JP2010065824A - Continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To determine the rotating direction of a belt with high accuracy when a belt slip occurs. <P>SOLUTION: This continuously variable transmission includes: a primary pulley 500; a secondary pulley 600; a belt 700 formed by arranging a plurality of elements like a ring and wrapped round the groove of the primary pulley 500 and the groove of the secondary pulley 600; and a gap sensor 702 provided on the outer peripheral side of the belt 700 to thereby detect each of the plurality of elements. The plurality of elements include a plurality of elements (1) 704 and a plurality of elements (2) 708 different in the detection result of the gap sensor 702 from each of the plurality of elements (1) 704. The plurality of elements (2) 708 are disposed at unequal spaces on the belt 700 in the moving direction of the belt 700. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a continuously variable transmission, and more particularly to a technique for accurately determining the rotation direction of a belt when a belt slip occurs.

  An automatic transmission mounted on a vehicle includes a transmission mechanism that is connected to an engine via a torque converter or the like and has a plurality of power transmission paths. An example of such a transmission mechanism is a belt-type continuously variable transmission (CVT). In this belt type continuously variable transmission, a belt is wound around a driving pulley (input shaft pulley, primary pulley) and a driven pulley (output shaft pulley, secondary pulley) each having a V-groove pulley groove. By increasing the groove width of the pulley and narrowing the groove width of the other pulley at the same time, the belt wrapping radius (effective diameter) for each pulley is continuously changed to set the transmission ratio steplessly. It is configured. Each pulley is composed of a fixed sheave and a movable sheave, and the movable sheave is configured to shift in the axial direction by a hydraulic actuator provided on the back side thereof to perform speed change.

  As a belt-type continuously variable transmission configured as described above, for example, Japanese Patent Laid-Open No. 2003-222234 (Patent Document 1) can accurately determine belt slip in a continuously variable transmission, reduce pump loss, and improve fuel efficiency. Disclosed is a continuously variable transmission control device. This continuously variable transmission control device is a continuously variable transmission control device having a pair of pulleys and a drive belt wound between the pair of pulleys. A plurality of detection points provided at a predetermined interval and a non-contact displacement sensor which is disposed apart from the drive belt and detects the passage of the detection points provided on the drive belt, and is detected by the non-contact displacement sensor. A first calculating means for calculating the belt speed of the driving belt based on the detection interval of the detected points, and a pulley peripheral speed for calculating the pulley peripheral speed based on the rotation speed of the pulley and the belt winding diameter of the pulley. 2 is used to determine the slip state of the drive belt based on the belt speed and the pulley peripheral speed, and the drive belt is clamped by the pulley according to the determination result. And having a control unit for controlling.

According to the control device for a continuously variable transmission disclosed in the above-mentioned publication, it is possible to always monitor the presence or absence of a belt slip and always detect the required hydraulic pressure according to the situation with high accuracy. As a result, the required hydraulic pressure can be reduced, so that the operation can be performed with the minimum hydraulic pressure. As a result, the consumption of excess hydraulic pressure is efficiently reduced, so that pump loss is reduced and fuel efficiency can be improved.
JP 2003-222234 A

  However, in the control device for a continuously variable transmission disclosed in the above-mentioned publication, the detection points are provided on the drive belt at predetermined intervals, so that when the belt slips, the belt rotates forward or backward. There is a problem that it is not possible to determine whether the rotation has occurred.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a continuously variable transmission that accurately determines the rotation direction of a belt when a belt slip occurs.

  A continuously variable transmission according to a first aspect of the present invention includes a driving pulley, a driven pulley, a belt formed by arranging a plurality of elements in an annular shape, and wound around a groove of the driving pulley and a groove of the driven pulley, Detecting means for detecting each of the plurality of elements provided on the outer peripheral side of the belt. The plurality of elements include a plurality of first elements and a plurality of second elements whose detection results by the detection means are different from the case of each of the plurality of first elements. The plurality of second elements are arranged at unequal intervals on the belt along the moving direction of the belt.

  According to the first invention, since the detection results of the plurality of first element detection means and the detection results of the plurality of second element detection means are different, when the belt is driven, the detection means Whether the detected element is each of the plurality of first elements or each of the plurality of second elements can be specified. Therefore, the actual moving speed of the belt can be detected with high accuracy based on the change in the time interval at which the plurality of second elements are detected. Therefore, the presence / absence of occurrence of belt slip can be determined with high accuracy. Further, since the plurality of second elements are arranged at unequal intervals on the belt, the order of change in the time intervals at which the plurality of second elements are detected differs between when the belt is rotating forward and when it is rotating backward. By doing so, it is possible to determine with high accuracy whether the belt is rotating forward or backward depending on the difference in order. Therefore, it is possible to provide a continuously variable transmission that accurately determines the moving direction of the belt when belt slippage occurs.

  In the continuously variable transmission according to the second invention, in addition to the structure of the first invention, the detecting means is provided at an intermediate position between the driving pulley and the driven pulley and protrudes to the outer peripheral side of the belt A change in the distance from the detection means to the detection means is detected. Each of the plurality of second elements is different from each of the plurality of first elements in the length of the portion protruding to the outer peripheral side of the belt.

  According to the second invention, since the belt includes each of the plurality of first elements and each of the plurality of second elements having different lengths on the outer peripheral side of the belt, the second element is detected. Based on the time interval, the actual moving speed of the belt can be detected with high accuracy. Therefore, the presence / absence of occurrence of belt slip can be determined with high accuracy. Further, since the plurality of second elements are arranged at unequal intervals, the order of change in the time intervals at which the plurality of second elements are detected differs between when the belt is rotating forward and when it is rotating backward. It is possible to determine with high accuracy whether the belt is rotating forward or backward depending on the difference in order.

  In the continuously variable transmission according to the third invention, in addition to the configuration of the first or second invention, in the continuously variable transmission, is the belt rotating forward or reverse based on the result of the detection means? Rotation direction determination means for determining.

  According to the third aspect of the invention, for example, if the order of change of the time intervals at which the plurality of second elements are detected is different between when the belt is rotating forward and when it is rotating backward, the belt is moved forward due to the difference in order. Whether it is rotating or rotating in reverse can be determined with high accuracy.

  In the continuously variable transmission according to the fourth invention, in addition to the configuration of any one of the first to third inventions, the belt is a portion in which each of the plurality of second elements is arranged at the first interval. And a portion arranged at a second interval different from the first interval and a portion arranged at a third interval different from the first and second intervals are continuous along the positive rotation direction. Includes interval. The belts are formed so that the order in which the time intervals at which each of the plurality of second elements is detected by the detection means is different between forward rotation and reverse rotation is different.

  According to the fourth invention, the belt includes the first section in which the portions arranged at the first, second, and third intervals are continuous along the forward rotation direction, and further, during the forward rotation and the reverse rotation Since the order in which the time intervals at which the plurality of second elements are detected changes is different, it is possible to accurately determine whether the belt is rotating forward or reverse depending on the difference in order. Can do.

  In the continuously variable transmission according to the fifth aspect of the invention, in addition to the configuration of the fourth aspect of the invention, the belt is arranged with the portion where the second element is arranged at the third interval and the second interval. The second section in which the portion and the portion arranged at the first interval are continuous along the positive rotation direction is formed so as not to be adjacent to or overlap the first section.

  According to the fifth invention, by forming the belt so that the second section does not adjoin or overlap the first section, the order in which the time intervals at which the plurality of second elements are detected changes is changed. Can be. Therefore, it can be determined with high accuracy whether the belt is rotating forward or backward depending on the order.

  In the continuously variable transmission according to the sixth aspect of the invention, in addition to the configuration of any one of the first to fifth aspects of the invention, the continuously variable transmission uses the first hydraulic pressure generated by supplying and discharging the hydraulic oil to the drive side. The first actuator that changes the groove width of the pulley, the second actuator that changes the groove width of the driven pulley using the second hydraulic pressure generated by supplying and discharging the hydraulic oil, and the rotational speed of the driving pulley are detected. On the basis of the first rotational speed detecting means for detecting the rotational speed of the driven pulley, the second rotational speed detecting means for detecting the rotational speed of the driven pulley, and the rotational speed of the driven pulley and the rotational speed of the driven pulley. A first calculating means for calculating a gear ratio of the stepped transmission, a rotational speed of the driving pulley, a rotational speed of the driven pulley, and a speed ratio for calculating the estimated moving speed of the belt; Based on the second calculation means, the estimated moving speed and the detection result of the detection means Based on the actual moving speed of the belt, a determination means for determining whether or not the belt has slipped, and a first actuator and a belt for increasing the belt tension when the belt slips. Control means for controlling at least one of the second actuators.

  According to the sixth invention, when the estimated moving speed deviates from the actual moving speed, the belt slip is suppressed by determining that the belt slip has occurred and increasing the belt tension. Can do.

  In the continuously variable transmission according to the seventh aspect of the invention, in addition to the configuration of the sixth aspect of the invention, the control means changes the degree of increase in the belt tension in accordance with the rotation direction of the belt.

  According to the seventh aspect of the invention, by changing the degree of increase in belt tension according to the belt rotation direction, it is possible to realize generation of appropriate belt tension according to the belt rotation direction. It is not necessary to increase the belt tension excessively to improve the rate. That is, while suppressing the occurrence of belt slip, the load on the belt can be reduced, and transmission efficiency and fuel efficiency can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  With reference to FIG. 1, a power train of a vehicle on which a continuously variable transmission according to the present embodiment is mounted will be described. The continuously variable transmission according to the present embodiment is a belt type continuously variable transmission.

  As shown in FIG. 1, the power train of the vehicle includes an engine 100, a continuously variable transmission 350, and a differential gear 800.

  The continuously variable transmission 350 includes a torque converter 200, a forward / reverse switching device 290, a belt-type continuously variable transmission mechanism 300, an ECU (Electronic Control Unit) 1000, and a hydraulic control unit 1100.

  The output shaft of engine 100 is connected to the input shaft of torque converter 200. Engine 100 and torque converter 200 are connected by a rotating shaft. Therefore, engine 100 output shaft rotational speed NE (engine rotational speed NE) detected by engine rotational speed sensor 432 and torque converter 200 input shaft rotational speed (pump rotational speed) are the same.

  The torque converter 200 includes a lock-up clutch 210 that directly connects the input shaft and the output shaft, a pump impeller 220 on the input shaft side, a turbine impeller 230 on the output shaft side, and a one-way clutch 250. It is comprised from the stator 240 which expresses an amplification function. Torque converter 200 and belt type continuously variable transmission mechanism 300 are connected by a rotating shaft. The output shaft rotational speed NT (turbine rotational speed NT) of the torque converter 200 is detected by the turbine rotational speed sensor 400.

  An oil pump 260 is provided between the torque converter 200 and the belt type continuously variable transmission mechanism 300. The oil pump 260 is a gear pump, for example, and operates as the pump impeller 220 on the input shaft side rotates. The oil pump 260 supplies hydraulic pressure to the line pressure control unit 1130.

  Belt type continuously variable transmission mechanism 300 is connected to torque converter 200 with forward / reverse switching device 290 interposed. The belt type continuously variable transmission mechanism 300 includes an input side primary pulley 500, an output side secondary pulley 600, and a metal annular belt 700 wound around the primary pulley 500 and the secondary pulley 600.

  The belt 700 is formed by annularly arranging a plurality of elements having contact surfaces with the primary pulley 500 and the secondary pulley 600.

  Primary pulley 500 includes a fixed sheave fixed to primary shaft 502 and a movable sheave supported on primary shaft 502 so as to be slidable only. The secondary pulley 600 includes a fixed sheave fixed to the secondary shaft 602 and a movable sheave supported on the secondary shaft 602 so as to be slidable only.

  Hydraulic oil is supplied to and discharged from the hydraulic actuator (1) 550 of the primary pulley 500. In addition, hydraulic oil is supplied to and discharged from the hydraulic actuator (2) of the secondary pulley 600. The speed change is performed by continuously changing the groove width between the fixed sheave and the movable sheave of each of the pulleys 500 and 600 so that the belt winding radius is changed to a large or small size.

  The hydraulic control unit 1100 supplies the hydraulic pressure (hereinafter, referred to as primary hydraulic pressure) supplied to the hydraulic actuator (1) 550 of the primary pulley 500 so that the speed ratio of the primary pulley 500 matches the target rotational speed. To control. Further, the hydraulic control unit 1100 presses the movable sheave of the secondary pulley 600 toward the fixed sheave side to pinch the belt so as to develop a tension necessary for transmitting torque, so that the hydraulic actuator (2) of the secondary pulley 600 is obtained. The hydraulic pressure supplied to 650 (hereinafter referred to as secondary hydraulic pressure) is controlled.

  The rotation speed NIN of the primary pulley 500 of the belt-type continuously variable transmission mechanism 300 (hereinafter referred to as primary pulley rotation speed NIN) is detected by the primary pulley rotation speed sensor 410 and the rotation speed NOUT of the secondary pulley 600 (hereinafter referred to as secondary). The pulley rotation speed NOUT) is detected by the secondary pulley rotation speed sensor 420.

  These rotation speed sensors are provided to face the teeth of the rotation detection gear attached to the rotation shafts of the primary pulley 500 and the secondary pulley 600 and the drive shaft connected thereto. These rotational speed sensors are sensors that can also detect slight rotations of the primary pulley 500 that is an input shaft and the secondary pulley 600 that is an output shaft of the belt-type continuously variable transmission mechanism 300. It is a sensor using a magnetoresistive element called a type sensor.

  Further, the gap sensor 702 detects a change in the distance from the element of the belt 700. Gap sensor 702 transmits a signal indicating a change in the distance from the element of belt 700 to ECU 1000.

  The forward / reverse switching device 290 includes a double pinion planetary gear, a reverse (reverse) brake B1 and an input clutch C1. In the planetary gear, its sun gear is connected to the input shaft, the carrier CR supporting the first and second pinions P1, P2 is connected to the primary side fixed sheave, and the ring gear R is a reverse friction engagement element. The reverse brake B1 is connected, and an input clutch C1 is interposed between the carrier CR and the ring gear R. The input clutch 310 is also called a forward clutch or a forward clutch, and is always used in an engaged state when a vehicle other than the parking (P) position, the R position, and the N position moves forward.

  The ECU 1000 and the hydraulic control unit 1100 that control the continuously variable transmission 350 will be described. ECU 1000 has a signal representing turbine speed NT from turbine speed sensor 400, a signal representing primary pulley speed NIN from primary pulley speed sensor 410, and a secondary pulley speed NOUT from secondary pulley speed sensor 420. Each signal is input. ECU 1000 calculates the gear ratio from gear ratio = primary pulley rotation speed NIN / secondary pulley rotation speed NOUT.

  The hydraulic control unit 1100 includes a transmission speed control unit 1110, a belt clamping pressure control unit 1120, a line pressure control unit 1130, a lockup engagement pressure control unit 1132, a clutch pressure control unit 1140, and a manual valve 1150. Including. The ECU 1000 includes a shift control duty solenoid (1) 1200, a shift control duty solenoid (2) 1210, a belt clamping pressure control linear solenoid 1220, a line pressure control linear solenoid 1230, and a lock. A control signal is output to duty solenoid 1240 for up engagement pressure control.

  The shift speed control unit 1110 increases the amount of hydraulic oil flowing into the hydraulic actuator of the primary pulley 500 by controlling the shift control duty solenoid (1) 1200 according to the vehicle speed based on the wheel speed and the accelerator opening. Controls the speed-side shift speed. Further, the shift speed control unit 1110 controls the amount of hydraulic oil flowing out from the hydraulic actuator (1) 550 of the primary pulley 500 by the shift control duty solenoid (2) 1210 according to the wheel speed and the accelerator opening. To control the shifting speed on the deceleration side. Shift control is performed by controlling the inflow and outflow of hydraulic fluid to the hydraulic actuator (1) 550 of the primary pulley 500 by the shift speed control unit 1110.

  The belt clamping pressure control unit 1120 controls the hydraulic pressure supplied to the hydraulic actuator (2) 650 of the secondary pulley 600 by the belt clamping pressure control linear solenoid 1220 according to the input torque of the primary pulley 500 and the gear ratio. Control the belt clamping pressure. The input torque may be estimated from, for example, the output torque of the engine 100 based on the accelerator pedal depression amount, the throttle opening, the engine speed or the intake air amount, and the torque ratio in the torque converter 200, or directly. May be detected automatically.

  The line pressure control unit 1130 controls the line pressure by the line pressure control linear solenoid 1230 from the instruction value for the belt clamping pressure control linear solenoid 1220 corresponding to the belt clamping pressure and the primary hydraulic pressure (estimated value or actual measurement value).

  In this embodiment, the “line pressure” is the hydraulic pressure supplied to the hydraulic actuator (1) 550 and the original pressure of the hydraulic pressure supplied to the hydraulic actuator (2) 650, and the hydraulic pressure supplied by the oil pump 260. Is a hydraulic pressure regulated by a regulator valve (not shown) and a linear solenoid 1230 for line pressure control.

  The line pressure controlled by the line pressure control unit 1130 is supplied to the shift control duty solenoid (1) 1200, the shift control duty solenoid (2) 1210, and the belt clamping pressure control linear solenoid 1220. The primary hydraulic pressure and the secondary hydraulic pressure are controlled using the supplied line pressure.

  The lockup engagement pressure control unit 1132 controls switching between engagement and disengagement of the lockup clutch 210 and gradual increase and decrease of the engagement pressure of the lockup clutch 210 by the lockup engagement pressure control duty solenoid 1240. .

  The manual valve 1150 operates in conjunction with the driver's operation of the shift lever to switch the oil passage. The clutch pressure control unit 1140 controls the hydraulic pressure supplied via the manual valve 1150 by the line pressure control linear solenoid 1230 when the input clutch C1 or the reverse brake B1 is engaged.

  ECU 1000 further indicates a signal representing the vehicle speed from wheel speed sensor 440, a signal representing the amount of depression of the accelerator pedal from accelerator position sensor 442, and the engine speed sensor 432 represents the engine speed (NE) of engine 100. Each signal is input. ECU 1000 includes a CPU (Central Processing Unit) (not shown) and memory 1002. Various information, programs, threshold values, maps, and the like are stored in the memory 1002, and data is read or stored by the CPU as necessary.

  Wheel speed sensor 440 detects the number of rotations of a wheel (not shown). Wheel speed sensor 440 transmits a wheel speed signal indicating the detected number of rotations of the wheel to ECU 1000. In the present embodiment, as long as the vehicle speed can be detected, the present invention is not particularly limited to detecting the rotational speed of the wheel. For example, the secondary pulley rotational speed and the reduction ratio from the continuously variable transmission to the drive wheel The vehicle speed may be calculated based on the above.

  In the vehicle on which the continuously variable transmission 350 having the above-described configuration is mounted, the present invention is configured so that the belt 700 has a plurality of elements (1) and the detection result of the gap sensor 702 is a plurality of elements (1). It includes a plurality of different elements (2), and is characterized in that the plurality of elements (2) are arranged on the belt at unequal intervals along the moving direction of the belt 700.

  As shown in FIG. 2, the gap sensor 702 is provided at an intermediate position between the primary shaft 502 and the secondary shaft 602 and on the outer peripheral side of the belt 700. In the present embodiment, the gap sensor 702 detects a change in the distance from the portion protruding to the outer peripheral side of the belt 700.

  Preferably, gap sensor 702 is a position that does not contact belt 700 when the wrapping radii of primary pulley 500 and secondary pulley 600 of belt 700 change due to the speed change of continuously variable transmission 350, and gap sensor It is desirable to provide at a position where the change in the shortest distance between 702 and the belt 700 is small.

  By providing the gap sensor 702 at the position as described above, the distance between the belt 700 and the gap sensor 702 can be kept constant regardless of the wrapping radius of the belt 700 around the primary pulley 500 and the secondary pulley 600. .

  The belt 700 includes a ring 710, an element (1) 704, and an element (2) 708.

  The ring 710 is a plate member formed in an annular shape along the circumferential direction of the belt 700. The belt 700 is formed by sandwiching a plurality of elements (1) 704 and a plurality of elements (2) 708 from a direction parallel to the rotation axis of the primary shaft 502 or the secondary shaft 602, with two sets of rings 710.

  The element (1) 704 and the element (2) 708 are plate members each formed in a predetermined shape, and a plurality of elements are arranged along the circumferential direction of the belt 700.

  In the present embodiment, the element (2) 708 is formed so that the length of the portion protruding to the outer peripheral side of the belt 700 is different from the length of the element (1). Different from 1).

  Specifically, as shown in FIG. 3, the element (2) 708 has a protruding portion that protrudes toward the outer peripheral side of the belt 700, which is a portion of the element (1) 704, as compared with the shape of the element (1) 704. 706 is formed in a chipped shape.

  Furthermore, the element (2) 708 is formed with notches 720 and 722 into which two sets of rings 710 are fitted, and contact surfaces 724 and 726 with the primary pulley 500 and the secondary pulley 600. Similarly, for element (1) 704, a contact surface with primary pulley 500 and secondary pulley 600 and a notch portion into which two sets of rings 710 are fitted are formed.

  In the belt 700, the element (2) 708 is different from the interval (1), the portion (2) different from the interval (1), the interval (1), and the interval (2). The section (1) including the portion arranged at the interval (3) is continuous along the positive rotation direction. Further, the belt 700 is formed such that the order in which the time intervals at which each of the plurality of elements (2) 708 is detected by the gap sensor 702 is different between forward rotation and reverse rotation is different.

  Specifically, in the belt 700, the portion where the elements (2) 708 are arranged at the interval (3), the portion arranged at the interval (2), and the portion arranged at the interval (1) are correct. The section (2) continuous along the rotation direction is formed so as not to be adjacent to or overlap with the section (1).

  For example, as shown in FIG. 4, the belt 700 includes a portion where the element (2) 708 is disposed at an interval (1) between which the two elements (1) 704 are sandwiched from the left side of the sheet, and one element (1 ) Including a section (1) in which a portion arranged at an interval (2) sandwiching 704 and a portion arranged at an interval (3) sandwiching three elements (1) 704 are continuous along the positive rotation direction. Formed as follows.

  The belt 700 is not particularly limited to the arrangement of the elements (2) 708 as shown in FIG. For example, as shown in FIG. 5, the belt 700 includes a portion where the element (2) 708 is arranged at an interval (1) between which one element (1) 704 is sandwiched from the left side of the sheet, and two elements (1 ) Including a section in which the portion arranged at the interval (2) sandwiching 704 and the portion arranged at the interval (3) sandwiching the three elements (1) 704 are continuous along the positive rotation direction. . The arrangement of the elements (2) 708 shown in FIGS. 4 and 5 is an example, and is not limited to the arrangement shown in FIGS.

  The detection of the actual moving speed and the determination of the rotation direction of the belt 700 having the structure as described above are performed based on the detection result of the gap sensor 702. In this embodiment, the gap sensor 702 is described as detecting changes in the distance between the element (1) 704 and the element (2) 708 and the gap sensor 702. However, at least the element (1) 704 and the element ( 2) What is necessary is just to be able to detect 708, and it is not limited to using a gap sensor in particular.

  In the present embodiment, the gap sensor 702 outputs a signal corresponding to the distance from the element of the belt 700 at a position facing the gap sensor 702. In the present embodiment, for example, the gap sensor 702 outputs a Hi signal when the element (1) 704 passes at a position facing the gap sensor 702, and the element (2 at the position facing the gap sensor 702). ) 708 passes, and before and after the passage of element (1) 704 and element (2) 708, the Lo signal is output.

  As shown in FIG. 6, the gap sensor 702 outputs a Hi signal when the element (1) 704 passes at a position facing the gap sensor 702, and passes the element (1) 704 and the element (2) 708. A Lo signal is output when the element (2) 708 passes in the front-rear direction and the position facing the gap sensor 702.

  Therefore, when the vehicle is moving forward (that is, when the belt 700 is rotating forward), the gap sensor 702 passes the section (1) of the belt 700 at a position facing the gap sensor 702. The Lo signal is output corresponding to the passage of the element (2) 708, and the Hi signal is output twice via the output of the Lo signal between the passages of the two elements (1) 704. Further, the gap sensor 702 outputs a Lo signal corresponding to the passage of the element (2) 708, and then outputs a Hi signal once corresponding to the passage of one element (1) 704. After that, the gap sensor 702 outputs the Lo signal corresponding to the passage of the element (2) 708, and then intervenes the output of the Lo signal in correspondence with the passage of the three elements (1) 704. Output the signal three times.

  On the other hand, when the vehicle is in the reverse drive state (that is, when the belt 700 is rotating in reverse), the gap sensor 702 passes the section (1) of the belt 700 at a position facing the gap sensor 702. The Lo signal is output corresponding to the passage of the element (2) 708, and the Hi signal is output three times via the output of the Lo signal between the passages of the three elements (1) 704. Further, after outputting the Lo signal corresponding to the passage of the element (2) 708, the Hi signal is output once corresponding to the passage of the single element (1) 704. After that, the gap sensor 702 outputs the Lo signal corresponding to the passage of the element (2) 708, and then intervenes the output of the Lo signal in correspondence with the passage of the two elements (1) 704. Output the signal twice.

  Therefore, ECU 1000 determines that if the order in which the output time interval of at least one of the Hi signal and Lo signal received from gap sensor 702 changes matches the order corresponding to the forward rotation of belt 700. It can be determined that 700 is rotating forward (that is, the vehicle is moving forward). Further, ECU 1000 determines that the order in which the sense of the output time of at least one of the Hi signal and Lo signal received from gap sensor 702 changes matches the order corresponding to the reverse rotation of belt 700. It can be determined that the belt 700 is rotating in reverse (that is, the vehicle is moving backward).

  In the present embodiment, for convenience of explanation, the gap sensor 702 compares an output value (that is, an analog signal) proportional to the distance from the belt 700 with a threshold value, and a Hi signal or a Lo signal (that is, a digital signal). In the above description, the gap sensor 702 outputs a Hi signal or a Lo signal. However, the present invention is not limited to this. is not. For example, a signal processing circuit in which the gap sensor 702 transmits an output value (analog signal) proportional to the distance from the belt 700 to the ECU 1000, and the ECU 1000 converts the received output value into a Hi signal or a Lo signal (digital signal). You may make it have.

  Further, ECU 1000 calculates the actual moving speed of belt 700 based on the detection result of gap sensor 702. For example, ECU 1000 converts the frequency of the pulse signal including the Hi signal and the Lo signal shown in FIG. 6 into a voltage using an F / V (Frequency to Voltage) converter, and sets a predetermined coefficient to the converted voltage value. The actual moving speed of the belt 700 may be detected by multiplication. Note that the change in the output signal shown in FIG. 6 is an example, and is not particularly limited to this.

  FIG. 7 shows a functional block diagram of ECU 1000 mounted on the continuously variable transmission according to the present embodiment. ECU 1000 includes a transmission ratio calculation unit 1010, an estimated movement speed calculation unit 1012, an actual movement speed calculation unit 1014, a belt slip determination unit 1016, a belt rotation direction determination unit 1018, and a belt clamping pressure control unit 1020. .

  The gear ratio calculation unit 1010 calculates the gear ratio based on the primary pulley rotation speed NIN and the secondary pulley rotation speed NOUT. The gear ratio calculation unit 1010 calculates the gear ratio by dividing the primary pulley rotation speed NIN by the secondary pulley rotation speed NOUT.

  The estimated moving speed calculation unit 1012 calculates the estimated moving speed of the belt 700 based on the primary pulley rotation speed NIN, the secondary pulley rotation speed NOUT, and the calculated gear ratio. The estimated moving speed calculation unit 1012 calculates, for example, the winding radius of the belt 700 in the primary pulley 500 and the winding radius of the belt 700 in the secondary pulley 600 based on the calculated gear ratio. The estimated moving speed calculation unit 1012 calculates the peripheral speed at the winding radius of the belt 700 in the primary pulley 500 calculated based on the primary pulley rotation speed NIN as the estimated moving speed. Alternatively, the estimated moving speed calculation unit 1012 may calculate the peripheral speed at the winding radius of the belt 700 in the secondary pulley 600 calculated based on the secondary pulley rotation speed NOUT as the estimated moving speed.

  The actual moving speed calculation unit 1014 calculates the actual moving speed based on the output signal from the gap sensor 702.

  The belt slip determination unit 1016 determines whether belt slip has occurred based on the estimated travel speed calculated by the estimated travel speed calculation unit 1012 and the actual travel speed calculated by the actual travel speed calculation unit 1014. The belt slip determination unit 1016 determines that belt slip has occurred when the estimated travel speed and the actual travel speed differ by more than a value set according to the shift state of the continuously variable transmission 350. Note that the speed change state of the continuously variable transmission 350 is, for example, the ratio of the wrapping radius of the belt 700 between the primary pulley 500 and the secondary pulley 600 (that is, the pulley ratio), but is not particularly limited thereto. . The value set according to the speed change state of the continuously variable transmission 350 may be adapted by experiment or the like, and may be a predetermined value.

  The belt slip determination unit 1016 may determine whether or not belt slip has occurred in each of the primary pulley 500 and the secondary pulley 600 based on the slip ratio.

  That is, the belt slip determination unit 1016 divides the absolute value of the relative speed difference between the actual moving speed of the belt 700 and the pulley peripheral speed at the belt winding radius of the primary pulley 500 by the estimated moving speed of the belt 700. Then, the slip ratio (1) in the primary pulley 500 is calculated.

  Further, the belt slip determining unit 1016 divides the absolute value of the relative speed difference between the actual moving speed of the belt 00 and the pulley peripheral speed at the belt winding radius of the secondary pulley 600 by the estimated moving speed of the belt 700. Then, the slip ratio (2) in the secondary pulley 600 is calculated.

  The belt slip determination unit 1016 compares the calculated slip rates (1) and (2) with a predetermined threshold value, thereby generating belt slip in each of the primary pulley 500 and the secondary pulley 600. The presence or absence may be determined. The predetermined threshold value may be adapted by experiments or the like. Different thresholds may be used for the slip ratio (1) and the slip ratio (2). The belt slip determination unit 1016 determines that belt slip has occurred when any of the slip ratios (1) and (2) is equal to or greater than a predetermined threshold value.

  The belt rotation direction determination unit 1018 causes the belt 700 to rotate forward based on the order in which the output time interval of at least one of the Hi signal and the Lo signal included in the output signal from the gap sensor 702 changes. It is judged whether it is or reverse rotation. Since the relationship between the rotation direction of belt 700 and the order in which the interval of the output time of Hi signal or Lo signal changes is as described with reference to FIG. 6, detailed description thereof will not be repeated.

  When the belt slip determining unit 1016 determines that belt slip has occurred, the belt clamping pressure control unit 1020 increases the tension of the belt 700 so that the tension of the belt 700 increases more than when it is not determined that belt slip has occurred. (1) Control at least one of 550 and hydraulic actuator (2) 650.

  In this embodiment, when it is determined that belt slip has occurred, the belt clamping pressure control unit 1020 increases the hydraulic pressure supplied to the hydraulic actuator (2) 650 to increase the clamping pressure applied to the belt 700 by the secondary pulley 600. By increasing the tension, the tension of the belt 700 is increased.

  Further, the belt clamping pressure control unit 1020 changes the degree of increase in the tension of the belt 700 according to the rotation direction of the belt 700. For example, an increase in belt clamping pressure when the vehicle moves forward and an increase in belt clamping pressure when the vehicle moves backward are set in advance, and an appropriate increase in belt clamping pressure is determined according to the determination result of the rotation direction of the belt 700. Minutes may be selected. Note that the increase in the belt clamping pressure when the vehicle moves forward or backward may be set based on, for example, the gear ratio from the engine 100 to the drive wheel when moving forward or backward, and is adapted by experiment or the like. In this way, the tension can be appropriately increased according to the load applied to the belt 700. For this reason, it is not necessary to increase the belt clamping pressure by an excessive increase in order to improve the safety factor. Therefore, it is possible to reduce the load on the belt 700 and suppress the decrease in transmission efficiency (fuel consumption).

  In the present embodiment, the gear ratio calculating unit 1010, the estimated moving speed calculating unit 1012, the actual moving speed calculating unit 1014, the belt slip determining unit 1016, the belt rotation direction determining unit 1018, and the belt clamping pressure control. The unit 1020 is described as functioning as software that is realized by the CPU of the ECU 1000 executing a program stored in the memory 1002, but may be realized by hardware. Such a program is recorded on a storage medium and mounted on the vehicle.

  With reference to FIG. 8, a control structure of a program executed by ECU 1000 mounted on continuously variable transmission according to the present embodiment will be described.

  In step (hereinafter, step is referred to as S) 100, ECU 1000 detects primary pulley rotation speed NIN and secondary pulley rotation speed NOUT.

  In S102, ECU 1000 calculates a gear ratio based on primary pulley rotation speed NIN and secondary pulley rotation speed NOUT. In S104, ECU 1000 calculates an estimated movement speed based on primary pulley rotation speed NIN or secondary pulley rotation speed NOUT and the gear ratio.

  In S106, ECU 1000 calculates the actual moving speed based on the output signal of gap sensor 702. In S108, ECU 1000 determines whether or not the absolute value of the difference between the estimated moving speed and the actual moving speed is greater than α. “Α” is a value set according to the speed change state of the continuously variable transmission 350. If the absolute value of the difference between the estimated moving speed and the actual moving speed is larger than α (YES in S108), the process proceeds to S110. If not (NO in S108), the process proceeds to S116.

  In S110, ECU 1000 determines that belt slip has occurred. In S112, ECU 1000 determines the rotation direction of belt 700. In S114, ECU 1000 controls hydraulic control unit 1100 to increase the clamping force of secondary pulley 600 against belt 700 according to the rotation direction of belt 700. In S116, ECU 1000 controls hydraulic control unit 1100 so that normal shift control is performed in continuously variable transmission 350. In normal shift control, the ECU 1000 controls the hydraulic control unit 1100 so that the belt clamping pressure is lower than at least the belt clamping pressure controlled in S112.

  The operation of the continuously variable transmission according to the present embodiment based on the above-described structure and flowchart will be described.

  A case is assumed in which the vehicle is traveling in a low speed region where the speed is lower than a predetermined speed and the detection accuracy of the primary pulley rotation speed NIN and the secondary pulley rotation speed NOUT is lower than a predetermined degree. . At this time, after the primary pulley rotation speed NIN and the secondary pulley rotation speed NOUT are detected (S100), the gear ratio is calculated (S102). Then, the estimated moving speed is calculated based on the primary pulley rotation speed NIN or the secondary pulley rotation speed NOUT and the gear ratio (S104).

  Further, the actual moving speed is calculated based on the output signal of the gap sensor 702 (S106). If the absolute value of the difference between the estimated moving speed and the actual moving speed is larger than α (YES in S108), the belt slip is detected. It is determined that it has occurred (S110). At this time, the rotation direction of the belt 700 is determined based on the order in which the intervals between the output times of the Hi signal and the Lo signal included in the output signal of the gap sensor 702 are changed (S112), and the belt according to the rotation direction of the belt 700. The clamping pressure is controlled (S114). If the absolute value of the difference between the estimated moving speed and the actual moving speed is less than or equal to α (NO in S108), normal hydraulic pressure control is performed (S116).

  As described above, according to the continuously variable transmission according to the present embodiment, the detection result by the gap sensor of element (1) is different from the detection result by the gap sensor of element (2). In this case, it can be specified whether the element detected by the gap sensor is the element (1) or the element (2). Therefore, the actual moving speed of the belt can be detected with high accuracy based on the change in the time interval at which the element (2) is detected. Therefore, the presence / absence of occurrence of belt slip can be determined with high accuracy. Furthermore, since the elements (2) are arranged at unequal intervals on the belt, the order of changes in the time intervals at which the plurality of elements (2) are detected differs between when the belt is rotating forward and when it is rotating backward. can do. Therefore, it can be determined with high accuracy whether the belt is rotating forward or backward depending on the order. Therefore, it is possible to provide a continuously variable transmission that accurately determines the moving direction of the belt when belt slippage occurs.

  In addition, when the estimated moving speed and the actual moving speed deviate, it is possible to suppress the belt slip by determining that the belt slip has occurred and increasing the belt tension.

  Further, in the low speed region where the vehicle speed is equal to or lower than a predetermined speed when the vehicle is moving forward or backward and including the stopped state of the vehicle, the detection accuracy of the secondary pulley rotation speed or the primary pulley rotation speed is improved. Even when the degree is low, the presence / absence of belt slip and the rotation direction of the belt can be accurately determined based on the estimated moving speed and the actual moving speed of the belt.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a control block diagram of a continuously variable transmission. It is the figure which looked at the belt drive part of the continuously variable transmission from the rotating shaft direction. It is an external view of the element which forms a belt. It is a figure (the 1) which shows arrangement | positioning of an element (1) and an element (2). It is FIG. (2) which shows arrangement | positioning of an element (1) and an element (2). It is a figure which shows the change of the signal output of a gap sensor. It is a functional block diagram of ECU mounted in the continuously variable transmission which concerns on this Embodiment. It is a flowchart which shows the control structure of the program performed by ECU mounted in the continuously variable transmission which concerns on this Embodiment.

Explanation of symbols

  100 engine, 200 torque converter, 210 lock-up clutch, 220 pump impeller, 230 turbine impeller, 240 stator, 250 one-way clutch, 260 oil pump, 290 forward / reverse switching device, 300 belt type continuously variable transmission mechanism, 310 input clutch , 350 continuously variable transmission, 400 turbine speed sensor, 410 primary pulley speed sensor, 420 secondary pulley speed sensor, 432 engine speed sensor, 440 wheel speed sensor, 442 accelerator position sensor, 500 primary pulley, 502 primary shaft , 600 Secondary pulley, 602 Secondary shaft, 700 belt, 702 Gap sensor, 704, 708 element, 706 Protruding part, 710 Ring 720, 722 Notch, 800 differential gear, 1002 memory, 1010 transmission ratio calculation unit, 1012 estimated movement speed calculation unit, 1014 actual movement speed calculation unit, 1016 belt slip determination unit, 1018 belt rotation direction determination unit, 1020 belt clamping Pressure control unit, 1100 Hydraulic control unit, 1110 Shift speed control unit, 1120 Belt clamping pressure control unit, 1130 Line pressure control unit, 1132 Lock-up engagement pressure control unit, 1140 Clutch pressure control unit, 1150 Manual valve, 1220 Belt clamping Linear solenoid for pressure control, 1230 Linear solenoid for line pressure control, 1240 Duty solenoid for lockup engagement pressure control.

Claims (7)

A driving pulley,
A driven pulley,
A belt formed by arranging a plurality of elements in an annular shape and wound around the groove of the driving pulley and the groove of the driven pulley;
Detecting means for detecting each of the plurality of elements, provided on the outer peripheral side of the belt;
The plurality of elements include a plurality of first elements, and a plurality of second elements whose detection results by the detection means are different from the case of each of the plurality of first elements,
The continuously variable transmission, wherein the plurality of second elements are arranged on the belt at unequal intervals along a moving direction of the belt. The detection means is provided at an intermediate position between the driving pulley and the driven pulley, and detects a change in distance from a portion protruding to the outer peripheral side of the belt to the detection means,
2. The continuously variable transmission according to claim 1, wherein each of the plurality of second elements and each of the plurality of first elements have different lengths of a portion protruding toward an outer peripheral side of the belt.   3. The continuously variable transmission according to claim 1, further comprising a rotation direction determination unit for determining whether the belt is rotating forward or backward based on a result of the detection unit. Step transmission. The belt includes a portion where each of the plurality of second elements is disposed at a first interval, a portion disposed at a second interval different from the first interval, and the first and second portions. Including a first section in which a portion arranged at a third interval different from the interval is continuous along the positive rotation direction,
4. The belt according to claim 1, wherein the belt is formed so that a time interval in which each of the plurality of second elements is detected by the detection unit is different between forward rotation and reverse rotation. A continuously variable transmission according to any one of the above.   In the belt, the portion where the second element is arranged at the third interval, the portion arranged at the second interval, and the portion arranged at the first interval are rotated in the forward direction. The continuously variable transmission according to claim 4, wherein the second section that is continuous along the direction is formed so as not to be adjacent to or overlap the first section. The continuously variable transmission is
A first actuator that changes a groove width of the driving pulley using a first hydraulic pressure generated by supplying and discharging hydraulic oil;
A second actuator that changes a groove width of the driven pulley using a second hydraulic pressure generated by supplying and discharging hydraulic oil;
First rotational speed detection means for detecting the rotational speed of the driving pulley;
Second rotational speed detection means for detecting the rotational speed of the driven pulley;
First calculating means for calculating a gear ratio of the continuously variable transmission based on the rotational speed of the driving pulley and the rotational speed of the driven pulley;
Second calculating means for calculating an estimated moving speed of the belt based on the rotational speed of the driving pulley, the rotational speed of the driven pulley, and the speed ratio;
Determining means for determining whether or not slippage of the belt has occurred based on the estimated moving speed and the actual moving speed of the belt based on the detection result of the detecting means;
And a control means for controlling at least one of the first actuator and the second actuator so that a tension of the belt is increased when the belt slips. The continuously variable transmission in any one of 1-5.   The continuously variable transmission according to claim 6, wherein the control means changes the degree of increase in the tension of the belt according to the rotation direction of the belt.