JP2013204718A - Device for detecting diameter wound with belt of continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely detect a diameter wound with a belt of a continuously variable transmission in noncontact.SOLUTION: A continuously variable transmission with a primary pulley, a secondary pulley, and a belt, includes: a rotation mechanism 60 which is provided between a movable pulley 13 out of the pulleys and a rotation shaft 11 thereof and relatively rotates the movable pulley 13 with respect to the rotation shaft 11 following movement in a shaft direction relative to the rotation shaft 11, of the moving pulley 13; a relative rotation measurement means for measuring a relative rotation amount of the movable pulley 13 to the rotation shaft 11; and a calculation means for calculating a movement amount in the shaft direction of the movable pulley 13 from the relative rotation amount measured by the relative rotation measurement means to calculate a diameter wound with a belt from the calculation result.

Description

  The present invention relates to a belt winding diameter detection device for a continuously variable transmission suitable for use in a vehicle transmission.

  A belt type continuously variable transmission (also simply referred to as CVT) includes a primary pulley connected to an input shaft, a secondary pulley connected to an output shaft, and a belt or chain wound around these pulleys (hereinafter referred to as a belt). Collectively). Each pulley is composed of a fixed pulley formed integrally with a shaft (input shaft or output shaft) and a movable pulley that rotates integrally with the shaft but is movable in the axial direction of the shaft. The belt is pressed against a V-shaped groove formed by the fixed pulley and the movable pulley to transmit power.

  The movement of each pulley in the axial direction of the movable pulley is performed by adjusting the hydraulic pressure in the hydraulic chamber formed on the back surface (rear surface) of the movable pulley, and the movable pulley and the fixed pulley are moved by the axial movement of the movable pulley. And the groove width of the V-shaped groove increases and decreases, and the winding diameter of the belt around the pulley (the effective radius of the pulley) is adjusted, so that the power transmission ratio from the primary pulley to the secondary pulley, that is, The gear ratio changes.

By the way, the transmission ratio of the CVT is a ratio between the rotation speed (rotation speed) of the primary pulley and the rotation speed (rotation speed) of the secondary pulley, and for example, the rotation speed of the input shaft of the transmission or the rotation portion corresponding thereto. It can be calculated as the rotation ratio with the output shaft of the transmission or the rotational speed of the corresponding rotating portion.
However, if slip occurs between the pulley and the belt, the assumption that the rotation ratio and the gear ratio are equivalent is not satisfied. Originally, the gear ratio is not simply the ratio between the input rotation speed and the output rotation speed of the transmission, but the ratio that amplifies or decreases the torque of the drive source and transmits it to the drive wheels. When the transmission is a gear mechanism, the rotation ratio between the input rotation speed and the output rotation speed of the transmission is the torque ratio (the reciprocal of the rotation ratio) as it is, but the torque is transmitted by friction as in CVT. There is a possibility that the belt slips, and if the belt slips, the rotational speed of the output shaft decreases by that amount. Therefore, if the torque ratio is estimated from the rotation ratio, an error occurs.

The gear ratio of the transmission is controlled in order to convert the output torque of the drive source into a desired drive torque. Therefore, the gear ratio accurately reflects the torque ratio regardless of whether the belt is slipping or not. It is necessary to obtain a gear ratio of For this reason, it is required to directly estimate the winding diameter of the belt around the pulley (the effective radius of the pulley), not the rotation ratio.
Also, one of the purposes of directly obtaining the belt winding diameter, not the rotation ratio, is to improve fuel efficiency by controlling the belt clamping force at each pulley to be near the belt slip limit. There is.

  In other words, the theoretical gear ratio (speed ratio reflecting the ratio of transmitted torque) is obtained from the belt winding diameter, and the actual gear ratio is obtained from the above rotation ratio. These theoretical gear ratios Since the slippage of the belt can be determined from the actual transmission ratio and the slippage limit of the belt can be grasped, the clamping force of each pulley can be controlled within the range where the belt does not slip. To suppress the clamping force of each pulley is to suppress the hydraulic pressure supply to the hydraulic chamber of each pulley. Normally, the hydraulic pressure is supplied by an engine-driven oil pump connected to the input side of the CVT. Therefore, if the hydraulic pressure supply can be suppressed, the engine load is reduced and the fuel consumption can be improved.

  Since the belt winding diameter corresponds to the axial position of the movable pulley of the pulley, if the axial position of the movable pulley is detected by a stroke sensor, the belt winding diameter can be obtained corresponding to the detected stroke. Since the stroke sensor is a contact type, friction related to axial movement of the movable pulley and friction related to rotation of the pulley are added, which is not preferable. In addition, the contact type stroke sensor has low robustness and it is difficult to obtain a stable detection result.

  In this regard, Patent Document 1 describes a technique for detecting a belt winding diameter in a non-contact manner. In this technique, a first tone wheel is attached to a fixed belt wheel (fixed pulley), a second tone wheel is attached to a movable belt wheel (movable pulley), and each tone wheel has a first and second pickup. Are installed facing each other. Around each tone wheel, a large number of teeth are provided at equal intervals with a notch, and the pickup generates a pulse each time the teeth pass.

  The teeth of the first tone wheel are provided parallel to the axial direction (direction perpendicular to the wheel rotation direction), and the teeth of the second tone wheel are inclined with respect to the axial direction (direction perpendicular to the wheel rotation direction). Therefore, when the second tone wheel moves in the axial direction, the phase of the tooth passing in front of the pickup changes corresponding to the axial movement, and this change is caused by the transmission of the first pickup. The time difference between the pulse and the transmission pulse of the second pickup is obtained, and the axial position of the second tone wheel, that is, the axial position of the movable pulley is obtained from the time difference between the transmission pulse and the belt winding diameter is obtained. Can do.

Japanese Patent Laid-Open No. 06-300102

By the way, according to the technique of Patent Document 1, the belt winding diameter can theoretically be detected in a non-contact manner, but when the passage of the tone wheel teeth is detected by a pickup, the teeth are inclined with respect to the axial direction. If it does, since the detection accuracy of a tooth | gear passage will fall, the detection accuracy of the winding diameter of a belt will also fall.
That is, the detection by the pickup uses a fact that a magnetic field is generated from the tip of the pickup and that the magnetic field spreads to the volume closest to the tip of the pickup. That is, when the iron tone wheel teeth approach the tip of the pickup, the magnetic field increases to induce a voltage in one direction, and when the iron teeth move away from the tip of the pickup, the magnetic field decreases to induce a voltage in the opposite direction. Therefore, the induced voltage has a sinusoidal waveform. A sine wave signal of this voltage is converted into a square wave pulse by a circuit in the microcomputer, the timing of the transmission pulse is specified based on the rising and falling edges of the square wave, and the axial position of the movable pulley is obtained. The belt winding diameter is obtained.

  However, if the teeth are inclined with respect to the axial direction, the increase or decrease of the magnetic field does not occur with high accuracy, and the phase of the sinusoidal waveform of the induced voltage also shifts. Since the phase shift of the sine waveform is a shift in the timing of the transmission pulse, an error occurs in the axial position of the movable pulley based on the timing of the transmission pulse, and the belt winding diameter obtained from the axial position of the movable pulley However, an error will occur.

  In view of such problems, the present invention provides a belt winding diameter detection device for a continuously variable transmission that can accurately detect the belt winding diameter in a belt-type continuously variable transmission without contact. The purpose is to do.

  In order to achieve the above object, a belt winding diameter detection device of a continuously variable transmission according to the present invention includes a primary pulley, a secondary pulley, and a belt wound around both pulleys. A belt winding diameter detecting device for detecting a belt winding diameter of at least one of the primary pulley and the secondary pulley, the belt winding diameter detecting device for the continuously variable transmission in the axial direction of the movable pulley; Measured by the rotation mechanism that rotates the movable pulley relative to the rotation axis with the movement, the relative rotation measurement unit that measures the relative rotation amount of the movable pulley with respect to the rotation shaft, and the relative rotation measurement unit. From the relative rotation amount, the axial movement amount of the movable pulley is calculated, and the belt winding diameter is calculated from the calculation result. It is characterized in that it comprises a means.

The rotation mechanism preferably rotates the movable pulley relative to the rotation axis in one direction as the movable pulley moves in the axial direction.
The ratio of the relative rotation of the movable pulley accompanying the movement of the movable pulley in the axial direction by the rotation mechanism is large in the low gear ratio region of the axial position of the movable pulley, and the shaft of the movable pulley It is preferable to make it small in the high gear ratio region in the direction position.

In addition, the ratio of the relative rotation of the movable pulley accompanying the movement of the movable pulley in the axial direction by the rotating mechanism may be reduced in a region where it is desired to shift at a high speed at the axial position of the movable pulley. preferable.
The rotating mechanism has a spline groove formed in at least one of an outer peripheral surface of the rotating shaft and an inner peripheral surface of the movable pulley in which the rotating shaft is inserted, and the spline groove is formed on the rotating shaft. It is preferable to incline with respect to the generatrix direction of the outer peripheral surface or the inner peripheral surface of the movable pulley.

  Further, the rotating mechanism includes a first spline groove formed on an outer peripheral surface of the rotating shaft, a second spline groove formed on an inner peripheral surface of the movable pulley into which the rotating shaft is inserted, and the first spline groove. A ball spline mechanism comprising a plurality of balls interposed between a spline groove and the second spline groove, wherein any one of the first spline groove and the second spline groove is formed on the rotating shaft. It is preferable that it inclines with respect to the bus-line direction of the outer peripheral surface of this or the inner peripheral surface of the said movable pulley.

When the rotation mechanism has the spline groove, the spline groove is preferably inclined with respect to the generatrix direction of the outer peripheral surface of the rotating shaft or the inner peripheral surface of the movable pulley.
In this case, it is preferable that the inclination of the spline groove is monotonously inclined in one direction with respect to the busbar direction.
Alternatively, it is preferable that the inclination of the spline groove is formed abruptly on the low side of the spline groove and gently on the high side of the spline groove.

  Alternatively, it is preferable that the inclination of the spline groove is gently formed in a region where the spline groove is desired to be shifted at a high speed.

  According to the belt winding diameter detection device of the continuously variable transmission of the present invention, when the movable pulley moves in the axial direction with respect to the rotation shaft, the movable pulley rotates relative to the rotation shaft by the rotation mechanism. The relative rotation measuring means measures the relative rotation amount of the movable pulley with respect to the rotating shaft, and the calculating means calculates the axial movement amount of the movable pulley from the measured relative rotation amount, and the belt winding diameter is calculated from the calculation result. calculate. Therefore, the belt winding diameter can be accurately calculated while using a general rotational phase measuring device as the relative rotational measuring means.

  If the movable mechanism is configured such that the movable pulley is in a relative rotational phase in one direction as the movable pulley moves in one axial direction, the axial position of the movable pulley and the relative rotation of the movable pulley are in a one-to-one relationship. The amount of movement of the movable pulley in the axial direction can be simply calculated from the relative rotation amount.

It is a figure which shows the rotating mechanism of the belt winding diameter detection apparatus of the continuously variable transmission concerning one Embodiment of this invention, (a) is a principal part cross-sectional view (AA arrow of FIG. 2) of a continuously variable transmission. (Cross-sectional view), (b) is a main part development view of a continuously variable transmission. 1 is a longitudinal sectional view of a continuously variable transmission according to an embodiment of the present invention. 1 is a perspective view showing a part of a continuously variable transmission according to an embodiment of the present invention in a broken state. It is a figure which shows the characteristic of the rotation mechanism of the belt winding diameter detection apparatus of the continuously variable transmission concerning one Embodiment of this invention, (a) shows embodiment, (a) shows the modification. It is a principal part expanded view which shows the rotation phase measurement apparatus of the relative rotation measurement means of the belt winding diameter detection apparatus of the continuously variable transmission concerning one Embodiment of this invention. FIG. 3 is a layout diagram showing a rotational phase measuring device of a relative rotational phase measuring means of a belt winding diameter detecting device of a continuously variable transmission according to an embodiment of the present invention. It is a block diagram which shows the structure of the winding diameter detection apparatus of the belt of the continuously variable transmission concerning one Embodiment of this invention. It is a figure which shows the process of the detection signal by the belt winding diameter detection apparatus of the continuously variable transmission concerning one Embodiment of this invention, (a) shows a detection voltage, (b) shows the converted pulse. It is a figure explaining the rotational phase change amount in the belt winding diameter detection apparatus of the continuously variable transmission concerning one Embodiment of this invention using a processing signal, (a) is a pulse signal concerning a fixed pulley, ( b1) to (b3) show pulse signals applied to the movable pulley.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In this embodiment, a belt-type continuously variable transmission (simply referred to as “CVT”) in which a belt is wound around a primary pulley and a secondary pulley will be described as an example. It can also be applied to a belt type continuously variable transmission to which is applied.

[Overall configuration of continuously variable transmission]
First, a belt type continuously variable transmission according to the present invention will be described.
As shown in FIGS. 2 and 3, the continuously variable transmission includes a primary pulley 1, a secondary pulley 2, and an endless belt wound around these pulleys 1 and 2 in a transmission case (not shown). 3 is configured. Both the primary pulley 1 and the secondary pulley 2 are integrally coupled to and supported by rotating shafts (primary shafts, secondary shafts, hereinafter simply referred to as shafts) 11 and 21 and the shafts 11 and 21 in both the rotating direction and the axial direction. Fixed pulleys 12, 22, and movable pulleys 13, 23 that are arranged to face the fixed pulleys 12, 22 and rotate integrally with the shafts 11, 21 but are movably connected and supported in the axial direction. I have it. The shafts 11 and 21 are supported by a casing (not shown) via bearings 18a, 18b, and 28a.

The primary pulley 1 and the secondary pulley 2 have a belt support surface (sheave surface) 12a, 22a of each fixed pulley 12, 22 and a belt support surface (sheave surface) 13a, 23a of each movable pulley 13, 23, V-groove portions 10 and 20 having a substantially V-shaped cross section are formed, and the belt 3 is wound around the V-groove portions 10 and 20 and installed.
A hydraulic chamber 15 is disposed adjacent to the movable pulley 13 of the primary pulley 1. The hydraulic chamber 15 includes a back surface (outside surface) 13b of each movable pulley 13, an outer cylinder member 13c coupled to the back surface 13b, and a partition member 14 fixed to the shaft 11 so as to face the back surface 13b. And the outer peripheral surface 13e of the hollow shaft portion 13d of the movable pulley 13 are partitioned and formed.

Here, the partition member 14 of the primary pulley 1 includes a cup-shaped member 14a that is fixed to the shaft 11 and includes a bowl-shaped part and a cylindrical part, and a bowl-shaped part that is fixed to the annular tip of the cup-shaped member 14a. 14b, and the hydraulic chamber 15 is partitioned and formed by a bowl-shaped portion 14b.
Further, the primary pulley 1 is provided with a centrifugal oil pressure cancel chamber 17 that cancels the centrifugal oil pressure generated in the hydraulic oil in the hydraulic chamber 15. The centrifugal hydraulic pressure cancellation chamber 17 includes a piston 17a fixed to the outer periphery of the hollow shaft portion 13d of the movable pulley 13, a cup-shaped member 14a of the partition member 14, and an outer peripheral surface 13e of the hollow shaft portion 13d of the movable pulley 13. Is enclosed and formed.

  When the hydraulic oil is supplied to the hydraulic chamber 15 and the hydraulic oil in the hydraulic chamber 15 increases due to the movement of the movable pulley 13, the piston 17a moves and the hydraulic oil in the centrifugal hydraulic pressure cancel chamber 17 decreases. Further, when the hydraulic oil in the hydraulic chamber 15 is discharged and the hydraulic oil in the hydraulic chamber 15 decreases due to the movement of the movable pulley 13, the piston 17 a moves to increase the hydraulic oil in the centrifugal hydraulic pressure cancellation chamber 17. Thereby, the fluctuation | variation of the centrifugal hydraulic pressure accompanying the fluctuation | variation of the hydraulic oil amount of the hydraulic chamber 15 is suppressed.

  A hydraulic chamber 25 is disposed adjacent to the movable pulley 23 of the secondary pulley 2. The hydraulic chamber 25 includes a back surface (outer surface) 23b of the movable pulley 23, an outer cylinder member 22c coupled to the back surface 23b, a partition member 24 fixed to the shaft 21 so as to face the back surface 23b, and a movable member. The outer peripheral surface 23e of the hollow shaft portion 23d of the pulley 23 and the outer peripheral surface 21a of the shaft 21 are surrounded and formed.

A spring 27 is interposed between the back surface 23 b of the movable pulley 23 in the hydraulic chamber 25 and the facing surface of the partition member 24. The spring 27 clamps the belt 3 in a state where no hydraulic pressure is generated, and prevents the belt 3 from slipping when power is transmitted.
An oil passage 16 communicating with the hydraulic chamber 15 is formed in the shaft 11 of the primary pulley 1, and an oil passage 26 communicating with the hydraulic chamber 25 is formed in the shaft 21 of the secondary pulley 2. Reference numeral 26 is connected to a hydraulic pressure source (oil pump or the like) through a control valve (not shown). The hydraulic chambers 15 and 25 are connected to a drain tank (not shown) through a return oil passage (not shown).

[Configuration of Rotation Phase Measurement Device]
The primary pulley 1 is equipped with rotational phase measuring devices 30 and 40 that measure the rotational phases of the fixed pulley 12 and the movable pulley 13, and the secondary pulley 2 is equipped with a rotational phase measurement that measures the rotational phase of the pulley 2. A device 50 is provided. The rotational phase measuring devices 30 and 40 constitute a relative rotational measuring unit (relative rotational measuring means).

  The rotational phase measuring device 30 includes a tone wheel 31 fixed to the fixed pulley 12 and rotating integrally with the fixed pulley 12, and a first pickup (detector) supported by a casing (not shown) and disposed opposite to the tone wheel 31. ) 32. The tone wheel 31 is formed with a plurality of teeth 31a radially at equal intervals on the outer peripheral portion of the disc with slits 31b therebetween.

  The rotational phase measuring device 40 includes a tone wheel 41 that is fixed to the movable pulley 13 and rotates integrally with the movable pulley 13, and a second pickup (detector) that is supported by a casing (not shown) and disposed opposite the tone wheel 41. 42). In the tone wheel 41, a plurality of teeth 41a are formed at equal intervals along the generatrix direction on the outer peripheral portion of the cylinder with slits 41b therebetween.

  The rotational phase measuring device 50 includes a tone wheel 51 fixed to the movable pulley 23 and rotating integrally with the movable pulley 23, and a third pickup (detector) supported by a casing (not shown) and disposed opposite to the tone wheel 51. ) 52. The tone wheel 51 is also formed with a plurality of teeth 51a having slits 51b between them at equal intervals along the generatrix direction on the outer peripheral portion of the cylinder.

  Since the tone wheels 41 and 51 move in the axial direction together with the movable pulleys 13 and 23, the respective teeth 41a and 51a and the slits 41b and 51b are formed to have a length corresponding to the movable range of the movable pulleys 13 and 23. Even if the tone wheels 41 and 51 move in the axial direction, the teeth 41a and 51a or the slits 41b and 51b are always located at the tips of the pickups 42 and 52.

  The pickups 32, 42, 52 generate a magnetic field from their tips, and when the teeth 31 a, 41 a, 51 a of the tone wheels 31, 41, 51 approach the tips of the pickups 32, 42, 52, the magnetic fields increase, When the slits 31b, 41b, 51b of the tone wheels 31, 41, 51 approach the tips of the pickups 32, 42, 52 (the teeth 31a, 41a, 51a are separated from the tips of the pickups 32, 42, 52), the magnetic field decreases. The rotational phases of the pulleys 12, 13, and 23 are detected using the characteristics to be used.

  For example, in the tone wheel 31, when the tooth 31a of the tone wheel 31 approaches the pickup 32, the magnetic field increases and induces a voltage in one direction, and the voltage peaks when the tooth 31a is adjacent to the tip of the pickup 32. . Also, as the tooth 31a moves away, the magnetic field decreases and induces a voltage in the opposite direction that peaks when the midpoint between the teeth is adjacent to the tip of the pickup 32. Therefore, the induced voltage has a sine wave shape as shown in FIG.

  By converting this sine wave shape into a square wave pulse as shown in FIG. 8B in an electronic control unit (ECU) 100 to be described later, for example, the leading edge of the square wave pulse, that is, the leading edge, or the square By counting the trailing edge or falling edge of the wave pulse as the phase reference of each pulley 12, 13, 23, the number of rotations of each pulley 12, 13, 23 can be determined in phase angle units corresponding to the number of teeth. It is possible to measure or to grasp the phase angle of each of the pulleys 12, 13, and 23.

  Here, the rotational phase measuring device 30 is used as a primary rotational speed sensor that detects the rotational speed of the primary shaft 11, and the rotational phase measuring device 50 is used as a secondary rotational speed sensor that detects the rotational speed of the secondary shaft 21.

[Configuration of ball spline mechanism]
Ball spline mechanisms 60 and 70 are provided as rotating mechanisms between the movable pulley 13 and the shaft 11 of the primary pulley 1 and between the movable pulley 23 and the shaft 21 of the secondary pulley 2.
The ball spline mechanisms 60 and 70 include first spline grooves 61 and 71 formed on the outer peripheral surfaces 11a and 21a of the shafts 11 and 21, and hollow shaft portions 13d of the movable pulleys 13 and 23 into which the shafts 11 and 21 are inserted. Consists of second spline grooves 62, 72 formed on the inner peripheral surfaces 13f, 23f, and a plurality of balls 63, 73 interposed between the first spline grooves 61, 71 and the second spline grooves 62, 72. Is done.

In the ball spline mechanism 70 of the secondary pulley 2, both the first spline groove 71 and the second spline groove 72 are formed so as to face the generatrix direction of the outer peripheral surface 21a and the inner peripheral surface 23f, that is, the axial direction.
On the other hand, FIG. 1A is a cross-sectional view taken along the line AA in FIG. 2, and FIG. 1B is a development view of the outer peripheral surface 11 a of the shaft 11 of the primary pulley 1. As shown in FIGS. 1A and 1B, a plurality (three in this case) of ball spline mechanisms 60 of the primary pulley 1 are provided at equal intervals, and in each case, the first spline groove 61 is formed on the shaft 11. Are formed in a curved line inclined with respect to the generatrix direction of the outer peripheral surface 11a, that is, the axial direction.

Due to this inclination, when the movable pulley 13 moves in the axial direction with respect to the shaft 11, the movable pulley 13 rotates with respect to the shaft 11 (changes the rotation phase).
FIG. 4A is a diagram for explaining the curve characteristics of the first spline groove 61. The horizontal position indicates the axial position SP of the movable pulley 13, and the vertical axis indicates the relative rotation amount (shaft) of the movable pulley 13 with respect to the shaft 11. 11 is a rotational phase shift amount ΔP with respect to 11. In FIG. 4A, the rotational phase of the movable pulley 13 with respect to the shaft 11 when the movable pulley 13 is at the position corresponding to the lowest position on one end side of the movable range is set as a reference (the rotational phase deviation amount ΔP is zero). .

  When the movable pulley 13 moves from the position corresponding to the lowest position on the one end side of the movable range toward the position corresponding to the highest position on the other end side of the movable range, the movable pulley 13 is located near the lowest position of the movable pulley 13. The ratio [change rate, in other words, the slope of the characteristic line in FIG. 4A] (ΔP / ΔSP) of the relative rotation amount (phase shift) ΔP with respect to the axial movement amount ΔSP is large, and the movable pulley 13 is at its maximum. The rate of change [slope] (ΔP / ΔSP) decreases as it approaches high.

  This is because when the rotational phase of the movable pulley 13 is changed by the ball spline mechanism 60 with respect to the movement of the movable pulley 13 in the axial direction, the rotational phase of the fixed pulley 12 and the movable pulley 13 changes. This causes a slip with respect to the primary pulley 1, and the torque transmission amount between the belt 3 and the primary pulley 1 is reduced in accordance with the slip.

  The ratio [inclination] (ΔP / ΔSP) of the relative rotation amount (phase shift) ΔP with respect to the axial movement amount ΔSP of the movable pulley 13 is large when the axial position SP of the movable pulley is in the low gear ratio region. If the pulley axial position SP is in the high gear ratio region, the belt 3 slips larger in the gear ratio low region, and the belt 3 slips smaller in the gear ratio high region. In the low gear ratio region, the torque transmission request between the belt 3 and the primary pulley 1 is relatively small, so even if the slip of the belt 3 is large and the torque transmission amount is reduced, the influence is small. On the other hand, in the high gear ratio region, the torque transmission request between the belt 3 and the primary pulley 1 is relatively large. However, in this region, since the slip of the belt 3 is small, there is little decrease in the torque transmission amount. Can respond. Here, the gear ratio low side indicates a case where the winding radius of the belt 3 in the primary pulley 1 is smaller than the gear ratio high side, and the output torque from the drive source such as the engine is changed to the gear ratio low side. It is larger than the high side and transmitted to the drive wheels.

Note that the ratio [inclination] (ΔP / ΔSP) of the relative rotation amount (phase shift) ΔP with respect to the axial movement amount ΔSP of the movable pulley 13 is not limited to that shown in FIG. It can set suitably what is shown.
Further, here, the first spline groove 61 is inclined with respect to the axial direction, but either or both of the first spline groove 61 and the second spline groove 62 are in the direction of the generatrix of the outer peripheral surface 11a and the inner peripheral surface 13f. It suffices if it is inclined with respect to the surface.

[Configuration of Calculation Unit (Calculation Means) for Belt Wrap Diameter]
This apparatus includes an electronic control unit (ECU) 100 as shown in FIG. The ECU 100 includes an input / output device, a storage device (ROM, RAM, BURAM, etc.) incorporating a large number of control programs, a central processing unit (CPU), a timer counter, and the like.
The ECU 100 includes a relative rotation amount calculation unit 101 that calculates (rotation phase change amount, rotation phase shift amount) ΔP with respect to the shaft 11 of the movable pulley 13, and the axial position SP of the movable pulley 13 from the relative rotation amount ΔP. A calculation unit including an axial position calculation unit 102 to calculate and a belt winding diameter calculation unit 103 to calculate a winding diameter (effective radius of the primary pulley 1) RRb of the belt 3 around the primary pulley 1 based on the axial position SP. (Calculation means) 104 is provided as a functional element.

The relative rotation amount calculation unit 101 constitutes a relative rotation measurement unit (relative rotation measurement means) according to the present invention together with the rotation phase measurement devices 30 and 40, and the rotation phase measurement device 30 measures the rotation phase and rotation phase of the fixed pulley 12. A relative rotation amount (rotation phase change amount) ΔP of the movable pulley 13 with respect to the shaft 11 is calculated from the rotation phase of the movable pulley 13 by the device 40.
That is, along with the rotation of the primary pulley 1, a pulse signal corresponding to the rotation of the fixed pulley 12 as shown in FIG. 9A is obtained by the rotation phase measurement device 30, and the rotation phase measurement device 40 shows, for example, FIG. 9. A pulse signal corresponding to the rotation of the movable pulley 13 as shown in (b1) is obtained.

  If calibration is performed so that the pulse signal of the fixed pulley 12 and the pulse signal of the movable pulley 13 at the reference axial direction position (here, the lowest position) of the movable pulley 13 are synchronized, the movable pulley 13 is connected to the shaft. The shaft 11 moves in the axial direction and rotates relative to the shaft 11. This relative rotation amount (rotation phase change amount) ΔP is a pulse signal [for example, FIG. 9 (a)] corresponding to the rotation of the fixed pulley 12 obtained by the rotation phase measurement device 30 and a movable value obtained by the rotation phase measurement device 40. It can be calculated as a phase difference from a pulse signal [for example, FIG. 9 (c), FIG. 9 (d)] corresponding to the rotation of the pulley 13. That is, focusing on the leading edge (rising edge) of each square wave pulse of the fixed pulley 12 and the movable pulley 13 or the trailing edge (falling edge) of each square wave pulse, the time difference between the leading edges of the pulses. (The amount of deviation) or the time difference (deviation amount) of the trailing edge of each pulse becomes the relative rotation amount (rotation phase change amount) ΔP.

  The axial position calculation unit 102 uses the characteristic of the curved first spline groove 61 that is provided in the ball spline mechanism 60 of the primary pulley 1 and is inclined with respect to the axial direction of the shaft 11, to thereby calculate the relative rotation amount ΔP. From this, the axial position SP of the movable pulley 13 is calculated. That is, the axial position SP of the movable pulley 13 and the relative rotation amount ΔP are in the relationship shown in FIG. 4A, and this correspondence is stored in the memory, and the axial position calculation unit 102 stores it in the memory. The axial position SP of the movable pulley 13 is calculated from the corresponding relationship and the relative rotation amount ΔP of the movable pulley 13 with respect to the shaft 11 calculated by the relative rotation amount calculation unit 101.

  The belt winding diameter calculation unit 103 calculates the belt winding diameter RRb from the axial position SP of the movable pulley 13 calculated by the axial position calculation unit 102. That is, according to the axial position SP of the movable pulley 13, the relative distance between the fixed pulley 12 of the primary pulley 1 and the belt support surfaces (sheave surfaces) 12 a and 13 a of the movable pulley 13 is adjusted, and the primary pulley 1 of the belt 3 is moved. The winding diameter RRb of this is a size corresponding to the relative distance between the fixed pulley 12 and the movable pulley 13. The axial position SP of the movable pulley 13 and the winding diameter RRb of the belt 3 are in a proportional relationship according to the inclination angles of the fixed pulley 12 of the primary pulley 1 and the belt support surfaces (sheave surfaces) 12a and 13a of the movable pulley 13. Since this relationship is known, the belt winding diameter calculation unit 103 calculates the winding diameter RRb of the belt 3 from the axial position SP of the movable pulley 13 using this relationship.

  In this embodiment, in addition to the arithmetic unit 104, the ECU 100 includes a theoretical gear ratio calculation unit 105 that estimates the theoretical gear ratio TRt, an actual gear ratio calculation unit 106 that calculates the actual gear ratio TRr, A belt slip determination unit 107 that determines the slip of the belt 3 from the gear ratio TRt and the actual gear ratio TRr, and a hydraulic pressure that adjusts the hydraulic pressure (line pressure supplied to the hydraulic chamber 15) to the belt slip determination unit 107 based on the determination result. The adjustment unit 108 includes a hydraulic adjustment system 109 as a functional element.

  The theoretical gear ratio calculation unit 105 estimates the theoretical gear ratio TRt from the winding diameter RRb of the belt 3 calculated by the belt winding diameter calculation unit 103. That is, when the belt winding diameter RRb of the primary pulley 1 is determined, the belt winding diameter RRb2 of the secondary pulley 2 is inevitably determined, and the theoretical transmission ratio TRt in the continuously variable transmission can be calculated from these belt winding diameters RRb and RRb2. (TRt = RRb2 / RRb).

The actual transmission ratio calculation unit 106 includes the rotation speed Npr of the primary shaft 11 obtained by the rotation phase measurement device (primary rotation speed sensor) 30 and the rotation speed of the secondary shaft 11 obtained by the rotation phase measurement device 50 (secondary rotation speed sensor) 30. The actual gear ratio TRr is calculated from the rotational speed Nsr (TRr = Nsr / Npr).
In the belt slip determination unit 107, when the difference between the theoretical transmission ratio TRt and the actual transmission ratio TRr is more than a predetermined value set in advance, or the ratio between the theoretical transmission ratio TRt and the actual transmission ratio TRr (for example, When (TRr / TRt) is equal to or greater than a predetermined value set in advance, it is determined that the belt 3 is slipping.

  When the belt slip determining unit 107 determines that the belt 3 is slipping, the hydraulic pressure adjusting unit 108 slightly increases the line pressure supplied to the hydraulic chamber 15 of the primary pulley 1 by a predetermined pressure ΔPO. When the belt slip determining unit 107 determines that the belt 3 has not slipped for a predetermined time or longer, the line pressure supplied to the hydraulic chamber 15 of the primary pulley 1 is slightly decreased by a predetermined pressure ΔPO.

[Action and effect]
Since the belt winding diameter detection device of a continuously variable transmission according to an embodiment of the present invention is configured as described above, when the movable pulley 13 moves in the axial direction with respect to the shaft 11 in the primary pulley 1, The movable pulley 13 rotates relative to the shaft 11 by the spline mechanism 60, and the calculation unit 104 calculates the winding diameter of the belt 3 using this.

  That is, in the relative rotation measurement units 30, 40, 101, the rotation phase measurement device 30 detects the rotation phase of the fixed pulley 12, the rotation phase measurement device 40 detects the rotation phase of the movable pulley 13, and the relative rotation amount calculation unit. A relative rotation amount (rotation phase change amount) ΔP of the movable pulley 13 with respect to the shaft 11 is calculated from the rotation phase of the fixed pulley 12 and the rotation phase of the movable pulley 13 for which 101 is measured.

Then, the axial position calculation unit 102 calculates the axial position of the movable pulley 13 based on the correspondence stored in the memory and the relative rotation amount ΔP of the movable pulley 13 with respect to the shaft 11 calculated by the rotation phase change amount calculation unit 101. SP is calculated.
The belt winding diameter calculation unit 103 uses the proportional relationship between the axial position SP of the movable pulley 13 determined by the continuously variable transmission and the winding diameter RRb of the belt 3, and the movable pulley calculated by the axial position calculation unit 102. The belt winding diameter RRb is calculated from the 13 axial positions SP.

  As described above, when the ball spline mechanism 60 moves in the axial direction with respect to the shaft 11 of the movable pulley 13, the movable pulley 13 rotates relative to the shaft 11, so that the rotational phase measuring device 40 of the relative rotation measuring unit 40 Since the tone wheel 41 having a general tooth configuration as shown in FIGS. 5 and 6 is used, the rotational phase of the movable pulley 13 can be accurately measured, and the belt can be wound with high accuracy. The diameter can be derived.

  In other words, the edges of the teeth 41a (boundaries of the slits 41b) formed at equal intervals on the outer periphery of the tone wheel 41 are straight lines that are perpendicular to the rotation direction of the tone wheel 41. The passage of each tooth 41a can be detected stably. For example, as in the case of Patent Document 1, the magnetic field is increased or decreased as in the case where each tooth 41a is inclined in order to detect the winding diameter of the belt 3. Thus, the problem that the detection accuracy by the pickup is reduced due to the variation in the position is avoided.

As a result, the winding diameter of the belt 3 can be detected with high accuracy, and as exemplified in the present embodiment, the slip of the belt 3 is determined from the detection information of the winding diameter of the belt 3 and the line pressure is controlled. In various controls in the step transmission, appropriate control can be performed with high accuracy by using detection information of the winding diameter of the belt 3.
In this embodiment, when the movable pulley 13 moves in one axial direction with respect to the shaft 11 by the ball spline mechanism 60, the movable pulley 13 rotates relative to the shaft 11 in one direction. The axial position of the movable pulley 13 and the relative rotation amount of the movable pulley 13 can be associated with each other on a one-to-one basis, and the axial movement amount of the movable pulley 13 can be simply calculated from the relative rotation amount of the movable pulley 13.

In the present embodiment, the ball spline mechanism 60 determines the ratio (ΔP / ΔSP) of the relative rotation amount ΔP to the axial movement amount ΔSP of the movable pulley 13 so that the axial position SP of the movable pulley 13 is in the low gear ratio region. If the axial position SP of the movable pulley 13 is in the high speed ratio region, the movable pulley 13 is made small. Therefore, the following effects can be obtained.
That is, when the movable pulley 13 is rotated relative to the axial movement of the movable pulley 13, the rotational phase of the fixed pulley 12 and the movable pulley 13 changes, so that the belt 3 slips with respect to the primary pulley 1. In addition to the normal slip of the belt 3 in the rotation direction of the primary pulley 1, the slip of the belt 3 in the radial direction of the primary pulley 1, that is, the so-called vertical slip of the belt 3 occurs. Due to the longitudinal slip of the belt 3, the wrapping radius of the belt 3 changes at a stretch, so that a high shift speed can be obtained.

  Generally, in a low gear ratio region, low return control is performed to shift the gear ratio to the low side in preparation for the next start when the vehicle decelerates. However, if the vehicle deceleration is large, it may not be possible to return to the lowest gear ratio and a desired starting torque may not be obtained. For this reason, conventionally, in order to obtain a gear change speed that can return the gear ratio to the lowest level even in the case of rapid deceleration, a high capacity is required for the oil pump.

  However, as in the present embodiment, in the low gear ratio region, it is not necessary to increase the transmission speed by the ability of the oil pump by increasing the transmission speed by sliding the belt, and the cost resulting from the increase in the size of the oil pump. Can be suppressed. In other words, by increasing the relative rotation of the fixed pulley 12 and the movable pulley 13 on the low gear ratio low side compared to the high gear ratio side, the relative rotation amount of the movable pulley 13 as a whole is suppressed to a constant amount, and the gear ratio is reduced. On the low side, the belt 3 is liable to cause a vertical slip so that a low reverse speed can be achieved.

Further, in the case of so-called upshift, in which the gear ratio is shifted to the high side, a high shift speed is not required as in the low return control, so that the normal shift speed is obtained. At such a shift speed, even if the movable pulley 13 rotates relative to the fixed pulley 12, the difference in rotational speed becomes small. Therefore, the slip of the belt 3 with respect to the primary pulley 1 is suppressed, and the transmitted torque is reduced. And the occurrence of problems in torque transmission during normal travel can be prevented.

Further, the rotation mechanism includes a first spline groove 61 formed on the outer peripheral surface 11 a of the shaft 11, a second spline groove 62 formed on the inner peripheral surface 13 f of the movable pulley 13, and a space between these spline grooves 61, 62. Since the ball spline mechanism 60 is composed of a plurality of balls 63 interposed between the movable pulley 13 and the movable pulley 13 in the axial direction, there is an advantage that the movable pulley can be easily relatively rotated.

  In addition to the ball spline mechanism 60, the rotation mechanism has a spline groove formed in at least one of the outer peripheral surface 11a of the shaft 11 and the inner peripheral surface 13f of the movable pulley 13 in which the shaft 11 is inserted. If this is the case, the spline groove is inclined with respect to the generatrix direction of the outer peripheral surface 11 a of the shaft 11 or the inner peripheral surface 13 f of the movable pulley 13, thereby rotating the movable pulley 13 with respect to the movement of the movable pulley 13 in the axial direction. The phase can be easily changed.

[Others]
As mentioned above, although embodiment of this invention was described, this invention is not limited to said embodiment, In the range which does not deviate from the meaning of this invention, said embodiment can be changed suitably and can be implemented. it can.
For example, the characteristic of the ratio (ΔP / ΔSP) of the relative rotation amount ΔP to the axial movement amount ΔSP of the movable pulley 13 can be set as appropriate. In the example illustrated in FIG. 4B, when the position of the movable pulley 13 in the axial direction is in a region near the highest gear ratio or in a region near the lowest gear ratio, it is desired to shift at high speed. Therefore, the relative rotation amount ΔP of the movable pulley is suppressed with respect to the axial movement amount ΔSP of the movable pulley 13. With this configuration, even when there is a desire to perform a shift (high speed shift) with a higher shift speed when the gear ratio is near the lowest or near the highest, The difference in rotational speed between the movable pulley and the fixed pulley can be suppressed, the slip of the belt 3 can be suppressed, and the torque transmission amount can be suppressed.

Of course, the ratio (ΔP / ΔSP) of the relative rotation amount ΔP to the axial movement amount ΔSP of the movable pulley 13 may be constant (linear) according to the output characteristics of the engine that is the drive source, and the ratio ( It is also conceivable to actively utilize the slip characteristics of the belt according to (ΔP / ΔSP).
Further, if the rotation mechanism has a spline groove formed in at least one of the outer peripheral surface of the rotation shaft and the inner peripheral surface of the movable pulley in which the rotation shaft is inserted, the spline groove is used as the rotation shaft. By tilting the outer peripheral surface of the movable pulley or the inner peripheral surface of the movable pulley with respect to the generatrix direction, the rotational phase of the movable pulley can be easily changed with respect to the movement of the movable pulley in the axial direction.

  In the above embodiment, the primary pulley is provided with a rotation mechanism for rotating the movable pulley relative to the rotation axis in accordance with the axial movement of the movable pulley relative to the rotation axis, and the relative rotation amount of the movable pulley relative to the rotation axis is measured. In the above description, the relative rotation measuring means for detecting the belt winding diameter with respect to the primary pulley has been described. However, the belt winding diameter with respect to the secondary pulley may be detected.

  In addition, a magnetic rotary encoder that uses a change in induced electromotive force in response to a change in magnetic field using a tone wheel and a pickup is applied to a rotational phase measurement device that constitutes a relative rotation measurement unit. The phase measurement device is not limited to this, and a photoelectric rotary encoder that detects the rotational state from the change in the light received by the passage of the wheel teeth in the light receiving element is also applied. it can.

  In addition to being effective for vehicle transmissions such as automobiles, it can be used for transmissions of various rotational force transmission systems.

DESCRIPTION OF SYMBOLS 1 Primary pulley 2 Secondary pulley 3 Belt 10, 20 V groove part 11 Primary shaft 21 Secondary shaft 12, 22 Fixed pulley 13, 23 Movable pulley 15, 25 Hydraulic chamber 17 Centrifugal hydraulic cancellation chamber 27 Spring 30 Rotation phase as a primary rotation speed sensor Measuring device (relative rotation measuring means)
40 Rotation phase measuring device (relative rotation measuring means)
50 Rotational phase measuring device as secondary rotational speed sensor 31, 41, 51 Tone wheel 31a, 41a, 51a Tone wheel tooth 31b, 41b, 51b Tone wheel slit 32, 42, 52 Pickup (detector)
60, 70 Ball spline mechanism (rotating mechanism)
61, 71 First spline groove 62, 72 Second spline groove 63, 73 Ball 100 Electronic control unit (ECU)
101 Relative rotation amount calculation unit (relative rotation measurement means)
DESCRIPTION OF SYMBOLS 102 Axial direction position calculation part 103 Belt winding diameter calculation part 104 Calculation part (calculation means)
105 theoretical gear ratio calculation unit 106 actual gear ratio calculation unit 107 belt slip determination unit 108 oil pressure adjustment unit 109 oil pressure adjustment system

Claims (6)

In a continuously variable transmission having a primary pulley, a secondary pulley, and a belt wound around both pulleys, a continuously variable diameter of the belt around at least one of the primary pulley and the secondary pulley is detected. A belt winding diameter detection device for a transmission,
A rotation mechanism for rotating the movable pulley relative to the rotation axis thereof in accordance with the movement of the one pulley in the axial direction of the movable pulley;
A relative rotation measuring means for measuring a relative rotation amount of the movable pulley with respect to the rotation shaft;
And a calculating means for calculating the axial movement amount of the movable pulley from the relative rotation amount measured by the relative rotation measuring means and calculating a winding diameter of the belt from the calculation result. A belt winding diameter detection device for a continuously variable transmission. The continuously variable transmission according to claim 1, wherein the rotating mechanism rotates the movable pulley in one direction relative to the rotating shaft as the movable pulley moves in one direction in the axial direction. Belt winding diameter detection device. The ratio of the relative rotation of the movable pulley accompanying the movement of the movable pulley in the axial direction by the rotation mechanism is large in the low gear ratio region of the axial position of the movable pulley, and the shaft of the movable pulley The belt winding diameter detection device for a continuously variable transmission according to claim 1 or 2, wherein the belt winding diameter detection device is made smaller in a high gear ratio region of the direction position. The ratio of the relative rotation of the movable pulley accompanying the movement of the movable pulley in the axial direction by the rotating mechanism is reduced in a region where the movable pulley is desired to shift at a high speed in the axial position. A belt winding diameter detection device for a continuously variable transmission according to claim 1 or 2. The rotating mechanism has a spline groove formed in at least one of an outer peripheral surface of the rotating shaft and an inner peripheral surface of the movable pulley in which the rotating shaft is inserted.
The continuously variable transmission according to any one of claims 1 to 4, wherein the spline groove is inclined with respect to a generatrix direction of an outer peripheral surface of the rotating shaft or an inner peripheral surface of the movable pulley. Belt winding diameter detection device. The rotating mechanism includes a first spline groove formed on an outer peripheral surface of the rotating shaft, a second spline groove formed on an inner peripheral surface of the movable pulley in which the rotating shaft is inserted, and the first spline groove. A ball spline mechanism composed of a plurality of balls interposed between the second spline groove and the second spline groove,
The spline groove of any one of the first spline groove and the second spline groove is inclined with respect to the generatrix direction of the outer peripheral surface of the rotating shaft or the inner peripheral surface of the movable pulley. 5. A belt winding diameter detection device for a continuously variable transmission according to claim 5.

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