JP3048577B2 - Control device for continuously variable transmission for vehicles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control device for a continuously variable transmission for a vehicle, and more particularly, to a case where the vehicle is hunting when traveling on an uneven road surface (bad road). The present invention relates to a control device for a continuously variable transmission for a vehicle, which does not cause a problem.

2. Description of the Related Art When a continuously variable transmission is mounted on an automobile, a motorcycle, or the like (hereinafter, referred to as a vehicle), the continuously variable transmission has a target whose transmission ratio is calculated according to an engine parameter or the like during traveling. Control is performed so that the speed matches the speed ratio or the engine speed of the vehicle matches the target engine speed calculated according to the running engine parameters and the like.

Such a control device for a continuously variable transmission for vehicles is described in, for example, Japanese Patent Application Laid-Open No. 62-273189.

(Problem to be Solved by the Invention) In the above-described conventional technology, when the vehicle travels on an uneven road surface (bad road), there is a possibility that the vehicle may hunt.

 The reason will be described below.

FIG. 9 is a diagram showing a relationship between a vehicle traveling on an uneven road surface while holding an accelerator constant, and a speed ratio of a continuously variable transmission mounted on the vehicle. In FIG. 9, the irregularities on the road surface 905 are exaggerated for easy viewing.

In the figure, when the vehicle travels on an uneven road surface 905 with the accelerator held constant, when the vehicle is traveling uphill as indicated by reference numeral 901, the engine load increases. The ratio is set to the low side (that is, the gear ratio is large).

When the vehicle is traveling on a flat road as indicated by reference numeral 902, the engine load is reduced, so that the gear ratio is changed to a high side (that is, a small gear ratio side).

Also, when the vehicle is in a down state as indicated by reference numeral 903, the engine load is further reduced, so that the gear ratio is further changed to the high side.

FIG. 10 is a diagram showing a change in the speed ratio of the continuously variable transmission when the vehicle travels on a level ground, an uneven road surface, a downhill, or an uphill with the accelerator kept constant. Note that this
In the table shown below FIG. 10, the sign of + indicates that the speed ratio increases, the sign of-indicates that the speed ratio decreases, and 0 indicates that the speed ratio does not change.

As shown in FIG. 10, when the accelerator is held constant and the vehicle travels on level ground, the gear ratio is constant, and when the vehicle travels downhill or uphill, The gear ratio is set from low to high or from high to low, respectively.

When the accelerator is kept constant and the vehicle travels on an uneven road surface (bad road), the speed ratio fluctuates between low and high as shown.

In general, the control of the continuously variable transmission is performed at every predetermined sampling period. However, depending on the relationship between this period and the period of unevenness of the rough road, for example, the control device of the vehicle may be configured such that the vehicle travels on an uphill. Even if it is determined that the vehicle is on the low side and the gear ratio is set to the low side, the vehicle is actually starting to go downhill, and thereafter, the control device determines that the vehicle is traveling downhill. Even when the gear ratio is set to the high side, the vehicle may actually start climbing uphill.

If such a situation occurs continuously, the vehicle may be hunted, resulting in an inconvenience of increased jerkyness when traveling on uneven road surfaces.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a control device for a continuously variable transmission for a vehicle that does not cause hunting even when the vehicle travels on a rough road. Is to provide.

(Means and Actions for Solving the Problems) In order to solve the above problems, the present invention determines whether or not a running road surface is a rough road having irregularities, and determines that the road surface is a rough road. In this case, the target gear ratio is fixed. Even when the control of the continuously variable transmission is performed so that the target engine speed and the actual engine speed match, the search or calculation of the target engine speed is stopped and the speed ratio of the continuously variable transmission is fixed. There is a characteristic in that it is done.

In this way, when the road surface is a rough road with unevenness,
Since the speed ratio of the continuously variable transmission is fixed, hunting is prevented.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings.

First, the configuration of the continuously variable transmission applied to the first embodiment of the present invention will be described with reference to FIG.

In FIG. 2, a continuously variable transmission 1 is formed in a casing 2, and includes a drive pulley 4 provided on an upper drive shaft 3 in the figure and a driven pulley 6 provided on a lower driven shaft 5 in the figure.
, The endless belt 7 is wound.

The drive pulley 4 is divided into a fixed pulley half 4a integral with the drive shaft 3 and a movable pulley half 4b separate from the drive shaft 3, and the movable pulley half 4b is In accordance with the oil pressure supplied into the pressure chamber 9 on the back side, it moves in the directions of arrows A and B while being prevented from rotating by the drive shaft 3. Therefore, by adjusting the hydraulic pressure supplied into the pressure chamber 9, the groove width of the driving pulley 4 is adjusted. The passage for introducing the hydraulic pressure is formed by an introduction port 2a formed in the casing 2, a hollow interior of the drive shaft 3, and a through hole 3a, regardless of whether the drive shaft 3 rotates or not. The hydraulic pressure can be introduced from.

On the other hand, the driven pulley 6 is divided into a fixed-side pulley half 6a integral with the driven shaft 5 and a movable-side pulley half 6b separate from the driven shaft 5, and the movable-side pulley half 6b is In accordance with the oil pressure supplied into the pressure chamber 10 on the back side, the rotation is moved in the directions of arrows A and B while being prevented from rotating by the driven shaft 5. Therefore, by adjusting the hydraulic pressure supplied into the pressure chamber 10, the groove width of the driven pulley 6 is adjusted. The passage for introducing the hydraulic pressure is formed by an introduction port 2b formed in the casing 2, a feed pipe 11 inside the hollow of the driven shaft 5, and a through hole 5a, regardless of whether the driven shaft 5 rotates. A hydraulic pressure can be introduced from outside the casing 2.

A rotating body 13 to which a gear 12 is attached is rotatably fitted to the left side of the drive shaft 3.
The gear meshes with a gear 15 attached to a crankshaft 14 of the engine. A clutch 16 is provided between the rotating body 13 and the drive shaft 3.
Is configured. In the clutch 16, a friction plate 18 on the clutch inner 17 side provided on the rotating body 13 and a friction plate 20 on the clutch outer 19 side provided on the drive shaft 3 are provided to face each other.
By introducing hydraulic pressure into the pressure chamber 21 provided on the drive shaft 3 side, the clutch piston 22 in the pressure chamber 21 is moved in the direction of arrow A, and the friction plates 18 and 20 are brought into strong contact with each other. I have. Naturally, when a high oil pressure is introduced into the pressure chamber 21 and the friction plates 18 and 20 are strongly pressed against each other, the clutch 16 is connected, and the rotational force of the engine is transmitted from the rotating body 13 to the drive shaft 3.
Will be transmitted to The passage for introducing the hydraulic pressure into the pressure chamber 21 is formed by an introduction port 2 c formed in the casing 2, a feed pipe 23 inside the hollow of the drive shaft 3, a through hole 3 b, and a pressure oil passage 24. The hydraulic pressure can be introduced from outside the casing 2 regardless of whether the drive shaft 3 rotates.

An oil supply path to the endless belt 7 is formed in the driven shaft 5. That is, pressure oil from the introduction port 2d formed in the casing 2 is guided into the flow path 5b in the driven shaft 5,
Further, the driven shaft 5 is discharged toward the endless belt 7 by a centrifugal force from a through hole 5c extending in a radial direction of the driven shaft 5.

As described above, the casing 2 includes the continuously variable transmission 1 and other related mechanisms.

Next, the first embodiment of the present invention, in which the continuously variable transmission 1 is controlled, is described.
A configuration example of the embodiment will be described. This control device has a mechanical component and an electrical component. Therefore, first, mechanical components will be described with reference to FIG.

In FIG. 2, 31 is a pump as a pressure oil supply source, 32 is a tank, 33 is a low / high pressure setting unit (hydraulic supply unit), and the low / high pressure setting unit 33 introduces pressure oil from the pump 31, The two types of high pressure and low pressure are changed while maintaining a constant differential pressure, and supplied to a switching valve 51 described later. Low / high voltage setting section 33
Has a cylinder 35 whose interior is divided into two by a differential pressure regulator piston (hereinafter, referred to as a "first piston") 34. The left side of the cylinder 35 is a high-pressure chamber, and the right side is a low-pressure chamber. The first piston 34 is urged toward the left high-pressure chamber side by a differential pressure regulator spring (hereinafter, referred to as “first spring”) 36. The left end of the high-pressure chamber is closed by a casing, The right end of the chamber is closed by a movable sleeve 37 and a ratio interlocking regulator piston 38. In such a combination, by introducing the pressure oil from the pump 31 into the high-pressure chamber, the pressure oil causes the first piston 34 to slide rightward against the first spring 36, and It is led into the right low-pressure chamber through the communicating flow path 39.
Therefore, the hydraulic pressure supplied from the high-pressure chamber through the high-pressure line 40 and the hydraulic pressure supplied from the low-pressure chamber through the low-pressure line 41 are larger in the former than in the first spring 36 than in the latter.
It is increased by the urging force. In other words, high and low hydraulic pressures having a constant differential pressure are supplied.

Further, the movable sleeve 37 that closes the low-pressure chamber in the cylinder 35 and the ratio-linked regulator piston 38 can adjust the oil pressure in the low-pressure chamber.

That is, the movable sleeve 37 is slidably fitted to the outside of the cylinder 35 in the left-right direction,
The ratio-linked regulator piston (hereinafter referred to as “
The piston 38 is slidably fitted in the left-right direction, and the second piston 38 is urged to the left by a ratio-linked regulator spring (hereinafter referred to as a “second spring”) 42. . When the oil pressure in the low-pressure chamber becomes higher than a predetermined value, the oil pressure
A movable sleeve that slides the second piston 38 to the right against the second spring 42 and opens by the slide
The gas is released into the tank 32 through the through hole 37a. Therefore, the hydraulic pressure in the low-pressure chamber matches the urging force of the second spring 42 when the through hole 37a opens. Moreover, since the position of the through hole 37a can be adjusted by sliding the movable sleeve 37, the hydraulic pressure in the low-pressure chamber can be adjusted according to the position of the through hole 37a.

Eventually, the low / high pressure setting unit 33 changes the two types of hydraulic pressure, high pressure and low pressure, while maintaining a constant differential pressure in accordance with the sliding position of the movable sleeve 37, and supplies it to the switching valve 51. I have.

The movable sleeve 37 is connected to the movable pulley half 4b of the drive pulley 4 of the continuously variable transmission 1 by a ratio interlocking sleeve lever 43. Therefore, according to the movement of the movable pulley half 4b,
The two types of hydraulic pressure, high pressure and low pressure, change while maintaining a constant differential pressure. That is, when the movable-side pulley half 4b moves in the direction A and the groove width of the drive pulley 4 decreases, that is, the diameter of the portion of the drive pulley 4 on which the endless belt 7 hangs increases, and the gear ratio increases. At this time, the movable sleeve 37 moves in the direction A, and the two types of hydraulic pressure, high pressure and low pressure, decrease while maintaining a constant differential pressure. On the other hand, the movable pulley half 4b moves in the direction B to
When the groove width becomes large, that is, when the diameter of the portion of the drive pulley 4 on which the endless belt 7 is hung becomes small and the gear ratio becomes small, the movable sleeve 37 moves in the B direction, and the high pressure and low pressure The two types of hydraulic pressure increase while maintaining a constant differential pressure. Such a relationship is shown in FIG. In addition,
In FIG. 2, reference numeral 44 denotes an orifice provided in the low pressure line 41 for regulating the flow rate of the pressure oil. Switching valve supplied with hydraulic pressure from the low-high pressure setting unit 33 having such a configuration
51 is configured as follows.

The switching valve 51 performs a switching operation by sliding a spool 53 in a cylinder 52 in the left-right direction. The cylinder 52 is connected to the introduction ports 52a and 52b connected to the high and low pressure lines 40 and 41 from the low and high pressure setting unit 33, and to the introduction ports 2a and 2b of the casing 2 of the continuously variable transmission 1 described above. Derivation ports 52c and 52d are provided. On the other hand, the spool 53 has first, second, and third ring grooves 53a, 53b, and 53c formed in the outer peripheral portion thereof, an oil passage 53d formed in an axial portion thereof, and first and third ring grooves. Ring groove 53a, 53c
And the oil passage 53d are communicated by through holes 53e and 53f.
A link 55 is provided on the right end of the spool 53 via a rod 54.
Is connected, and the other end of the link 55 is rotated in the arrow direction by a pulse motor 71 described later, so that the spool 53 slides in the left-right direction.

The switching valve 51 having such a configuration is switched to a total of three states when the spool 53 slides left and right with the illustrated state being a neutral state.

That is, in the illustrated neutral state, the high pressure line 40
From the introduction port 52a of the first ring groove 53a to the outlet port 52
While a series of flow paths leading to c are formed, a series of flow paths leading from the first ring groove 53a to the through hole 53e, the oil passage 53d, the through hole 53f, the third ring groove 53c, and the outlet port 52d are formed. Is done. Therefore, in this neutral state, the introduction port 2a of the driving pulley 4 and the introduction port 2B of the driven pulley 6
Are supplied with the high pressure from the high pressure line 40. If the spool 53 slides to the right,
A flow path is formed from the introduction port 52a of the forty through the first ring groove 53a to the derivation port 52c, and also communicates from the introduction port 52b of the low-pressure line 41 to the derivation port 52d through the second ring groove 53b. A channel is formed. Therefore,
In the sliding state to the right, high pressure from the high pressure line 40 is supplied to the introduction port 2a on the drive pulley 4 side, and low pressure from the low pressure line 41 is supplied to the introduction port 2b of the driven pulley 6. Is done. When the spool 53 slides to the left, the introduction port 52a of the high-pressure line 40
From the first ring groove 53a, through hole 53e, oil passage 53d, through hole 53
f, a series of flow paths leading to the outlet port 52d through the third ring groove 53c is formed, and the outlet port 52c from the introduction port 52b of the low-pressure line 41 through the second ring groove 53b.
Is formed. Therefore, in the state of sliding to the left, the introduction port on the drive pulley 4 side
A low pressure is supplied from the low pressure line 41 to 2a, and a high pressure is supplied from the high pressure line 41 to the introduction port 2b of the driven pulley 6.

The three switching states of the switching valve 51 and the spool
The relationship with 53 slides is shown in FIG.

Introduction port 2c for introducing hydraulic pressure to the clutch 16 described above
, A pump 31 is connected to a clutch switching valve 61. This clutch switching valve 61 is provided in a casing 62.
The lower piston 63 in FIG. 2 and the upper piston 64 in FIG.
The piston 63 is urged upward by a spring 64e, and the piston 64 is urged upward by a spring 65. The upper end of the upper piston 64 is the casing 62
And is moved downward by the rotation of an arm 66 interlocked with a clutch lever (not shown). In the state shown, both pistons 63, 6
4 are both in the upper movement limit position and both pistons 63,
64 are located above and below at a predetermined interval.

In the state shown, the clutch 16 is engaged. That is, the hydraulic pressure supplied from the pump 31 through the introduction port 62a includes an opening 63a of the lower piston 63, an oil passage 63b in the piston 63, an oil passage 64a in the upper piston 64, an opening 64b of the piston 64, Through the outlet port 62b, the clutch 16
The friction plates 18 and 20 are strongly pressed against each other, and the clutch 16 is connected. On the other hand, when disengaging the clutch 16, operate the clutch lever to
Is rotated downward. That is, the rotation of the arm 66 moves the upper piston 64 downward, the opening 64b of the piston 64 shifts from the position facing the outlet port 62b, and the supply of the hydraulic pressure to the clutch 16 is cut off. The oil release hole 64c formed in the cylinder 64 faces the outlet port 62b, the pressure oil in the clutch 16 is drained, and the clutch 16 is disengaged. Thereafter, when the clutch 16 is to be engaged again, the operation of the clutch lever may be released to return to the state shown in the figure.

Note that the clutch switching valve 61 of the present example is configured to maintain the hydraulic pressure led to the clutch 16 at a predetermined pressure. That is,
If the hydraulic pressure introduced from the pump 31 is too high, the pressure in the oil passage 63b of the lower piston 63 increases, and the piston 6
3 is moved downward against the spring 64, whereby the opening 63a of the piston 63 is
The pressure oil is automatically regulated so as to deviate from the position facing 2a. In FIG. 2, reference numeral 67 denotes an orifice provided in a hydraulic passage between the clutch switching valve 61 and the clutch 16 for regulating the flow rate of the pressure oil.

Here, the operation of the above mechanical components will be summarized.

This mechanical component adjusts the speed ratio of the continuously variable transmission 1 by moving and adjusting the spool 53 of the switching valve 51 by the pulse motor 71. The pulse motor 71 itself is controlled by an electric component described later. Basically, as described later, the electrical component determines the ideal engine speed from data stored in advance according to the throttle opening, and then calculates the ideal engine speed and the actual engine speed. The drive signal of the pulse motor 71 is output in accordance with the difference between the engine speed and the difference between them. Based on the drive signal, the spool 53 of the switching valve 51 is output.
Moves left and right.

Thus, the low and high pressure oil pressures from the low and high pressure setting unit 52 are selectively supplied to the drive pulley 4 side and the driven pulley 6 side, respectively, to change the speed ratio of the continuously variable transmission 1.
By changing the gear ratio in this manner, the load applied to the engine is changed, and the engine speed is adjusted to an ideal speed.

When the actual engine speed reaches the ideal engine speed, the spool 53 enters the illustrated neutral state, and high-pressure oil pressure is supplied to both the drive pulley 4 and the driven pulley 6. As a result, a predetermined lateral pressure is applied to each of the pulleys 4 and 6, and the speed ratio of the continuously variable transmission 1 is maintained as it is. By operating the clutch lever to rotate the arm 66 of the clutch switching valve 61 up and down, regardless of the shift state of the continuously variable transmission 1,
The clutch 16 is disconnected or connected.

In addition to such an operation, control is also performed so that the actual gear ratio matches a planned target gear ratio, as described later.

Now, a configuration of the first embodiment of the present invention in which such a continuously variable transmission is a controlled device will be described.

FIG. 5 is a block diagram showing the configuration of the first embodiment of the present invention.

In FIG. 5, an engine speed Ne sensor (hereinafter, Ne sensor)
A sensor 204 detects the rotation speed of the driving pulley 4, and a vehicle speed V sensor (hereinafter, referred to as V sensor) 501 detects the rotation speed of the driven pulley 6.

The Ne sensor 204, V sensor 501, and throttle opening θth sensor (hereinafter referred to as θth sensor) 207 are connected to a microcomputer 503 that controls the vehicle.

As is well known, this microcomputer 503 has a CPU
504, ROM 505, RAM 506, input / output interface 507, and common bus 508 connecting them.

The pulse motor 71 for controlling the position of the spool 53 includes:
The microcomputer 503 is connected to the microcomputer 503 via a driving unit 502.

6 and 7 are flowcharts showing the operation of the first embodiment of the present invention.

First, in FIG. 6, in step S1, the microcomputer 503 is initialized.

Next, in step S2, it is determined whether or not a ratio hold flag described later with reference to FIG. 7 is set. If set, the process is a step
The process proceeds to S3, where the gear ratio fixed control according to the present invention is executed. This gear ratio fixing control is for controlling the continuously variable transmission such that the gear ratio of the continuously variable transmission matches the target gear ratio set in FIG.

If not set, the process proceeds to step S4
The target engine speed of the continuously variable transmission is set by a known method.

When the process in step S3 or S4 is completed, the pulse motor 71 is controlled so that the actual speed ratio or the actual engine speed Ne of the continuously variable transmission matches the set target speed ratio or the target engine speed. It is driven and the position of the spool 53 is controlled. Thereafter, the process returns to step S2.

Next, the operation of FIG. 7 will be described. The control shown in FIG. 7 is a fixed time interrupt control, and is executed by the microcomputer 503 (FIG. 5) at predetermined time intervals.

First, in step S11, the throttle opening θthi
Is taken in. The subscript i is incremented by one each time the process is completed once, and is reset to 1 when it becomes n. The same applies to steps S12 to S14.

In step S12, the throttle opening obtained by the previous or predetermined number of times before is subtracted from the obtained throttle opening θthi to calculate Δθthi.

In step S13, the actual speed ratio Ri of the vehicle is calculated. That is, the output signal of the Ne sensor 204 is divided by the output signal of the V sensor 501 to calculate the actual speed ratio Ri of the continuously variable transmission.

In step S14, ΔRAi is calculated by subtracting the actual speed ratio calculated by the previous or predetermined number of previous processes from the calculated actual speed ratio Ri.

In step S15, as shown in FIG.
Each value is stored in a memory having an area for storing Δθthi, ΔRAi, and Ri. Here, the subscript i of each numerical value
Reaches a predetermined number n, and returns to the position of the subscript 1 again.
Data is overwritten.

In step S16, it is determined whether or not all of the n Δθth stored in the memory are within ± K (predetermined value). If the absolute value of Δθth exceeds K, the ratio hold flag is reset in step S21. Then, the process ends.

All of the n Δθth stored in the memory are ± K
If not, in step S17, it is determined whether or not any of the n ΔRAs stored in the memory is greater than or equal to + L (predetermined value). If there is no more than + L, the process ends.

If there is a value greater than + L, it is determined in step S18 whether or not there is a value less than -L among the n ΔRAs stored in the memory. If there is no -L or less, the process ends.

If there is one less than or equal to -L, in step S19, the largest R (Rm among the n Rs stored in the memory)
ax) is the target speed ratio of the continuously variable transmission.

Then, after the ratio hold flag is set in step S20, the process ends.

FIG. 1 is a functional block diagram of a first embodiment of the present invention. 1, the same reference numerals as those in FIG. 5 indicate the same or equivalent parts.

In FIG. 1, the θth sensor 207 is
And Δθth calculating means 518.

The Net setting means 511 includes the throttle opening θth and the θ
The target engine speed Net corresponding to th is stored. The Net setting means 511 may store a function as shown in FIG.

The Δθth calculating means 518 calculates the deviation Δθth according to the input throttle opening θth.

The Net setting means 511 and the Ne sensor 204 have a subtraction means 512
It is connected to the. This subtraction means 512 is provided by the Net setting means 51.
Target engine speed Net output from 1 and Ne sensor 20
The difference ΔNe is calculated by subtracting the actual engine speed Ne output from 4.

The θmt setting means 513 includes a deviation ΔNe of the engine speed.
And the drive angle θmt of the pulse motor 71 corresponding to ΔNe. When the deviation ΔNe of the engine speed Ne is input from the subtraction unit 512, the θmt setting unit 513 sends the driving angle θmt of the pulse motor 71 corresponding to the deviation ΔNe to the driving unit 502 via the switching unit 514. Output.
Note that the θmt setting means 513 may also store a function as shown in FIG.

As a result, the pulse motor 71 rotates by a predetermined angle in the predetermined direction, and the spool 53 is moved in the predetermined direction. Then, the continuously variable transmission is controlled such that the actual engine speed Ne matches the target engine speed Net.

Ne sensor 204, θth sensor 207, and Net setting means 5 described above
11, the feedback control means including the subtraction means 512 and the θmt setting means 513 is a control device for a conventional continuously variable transmission for a vehicle. With only this configuration, θth is constant and the target engine speed is constant. Also, since the actual engine speed fluctuates, θmt, that is, the actual gear ratio fluctuates. Therefore, the vehicle may cause hunting.

The switching unit 514 always connects the θmt setting unit 513 and the driving unit 502, but when a control signal is output from the determining unit 522 described later, the θmt setting unit 521 and the driving unit 502 are connected. Connecting.

The V sensor 501 and the Ne sensor 204 are connected to a speed ratio R calculating means 515. This speed ratio R calculation means 515
The actual speed of the continuously variable transmission is obtained by dividing the rotational speed of the drive pulley 4 output from the Ne sensor 204 (that is, the actual engine rotational speed Ne) by the rotational speed of the driven pulley 6 output from the V sensor 501. Calculate the ratio R. This speed ratio R is Δ
It is input to the RA calculating means 517, and the ΔRA calculating means 517 calculates the deviation ΔRA of the gear ratio R.

The storage means 516 stores the speed ratio R, ΔRA and the throttle opening change rate Δθth output from the speed ratio R calculating means 515, ΔRA calculating means 517 and Δθth calculating means 518.
Maximum value Rmax of gear ratio R stored in storage means 516
Is transferred to and stored in the target gear ratio storage means 519.

The subtraction means 520 subtracts the gear ratio R output from the gear ratio R calculating means 515 from the maximum gear ratio Rmax stored in the target gear ratio storage means 519 to obtain ΔRB, and the θmt setting means 52
Output to 1.

The θmt setting means 521 stores ΔRB and the drive angle θmt of the pulse motor 71 corresponding to ΔRB.

The θmt setting means 521 may also store a function as shown in FIG.

When ΔRB is input from the subtraction means 520, the θmt setting means 521 switches the drive angle θmt of the pulse motor 71.
Output to 514.

The determination means 522 determines that Δθth stored in the storage means 516 is within a predetermined value ± K and ΔR stored in the storage means 516 as shown in steps S16 to S18 in FIG.
Only when A exceeds a predetermined value ± L, the switching means 514 is energized, and the connection between the θmt setting means 513 and the driving means 502 is changed to the connection between the θmt setting means 521 and the driving means 502. Switch.

When the θmt setting means 521 and the driving means 502 are connected, the pulse motor 71 rotates by a predetermined angle in a predetermined direction, and the spool 53 is moved in the predetermined direction. Then, the continuously variable transmission is controlled such that the actual gear ratio of the continuously variable transmission matches the target gear ratio stored in the target gear ratio storage means 519.

Thus, in this embodiment, the throttle opening θ
When the change in th is small, and in this case, the fluctuation of the actual speed ratio R of the continuously variable transmission is large, the speed ratio of the continuously variable transmission becomes the maximum value of R stored in the storage means 516. Rmax (that is, the gear ratio on the lowest side) is fixed.

That is, during normal driving, the throttle opening θ
th, the feedback control of the continuously variable transmission is performed so that the actual engine speed matches the target engine speed set in accordance with th. When it is determined that the vehicle is traveling on the road, the feedback control of the engine speed is stopped, and
Feedback control is performed so that the actual gear ratio matches the largest gear ratio Rmax stored in 516.

As a result, even when the vehicle travels on a rough road having many irregularities, there is no possibility that the vehicle will hunt.

Further, when the change in the throttle opening θth is large, that is, when the driver is performing accelerator control, the gear ratio is not fixed, so that the intention of the driver is favorably reflected in the traveling of the vehicle. can do.

Now, as shown in step S15 of FIG. 7, in the fixed-time interrupt control, each time the storage means 516 (first
Since the data in the figure is updated, when the vehicle travels on a rough road with more unevenness after the maximum speed ratio Rmax in the storage means 516 is set to the target speed ratio, the value of the maximum speed ratio is further increased. In some cases, the value of the target speed ratio also increases.

In other words, the control of the continuously variable transmission according to this embodiment has a configuration in which a so-called filter means is added to the conventional control system so that the target gear ratio is always set to only the low side.

However, the present invention is not particularly limited to this.After the maximum speed ratio Rmax is once set to the target speed ratio, even if a larger speed ratio is detected, the speed ratio is set as the target speed ratio. It may not be adopted.

In the description relating to FIG.
Θmt read from 513 or 521 is the driving means
Although output to 502 is provided, for example, a sensor for detecting the position of the spool 53 or the drive angle of the pulse motor 71 is provided, and an output signal of the sensor and the θmt setting means 51 are provided.
A comparison means for comparing the output signal of 3 or 521 is provided, and the output of the comparison means is input to the drive means 502 so that the current position of the spool 53 or the current drive angle of the pulse motor 71 is The driving means 502 may be configured to be energized.

In the above-described first embodiment of the present invention, the actual speed ratio of the continuously variable transmission is detected, and when the actual speed ratio fluctuates greatly, it is determined that the vehicle is traveling on a rough road. Also, the second
In the embodiment of the present invention, when the fluctuation of the actual engine speed is large, it is determined that the vehicle is traveling on a rough road.

The determination as to whether or not the road is rough is not particularly limited to this, and a sensor (torque sensor) that detects a torsion of a rotating shaft of a power transmission system from the continuously variable transmission to the drive wheels is provided. ) May be provided, and when the variation of the output signal value of the sensor is equal to or greater than a predetermined value, it may be determined that the vehicle is traveling on a rough road.

Also, the first embodiment has been described as being applied to a continuously variable transmission including two pulleys whose groove width is adjusted by hydraulic pressure and an endless belt wound around the pulleys. A continuously variable transmission composed of a constant displacement type swash plate type hydraulic pump and a variable displacement type swash plate type hydraulic motor, or a toroidal type continuously variable transmission as described in JP-A-62-273189. May be applied.

(Effects of the Invention) As is clear from the above description, according to the present invention, the following effects are achieved.

That is, if the vehicle is traveling on a bad road,
Since the target speed ratio of the continuously variable transmission is fixed, hunting does not occur.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of a first embodiment of the present invention. FIG. 2 is a diagram showing a configuration of a continuously variable transmission applied to the first embodiment of the present invention. FIG. 3 is an explanatory diagram of a relationship between a low pressure and a high pressure derived from a low / high pressure setting section of the continuously variable transmission shown in FIG. FIG. 4 is an explanatory diagram of the relationship between high pressure and low pressure switched by the switching valve of the continuously variable transmission shown in FIG. FIG. 5 is a block diagram showing the configuration of the first embodiment of the present invention. 6 and 7 are flowcharts showing the operation of the first embodiment of the present invention. FIG. 8 is a configuration diagram of a memory for storing Δθthi, ΔRAi, and Ri. FIG. 9 is a diagram showing a relationship between a vehicle traveling on an uneven road surface while holding an accelerator constant, and a speed ratio of a continuously variable transmission mounted on the vehicle. Fig. 10 shows that the vehicle is held on a flat ground, rough road,
It is a figure which shows the change of the gear ratio at the time of driving | running | working downhill and uphill. 53: spool, 71: pulse motor, 128: gear ratio detection sensor, 204: Ne sensor, 206: Pb sensor, 207
... Θth sensor, 304, transmission ratio storage means, 306, feedback control means, 501, V sensor, 502, driving means, 511, Net setting means, 512, subtraction means, 513, θ
mt setting means, 514 switching means, 515 speed ratio calculating means 516 storage means 517 ΔRA calculating means 518
Δθth calculating means, 519 ... Target gear ratio storing means, 520 ...
Subtraction means, 521... Θmt setting means, 522.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-155146 (JP, A) JP-A-63-251658 (JP, A) JP-A-1-312259 (JP, A) JP-A-2- 106446 (JP, A) Fully open 1988-86455 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16H 61/16 F16H 9/00

Claims (2)

(57) [Claims] 1. A control device for a continuously variable transmission for a vehicle for transmitting an engine output to drive wheels at an arbitrary speed ratio, comprising: means for calculating a target speed ratio in accordance with an engine parameter, a traveling parameter, and the like; Disturbance detection means for detecting a disturbance from a road surface that changes the speed ratio of the continuously variable transmission for a vehicle by increasing or decreasing a load; and when the disturbance is detected by the disturbance detection means, the target speed ratio is calculated by the calculation result. Irrespective of the vehicle speed and the transmission control means for controlling the speed ratio of the continuously variable transmission for the vehicle to the target speed ratio, wherein the disturbance detection means opens the throttle every predetermined time. Means for detecting the degree of throttle opening and calculating the difference between the throttle opening before the predetermined time and the current throttle opening as a fluctuation width of the throttle opening; and storing a predetermined number of the fluctuations of the throttle opening continuously. A first storage unit that detects that the absolute ratio of the variation width of the predetermined number of throttle openings stored in the first storage unit is smaller than a predetermined reference variation width; Means for detecting an actual gear ratio of the transmission at each of the predetermined times, and calculating a difference between the actual gear ratio before the predetermined time and the current actual gear ratio as an increase / decrease width of the actual gear ratio; A second storage means for continuously storing the increase / decrease range of the predetermined number, and a positive value among the increase / decrease ranges of the predetermined number of actual speed ratios stored in the second storage means, and Means for detecting that a value greater than a predetermined reference amplification width is present as a reference value for causing the transmission to cause a delay in response to an increase or decrease in engine load, and stored in the second storage means. Within the predetermined number of actual speed ratios Means for detecting that there is a negative value, and the absolute value of which is greater than the reference increase / decrease width, wherein the absolute value of the predetermined width of the variation in the throttle opening degree is any of: A positive value among the increase / decrease ranges of the predetermined number of actual speed ratios, the value of which is larger than the reference increase / decrease range; and When there is a negative value in the increase / decrease range of the actual speed ratio of the number and whose absolute value is larger than the reference increase / decrease range, this is detected as a disturbance. Control device for continuously variable transmission for vehicles. Means for fixing the target gear ratio, wherein when the disturbance is detected by the disturbance detecting means, the maximum value of the target gear ratio detected as a steady operation state up to that time is obtained by:
2. The control device for a continuously variable transmission for a vehicle according to claim 1, wherein the target speed ratio is set.