line becomes the target turbine speed limit value characteristic with a 6% gradient. The target turbine speed limit value based on the load / load speed is a value that increases the limit of the target turbine speed as the gradient increases from 0% → 6% → 10%, as is apparent from FIG. It becomes.
[0058]
[When driving uphill]
When traveling on an uphill, for example, when controlling the gear ratio so as to obtain a target turbine speed set according to the throttle opening and the vehicle speed, the target turbine speed is set based on a preset control characteristic based on flat road travel. By setting the number, the target turbine speed will be too low and the gear ratio will not be changed sufficiently to the deceleration side, the engine driving force against running resistance will be insufficient and the running performance will be inferior, and the driver will run It is necessary to perform a selection operation from the range to a low range in which the target engine speed is set in advance.
[0059]
On the other hand, when traveling, the running resistance including the road surface gradient is calculated in step 52. In step 53, for example, when the vehicle speed is the same, the target turbine speed limit value TNt.LIM increases as the running resistance increases. In step 54 and step 56, the target turbine speed TNt is limited to be equal to or higher than the target turbine speed limit value TNt.LIM, and the gear ratio control is performed.
[0060]
Therefore, when the vehicle travels uphill such that the target turbine speed TNt calculated in step 51 is equal to or less than the target turbine speed limit value TNt.LIM, the target turbine speed TNt is automatically set to the target turbine speed limit value TNt.LIM. By limiting to this, a decrease in the turbine rotational speed, that is, a decrease in the engine driving force is suppressed, and acceleration performance is ensured during uphill traveling.
[0061]
Moreover, since the target turbine rotational speed limit value TNt.LIM is set to a larger value as the running resistance increases, the same acceleration performance is ensured regardless of the road surface gradient.
[0062]
Furthermore, manual operation for switching the range position is not required to obtain acceleration performance when traveling on an uphill.
[0063]
In addition, the load turbine speed that balances the running resistance including road surface gradient and the transmission output torque is set as the target turbine speed limit value TNt.LIM so that the target turbine speed is limited, so that the accelerator operation is not performed. However, there is no acceleration, and a good running feeling during climbing is ensured.
[0064]
Next, the effect will be described.
[0065]
(1) In a shift control device for a half toroidal continuously variable transmission that continuously controls the gear ratio according to the operation amount of the stepping motor 13, a target turbine speed limit value that is set to a larger value as the running resistance increases. When it is less than TNt.LIM, the target turbine speed TNt set in accordance with the throttle opening TVO and the vehicle speed VSP is defined as the target turbine speed limit value TNt.LIM. When traveling, it is possible to ensure acceleration performance without requiring manual operation and irrespective of the road surface gradient.
[0066]
(2) Since the load turbine speed that balances the running resistance including road surface gradient and the transmission output torque is set as the target turbine speed limit value TNt.LIM, the target turbine speed is limited. In this way, it is possible to ensure a good running feeling when climbing up.
[0067]
(Second embodiment)
Claim 3 A transmission control apparatus for a continuously variable transmission according to a second embodiment corresponding to the described invention will be described. Since the system configuration of the second embodiment is the same as that of the first embodiment, illustration and description thereof are omitted.
[0068]
Next, the operation will be described.
[0069]
[Shift control operation]
FIG. 8 is a flowchart showing the flow of the shift control processing operation performed by the CVT control unit 30, and each step will be described below.
[0070]
In step 80, the throttle opening TVO, the vehicle speed VSP, and the turbine speed Nt are input.
[0071]
In step 81, the target turbine speed TNt is calculated from the throttle opening TVO and the vehicle speed VSP indicating the vehicle operating state and the D range shift pattern shown in the step frame (corresponding to the target engine speed setting means d).
[0072]
In step 82, the running resistance is calculated by the same calculation process as in step 52 (corresponding to the running load detecting means c).
[0073]
In step 83, the turbine rotation speed reduction allowable value ΔN is calculated as a function of the running resistance obtained in step 82.
[0074]
Here, the turbine rotational speed reduction allowable value ΔN is a larger value as the traveling resistance is smaller, and a smaller value as the traveling resistance is larger. However, it is given by ΔN ≧ 0.
[0075]
In step 84, it is determined whether the running resistance exceeds a predetermined value.
[0076]
In step 85, when it is determined in step 84 that the running resistance> predetermined value, the target turbine speed limit value TNt.LIM is calculated by the following equation.
[0077]
TNt.LIM = Nt−ΔN
Nt is the actual turbine speed detected by the sensor.
[0078]
In step 86, it is determined whether or not the target turbine speed TNt set in step 81 is less than the target turbine speed limit value TNt.LIM set in step 85.
[0079]
In step 87, when TNt <TNt.LIM, the target turbine speed TNt is set to TNt = TNt.LIM. Here, Step 83 to Step 87 correspond to the target engine speed limiting means e.
[0080]
In step 88, a control command for controlling the gear ratio is output so that the actual turbine speed Nt matches the target turbine speed TNt set in step 81 or step 87 (corresponding to the gear ratio control means f).
[0081]
[When driving uphill]
When traveling uphill, in step 82, the running resistance including the road surface gradient is calculated. In step 83, as the running resistance increases, the turbine rotation speed reduction allowable value ΔN with a smaller value is calculated. If the running resistance exceeds a predetermined value, In step 85, the target turbine speed limit value TNt.LIM is set by the difference between the actual turbine speed Nt and the turbine speed reduction allowable value ΔN, and in step 86 and step 87, the target turbine speed limit TNt is set to the target turbine speed limit. Transmission ratio control is performed while being limited to the value TNt.LIM or more.
[0082]
Therefore, when the vehicle travels uphill such that the target turbine speed TNt calculated in step 81 is equal to or less than the target turbine speed limit value TNt.LIM, the target turbine speed TNt is automatically set to the target turbine speed limit value TNt.LIM. By limiting to this, a decrease in the turbine rotational speed, that is, a decrease in the engine driving force is suppressed, and acceleration performance is ensured during uphill traveling.
[0083]
In addition, the turbine rotational speed reduction allowable value ΔN is set to be a smaller value as the running resistance increases, and is set by the difference between the actual turbine rotational speed Nt and the turbine rotational speed reduction allowable value ΔN, as shown in FIG. Since the target turbine speed limit value TNt.LIM is set to a larger value as the running resistance is larger, the same acceleration performance is ensured regardless of the road surface gradient.
[0084]
Furthermore, manual operation for switching the range position is not required to obtain acceleration performance when traveling on an uphill.
[0085]
The target turbine speed limit value TNt.LIM is calculated by the formula TNt.LIM = Nt−ΔN, and the target turbine speed TNt does not exceed the actual turbine speed Nt. Even when the accelerator is returned, the target turbine speed does not decrease greatly, and thereafter, the acceleration performance and response when reacceleration by depressing the accelerator can be improved.
[0086]
Next, the effect will be described.
[0087]
(3) In a shift control device for a half toroidal continuously variable transmission that continuously controls the gear ratio according to the operation amount of the stepping motor 13, when the running resistance is greater than or equal to a predetermined value, the actual turbine speed Nt and the turbine speed The target turbine speed limit value TNt.LIM is set to a larger value as the running resistance increases due to the difference from the number reduction allowable value ΔN, and the target turbine speed TNt set according to the throttle opening TVO and the vehicle speed VSP is set as the target. When the turbine speed limit value is less than TNt.LIM, the target turbine speed TNt is defined as the target turbine speed limit value TNt.LIM so that the gear ratio is controlled. Moreover, acceleration performance can be ensured regardless of the road surface gradient.
[0088]
(4) The target turbine speed TNt limited by the target turbine speed limit value TNt.LIM is given as a value that does not exceed the actual turbine speed Nt. It can be improved.
[0089]
While the embodiments have been described with reference to the drawings, the specific configuration is not limited to the embodiments, and modifications and additions within the scope not departing from the gist of the present invention are included in the present invention.
[0090]
For example, in the embodiment, the application example to the half-toroidal continuously variable transmission is shown, but the present invention can also be applied to a V-belt type continuously variable transmission.
[0091]
In the embodiment, an example is shown in which the target value is the target turbine speed, but it may be the target engine speed.
[0092]
In the embodiment, an example in which the traveling load detection means is obtained by calculation using the transmission output torque and the vehicle acceleration is shown, but the road load may be directly detected to obtain the traveling load.
[0093]
【The invention's effect】
As described above, according to the first aspect of the present invention, in the shift control device for a continuously variable transmission that continuously controls the gear ratio according to the operation amount of the gear ratio actuator, the detected traveling load is The bigger it is And the higher the vehicle speed, The minimum target engine speed is limited to be high (or large), and if the current target engine speed is lower (or smaller) than the minimum target engine speed, the current target engine speed is set to the minimum target engine speed. Target engine speed limiting means for setting is provided, the target engine speed set according to a predetermined vehicle state is limited by the minimum target engine speed, and the target engine speed used for control is set. Because it is a device that performs gear ratio control that can obtain a number, when climbing uphill, manual operation is not required and the road surface gradient And vehicle speed Regardless of whether the acceleration performance can be ensured.
[0094]
In the invention according to claim 2, Claim 1 In the described transmission control device for continuously variable transmission, The target engine speed setting means is a means for setting the target engine speed in accordance with at least the accelerator opening and the vehicle speed, and the target engine speed limit means is more than the load / load speed calculated by the traveling load. A means to limit the target engine speed to a target engine speed at a low speed and above the normal minimum engine speed. Set the target engine speed according to at least the accelerator opening and the vehicle speed. In addition to the above effects, Appropriately set the minimum target engine speed to be limited according to the driving load to ensure good driving feeling when climbing The effect that it can be obtained.
[0095]
According to a third aspect of the present invention, in the transmission control device for a continuously variable transmission that controls the transmission ratio steplessly in accordance with the operation amount of the transmission ratio actuator, the minimum target engine increases as the detected traveling load increases. In order to increase (or increase) the rotational speed, the rotational speed reduction allowable value that becomes a smaller value as the traveling load increases from the actual engine rotational speed. Subtraction The target engine speed is set to the minimum target engine speed when the current target engine speed is lower (or smaller) than the minimum target engine speed. A speed limiter is provided to set a target engine speed used for control by limiting the target engine speed set according to a predetermined vehicle state by the minimum target engine speed and to obtain the target engine speed. Since the apparatus performs the ratio control, it is possible to improve the acceleration performance and response at the time of reacceleration without requiring a manual operation when traveling uphill and regardless of the road surface gradient.
[Brief description of the drawings]
FIG. 1 is a claim correspondence diagram showing a transmission control device for a continuously variable transmission according to the present invention.
FIG. 2 is a cross-sectional view showing a half-toroidal continuously variable transmission to which the shift control device of the first embodiment is applied.
3 is a cross-sectional view taken along line AA of FIG. 2 showing a half-toroidal continuously variable transmission to which the shift control device of the first embodiment is applied.
FIG. 4 is a block diagram showing an electronic control system of the speed change control device of the first embodiment.
FIG. 5 is a flowchart showing a flow of a shift control processing operation performed by the CVT control unit of the first embodiment device.
FIG. 6 is a transmission output torque characteristic diagram with respect to vehicle speed for explaining a road load vehicle speed used for shift control in the continuously variable transmission of the first embodiment.
FIG. 7 is a target turbine speed characteristic diagram for explaining a turbine speed limit value used in the first embodiment device;
FIG. 8 is a flowchart showing a flow of a shift control process performed by a CVT control unit of the second embodiment.
[Explanation of symbols]
a Gear ratio actuator
b Continuously variable transmission
c Running load detection means
d Target engine speed setting means
e Target engine speed limiting means
f Gear ratio control means

Claims (3)

A gear ratio actuator operated by an external command;
A continuously variable transmission in which the gear ratio is controlled in a stepless manner according to the operation amount of the gear ratio actuator;
Traveling load detection means for detecting the traveling load;
Target engine speed setting means for setting the target engine speed in accordance with a predetermined vehicle state to be detected;
The higher the traveling load detected and the higher the vehicle speed, the higher (or larger) the minimum target engine speed is limited, and the current target engine speed is lower (or smaller) than the minimum target engine speed. The target engine speed limiting means for setting the current target engine speed to the minimum target engine speed,
Gear ratio control means for outputting a control command for obtaining a set target engine speed while receiving a restriction on the minimum target engine speed, to the speed ratio actuator;
A transmission control device for a continuously variable transmission, comprising: The transmission control device for a continuously variable transmission according to claim 1,
The target engine speed setting means is a means for setting the target engine speed according to at least the accelerator opening and the vehicle speed,
The target engine speed limiting means is a means for limiting the target engine speed to a target engine speed that is lower than a normal load engine speed that is lower than a road load speed calculated by a traveling load. A transmission control device for a continuously variable transmission. A gear ratio actuator operated by an external command;
A continuously variable transmission in which the gear ratio is controlled in a stepless manner according to the operation amount of the gear ratio actuator;
Traveling load detection means for detecting the traveling load;
Target engine speed setting means for setting the target engine speed in accordance with a predetermined vehicle state to be detected;
The minimum target engine speed is obtained by subtracting the engine speed reduction allowable value that becomes smaller as the travel load increases from the actual engine speed so that the minimum target engine speed increases (or increases) as the detected travel load increases. A target engine speed limiting means for setting the current target engine speed to the minimum target engine speed when the current target engine speed is lower (or smaller) than the minimum target engine speed;
Gear ratio control means for outputting a control command for obtaining a set target engine speed while receiving a restriction on the minimum target engine speed, to the speed ratio actuator;
A transmission control device for a continuously variable transmission, comprising:

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