JP2018123838A - Continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a continuously variable transmission capable of avoiding omission of elements even if an end play is concentrated.SOLUTION: A continuously variable transmission 2 includes: a primary pulley 21; a secondary pulley 22; and a belt 23 that is wound around the primary pulley 21 and the secondary pulley 22 and includes a plurality of elements 231 tied by a ring 232. The continuously variable transmission 2 includes an element support body 24 that is close to the belt 23 and is extended along the belt 23 between the most upstream position Pup pertaining to a rotary direction of the primary pulley 21 in a contact area of the belt 23 and the primary pulley 21, and the most downstream position Pds pertaining to a rotary direction of the secondary pulley 22 in a contact area of the belt 23 and the secondary pulley 22.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a continuously variable transmission including a belt configured by binding a plurality of elements by a ring.

  A first variable pulley disposed on the input side, a second variable pulley disposed on the output side, and a belt wound around the pair of pulleys, the first and second 2. Description of the Related Art A continuously variable transmission is known that is configured such that a transmission gear ratio can be adjusted steplessly by changing a radius of a contact portion of a belt with respect to a variable pulley. Patent Document 1 discloses a continuously variable transmission including a belt configured by binding a plurality of elements with a hoop.

  Furthermore, Patent Document 2 discloses a continuously variable transmission including a belt configured by binding a plurality of lateral members by a ring or a band. In this continuously variable transmission, the transverse member has an opening that opens in the radial direction of the belt.

JP 2004-144199 A (paragraph 0019) International Publication No. 2015/17737252 (page 6, lines 19-27)

  In push belt type continuously variable transmissions that transmit power via elements, gaps between adjacent elements (called "end play") are concentrated under operating conditions in which the direction of torque applied to the belt changes frequently There is. Here, when the travel distance of the vehicle is extended and the elements are rubbed and worn, the individual end plays gradually spread, and there is a concern that the elements fall off the ring when the end plays are concentrated. Furthermore, even if it does not fall off, the engagement mechanism consisting of a male and female pair provided on the element is disengaged due to concentration of the end play, and the re-engagement fails due to rattling, so the continuously variable transmission There are also concerns that hinder the operation of the system.

  An object of the present invention is to provide a continuously variable transmission in consideration of the above problems.

  In one aspect, the present invention provides a primary pulley, a secondary pulley, a belt having a plurality of elements wound around the primary pulley and the secondary pulley and bound by a ring, and a primary pulley of contact areas of the belt and the primary pulley. An element support extending along the belt in the vicinity of the belt between the most upstream position in the rotation direction of the belt and the most downstream position in the rotation direction of the secondary pulley in the contact area between the belt and the secondary pulley. A continuously variable transmission is provided.

  According to the said form, when an end play concentrates, an element is supported by the element support body provided close to a belt, and the malfunction which arises in a continuously variable transmission can be suppressed.

FIG. 1 is a schematic diagram showing the overall configuration of a power transmission system of a vehicle equipped with a continuously variable transmission according to an embodiment of the present invention. FIG. 2 is an explanatory view schematically showing the configuration of the continuously variable transmission. FIG. 3 is a cross-sectional view showing a configuration of a belt provided in the continuously variable transmission.

  Embodiments of the present invention will be described below with reference to the drawings.

(Configuration of vehicle drive system)
FIG. 1 schematically shows an overall configuration of a power transmission system (hereinafter referred to as “drive system”) P of a vehicle equipped with a continuously variable transmission 2 according to an embodiment of the present invention.

  The drive system P according to the present embodiment includes an internal combustion engine (hereinafter simply referred to as “engine”) 1 as a drive source, and a continuously variable transmission 2 on a power transmission path that connects the engine 1 and left and right drive wheels 5. I have. The engine 1 and the continuously variable transmission 2 can be connected via a torque converter. The continuously variable transmission 2 converts the rotational power input from the engine 1 at a predetermined gear ratio and outputs it to the drive wheels 5 via the differential gear 3.

  The continuously variable transmission 2 includes a primary pulley 21 on the input side as a shift element and a secondary pulley 22 on the output side. The continuously variable transmission 2 includes a metal belt 23 wound between a primary pulley 21 and a secondary pulley 22, and changes the ratio of the contact radius of the metal belt 23 in the pulleys 21 and 22 to change the speed. It is possible to change the ratio steplessly.

  The primary pulley 21 and the secondary pulley 22 are fixed sheaves 211 and 221 and a movable sheave 212 arranged coaxially with the fixed sheave so as to be movable along rotation center axes Cp and Cs (FIG. 2) of the fixed sheave. 222. A fixed sheave 211 of the primary pulley 21 is connected to the input shaft of the continuously variable transmission 2, and a fixed sheave 221 of the secondary pulley 22 is connected to the output shaft. The transmission ratio of the continuously variable transmission 2 is adjusted by adjusting the hydraulic pressure acting on the movable sheaves 212 and 222 of the primary pulley 21 and the secondary pulley 22, and is formed between the fixed sheaves 211 and 221 and the movable sheaves 212 and 222. It is controlled by changing the width of the groove.

  In this embodiment, an oil pump 6 that uses the engine 1 or an electric motor (not shown) as a power source is provided as a source of operating hydraulic pressure of the continuously variable transmission 2. The oil pump 6 increases the operating oil to a predetermined pressure, and supplies the increased operating oil to the hydraulic chambers of the movable sheaves 212 and 222 via the hydraulic control circuit 7. FIG. 1 shows a hydraulic pressure supply path from the hydraulic pressure control circuit 7 to each part by dotted lines with arrows.

  The rotational power output from the continuously variable transmission 2 is transmitted to the drive shaft 4 via the final gear train or sub-transmission (none shown) and the differential gear 3 set to a predetermined reduction ratio, and driven. The wheel 5 is rotated.

(Control system configuration and basic operation)
The operations of the engine 1 and the continuously variable transmission 2 are controlled by the engine controller 101 and the transmission controller 201, respectively. Each of the engine controller 101 and the transmission controller 201 is configured as an electronic control unit, and includes a central processing unit (CPU), various storage devices such as a RAM and a ROM, a microcomputer equipped with an input / output interface and the like.

  The engine controller 101 receives a detection signal from an operation state sensor that detects the operation state of the engine 1, executes a predetermined calculation based on the operation state, and performs a fuel injection amount, fuel injection timing, ignition timing, and the like of the engine 1. Set. As driving state sensors, an accelerator sensor 111 that detects the amount of operation of the accelerator pedal (hereinafter referred to as “accelerator opening”) by the driver, a rotational speed sensor 112 that detects the rotational speed of the engine 1, and a temperature of engine cooling water are detected. In addition to the cooling water temperature sensor 113 and the like, an air flow meter, a throttle sensor, a fuel pressure sensor, an air-fuel ratio sensor, and the like (not shown) are provided.

  The transmission controller 201 is communicably connected to the engine controller 101 via a CAN standard bus. Further, in connection with the control of the continuously variable transmission 2, a vehicle speed sensor 211 that detects the traveling speed of the vehicle, an input side rotational speed sensor 212 that detects the rotational speed of the input shaft of the continuously variable transmission 2, a continuously variable transmission. An output-side rotational speed sensor 213 that detects the rotational speed of the output shaft 2, an oil temperature sensor 214 that detects the temperature of hydraulic oil in the continuously variable transmission 2, a shift position sensor 215 that detects the position of the shift lever, and the like. The transmission controller 201 inputs the accelerator opening and the like as the operating state of the engine 1 from the engine controller 101 and also inputs detection signals of these sensors.

  Then, the transmission controller 201 determines the shift range selected by the driver based on the signal from the shift position sensor 215, and sets the target speed ratio of the continuously variable transmission 2 based on the accelerator opening and the vehicle speed. The hydraulic pressure control circuit 7 controls the hydraulic pressure generated by the oil pump 6 as a source pressure so that a predetermined hydraulic pressure corresponding to the target gear ratio acts on the movable sheaves 212 and 222 of the primary pulley 21 and the secondary pulley 22. Output a signal.

(Configuration of continuously variable transmission)
FIG. 2A shows a configuration of the continuously variable transmission 2 according to the present embodiment by a cross section taken along line xx shown in FIG.

  In the present embodiment, the continuously variable transmission 2 includes a pair of variable pulleys, specifically, a primary pulley 21 and a secondary pulley 22, and a metal belt 23 wound around the pair of pulleys 21 and 22. . FIG. 2A shows the movable sheave 212 of the primary pulley 21 and the fixed sheave 221 of the secondary pulley 22 for convenience of showing in a cross section. The continuously variable transmission 2 is a push belt type, and the metal belt 23 includes a plurality of elements 231 that are power transmission elements arranged in the plate thickness direction, and may be called a ring 232 (“hoop” or “band”). ) Are bound together.

  FIG. 3A shows the element 231 according to this embodiment in a front view.

  The element 231 may constitute a metal belt for any known continuously variable transmission. In the present embodiment, the element 231 generally includes a base 231a and a narrow neck 231b with respect to the base 231a. And a continuous top portion 231c. A gap is formed between a portion on each of the left and right sides of the base portion 231a and a portion of the top portion 231c that protrudes in the width direction w from the neck portion 231b, and the ring 232 is inserted into each of the gaps. Element 231 is attached to ring 232. Then, the plurality of elements 231 are sequentially attached to the ring 232 in the same manner, and the convex portion p provided on the front surface of the element 231 is engaged with the concave portion provided on the rear surface of the adjacent element 231. The elements 231 are bound together to form the metal belt 23. In the present embodiment, the ring 232 is a laminated ring, and is configured by laminating a plurality of ring members 232a to 232c.

  Here, with all the elements 231 assembled to the ring 232, there is a slight gap called an end play between the individual elements 231, and the direction of the torque applied to the metal belt 23 is frequently switched. In certain conditions, end play may be concentrated. When the travel distance of the vehicle increases and the elements 231 rub against each other and wear, there is a concern that the individual end play gradually spreads and the element 231 drops from the ring 232 when the end play is concentrated.

  Therefore, in the present embodiment, the element support 24 is provided to prevent the element 231 from falling off.

(Element support structure)
2A shows the relative positional relationship between the pulleys 21 and 22, the metal belt 23 and the element support 24 in the continuously variable transmission 2, and FIG. 2B schematically shows the shape of the element support 24. Is shown.

  As shown in FIG. 2B, the element support 24 includes a plate-like portion 241 that is rectangular or long in plan view, and a shaft support portion 242 that extends in the thickness direction with respect to the plate-like portion 241. And has a T-shape as viewed from the side.

  As shown in FIG. 2A, the element support 24 is disposed on the inner peripheral side of the continuously variable transmission 2 with respect to the metal belt 23, and the shaft support 242 with respect to the shell of the continuously variable transmission 2. Thus, it is supported so as to be swingable about the rotation axis Cr (FIG. 1).

  Here, the plate-like portion 241 is interposed between the primary pulley 21 and the secondary pulley 22 in a state where the element support 24 is supported on the shell, and the fixed sheaves 211 and 221 of the pulleys 21 and 22. And the movable sheaves 212 and 222, and further, as shown in FIG. 2A, the metal belt 23 is close to the inner peripheral surface. Here, in the present embodiment, the “close state” means that the element support body 24 is in the case where the element 231 is likely to fall off the ring 232 even if the element support body 24 contacts the element 231 or does not contact in the normal state. The distance 24 is close to the extent of contact with the element 231 (for example, within 10 mm).

  In the present embodiment, as shown in FIG. 2A, the plate-like portion 241 has a region where the metal belt 23 is in contact with each sheave surface of the primary pulley 21 (from the point Pup in the rotation direction indicated by the arrow in the figure). The region up to Pdp (hereinafter referred to as “contact region”) from the position Pup most upstream in the rotation direction of the primary pulley 21 (hereinafter referred to as “most upstream position”) from the metal belt 23 and the secondary pulley 22. Of the contact areas Pus to Pds, the length is set so as to extend over the entire linear range R up to the position Pds on the most downstream side (hereinafter referred to as “most downstream position”) with respect to the rotation direction of the secondary pulley 22. Has been. The plate-like portion 241 is arranged below the gravitational direction with respect to the region of the linear range R of the metal belt 23.

  Further, the shaft support 242 is positioned so that the rotation axis Cr is on a straight line L connecting the rotation center axis Cp of the primary pulley 21 (movable sheave 212) and the rotation center axis Cs of the secondary pulley 22 (fixed sheave 221). The dimension or length is set. The element support 24 has a rotation axis Cr that is perpendicular to the straight line L, and is freely swingable about the rotation axis Cr. Therefore, in the cross section shown in FIG. , Cs is inclined with respect to the straight line L. As shown in FIG. 1, in the present embodiment, the electric motor 8 is disposed so that the inclination of the element support 24 can be adjusted, and the transmission controller 201 determines the inclination of the continuously variable transmission 2 according to the transmission ratio. The operation of the electric motor 8 and the inclination of the element support 24 are controlled.

  In this embodiment, as shown in FIG. 2B, end play sensors 25 are respectively installed at both ends of the plate-like portion 241 in the length direction. The end play sensor 25 detects when the end play is concentrated on the metal belt 23 or measures the size of the concentrated end play. As the end play sensor 25, for example, various sensors such as an optical type, a magnetic type, and an eddy current type can be adopted.

(Explanation of effects)
The continuously variable transmission according to the present embodiment is configured as described above. Hereinafter, effects obtained by the present embodiment will be described.

  First, the element support 24 that extends along the metal belt 23 when the end play of the element 231 is concentrated due to the operating condition of the continuously variable transmission 2 and the element 231 may fall off the ring 232. The element 231 can be supported by (specifically, the plate-like portion 241) and can be prevented from falling off (effect corresponding to claim 1).

  Here, in the push belt type continuously variable transmission 2, end play is concentrated in the most upstream position Pup in the rotation direction of the primary pulley 21 among the contact regions Pup to Pdp of the metal belt 23 and the primary pulley 21, and the metal belt. Of the contact areas Pus to Pds of the secondary pulley 22 and the secondary pulley 22, it tends to occur at the most downstream position Pds in the rotational direction of the secondary pulley 22. FIG. 2 shows a state where end play is actually concentrated by a region surrounded by dotted lines A and B. FIG. Therefore, by disposing the element support 24 or the plate-like portion 241 between the most upstream position Pup on the primary pulley 21 side and the most downstream position Pds on the secondary pulley 22 side, the element 231 is effectively prevented from falling off. It is possible.

  Furthermore, even if the end play does not fall off, when the engagement between the convex portion p and the concave portion of the element 231 is disengaged due to the concentration of the end play, the re-engagement is facilitated by the guide of the element support 24, and the continuously variable transmission It is possible to suppress troubles in the smooth operation of 2.

  Secondly, the element support 24 (plate-like portion 241) is disposed below the gravitational direction with respect to the region of the linear range R connecting the most upstream position Pup and the most downstream position Pds of the metal belt 23. The element 231 can be effectively prevented from falling off (an effect corresponding to claim 2).

  Third, the element support 24 (plate-like portion 241) is arranged over the entire linear range R connecting the most upstream position Pup and the most downstream position Pds, so that the end play concentration is the most upstream position Pup or It is possible to cope with a case that occurs at a position distant from the most downstream position Pds, for example, near the middle (effect corresponding to claim 3).

  Fourthly, by arranging the element support 24 on the inner peripheral side with respect to the metal belt 23, the empty space of the continuously variable transmission 2 can be effectively utilized and the layout can be improved. Effect corresponding to 5).

  Fifth, the element support 24 is configured to be swingable about the rotation axis Cr, and in the cross section perpendicular to the rotation center axis Cp of the primary pulley 21 and the rotation center axis Cs of the secondary pulley 22, the rotation center axes Cp, Cs The inclination of the element support 24 with respect to the straight line L connecting the rotation center axes Cp and Cs of the pulleys 21 and 22 with respect to the movement of the metal belt 23 according to the change of the transmission ratio is made variable. It becomes possible to follow by changing the inclination (effect corresponding to claim 6).

  Here, FIG. 2 shows that the gear ratio is lowered with respect to the element support 24 (shown by the solid line) when the continuously variable transmission 2 is at the low speed gear ratio (specifically, the maximum gear ratio). The state of the element support 24 in this case is indicated by a two-dot chain line.

  Fifth, since the end play sensor 25 is installed on the element support 24 (plate portion 241), the end play can be monitored and a special means for installing the end play sensor 25 is provided. Since there is no need to provide them separately, the number of components can be reduced, and deterioration of layout can be suppressed (effect corresponding to claim 7).

  When the end play concentration is detected by the end play sensor 25, the tension applied to the metal belt 23 can be reduced by actively reducing the end play concentration by reducing the engine torque.

  In the present embodiment, the case where the end play sensor 25 is installed at both ends of the plate-like portion 241 has been described. It is also possible to confirm in advance an experiment or the like where the end play is likely to occur, and install it at a position corresponding to the result.

  In the above description, the element support 24 (plate-shaped portion 241) is disposed below the gravitational direction with respect to the region of the linear range R connecting the most upstream position Pup and the most downstream position Pds of the metal belt 23. Explained. However, the present invention is not limited to this, and it is possible to change the arrangement according to the behavior when the element 231 falls off and arrange the element 231 above the gravitational direction.

  Furthermore, if the end play concentration tends to occur below the straight line L connecting the rotation center axes Cp and Cs of the pulleys 21 and 22 due to differences in the rotation directions of the pulleys 21 and 22, the metal belt 23. The element support 24 may be installed in correspondence with the area below the straight line L.

  Furthermore, in the above description, the base 231a and the top 231c are connected to each other via the central neck 231b, and the element 231 (FIG. 3) into which the ring 232 is inserted from the side with respect to the gap between the base 231a and the top 231c. The case where (A)) is employed has been described. However, the present invention is not limited to this, and the element has an opening that opens in the outer peripheral side or inner peripheral side of the metal belt 23, in other words, in the radial direction of the metal belt 23, and the ring from above or below the opening May be inserted.

  FIG. 3B shows a modification example (element 331) of the element in that case.

  The element 331 generally includes a base portion 331a and side portions 331b extending perpendicularly to the width direction w from both ends of the base portion 331a. An opening h that opens in a direction perpendicular to the width direction w is formed by the mutually facing inner surfaces of the pair of side portions 331b and the upper surface of the base portion 331a, and the ring 332 is fitted into the opening h. Individual elements 331 are attached to the ring 332.

  Here, the direction in which the opening h opens in a state where the element 331 is assembled to the ring 332 may be the outer peripheral side or the inner peripheral side of the metal belt 23. However, by configuring the metal belt 23 so that the opening h opens to the outer peripheral side, in the continuously variable transmission 2 of the form shown in FIG. 2, the element support 331 disposed below the gravity direction causes the element 331. Can be effectively prevented from falling off.

  A plurality of elements 331 are sequentially attached to the ring 332 in the same manner, and provided on the front surface of the element 331, specifically, on the convex portion p provided on the front surface of the side portion 331b and on the back surface of the adjacent element 331. The element 331 is bound to each other by engaging the recessed portion thus formed, and the metal belt 23 is configured. Also in this embodiment, the ring 332 is a laminated ring, and is configured by laminating a plurality of ring members 332a to 332d.

  Thus, according to the element 331 that has the opening h that opens on the outer peripheral side or the inner peripheral side of the metal belt 23 and receives the ring 332 in the opening h, the ring 332 is prevented while the element 331 is prevented from falling off. As a result, the workability can be improved by easily assembling the element 331 with respect to the above (effect corresponding to claim 4).

  Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various changes and modifications can be made within the scope of the matters described in the claims. Not too long.

P ... Drive system 1 ... Engine 2 ... Continuously variable transmission 21 ... Primary pulley 211 ... Fixed pulley 212 ... Movable pulley 22 ... Secondary pulley 221 ... Fixed pulley 222 ... Movable pulley 23 ... Belt 231 ... Element 232 ... Ring 24 ... Element support Body 241 ... Plate-like part 242 ... Shaft support part 3 ... Differential gear 4 ... Drive shaft 5 ... Drive wheel 6 ... Oil pump 7 ... Hydraulic control circuit 8 ... Electric motor 101 ... Engine controller 201 ... Transmission controller

Claims (7)

A primary pulley,
A secondary pulley,
A belt having a plurality of elements wound around the primary pulley and the secondary pulley and bound by a ring;
Between the most upstream position in the rotation direction of the primary pulley in the contact area of the belt and the primary pulley, and the most downstream position in the rotation direction of the secondary pulley in the contact area of the belt and the secondary pulley, An element support extending along the belt in proximity to the belt;
A continuously variable transmission.   2. The continuously variable transmission according to claim 1, wherein the element support is located below a gravitational direction with respect to a region connecting the most upstream position and the most downstream position of the belt.   3. The continuously variable transmission according to claim 1, wherein the element support extends along an entire region of the belt connecting the most upstream position and the most downstream position.   The continuously variable transmission according to any one of claims 1 to 3, wherein the element has an opening that opens on an outer peripheral side or an inner peripheral side of the belt, and receives the ring in the opening. .   The continuously variable transmission according to any one of claims 1 to 4, wherein the element support is located on an inner peripheral side of the belt.   2. The element support body according to claim 1, wherein an inclination of the element support body with respect to a straight line connecting the rotation center axes is variable in a cross section perpendicular to the rotation center axes of the primary pulley and the secondary pulley. The continuously variable transmission according to claim 5.   7. The apparatus according to claim 1, further comprising an end play sensor that is installed on the element support and detects occurrence of an end play in the belt or measures a size of the end play. Continuously variable transmission.

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