JP5581252B2 - Shift control device for continuously variable transmission and shift control method therefor - Google Patents

Description

  The present invention relates to control of secondary thrust in a continuously variable transmission.

  2. Description of the Related Art A continuously variable transmission that performs a speed change operation by driving a drive belt around a primary pulley and a secondary pulley and changing each pulley width of the primary pulley and the secondary pulley is known. Each of the primary pulley and the secondary pulley receives thrust in the axial direction to change the pulley width and change the contact radius with the drive belt. Accordingly, the pulley ratio changes.

  The pulley ratio is controlled according to the thrust of the primary pulley and the secondary pulley as described above, and feedback control is performed so that the actual pulley ratio becomes the target pulley ratio set according to the driving conditions such as the vehicle speed and the throttle opening. Is done. The actual pulley ratio is calculated from a map set in advance based on the detected value, for example, by detecting the sliding position of the movable pulley of each pulley by a position sensor.

  However, the drive belt stretches due to belt tension, and when the drive belt is stretched, the relationship of the actual pulley ratio to the detected value of the position sensor changes, so the actual pulley ratio is calculated as a value different from the actual pulley ratio. There is a possibility that the shift control cannot be performed properly.

  Therefore, Patent Document 1 describes that the pulley ratio calculated as the rotation speed ratio of each pulley is corrected by a deviation width calculated according to the input torque.

JP 7-158706 A

  When elongation occurs in the drive belt, an error occurs between the pulley ratio calculated as the rotation speed ratio of each pulley and the pulley ratio calculated as the belt contact diameter of each pulley. It becomes higher than the pulley ratio due to the belt contact diameter (becomes a pulley ratio on the Low side).

  In the above conventional technique, the pulley ratio based on the rotational speed ratio is corrected according to the input torque to obtain the target pulley ratio, so that the target pulley ratio is set higher than the actually required pulley ratio. Thereby, the thrust of the secondary pulley set higher as the pulley ratio is higher is set higher than necessary.

  The present invention has been made in view of such technical problems, and an object thereof is to prevent the thrust of the secondary pulley from being set higher than necessary when the elongation of the drive belt is taken into consideration.

According to an aspect of the present invention, an input-side primary pulley, an output-side secondary pulley, and a belt-like driving force transmission member that is hung around each pulley, the groove width of each pulley is set in the axial direction. A speed change control device for a continuously variable transmission, in which a pulley ratio is changed by changing a contact radius with a driving force transmission member that is changed by an acting thrust, and a rotation speed ratio of each pulley due to an extension of the driving force transmission member The pulley ratio when the driving force transmission member is not stretched based on the rotational speed ratio change amount estimating means for estimating the change amount of the pulley, and the input torque to the primary pulley and the change amount of the rotational speed ratio of each pulley A non-elongation pulley ratio estimation means for estimating the non-elongation pulley ratio, and a secondary that calculates the secondary thrust of the secondary pulley based on the input torque to the primary pulley and the non-elongation pulley ratio. Drive and Li thrust calculation means, with estimates the elongation after primary diameter of the contact radius between the primary pulley and the driving force transmitting member after the driving force transmitting member is extended, a secondary pulley after the driving force transmitting member is extended A pulley diameter calculating means for calculating a secondary diameter after elongation which is a contact radius with the force transmission member, a secondary thrust calculating means for correcting secondary thrust based on the secondary diameter after extension, and calculating a corrected secondary thrust; Thrust control means for controlling the secondary thrust to become the corrected secondary thrust, and the rotational speed ratio change amount estimating means increases the rotational speed ratio of each pulley as the rotational speed ratio of each pulley increases. The non-elongation pulley ratio estimation means is configured such that the non-elongation pulley ratio increases as the amount of change in the rotational speed ratio of each pulley increases. The pulley diameter calculation means estimates that the primary diameter after elongation increases as the input torque to the primary pulley increases, and calculates so that the secondary diameter after extension increases as the primary diameter increases. The rear secondary thrust calculation means calculates the secondary thrust after correction so that the corrected secondary thrust increases as the secondary diameter increases .

Further, according to another aspect of the present invention, an input-side primary pulley, an output-side secondary pulley, and a belt-like driving force transmission member that is wound around each pulley, the groove width of each pulley is set. A transmission control method for a continuously variable transmission in which a pulley ratio is changed by changing a contact radius with a driving force transmission member by changing the thrust acting in the axial direction. Based on the procedure for estimating the amount of change in the rotational speed ratio, the input torque to the primary pulley, and the amount of change in the rotational speed ratio of each pulley, the elongation that is the pulley ratio when the drive force transmission member is not stretched procedures and, based on the input torque and stretch without pulley ratio of the primary pulley, a step of calculating a secondary thrust Sekadaripuri ply after the driving force transmitting member is extended to estimate the free pulley ratio Estimate the stretched primary diameter, which is the contact radius between the repulley and the driving force transmission member, and calculate the stretched secondary diameter, which is the contact radius between the secondary pulley and the driving force transmission member after the driving force transmission member is stretched. and procedures, and corrected based on the secondary diameter after elongation secondary thrust, comprising a step of calculating the corrected secondary thrust, the procedures for controlling such secondary thrust is corrected secondary thrust, the rotation speed of each pulley The procedure for estimating the amount of change in the ratio is such that the higher the rotational speed ratio of each pulley is, the larger the amount of change in the rotational speed ratio of each pulley is. The procedure for calculating the secondary diameter after elongation is as follows: The larger the is, the larger the primary diameter after elongation is estimated, the larger the primary diameter after elongation is, the larger the secondary diameter after elongation is, and the procedure for calculating the corrected secondary thrust is that the secondary diameter after elongation is large. There is provided a speed change control method for a continuously variable transmission, wherein the post-correction secondary thrust is calculated so as to increase .

  According to these aspects, the pulley ratio without elongation is estimated based on the amount of change in the rotational speed ratio of each pulley, the secondary thrust when the driving force transmission member is not stretched is calculated, and this secondary thrust is It correct | amends based on the variation | change_quantity of the contact radius of the secondary pulley by extension. As a result, the secondary thrust is calculated based not on the pulley ratio based on the rotation speed ratio but on the pulley ratio based on the winding radius ratio. Therefore, when considering the extension of the driving force transmission member, the secondary thrust is made higher than necessary. Setting can be prevented.

It is a schematic block diagram of the transmission control apparatus of the continuously variable transmission which concerns on this embodiment. It is a figure for demonstrating the change of the pulley ratio by the elongation of a belt. It is a flowchart which shows the flow of control performed by CVTCU. It is a map for calculating the pulley ratio change amount by belt elongation. It is a map which shows the relationship between a pulley ratio, input torque, and pulley ratio variation | change_quantity. It is a flowchart which shows the flow of control performed by CVTCU. It is a map for calculating the primary diameter after belt extension. It is a map for calculating a thrust correction coefficient. It is a figure explaining the effect | action of the transmission control apparatus of the continuously variable transmission which concerns on this embodiment. It is a figure explaining the effect | action of the transmission control apparatus of the continuously variable transmission which concerns on this embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a shift control device of a continuously variable transmission 10 according to the present embodiment. The continuously variable transmission 10 includes a primary pulley 11, a secondary pulley 12, a belt 13, a CVT control unit 20 (hereinafter referred to as “CVTCU”), and a hydraulic control unit 30. I do.

  The primary pulley 11 is an input shaft side pulley that inputs the rotation of the engine 1 to the continuously variable transmission 10. The primary pulley 11 forms a V-shaped pulley groove that is disposed opposite to the fixed conical plate 11b that rotates integrally with the input shaft 11d, and acts on the primary pulley cylinder chamber 11c. And a movable conical plate 11a that can be displaced in the axial direction by hydraulic pressure. The primary pulley 11 is connected to the engine 1 through a torque converter 2 having a forward / reverse switching mechanism 3 and a lock-up clutch, and inputs the rotation of the engine 1. The rotation speed of the primary pulley 11 is detected by a primary pulley rotation speed sensor 26.

  The belt 13 is wound around the primary pulley 11 and the secondary pulley 12, and transmits the rotation of the primary pulley 11 to the secondary pulley 12. The belt 13 is a chain belt configured by connecting a number of blocks in a band shape by links and pins, and is simply referred to as “belt” in the following specification. The belt is not limited to a chain belt, and may be a V-belt in which a number of elements are connected by a belt-like ring.

  The secondary pulley 12 outputs the rotation transmitted by the belt 13 to the differential 4. The secondary pulley 12 forms a V-shaped pulley groove so as to be opposed to the fixed conical plate 12b that rotates integrally with the output shaft 12d and the fixed conical plate 12b, and acts on the secondary pulley cylinder chamber 12c. And a movable conical plate 12a that can be displaced in the axial direction according to the hydraulic pressure.

  The secondary pulley 12 connects the differential 4 via an idler gear 14 and an idler shaft, and outputs rotation to the differential 4. The rotational speed of the secondary pulley 12 is detected by the secondary pulley rotational speed sensor 27. The vehicle speed can be calculated from the rotational speed of the secondary pulley 12.

  The CVTCU 20 is based on signals from the inhibitor switch 23, accelerator pedal stroke amount sensor 24, oil temperature sensor 25, primary pulley rotational speed sensor 26, secondary pulley rotational speed sensor 27, etc., and input torque information from the engine control unit 21. The pulley ratio (the value obtained by dividing the effective radius of the secondary pulley 12 by the effective radius of the primary pulley 11) and the contact friction force are determined with reference to the previously stored shift line, and a command is transmitted to the hydraulic control unit 30. Thus, the continuously variable transmission 10 is controlled.

  The hydraulic control unit 30 responds based on a command from the CVTCU 20. The hydraulic control unit 30 supplies hydraulic pressure to the primary pulley 11 and the secondary pulley 12 to reciprocate the movable conical plate 11a and the movable conical plate 12a in the rotation axis direction.

  When the movable conical plate 11a and the movable conical plate 12a move, the pulley groove width changes. Then, the belt 13 moves on the primary pulley 11 and the secondary pulley 12. As a result, the contact radius of the belt 13 with respect to the primary pulley 11 and the secondary pulley 12 changes, and the pulley ratio and the contact friction force of the belt 13 are controlled.

  The rotation of the engine 1 is input to the continuously variable transmission 10 via the torque converter 2 and the forward / reverse switching mechanism 3, and is transmitted from the primary pulley 11 to the differential 4 via the belt 13 and the secondary pulley 12.

  When the accelerator pedal is depressed or shift-changed in the manual mode, the movable conical plate 11a of the primary pulley 11 and the movable conical plate 12a of the secondary pulley 12 are displaced in the axial direction to change the contact radius with the belt 13. As a result, the pulley ratio is continuously changed.

  The pulley ratio is obtained by searching for the primary rotational speed corresponding to the vehicle speed and the throttle opening based on a shift map in which a plurality of shift lines indicating the relationship between the vehicle speed and the primary rotational speed are prepared for each throttle opening. Is set.

  Next, a change in the pulley ratio due to the elongation of the belt 13 will be described with reference to FIG.

  The belt 13 is stretched by belt tension between the primary pulley 11 and the secondary pulley 12. When the belt 13 is extended, the contact radius between the belt 13 and each of the pulleys 11 and 12 increases, so that the pulley ratio changes. When the pulley ratio is 1, the groove widths of the pulleys 11 and 12 change uniformly, so the pulley ratio does not change. However, when the pulley ratio is larger or smaller than 1, the pulley ratio becomes low. Change.

  As shown in FIG. 2, when the belt is extended, the actual pulley ratio changes to the low side. In this case, an error occurs between the actual pulley ratio calculated from the rotational speed ratio of the pulleys 11 and 12 and the actual pulley ratio calculated from the winding radius ratio of the pulleys 11 and 12, and the actual pulley ratio is calculated based on the rotational speed ratio. The pulley ratio becomes lower than the actual pulley ratio by the winding radius ratio. However, since the actual pulley ratio is the pulley ratio based on the winding radius ratio, if the secondary thrust is set based on the actual pulley ratio based on the rotational speed ratio, the secondary thrust is set higher than the actually required thrust. .

  Therefore, in the present embodiment, the following control is performed. FIG. 3 is a flowchart showing a flow of control performed by the CVTCU 20. The control shown in FIG. 3 is repeatedly performed every minute time (for example, 10 ms).

  In step S1, the CVTCU 20 reads the rotational speeds and input torques of the pulleys 11 and 12. In the following description, a location that is calculated based on the input torque may be calculated according to pulley thrust (hydraulic pressure), pulley rotation speed, oil temperature, etc. in addition to the input torque.

  In step S <b> 2, the CVTCU 20 calculates a pulley ratio based on the rotational speed ratio between the pulleys 11 and 12.

  In step S <b> 3, the CVTCU 20 estimates a pulley ratio change amount due to the belt 13 extending. The amount of pulley ratio change due to elongation is calculated with reference to the map of FIG. FIG. 4 is a map showing the relationship between the pulley ratio based on the rotational speed ratio of the pulleys 11 and 12, the input torque, and the amount of change in the pulley ratio due to elongation. The amount of change in pulley ratio due to elongation is calculated so as to increase as the pulley ratio increases and as the input torque increases.

  In step S <b> 4, the CVTCU 20 estimates a pulley ratio without belt elongation, which is a pulley ratio based on a winding radius ratio when the belt 13 is not stretched. The pulley ratio without belt elongation is calculated with reference to the map of FIG. FIG. 5 is a map showing a relationship between a pulley ratio without elongation, an input torque, and a pulley ratio change amount due to elongation. The pulley ratio without belt elongation is calculated as a pulley ratio higher than 1 (on the low side) when the pulley ratio change amount is a positive value based on the pulley ratio change amount and the input torque estimated in step S3. When the pulley ratio change amount is a negative value, it is calculated as a pulley ratio lower than 1 (high side).

  In step S5, the CVTCU 20 calculates a basic secondary thrust. The basic secondary thrust is calculated according to a preset map based on the pulley ratio without belt elongation calculated in step S4 and the input torque.

  In step S6, the CVTCU 20 calculates the secondary diameter after belt extension. The secondary diameter after the belt extension is a contact diameter of the belt 13 with respect to the secondary pulley 12 when the belt 13 is extended, and is calculated according to the flowchart of FIG.

  That is, in step S61, the CVTCU 20 reads the vehicle speed and the throttle opening.

  In step S62, the CVTCU 20 calculates a target rotation speed. For the target rotation speed, the primary rotation speed corresponding to the vehicle speed and the throttle opening is searched based on a shift map in which a plurality of shift lines indicating the relationship between the vehicle speed and the rotation speed of the primary pulley 11 are prepared for each throttle opening. Is set.

  In step S63, the CVTCU 20 calculates a target pulley ratio. The target pulley ratio is calculated by dividing the rotational speed of the secondary pulley 12 from the target rotational speed.

  In step S <b> 64, the CVTCU 20 reads an input torque that causes the belt 13 to stretch.

  In step S65, the CVTCU 20 estimates the pulley ratio change amount. The pulley ratio change amount is a change amount of the pulley ratio due to the elongation of the belt 13, and is calculated with reference to the map of FIG. 5 based on the target pulley ratio and the input torque. In this step, the pulley ratio change amount is searched with the horizontal axis of the map of FIG. 5 as the target pulley ratio.

  When the target pulley ratio is 1, the pulley ratio change amount is a positive value when it is larger than 1 and a negative value when it is smaller than 1. The pulley ratio change amount is calculated so that the absolute value increases as the input torque increases.

  In step S66, the CVTCU 20 calculates a pulley ratio after belt extension. The pulley ratio after belt extension is the target pulley ratio when the belt 13 is extended, and is calculated by adding the pulley ratio change amount calculated in step S65 to the target pulley ratio calculated in step S63. For example, when the target pulley ratio is 1.5 and the pulley ratio change amount is 0.01, the corrected target pulley ratio is 1.5 + 0.01 = 1.51, the target pulley ratio is 0.5, and the pulley When the ratio change amount is −0.01, the corrected target pulley ratio is 0.5 + (− 0.01) = 0.49.

  In step S67, the CVTCU 20 estimates the primary diameter after belt extension. The primary diameter after the belt extension is a contact diameter of the belt 13 with respect to the primary pulley 11 when the belt 13 is extended, and is calculated with reference to the map of FIG. FIG. 7 is a map showing the relationship between the target pulley ratio, the input torque, and the primary diameter after elongation. The post-elongation primary diameter is calculated such that the smaller the target pulley ratio (higher side) and the greater the input torque, the larger the primary diameter.

  In step S68, the CVTCU 20 calculates the secondary diameter after belt extension. The secondary diameter after belt extension is the contact diameter of the belt 13 with respect to the secondary pulley 12 when the belt 13 is extended, and is calculated by adding the pulley ratio after belt extension to the primary diameter after belt extension calculated in step S67. The

  Returning to FIG. 3, in step S7, the CVTCU 20 calculates a thrust correction coefficient of the secondary thrust. The thrust correction coefficient is calculated with reference to the map of FIG. 8 showing the relationship between the pulley ratio without elongation, the secondary diameter after elongation, and the thrust correction coefficient. The thrust correction coefficient is calculated so as to increase as the non-elongation pulley ratio becomes higher (on the low side) and as the secondary diameter after extension becomes larger.

  In step S8, the CVTCU 20 calculates the corrected basic secondary thrust. The corrected basic secondary thrust is calculated by adding a thrust correction coefficient to the basic secondary thrust.

  In step S9, the CVTCU 20 performs thrust control so that the secondary thrust becomes the corrected basic secondary thrust.

  Next, the operation of the present embodiment will be described with reference to FIG.

  FIG. 9 is a diagram showing a change in the actual pulley ratio by the control of the present embodiment. In this embodiment, the pulley ratio based on the rotation speed ratio is replaced with the pulley ratio based on the winding radius ratio in a state where there is no elongation, and the basic secondary thrust calculated based on this pulley ratio is changed according to the change in the secondary diameter due to elongation. It is corrected. That is, the actual pulley ratio is calculated based on the pulley ratio based on the wound radius ratio after elongation. Thereby, the secondary thrust considering the elongation of the belt 13 is calculated on the assumption that the actual pulley ratio is not the point A but the point B. The secondary thrust is set higher as the pulley ratio is higher, and the point B has a pulley ratio lower than that at the point A, so that the secondary thrust can be prevented from being set higher than necessary.

  This is shown in a time chart as shown in FIG. When the driver depresses the accelerator pedal at time t1 from the state where the vehicle is stopped, the extension correction is turned on, and the basic thrust of the secondary pulley 12 is corrected according to the change in the pulley ratio. As a result, the basic thrust of the secondary pulley 12 is set to a lower thrust than when no correction is made.

  Thereafter, the thrusts of the pulleys 11 and 12 change according to changes in the vehicle speed and the throttle opening, but the secondary thrust after correction is always lower than that without correction while the extension correction is performed. Set to thrust. This can prevent the secondary thrust from being set higher than necessary.

  As described above, in the present embodiment, the pulley ratio without elongation when the belt 13 is not stretched is estimated from the amount of change in the rotational speed ratio between the pulleys 11 and 12, and the belt 13 is not stretched. The basic secondary thrust is calculated, and the basic secondary thrust is corrected based on the secondary pulley diameter after the belt is extended. As a result, the secondary thrust is calculated based not on the pulley ratio based on the rotation speed ratio but on the pulley ratio based on the winding radius ratio, so that the secondary thrust is set to be higher than necessary in consideration of the elongation of the belt 13. This can be prevented (corresponding to claims 1 and 3).

  The pulley ratio without elongation is calculated as a pulley ratio higher than 1 (Low side) when the amount of change in the rotational speed ratio is a positive value, and is lower than 1 (High side when it is a negative value). ) Since it is calculated as a pulley ratio, the pulley ratio without elongation can be appropriately estimated according to the amount of change in the pulley ratio, and the secondary thrust can be more reliably prevented from being set higher than necessary. (Corresponding to claim 2).

  The embodiment of the present invention has been described above. However, the above embodiment is merely one example of application of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.

11 Primary pulley 12 Secondary pulley 13 Chain belt (driving force transmission member)
S3 Rotational speed ratio change estimation means S4 Non-elongation pulley ratio estimation means S5 Secondary thrust calculation means S6 Contact radius change estimation means S8 Corrected secondary thrust calculation means S9 Thrust control means

Claims (3)

An input-side primary pulley, an output-side secondary pulley, and a belt-like driving force transmission member that is wound around each pulley, the groove width of each pulley being changed by a thrust acting in the axial direction, and the driving A transmission control device for a continuously variable transmission in which a pulley ratio changes by changing a contact radius with a force transmission member,
A rotational speed ratio change amount estimating means for estimating a change amount of the rotational speed ratio of each pulley due to the extension of the driving force transmission member;
A non-elongation pulley that estimates a non-elongation pulley ratio, which is a pulley ratio when the drive force transmission member is not elongated, based on the input torque to the primary pulley and the amount of change in the rotational speed ratio of each pulley. A ratio estimation means;
Secondary thrust calculation means for calculating secondary thrust of the secondary pulley based on the input torque to the primary pulley and the pulley ratio without elongation;
Estimating a primary diameter after extension, which is a contact radius between the primary pulley and the driving force transmission member after the driving force transmission member is extended, and the secondary pulley and the drive after the driving force transmission member is extended Pulley diameter calculating means for calculating a secondary diameter after extension, which is a contact radius with the force transmission member,
Corrected secondary thrust calculating means for correcting the secondary thrust based on the secondary diameter after extension and calculating the corrected secondary thrust;
Thrust control means for controlling the secondary thrust to be the corrected secondary thrust ;
Equipped with a,
The rotational speed ratio change amount estimation means estimates that the amount of change in the rotational speed ratio of each pulley increases as the rotational speed ratio of each pulley increases.
The non-elongation pulley ratio estimation means estimates that the non-elongation pulley ratio increases as the amount of change in the rotational speed ratio of each pulley increases.
The pulley diameter calculation means estimates that the primary diameter after extension increases as the input torque to the primary pulley increases, and calculates so that the secondary diameter after extension increases as the primary diameter after extension increases. ,
The post-correction secondary thrust calculating means calculates the post-correction secondary thrust to be larger as the post-extension secondary diameter is larger.
A transmission control apparatus for a continuously variable transmission. A transmission control device for a continuously variable transmission according to claim 1,
The non-elongation pulley ratio estimated by the non-elongation pulley ratio estimation means is calculated as a pulley ratio higher than 1 when the amount of change in the rotational speed ratio is a positive value, and from 1 when the change is a negative value. Calculated as a low pulley ratio,
A transmission control apparatus for a continuously variable transmission. An input-side primary pulley, an output-side secondary pulley, and a belt-like driving force transmission member that is wound around each pulley, the groove width of each pulley being changed by a thrust acting in the axial direction, and the driving A speed change control method for a continuously variable transmission in which a pulley ratio is changed by changing a contact radius with a force transmission member,
A procedure for estimating the amount of change in the rotational speed ratio of each pulley due to the extension of the driving force transmission member;
A procedure for estimating a non-elongation pulley ratio, which is a pulley ratio when no elongation occurs in the driving force transmission member, based on the input torque to the primary pulley and the amount of change in the rotational speed ratio of each pulley;
A procedure for calculating the secondary thrust of the secondary pulley based on the input torque to the primary pulley and the pulley ratio without elongation.
Estimating a primary diameter after extension, which is a contact radius between the primary pulley and the driving force transmission member after the driving force transmission member is extended, and the secondary pulley and the drive after the driving force transmission member is extended A procedure for calculating a secondary diameter after extension, which is a contact radius with the force transmission member;
Correcting the secondary thrust based on the secondary diameter after extension, and calculating the corrected secondary thrust;
A procedure for controlling the secondary thrust to be the corrected secondary thrust ;
Equipped with a,
The procedure for estimating the amount of change in the rotational speed ratio of each pulley estimates that the amount of change in the rotational speed ratio of each pulley increases as the rotational speed ratio of each pulley increases.
The procedure for estimating the non-elongation pulley ratio is such that the non-elongation pulley ratio increases as the amount of change in the rotational speed ratio of each pulley increases.
The procedure for calculating the secondary diameter after extension is such that the primary diameter after extension increases as the input torque to the primary pulley increases, and the secondary diameter after extension increases as the primary diameter after extension increases. Operate as
The procedure for calculating the corrected secondary thrust is calculated so that the corrected secondary thrust becomes larger as the secondary diameter after extension becomes larger.
A transmission control method for a continuously variable transmission.

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