JP4425040B2 - Control device for continuously variable transmission - Google Patents

Description

  The present invention relates to a control device for a continuously variable transmission configured by winding a metal belt between a drive pulley and a driven pulley each having a variable pulley width, and more particularly to a control device for suppressing noise and vibration of a metal belt. .

  As described above, the continuously variable transmission wraps an endless metal belt between two pulleys (drive pulley and driven pulley) each having a belt receiving groove having a substantially V-shaped cross-sectional shape whose groove width can be changed. The gear ratio is continuously changed by changing the pulley width of the belt receiving grooves of both pulleys. Such belt-type continuously variable transmissions have been proposed in various ways and put into practical use.

  Some belts used in belt-type continuously variable transmissions have a so-called chain type structure made of a metal material such as steel. This chain-type metal belt includes a link plate having a pair of pin holes and a rocker pin inserted into the pin hole, and the link plates are alternately combined through the pin hole, and the rocker pin is inserted into the pin hole. Thus, the link plates are configured to be flexibly connected to each other by rocker pins.

When such a metal belt rotates and bites into the pulley, a collision sound is generated. When the biting frequency at that time coincides with the frequency of other noise or vibration source, the noise or vibration deteriorates. As a means for improving noise and vibration of a continuously variable transmission, for example, a method of setting a speed change characteristic so as to traverse an operating region in which the engagement frequency and the natural resonance frequency of the pulley substantially coincide with each other in the shortest time (for example, Patent Document 1). ) Etc.
Japanese Patent No. 3154760

  By the way, the problem of noise and vibration of a continuously variable transmission using a metal belt often depends on the vibration of the string portion of the metal belt. The magnitude of the vibration level of the string portion depends greatly on the value of the resonance frequency of the string portion determined by the length of the string portion, the tension applied to the string portion, and the like. Further, the length of the string portion and the tension applied to the string portion change due to the influence of parameters that determine the operation state such as the gear ratio or torque (hereinafter also referred to as input torque) input to the drive pulley. The resonance frequency of the string portion changes according to changes in the operating state. On the other hand, the biting frequency changes depending on the rotational speed of the drive pulley, and when the biting frequency coincides with the chord resonance frequency, the energy is amplified (becomes close to resonance). There is a problem that noise and vibration levels are deteriorated.

  In order to avoid such resonance, even if the gear ratio, etc. is controlled to a value set in advance so as to be optimal for resonance avoidance in a certain state, it is affected by, for example, increase / decrease in electric load. If the operating condition such as the input torque changes, the chord resonance frequency depends on the input torque value as described above. Thus, there has been a problem that when the resonance frequency of the string portion is changed in response to the change of the operating state, the energy may be amplified (becomes a state close to resonance) in accordance with the biting frequency. Further, when this state is a state where the engine noise is small, such as a state where the shift position is in the traveling range and the start clutch and the torque converter slide (when idling in the in-gear state), noise and vibration are easily perceived by the passenger. Especially problematic.

  In view of the above problems, an object of the present invention is to avoid a coincidence state (a state close to resonance) between a biting frequency and a chordal resonance frequency that change depending on an operation state, and suppress deterioration of noise and vibration level.

The present invention for the above purpose achieve, comprises a drive pulley of the pulley width variable, a driven pulley of the pulley width variable, and a belt wound around between the drive pulley and the driven pulley, depending on operating conditions change the pulley width of said drive and driven pulley, the rotational speed of the drive pulley in the CVT control apparatus configured to transmit to the driven pulley and steplessly, the pulley of the belt a bite frequency calculating means for calculating according to bite frequency to the rotational speed of the pulley, chord portion resonance frequency calculation for calculating the chord portion resonance frequency of the belt with a speed ratio is calculated according to the operating conditions means, a resonance determination value calculating means for calculating a resonance determination value for determining the resonance of the said two frequencies from said chord portion resonance frequency and the bite frequency, the resonant When determining the magnitude of the resonance judgment value calculated by the cutoff value calculation means and a preset reference judgment value, and determining that the resonance judgment value is smaller than the reference judgment value, the gear ratio is set. change to the overdrive side, the if the resonance determination value is determined to be larger than the reference determination value; and a resonance avoidance means for changing the speed ratio to the low side.

In the continuously variable transmission control apparatus having the above-described configuration, it is preferable that the reference determination value in the resonance avoidance unit is set as a value when the degree of resonance is minimum.
In the control device for a continuously variable transmission configured as described above, the resonance avoidance unit is preset with a first determination value smaller than the reference determination value and a second determination value larger than the reference determination value. When it is determined that the resonance determination value is smaller than the first determination value, the transmission ratio is changed to the overdrive side, and when it is determined that the resonance determination value is larger than the second determination value. The speed ratio is changed to the low side, and the speed ratio is maintained when it is determined that the resonance judgment value is between the first judgment value and the second judgment value including the reference judgment value. It is preferable to perform control. Further, the resonance avoiding means may be configured to perform control so as to change the gear ratio so that the resonance determination value matches the reference determination value.
In a continuously variable transmission configured to change the pulley width of both pulleys by controlling the operation of a shift control valve that controls the supply and discharge hydraulic pressure of hydraulic oil to both pulleys, control is performed during engine idling in the in-gear state. The device controls the transmission control valve so that the predetermined transmission gear ratio is set in advance, and controls the operation of the transmission control valve according to the resonance judgment value so as to change the preset transmission gear ratio. You may comprise so that it may perform.

The control device according to the present invention calculates a biting frequency and a string resonance frequency, calculates a resonance determination value for determining a resonance degree of both frequencies, and calculates a string resonance frequency according to the calculated resonance determination value. It has resonance avoiding means for changing the gear ratio, which is a parameter influencing on, to the overdrive side or the low side . For this reason, even if the resonance frequency of the string portion changes due to the influence of a certain electric load or the like and the resonance frequency tends to resonate, the control device according to the present invention controls the change of the gear ratio. Thus, the value of the string resonance frequency can be changed to avoid the coincidence state of both frequencies, and the deterioration of noise and vibration level can be prevented in advance.

  Further, by performing the above control particularly during engine idling in the in-gear state, it is possible to prevent the noise and vibration level from being deteriorated in a vehicle state in which noise and vibration are easily perceived by the passenger. Further, the control by the method of avoiding the coincidence state with the meshing frequency by changing the gear ratio by changing the gear ratio can be easily performed by using an existing speed change control device for the continuously variable transmission. it can.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. 1 and 2 show a belt type continuously variable transmission CVT including a control device according to the present invention. The continuously variable transmission CVT includes a transmission input shaft 1 connected to the output shaft Es of the engine ENG via a coupling mechanism CP, a transmission counter shaft 2 disposed in parallel thereto, 2, a metal belt mechanism 10 disposed between the two, a forward / reverse switching mechanism 20 disposed on the transmission input shaft 1, a starting clutch mechanism 40 disposed on the transmission counter shaft 2, The output transmission gear trains 6a, 6b, 7a, 7b and the differential mechanism 8 are provided in the transmission housing HSG.

  First, the metal belt mechanism 10 is wound between a drive pulley 11 disposed on the transmission input shaft 1, a driven pulley 16 disposed on the transmission counter shaft 2, and both pulleys 11, 16. And a metal belt 15. The drive pulley 11 includes a fixed pulley half 12 that is rotatably disposed on the transmission input shaft 1, and a movable pulley half 13 that is movable in the axial direction with respect to the fixed pulley half 12 and rotates integrally therewith. The movable pulley half 13 is controlled to move in the axial direction by the hydraulic pressure supplied to the drive pulley cylinder chamber 14. On the other hand, the driven pulley 16 includes a fixed pulley half 17 fixed to the transmission countershaft 2, and a movable pulley half 18 that is movable in the axial direction with respect to the fixed pulley half 17 and integrally rotates. The movable pulley half 18 is controlled to move in the axial direction by the hydraulic pressure supplied to the driven pulley cylinder chamber 19.

  For this reason, by appropriately controlling the hydraulic pressure supplied to the cylinder chambers 14 and 19, the axial movement force acting on the movable pulley halves 13 and 18 is controlled, and the pulley widths of the pulleys 11 and 16 are changed. be able to. Thereby, it is possible to perform control to change the gear ratio steplessly by changing the winding radii r11 and r16 of the metal belt 15 with respect to both the pulleys 11 and 16 schematically shown in FIG.

  The forward / reverse switching mechanism 20 rotatably holds a sun gear 21 connected to the transmission input shaft 1, a plurality of pinion gears 22a meshing with the sun gear 21, and a carrier 22 rotatable coaxially with the sun gear 21, and a pinion gear 22a. It consists of a single pinion type planetary gear mechanism that meshes and has a sun gear 21 and a ring gear 23 that can rotate coaxially. And a forward clutch 30 connected to.

  In the forward / reverse switching mechanism 20 configured as described above, when the forward clutch 30 is engaged with the reverse brake 25 released, the sun gear 21 and the ring gear 23 are coupled to each other to rotate integrally, and the sun gear 21, All of the carrier 22 and the ring gear 23 rotate integrally with the transmission input shaft 1, and the drive pulley 11 is driven to rotate in the same direction (forward direction) as the transmission input shaft 1. On the other hand, when the forward clutch 30 is released and the reverse brake 25 is engaged, the carrier 22 is fixed and held, the ring gear 23 is rotated in the opposite direction to the sun gear 21, and the drive pulley 11 is opposite to the transmission input shaft 1. It is in a state of being rotationally driven in the direction (reverse direction).

  The forward clutch 30 is composed of a hydraulically operated wet multi-plate clutch, and is engaged and disengaged by receiving hydraulic pressure. Similarly, the reverse brake 25 is composed of a hydraulically operated wet multi-plate brake, and is engaged / disengaged under the hydraulic pressure.

  As described above, when the rotation of the transmission input shaft 1 is switched by the forward / reverse switching mechanism 20 and the drive pulley 11 is rotationally driven in the forward or reverse direction, this rotation is steplessly performed by the metal belt mechanism 10. The speed is changed and transmitted to the transmission countershaft 2. The transmission countershaft 2 is provided with a starting clutch 40, which controls driving force transmission to the output transmission gear 6a. The starting clutch 40 is composed of a hydraulically operated wet multi-plate clutch, and is engaged by receiving hydraulic pressure.

  Thus, the rotational driving force controlled by the starting clutch 40 and transmitted to the output transmission gear 6a is transmitted to the left and right via the output transmission gear trains 6a, 6b, 7a, 7b having the output transmission gear 6a and the differential mechanism 8. It is transmitted to wheels (not shown). Further, when the starting clutch 40 is released, a neutral state in which power cannot be transmitted is obtained.

  In the continuously variable transmission CVT configured as described above, the supply and discharge control of the hydraulic oil to the drive pulley cylinder chamber 14 and the driven pulley cylinder chamber 19 constituting the metal belt mechanism 10 is performed as described above. Shift control is performed. Hereinafter, the shift control valve 70 for controlling the supply / discharge hydraulic pressure to both the cylinder chambers 14 and 19 shown in FIG. 2 and the control unit 100 for controlling the operation of the shift control valve 70 will be described.

  The shift control valve 70 includes two solenoid valves that control the hydraulic pressure supplied to the drive pulley cylinder chamber 14 and the driven pulley cylinder chamber 19, and these shift control signals are supplied from the control unit 100. Is operated to control the shift. As a result, the hydraulic pressure in both cylinder chambers 14 and 19 is set based on the shift control signal, and the axial thrust acting on both pulleys 11 and 16 is set.

For this speed change control, the control unit 100 includes an engine speed signal Ne detected by the engine speed sensor 101, a drive pulley speed signal N _DR detected by the drive pulley speed sensor 102, and a driven pulley speed sensor 103. a driven pulley rotational signal N _DN to be detected, the shift position signal is detected by the shift position sensor 104 S _P, such as the engine throttle opening degree signal T _H is detected by a throttle opening sensor 105, various sensors for detecting operating conditions The detection signal output by is input. Further, in a state where the shift position is in the traveling range and the start clutch 40 is slid (during idling in the in-gear state), it is optimal for starting and is set in advance so as to suppress noise and vibration. The supply / discharge hydraulic pressures for both cylinder chambers 14 and 19 are set so that the control unit 100 controls the energization of the solenoid of the shift control valve 70 (for example, the gear ratio: 2.360).

The control device according to the present invention performs control for avoiding deterioration of noise and vibration level using the control unit 100 that performs such shift control. Noise and vibration in the continuously variable transmission CVT are wound between the pulleys 11 and 16 and the meshing frequency, which is the frequency of the collision sound generated when the metal belt 15 is meshed with the pulley by the rotation of the drive pulley 11. This is aggravated by the fact that the resonance frequency of the chord portion 15a (see FIG. 3) of the metal belt to be hung matches the resonance frequency of the chord portion 15a and the energy is amplified (a state close to resonance). Incidentally, the primary component F _a primary component F _i and chord resonant frequency of the bite frequency, respectively the following formulas (1), represented by (2).

(Equation 1)
F _i = A · N _in (1)

(Equation 2)
F _a ＝ B ・ C ・ T ^1/2 (2)

Here, N _in is the rotational speed of the drive pulley 11, T is the tension of the string portion 15a, and A and B are constants. Further, C shown in equation (2) is a variable depending on the gear ratio, and the tension T varies depending on the input torque and the gear ratio. In addition, as shown in the above equation, the biting frequency changes in proportion to the pulley rotation speed, for example, the primary frequency component at idling in the in-gear state is about 300 Hz, while the increase in pulley rotation speed is approximately 3000 Hz. The frequency rises to the extent. The string resonance frequency is proportional to the square root of the string tension, and the frequency change according to the operating state is smaller than the biting frequency, and the frequency primary component changes in a range of approximately 150 to 200 Hz.

As shown in FIG. 3, when the winding radii r11 and r16 change, the winding angle θ of the metal belt 15 with respect to the drive pulley 11 changes. Here, if the distance between the centers of the pulleys 11 and 16 is L, the length of the chord portion 15a is Lsinθ. Therefore, the length of the chord portion 15a is changed according to the change of the winding angle θ, that is, the change of the gear ratio. Will change.

In the present invention, the above bite frequency of the primary component F _i and chords primary component F _a and the resonance tend to a certain whether the decision to the following equation resonance determination value d for the resonant frequency (3) Calculated from (4).

(Equation 3)
d = k− [k] ([] is a Gaussian symbol) (3)

(Equation 4)
k ＝ F _i / F _a (4)

In equations (3) and (4), the resonance judgment value d is a fractional part of a value k obtained by dividing the primary component of the biting frequency by the primary component of the chordal resonance frequency. Since the noise and vibration levels due to the amplification of energy at both frequencies are deteriorated when both frequencies F _a and F _i coincide with each other, k = 1 at this time. Further, by multiplying the primary component F _i of the chord resonance frequency by n, the n th component of the chord resonance frequency is obtained, and even when this value matches the primary component of the biting frequency, the energy is amplified, At this time, k = n (n is an integer of 2 or more). Therefore, the closer k is to an integer, that is, the closer the resonance judgment value d is to 0 or 1 as shown in FIG. 7, the more the both frequencies tend to resonate. Indicates that the condition is getting worse. On the other hand, when the resonance judgment value is 0.5, which is an intermediate point between 0 and 1, it is most likely that energy amplification of both frequencies due to coincidence hardly occurs, and that the noise and vibration level are relatively reduced. Show. In the metal belt mechanism 10 of the continuously variable transmission CVT according to the present invention, both frequencies change in the above range. For example, the primary component of the string resonance frequency coincides with the secondary component of the biting frequency, and F _a = When 2F _i and d = 0.5, both frequencies do not tend to resonate.

  Further, the deterioration of noise and vibration level due to the coincidence of the biting frequency and the string resonance frequency is easily perceived by the occupant particularly when the engine noise is small, such as when idling in an in-gear state. Here, the control content for avoiding the coincidence state between the primary component of the biting frequency and the chord resonance frequency during idling in the in-gear state will be described with reference to the flowchart of FIG.

In step S1, it is determined whether gear state receives a shift position signal S _P output from the shift position sensor 105. If it is determined that the shift position is in the neutral range, the process proceeds to step S2, and energization control is performed on the solenoid of the speed change control valve 70 in order to avoid the coincidence state between the biting frequency and the string resonance frequency. As a result, the hydraulic pressure supplied to both the cylinder chambers 14 and 19 is adjusted. As described above, in step S2, control is performed so that the transmission gear ratio is preset and stored so that the resonance frequency of the chord part can be avoided in the neutral range. In this embodiment, the speed ratio set in step S2 is the same value as the reference speed ratio in the in-gear state.

If it is determined in step S1 that the shift position is in the travel range and the gear is in the in-gear state, the process proceeds to step S3 to receive the rotation signal _NDR input from the drive pulley rotation speed sensor 102 and use equation (1). The primary component F _i of the biting frequency is calculated. Followed by a calculation of the primary component F _a chord portion resonance frequency in step S4. In the control unit 100, a variable C, which is measured in advance with respect to the gear ratio as shown in FIG. 5, is set as a map. As shown in FIG. 6, the string tension measured in advance with respect to the gear ratio and input torque. T is mapped, the engine speed signal Ne of the engine speed sensor 101, the drive pulley speed signal N _DR of the drive pulley speed sensor 102, the driven pulley speed signal N _DN of the driven pulley speed sensor 103, the throttle opening The gear ratio and the input torque are calculated in response to the engine throttle opening signal _TH etc. of the sensor 105, and the variable C and the string tension T are calculated by comparing the calculation results with the above map. calculation of the primary component F _a chord portion resonance frequency is performed using the. Further, in step S5, it receives the calculation result of the bite frequency F _i and the chord resonant frequency F _a at step S3, S4, the formula (3), the resonance determination value d is calculated using (4).

  In step S6, the threshold value set in the control unit 100 in advance and the resonance judgment value obtained in step S5 are compared in magnitude, and within the range of a plurality of numerical ranges provided based on the threshold value by this magnitude comparison. In this step, it is determined whether the resonance judgment value belongs to determine the level of resonance. As shown in FIGS. 4 and 7, in this embodiment, three numerical ranges R1, R2, and R3 are set using two thresholds (for example, threshold 1: 0.35, threshold 2: 0.65). In step S6a, a comparison with the threshold value 1 is performed, and in step S6b, a comparison with the threshold value 2 is performed to determine which of the numerical ranges R1, R2, and R3 belongs.

  When it is determined in step S6a that the resonance determination value is smaller than the threshold value 1, that is, when it is determined that the resonance determination value is high and the resonance determination value belongs to the numerical range R1 smaller than 0.5 as shown in FIG. Proceeds to step S7a, performs energization control to the solenoid of the speed change control valve 70 so as to shift the speed ratio to the OD (overdrive) side of the reference speed ratio, and supplies the hydraulic pressure supplied to both cylinder chambers 14, 19 Is adjusted. The value of the gear ratio to be shifted here is set and stored in advance in the control unit 100 (for example, gear ratio: 2.410).

  If it is determined in step S6a that the resonance determination value is larger than the threshold value 1 and the process proceeds to step S6b, and it is determined in step S6b that it is smaller than the threshold value 2, that is, the resonance determination value is within the range as shown in FIG. If it is determined that it belongs to the numerical range R2 having a low resonance level including 0.5, the process proceeds to step S7b, and energization control is performed on the solenoid of the speed change control valve 70 so as to maintain the reference speed change ratio. The hydraulic pressure supplied to the cylinder chambers 14 and 19 is adjusted.

  If it is determined in step S6a that the resonance determination value is larger than the threshold value 1 and the process proceeds to step S6b, and it is determined in step S6b that it is larger than the threshold value 2, that is, the resonance determination value is high as shown in FIG. Is determined to belong to the numerical range R3 larger than 0.5, the process proceeds to step S7c, and the energization control to the solenoid of the speed change control valve 70 is performed so as to shift the speed ratio to the LOW side from the reference speed ratio. The hydraulic pressure supplied to both cylinder chambers 14 and 19 is adjusted. Note that the value of the gear ratio to be shifted here is preset and stored in the control unit 100 (for example, gear ratio: 2.310) in the same manner as the change in step S7a.

As described above, in steps S7a to S7c, control for shifting the gear ratio from the reference gear ratio to the OD side or the LOW side or control for maintaining the reference gear ratio is performed according to the numerical range to which the resonance judgment value belongs. Done. The speed ratio by this control is shifted changed to the OD side or LOW side, primary component F _a chord portion resonance frequency variable C is changed is changed.

  Here, in FIG. 8, as an example showing the effect of the control device according to the present invention, the noise level of the continuously variable transmission of the conventional example and the control device according to the present invention when the resonance judgment value d belongs to the numerical value range R3. The measurement result of the noise level of the continuously variable transmission to which is applied is shown. In addition, the measurement result of the noise level by the agreement with the primary component of a biting frequency and a string part resonance frequency is shown as the continuous line. From this figure, it can be seen that the noise level is reduced as compared with the conventional example in which the speed change ratio is always kept at the reference speed change ratio by the control device according to the present invention. The white plot shows an example of changing the gear ratio that is changed when the resonance judgment value belongs to the numerical value range R3. Similarly, by changing the shift from the reference gear ratio to the OD side, the conventional example is also shown. It can be seen that the noise level can be further reduced.

  In this way, the control unit 100 of the continuously variable transmission according to the present invention that performs the above control contents receives a change in the operating state such as when the air conditioner is turned on and the engine speed is increased while the in-gear state is stopped. Even if the chord resonance frequency changes and tends to coincide with the biting frequency, the gear ratio depends on the range to which the resonance judgment value calculated by receiving the detection signals of various sensors that detect the driving state belongs. Therefore, the chord resonance frequency is changed in accordance with the change in the gear ratio to avoid the coincidence with the biting frequency, and the noise and the vibration level can be prevented from deteriorating.

  Up to this point, the control content of the control device for a continuously variable transmission according to the present invention has been described. However, the present invention is not limited to this embodiment, and various modifications are possible. For example, in the control content of the present embodiment, control is performed to determine the gear ratio by determining the resonance level of only the primary component of the biting frequency, but the secondary component of the biting frequency is similarly calculated. Thus, the resonance judgment value may be obtained on both the primary and secondary sides, and control to change the gear ratio based on both resonance judgment values may be performed. By performing control in consideration of both resonance judgment values in this way, the noise and vibration levels can be further reduced as shown by the one-dot chain line in FIG. It is also possible to obtain a resonance judgment value with respect to the chord part resonance frequency in the same manner for the third and higher order components of the biting frequency, and perform control in consideration of the resonance judgment value of each order component.

  Since the threshold value 1 and the threshold value 2 to be set are close to 0.5, the boundary line BL as to whether or not to change the speed change ratio indicated by the alternate long and short dash line in FIG. 7 changes downward (on the low resonance side). Control for avoiding the coincidence state of both frequencies can be performed at a severe level. Further, in this embodiment, two threshold values for setting the numerical value range are provided and the resonance degree determination (step S6) is performed, but three or more threshold values are provided to further narrow the numerical value range setting. Thus, control for changing the gear ratio may be performed.

  In the present embodiment, in order to change the resonance frequency of the chord portion and avoid the coincidence with the biting frequency, a plurality of numerical ranges are provided by preset threshold values, and preset storage is performed according to each range. However, the method is not limited to such a method. For example, from each term such as the biting frequency and the chord resonance frequency, the resonance determination value d is determined at each determination. A method may be employed in which an optimum speed ratio is calculated in order to avoid the coincidence state of both frequencies being 0.5, and the solenoid of the speed change control valve 70 is energized and controlled so that the calculated optimum speed ratio is obtained.

  In addition, what is subjected to change control in order to avoid the coincidence state of both frequencies in step S7 is not limited to the gear ratio, and the coincidence state is changed by changing the biting frequency or the chord resonance frequency according to the range to which the resonance judgment value belongs. If this can be avoided, control by other means may be performed. For example, according to the range to which the resonance judgment value belongs, an electric signal for adjusting and controlling the throttle opening is output from the control unit 100, and the input torque is changed to change the tension of the string portion 15a to change the string portion resonance frequency. The control unit 100 is provided with a control unit 100 for calculating a correction coefficient for correcting the supply / discharge hydraulic pressure for both cylinder chambers 14 and 19 or a correction term to be added, and this correction coefficient or correction term is applied according to the resonance judgment value. The coincidence state may be avoided by performing control to change the string portion resonance frequency by changing the tension 15a of the string portion by performing the hydraulic control.

It is the schematic which shows the structure of the control apparatus of the continuously variable transmission which concerns on this invention. It is sectional drawing of the said continuously variable transmission. It is a schematic diagram of the metal belt mechanism of the continuously variable transmission. It is a flowchart which shows the control content by the said control apparatus. 3 is a graph showing a relationship between a gear ratio and a variable C. It is a graph which shows the relationship between a gear ratio, the torque input into a drive pulley, and the tension | tensile_strength of a string part. It is the schematic which shows the relationship between a resonance judgment value, and the resonance degree of a biting frequency and a string part resonance frequency, and is explanatory drawing of step S6. It is a graph showing transition of the noise level accompanying a gear ratio change when a resonance judgment value belongs to numerical value range R3 in a present Example.

Explanation of symbols

CVT continuously variable transmission ECU control unit CP coupling mechanism 10 metal belt mechanism 11 drive pulley 14 drive pulley cylinder chamber 15 metal belt (15a string portion)
16 Driven pulley 19 Driven pulley cylinder chamber 70 Shift control valve

Claims (5)

A pulley having a variable pulley width, a driven pulley having a variable pulley width, and a belt wound between the drive pulley and the driven pulley, and the pulley widths of the drive and driven pulleys are set according to an operating state. In the control device for the continuously variable transmission, which is configured to change and transmit the rotational speed of the drive pulley steplessly to the driven pulley,
Biting frequency calculating means for calculating the biting frequency of the belt into the pulley according to the number of rotations of the pulley;
A chordal resonance frequency calculating means for calculating a chordal resonance frequency of the belt using a gear ratio calculated according to a driving state ;
Resonance judgment value calculating means for calculating a resonance judgment value for judging the degree of resonance of both frequencies from the biting frequency and the string part resonance frequency;
It is determined whether the resonance determination value calculated by the resonance determination value calculation means is larger than a preset reference determination value, and when it is determined that the resonance determination value is smaller than the reference determination value, the speed change is performed. A continuously variable transmission characterized by comprising: a resonance avoiding means for changing the ratio to the overdrive side and changing the transmission ratio to the low side when it is determined that the resonance determination value is greater than the reference determination value; Machine control device. 2. The control device for a continuously variable transmission according to claim 1, wherein in the resonance avoidance unit, the reference determination value is set as a value when the resonance degree is minimum. 3. In the resonance avoidance means, a first judgment value smaller than the reference judgment value and a second judgment value larger than the reference judgment value are preset, and the resonance judgment value is smaller than the first judgment value. The transmission ratio is changed to the overdrive side, and when the resonance determination value is determined to be larger than the second determination value, the transmission ratio is changed to the low side, and the resonance determination value is 3. The continuously variable transmission according to claim 2, wherein the speed ratio is maintained when it is determined that the speed ratio is between the first determination value and the second determination value including the reference determination value. Control device. 3. The continuously variable transmission control device according to claim 2, wherein the resonance avoidance unit changes the speed ratio so that the resonance determination value matches the reference determination value. The continuously variable transmission includes a shift control valve for controlling hydraulic oil supply / discharge hydraulic pressure to the drive and driven pulley, and the pulley width of the drive and driven pulley is changed by the operation control of the shift control valve. Configured,
When the engine is idling in-gear condition, wherein the controller the performs operation control of the transmission control valve so that the preset predetermined of said gear ratio, operation controls the shift control valve in response to said resonant determination value The control device for the continuously variable transmission according to any one of claims 1 to 4, wherein control for changing the speed ratio is performed.

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