JP2014141984A - Thrust mechanism of dry belt continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve good belt return and avoid a reduction in a frictional coefficient due to oil of a hydraulic actuator assisting thrust.SOLUTION: A thrust mechanism of a dry belt continuously variable transmission including: a hydraulic actuator 21 shielded from a dry chamber 23 in which a fixed sheave 12, a movable sheave 13, and a belt 3 are contained in a liquid tight state, having a piston moved forward or backward by a hydraulic pressure; and coupling members 31 and 32 coupling the piston with the movable sheave, and causing the hydraulic pressure acting on the piston 25 to act on the movable sheave 13 as a thrust for making the movable sheave 13 closer to the fixed sheave 12.

Description

  The present invention is configured to transmit torque between a belt and a pulley without continuously supplying a lubricant, and to change speed by continuously changing a belt winding radius with respect to the pulley. The present invention relates to a dry belt type continuously variable transmission capable of changing a ratio steplessly, and more particularly to a mechanism that generates or controls a thrust force that causes a pulley to pinch a belt.

  2. Description of the Related Art Conventionally, a belt type continuously variable transmission configured to continuously change a belt winding radius by changing a groove width of a pulley around which the belt is wound is known. In this type of continuously variable transmission, torque is transmitted by the frictional force between the belt and the pulley. Therefore, it is necessary to constantly apply a so-called clamping pressure that clamps the belt according to the torque to be transmitted. In order to change the width, thrust in the axial direction is required. Therefore, for example, in the belt-type continuously variable transmission described in Patent Document 1, a pulley is configured by a fixed sheave integrated with a rotating shaft and a movable sheave that approaches and separates from the fixed sheave, and the sheaves are opposed to each other. The surface is a tapered surface, and a hydraulic servo mechanism is provided on the back side of the movable sheave. The hydraulic servo mechanism is configured to generate a belt clamping pressure and to generate a thrust that changes the groove width.

  In the continuously variable transmission described in Patent Document 1, a metal piece (sometimes referred to as a block or an element) constituting a belt and a pulley come into contact with each other. It is a wet-type continuously variable transmission that is lubricated with The wet belt type continuously variable transmission must be lubricated with oil, and the friction coefficient between the belt and pulley decreases accordingly, so the belt clamping pressure must be set to transmit the necessary and sufficient torque. This increases the diameter of the pulley or increases the diameter of the pulley, which increases the consumption of power for generating high hydraulic pressure, and increases the overall size of the apparatus.

  On the other hand, a belt type continuously variable transmission called a dry type is a pulley that can change the groove width of a composite belt in which metal pieces called blocks covered with synthetic resin are bound with a tension band made of synthetic resin. The transmission is configured to transmit torque with a frictional force between them by winding and bringing the synthetic resin block and the tension band into contact with the pulley. In this type of continuously variable transmission, the friction coefficient between the belt and the pulley is larger than the friction coefficient when the metals are in contact with each other, so that the so-called clamping pressure for clamping the belt by the pulley can be reduced. There are advantages. On the other hand, when oil enters the contact area between the belt and the pulley, there is a problem that the friction coefficient is lowered and the desired torque capacity cannot be obtained, and the thrust mechanism for generating the clamping pressure is restricted.

  Therefore, for example, the belt-type continuously variable transmission described in Patent Document 2 uses a pressing cam that converts torque into axial thrust. In the continuously variable transmission described in Patent Document 2, each of a driving pulley and a driven pulley around which a belt is wound is moved toward and away from a fixed sheave integrated with a rotating shaft and the fixed sheave. It is composed of movable sheaves that move in the axial direction, and the surfaces of these sheaves that are opposed to each other are tapered surfaces, so that the belt wrapping radius is continuous according to the interval between these sheaves, that is, the groove width. It is comprised so that it may change. A coil spring is arranged between the back surface of one pulley (for example, a driven pulley) and a support disk as a spring receiver attached to the rotating shaft, and the movable sheave is moved in the direction in which the groove width is narrowed by the coil spring. It is comprised so that it may press. Further, a pressing cam that generates thrust in the axial direction according to torque is provided between the back surface of the movable sheave and the rotating shaft. Therefore, if the torque to be transmitted between the movable sheave and the rotating shaft increases, the thrust that pushes the movable sheave toward the fixed sheave, that is, the clamping force increases, and the frictional force (that is, the transmission torque) corresponding to the torque that should be transmitted Torque capacity) is generated.

  A belt type continuously variable transmission provided with a torque cam corresponding to the above-described pressing cam is also described in Patent Document 3.

JP 2007-309462 A JP-A-9-112461 JP 2000-110858 A

  In a dry belt-type continuously variable transmission, a so-called torque cam is used as described in Patent Document 2 above, so that a clamping force or axial thrust (hereinafter simply referred to as thrust) according to the torque to be transmitted is used. May be noted). However, the thrust is not only required when transmitting torque from the driving force source of the vehicle toward the driving wheel, but also when thrust is changed by changing the groove width of the pulley. There is a case. For example, when the vehicle is suddenly braked to stop at a short distance, the gear ratio needs to be a large gear ratio in preparation for re-starting after stopping, so the groove width of the drive pulley increases rapidly, On the other hand, the groove width of the driven pulley is narrowed rapidly. Therefore, in the driven pulley, it is necessary to apply a large thrust to the movable sheave and move it quickly toward the fixed sheave.

  However, since the torque cam is configured to generate a thrust according to the torque to be transmitted as described above, a necessary and sufficient thrust cannot be obtained due to a decrease in torque during sudden braking, and therefore the belt in the driven pulley. There is a possibility that a so-called belt return failure may occur in which the winding radius of the belt does not increase as expected. Such a situation is the same when the spring is used together with the torque cam.

  The thrust for changing the belt winding radius can also be generated by the hydraulic servo mechanism described in Patent Document 1 described above. However, if the movable sheave is pressed directly by hydraulic pressure, the movable sheave is attached so as to be rotatable with respect to the rotating shaft and slidable in the axial direction, so inevitable oil leakage at the sliding portion. In addition, oil leakage due to changes over time may occur, and the leaked oil may adhere to the surface of the pulley or the belt, reducing the coefficient of friction between the belt and the pulley, and thus reducing the transmission torque capacity. There is sex.

  The present invention has been made paying attention to the above technical problem, and it is necessary and sufficient to reduce the thrust of the pulley in the dry belt type continuously variable transmission without reducing the friction coefficient between the belt and the pulley. An object of the present invention is to provide a thrust mechanism that can be enlarged and, in turn, avoid or suppress a belt return failure.

  In order to achieve the above-mentioned object, the invention according to claim 1 is characterized in that a pulley around which a belt is wound is fixed to the rotary shaft so that the pulley is close to and away from the fixed sheave. Provided with a movable sheave that is fitted so as to be movable back and forth in the axial direction of the rotary shaft, and a torque cam that generates a thrust to press the movable sheave toward the fixed sheave according to the torque is provided. In the thrust mechanism of the dry belt type continuously variable transmission in which the belt winding radius with respect to the pulley increases when the belt approaches the stationary sheave, the stationary sheave, the movable sheave, and the dry chamber in which the belt is accommodated On the other hand, a hydraulic actuator that is shielded in a liquid-tight state and moves back and forth by hydraulic pressure, and the piston and the movable sheave can only be connected Is to, characterized in that a coupling member to act on said movable sheave and hydraulic pressure acting on the piston as a thrust to approach the movable sheave relative to the fixed sheave.

  According to a second aspect of the present invention, in the first aspect of the invention, the dry belt type continuously variable transmission has a casing that forms the dry chamber, and the hydraulic actuator is provided outside the casing. This is a thrust mechanism of a dry belt type continuously variable transmission.

  According to a third aspect of the present invention, in the second aspect of the invention, the hydraulic actuator is disposed such that the piston moves back and forth on an extension line of the rotating shaft of the rotating shaft, and the rotating shaft is moved from an end thereof. An insertion hole formed extending to the inner peripheral side of the portion where the movable sheave is fitted, and an insertion hole formed from the outer peripheral surface of the portion where the movable sheave is fitted to the insertion hole and extending in the axial direction The connecting member connects the rod penetrating the elongated hole and the rod and the movable sheave through the casing. A thrust mechanism for a dry belt type continuously variable transmission, characterized in that it has a connecting pin.

  According to a fourth aspect of the present invention, in the third aspect of the present invention, the connecting pin is slidably in contact with an inner surface of the elongated hole so as to transmit torque between the rotating shaft and the movable sheave. This is a thrust mechanism for a dry belt type continuously variable transmission.

  According to a fifth aspect of the invention, in the invention of the fourth aspect, the inner surface of the elongated hole is subjected to a friction coefficient lowering process for reducing a friction coefficient with the connecting pin. This is a thrust mechanism of a continuously variable transmission.

  According to a sixth aspect of the present invention, in the first to fifth aspects of the invention, the dry belt type continuously variable transmission is mounted on a vehicle, and the deceleration of the vehicle is equal to or greater than a predetermined value, or the control of the vehicle. The hydraulic actuator is configured to supply hydraulic pressure so that a thrust for moving the movable sheave toward the fixed sheave increases when power is equal to or greater than a predetermined braking force. This is a thrust mechanism of a dry belt type continuously variable transmission.

  According to the present invention, even if the torque acting between the movable sheave and the rotating shaft is reduced, and the pressing force that presses the movable sheave toward the fixed sheave due to the torque is reduced, the thrust by the hydraulic actuator And the movable sheave can be pushed toward the fixed sheave. Therefore, for example, when the hydraulic actuator is configured to reduce the groove width of the driven pulley and increase the belt winding radius, the thrust that presses the movable sheave toward the fixed sheave side is necessary and sufficient even during sudden braking. By enlarging it, the so-called belt return can surely occur. Further, the hydraulic actuator that generates such thrust is isolated in a liquid-tight state with respect to the dry chamber in which each sheave or belt is accommodated, and its piston is connected to the movable sheave via a connecting member. Therefore, it is possible to prevent or suppress the situation where the oil of the hydraulic actuator enters the dry chamber or adheres to the pulley or belt, and avoids the reduction of the transmission torque capacity of the belt type continuously variable transmission. Can do.

1 is a schematic diagram schematically showing an example of a dry belt type continuously variable transmission including a thrust mechanism according to the present invention. It is typical sectional drawing which shows an example of the thrust mechanism about the driven pulley. It is sectional drawing which follows the III-III line of FIG. It is sectional drawing similar to FIG. 2 which shows the other example of this invention typically. It is a fragmentary perspective view which shows the shape of the connection pin.

  Next, the present invention will be specifically described based on the embodiment shown in the drawings. The present invention is a thrust mechanism for a dry belt type continuously variable transmission, and the dry belt type continuously variable transmission itself may be a conventionally known one. FIG. 1 schematically shows an example thereof. The belt-type continuously variable transmission shown here is a transmission mounted on a vehicle, and includes a driving pulley 1 and a driven pulley 2 that can change the groove width. The belt 3 is wound around these pulleys 1 and 2. The drive pulley 1 is a pulley to which power is input from a driving force source such as an engine (not shown), and a fixed sheave 5 integrated with a rotating shaft (input shaft) 4, and the approach to the fixed sheave 5. The movable sheave 6 is separated. The mutually facing surfaces of these sheaves 5 and 6 are formed in a taper shape, and a belt groove around which the belt 3 is wound is formed between these tapered surfaces. Therefore, the belt 3 is configured such that the winding radius of the belt 3 is reduced when the width of the belt groove is wide, and the winding radius of the belt 3 is increased when the width of the belt groove is narrow.

  The movable sheave 6 is fitted to the rotary shaft 4 so as to be able to move back and forth in the axial direction. Between the movable sheave 6 and the rotary shaft 4, a mechanism for preventing rotation such as a slide key or a spline ( Therefore, the movable sheave 6 is configured to rotate integrally with the rotary shaft 4 and to be relatively movable in the axial direction.

  The belt 3 is made of a non-metallic material such as a synthetic resin at least in contact with the pulleys 1 and 2. More specifically, the belt 3 is a so-called tension type belt and is made of a large number of synthetic resins. This is a composite belt in which metal pieces called coated blocks are bundled with a tension band made of synthetic resin, and the block made of synthetic resin and the tension band are configured to come into contact with pulleys 1 and 2. Accordingly, there is no contact between metals, and therefore it is not necessary to perform lubrication with oil. Rather, it is necessary to avoid the presence of oil between the belt 3 and the pulleys 1 and 2. Thus, it is called "dry type" because it does not require lubricating oil.

  The mechanism for changing the width of the belt groove (hereinafter simply referred to as groove width) in the drive pulley 1 is constituted by a mechanical actuator that does not require hydraulic pressure. In the example shown in FIG. 1, the mechanical actuator is constituted by a feed screw mechanism, a screw shaft 7 is arranged in parallel with the rotary shaft 4, and a screw groove engaged with the screw shaft 7 is formed on the outer periphery. A screw wheel 8 formed in the portion is attached to the movable sheave 6 so as to be rotatable and integrated in the axial direction. Further, the screw shaft 7 is connected to a speed change motor 10 via a reduction gear mechanism 9. That is, when the screw shaft 7 is rotated forward or reverse by the speed change motor 10, the movable sheave 6 approaches the fixed sheave 5 to narrow the groove width, and conversely moves away from the fixed sheave 5. Thus, the groove width is increased. The transmission motor 10 is attached to the outer surface of the casing 11 of the belt type continuously variable transmission.

  The driven pulley 2 has a fixed sheave 12 and a movable sheave 13 in the same manner as the drive pulley 1 described above, and the opposing surfaces of these sheaves 12 and 13 are formed in a taper shape. The groove width, which is the distance between the sheaves 12, 13, changes according to the distance between the sheaves 12, 13, and the wrapping radius of the belt 3 changes depending on the change in the groove width. The fixed sheave 12 is integrated with a rotating shaft (output shaft) 14, while the movable sheave 13 can move back and forth in the axial direction of the rotating shaft 14 and is integrated with the rotating shaft 14 in the rotating direction. It is made to fit. A mechanism for generating a pressing force (thrust) for pushing the movable sheave 13 toward the fixed sheave 12 is provided on the back side of the movable sheave 13 (the side opposite to the fixed sheave 12).

  That is, as shown in FIG. 2, a cam member 16 having a cylindrical portion 15 projecting toward the back surface of the movable sheave 13 is rotatably fitted to the rotating shaft 14, and the cam member 16 is an output gear (not shown). It is connected to output members such as. The front end surface of the cam member 16 in the axial direction is an uneven surface that continuously protrudes and retreats in the axial direction, and this uneven surface is the cam surface. On the other hand, the movable sheave 13 is integrally formed with a boss portion 17 extending to the back side, and the tip end portion in the axial direction of the boss portion 17 is slidably brought into contact with the cam surface. A cam portion is provided. A torque cam 18 is constituted by the cam surface and the cam portion which are in contact with each other. That is, the cam surface is an inclined surface that is inclined with respect to the axial direction and the circumferential direction of the rotating shaft 14 or the cam member 16, whereas the cam portion is directed in the axial direction with respect to the so-called inclined surface. Since they are pressed, when a torque acts between them, a component in the axial direction corresponding to the torque, that is, a thrust is generated. The configuration of the torque cam may be the same as a conventionally known torque cam.

  Further, the cam member 16 is provided with a flange portion 19 projecting outward from the cylindrical portion 15, and a coil spring 20 is disposed between the flange portion 19 and the back surface of the movable sheave 13. The coil spring 20 is in a compressed state and is fitted to the outer peripheral side of the cylindrical portion 15 and the boss portion 17. Therefore, the movable sheave 13 is always subjected to an elastic force that presses against the fixed sheave 12 side. The elastic force and the axial load by the torque cam are the thrust.

  The thrust mechanism according to the present invention further includes a hydraulic actuator 21. The hydraulic actuator 21 is for assisting a thrust force that presses the movable sheave 13 toward the fixed sheave 12 when the movable sheave 13 is brought close to the fixed sheave 12 rapidly, and is located away from the driven pulley 2. And is configured to apply a thrust to the movable sheave 13 via a connecting member. Such a configuration is a configuration for preventing the oil from adhering to the pulleys 1, 2, the belt 3, and the like and reducing the coefficient of friction when the oil leaks. Then, the mechanism for setting the gear ratio such as the pulleys 1 and 2 and the belt 3 described above is accommodated in the casing 11 of the continuously variable transmission, so that the lubricating oil does not enter the casing 11. The so-called dry chamber 23 is sealed in a liquid-tight state with respect to the outside. The hydraulic actuator 21 is shielded from the dry chamber 23 in a liquid-tight state. In the example shown in FIGS. 1 and 2, the rotary shaft 14 is disposed on the outer surface of the casing 11 at a position extending in the axial direction. Has been. The hydraulic actuator 21 is configured such that the piston 25 moves back and forth along the central axis of the rotary shaft 14 by hydraulic pressure inside the cylinder 24 integrated with the casing 11.

  The configuration for moving the movable sheave 13 in the axial direction by the hydraulic actuator 21 will be described. The movable sheave 13 described above can be moved back and forth with respect to the rotary shaft 14 via a bush 26 disposed on the inner peripheral side thereof. And it is made to fit so that relative rotation is possible. A slide key 27 is provided between the movable sheave 13 and the rotating shaft 14. The slide key 27 is fitted into a key groove formed on the outer peripheral portion of the rotary shaft 14, while a portion protruding toward the outer peripheral side of the rotary shaft 14 is at least the longitudinal movement length of the movable sheave 13 on the inner peripheral portion of the movable sheave 13. It is inserted into a key groove 28 formed along the axial direction. Further, the rotary shaft 14 is formed along the axial direction from the end portion (the end portion on the hydraulic actuator 21 side in the example shown in FIG. 2) to the portion where the movable sheave 13 is fitted. The inserted insertion hole 29 is formed. And the long hole 30 penetrated toward the radial direction so that it may reach the outer peripheral surface of the rotating shaft 14 from this insertion hole 29 is formed. The long hole 30 is formed to extend in the axial direction at a position where it does not interfere with the above-described bush 26, slide key 27, etc., and the length thereof is set to be longer than the longitudinal movement length of the movable sheave 13.

  A rod 31 penetrating the casing 11 and connected to the piston 24 is inserted into the insertion hole 29 so as to be able to move back and forth. In addition, the part which has penetrated the casing 11 is maintained in a liquid-tight state by an appropriate seal ring 22. The distal end portion of the rod 31 extends to the long hole 30, and a connecting pin 32 projecting in the radial direction is attached to the distal end portion as shown in a sectional view in FIG. 3. The connecting pin 32 passes through the long hole 30 and is fixed to the movable sheave 13. Therefore, the rod 31 and the movable sheave 13 are connected by the connecting pin 32 so as to move together in the axial direction. These rod 31 and connecting pin 32 correspond to the connecting member in the present invention.

  When mounted on a vehicle, the hydraulic pressure supplied to the hydraulic actuator 21 is generated by driving a hydraulic pump with a power source such as an engine as in a conventional general automatic transmission for a vehicle. Can be made. Further, the supply and discharge of the hydraulic pressure to the hydraulic actuator 21 can be controlled by electrically controlling the supply solenoid valve and the discharge solenoid valve. In particular, the hydraulic actuator 21 described above is for assisting thrust when the groove width of the driven pulley 2 is rapidly narrowed to increase the winding radius of the belt 3, so that the deceleration of the vehicle is predetermined. It is preferable that the supply electromagnetic valve is opened to supply the hydraulic pressure to the hydraulic actuator 21 when the threshold value is exceeded or when the braking force is greater than a predetermined value.

  Next, the operation of the belt-type continuously variable transmission and the thrust mechanism will be described. The torque transmitted to the drive-side rotary shaft 4 causes the rotary shaft 4 and the drive pulley 1 integrated therewith to rotate. Torque is transmitted to the belt 3 wound around the pulley 1 so that the belt 3 travels. The elastic force of the coil spring 20 is constantly acting on the movable sheave 13 in the driven pulley 2, and the belt 3 is sandwiched between the movable sheave 13 and the fixed sheave 12, and the thrust corresponding to the torque is generated by the torque cam 18. Presses the movable sheave 13 toward the fixed sheave 12, and the belt 3 is also sandwiched between the movable sheave 13 and the fixed sheave 12 by the thrust. Since the facing surfaces of the sheaves 12 and 13 are tapered surfaces, a force in the direction of increasing the winding radius acts on the belt 3, and this is the tension of the belt 3. Accordingly, when the groove width in the drive pulley 1 is changed by the above-described speed change motor 10 while the belt 3 is running, the wrapping radius of the belt 3 in the drive pulley 1 changes according to the groove width. Thus, the groove width in the driven pulley 2 is expanded or reduced, and a predetermined gear ratio is set. In such shift control, for example, the target engine speed is calculated based on the running state of the vehicle, and the above-described speed change motor 10 is feedback-controlled so that the actual engine speed matches the target engine speed. Is done.

  The torque cam 18 described above generates an axial force, that is, thrust, according to the torque transmitted between the movable sheave 13 and the rotating shaft 14, so that, for example, an acceleration request for the vehicle increases and is transmitted via the belt 3. When the torque to be increased increases, the thrust for pressing the movable sheave 13 in the driven pulley 2 toward the fixed sheave 12 increases. As a result, the transmission torque capacity of the belt-type continuously variable transmission increases, so that torque is transmitted from the input-side rotating shaft 4 to the output-side rotating shaft 14 without causing the belt 3 to slip.

  When the vehicle is braked and decelerated, the gear ratio is changed to the maximum gear ratio or a gear ratio close to the maximum gear ratio in preparation for starting after the vehicle stops. This is because by increasing the groove width in the drive pulley 1, the wrapping radius of the belt 3 around the drive pulley 1 is decreased, and at the same time, the movable sheave 13 in the driven pulley 2 is rapidly moved to the fixed sheave 12 side to drive the driven pulley 2. This is performed by increasing the wrapping radius of the belt 3 with respect to. In this case, since the braking operation is performed, the torque transmitted from the input side rotary shaft 4 to the output side rotary shaft 14 is reduced, and accordingly, the distance between the movable sheave 13 and the rotary shaft 14 in the driven pulley 2 is reduced. , In other words, the torque acting on the torque cam 18 is reduced, so that the axial thrust generated by the torque cam 18 is reduced. On the other hand, if the braking force is greater than or equal to a predetermined value, or if the deceleration caused by the braking operation is greater than or equal to a predetermined threshold value, the hydraulic pressure is supplied to the hydraulic actuator 21 described above, and the piston 24 is moved to FIG. Pressure to move to the left is generated. Since the piston 24 and the movable sheave 13 in the driven pulley 2 are connected by the rod 31 and the connecting pin 32, the pressure acting on the piston 24 acts as a thrust for pressing the movable sheave 13 toward the fixed sheave 12 side. In other words, the thrust for reducing the groove width of the driven pulley 2 is assisted by the hydraulic actuator 21. As a result, as shown in the upper half of FIG. The gear ratio of the step transmission is quickly changed to a large gear ratio in preparation for starting after stopping. Therefore, the belt return at the time of so-called sudden braking or sudden deceleration toward the stop is improved.

  The thrust mechanism according to the present invention is configured to reliably generate belt return using hydraulic pressure as described above. The hydraulic actuator 21 includes the pulleys 1 and 2 and the belt 3 accommodated therein. Since the hydraulic actuator 21 and the movable sheave 13 are connected to each other by the connecting member such as the rod 31 and the connecting pin 32, the oil in the hydraulic actuator 21 is pulled out of the pulley. It can prevent or suppress adhering to 1, 2 and the belt 3 or the like. As described above, according to the thrust mechanism according to the present invention, so-called belt return can be surely generated by the hydraulic pressure, and a decrease in transmission torque capacity due to oil can be prevented or suppressed.

  Another example of the thrust mechanism according to the present invention is shown in FIGS. In the example shown here, the connecting pin 32 that connects the rod 31 and the movable sheave 13 is configured so as to function as a key for transmitting torque between the rotating shaft 14 and the movable sheave 13, and the slide described above accordingly. This is an example in which the key 27 is abolished. That is, as shown in FIGS. 4 and 5, the connecting pin 32 is formed in a thin plate shape that is long in the axial direction of the rotating shaft 14, and the connecting pin 32 moves the movable sheave 13 and the rotating shaft 14 in the respective radial directions. It penetrates and is fixed to each. The connecting pin 32 is fitted to the elongated hole 30 so as to be movable in the axial direction. Therefore, when the rotation shaft 14 and the movable sheave 13 are relatively rotated at an angle corresponding to the gap between the connection pin 32 and the inner surface of the long hole 30, the connection pin 32 and the inner surface of the long hole 30 come into contact with each other. Torque is transmitted between the rotating shaft 14 and the movable sheave 13. That is, the connecting pin 32 shown in FIG. 4 and FIG. 5 has a key for mutually restraining the rotating shaft 14 and the movable sheave 13 with respect to the rotation direction in addition to the function of transmitting the thrust by the hydraulic actuator 21 to the movable sheave 13. It has the function as.

  In this way, the connecting pin 32 is in close contact with the inner surface of the long hole 30 to transmit torque, and in that state, the connecting pin 32 may be moved in the axial direction to slide on the inner surface of the long hole 30. Therefore, the inner surface of the long hole 30 is subjected to a friction coefficient lowering process in order to make the relative sliding of the connecting pin 32 smooth and to suppress wear. The friction coefficient reduction process is a process of coating the inner surface of the long hole 30 with a self-lubricating resin, a highly wear-resistant resin, DLC (diamond-like carbon), or the like.

  When configured as shown in FIGS. 4 and 5, since the connecting pin 32 also has a function as a key, the slide key can be eliminated as shown in FIG. As a result, the number of parts arranged side by side in the axial direction is reduced, and the overall axial length of the belt-type continuously variable transmission can be shortened.

  If an actuator for assisting the thrust of the movable sheave 13 is provided outside the casing 11, the actuator may be changed from the hydraulic type described above to an electric motor or an electromagnetic actuator. With such a configuration, there is no possibility of oil influence on the pulleys 1, 2 and the belt 3, but there are parts that occupy the internal space of the casing 11 due to the increase in thrust described above. Therefore, there is an advantage that the assemblability is not impaired.

  DESCRIPTION OF SYMBOLS 3 ... Belt, 11 ... Casing, 12 ... Fixed sheave, 13 ... Movable sheave, 14 ... Rotating shaft (output shaft), 16 ... Cam member, 18 ... Torque cam, 20 ... Coil spring, 21 ... Hydraulic actuator, 23 ... Dry chamber 24 ... Cylinder, 25 ... Piston, 27 ... Slide key, 28 ... Keyway, 29 ... Insertion hole, 30 ... Long hole, 31 ... Rod, 32 ... Connecting pin.

Claims (6)

A pulley around which a belt is wound is fitted to the rotary shaft so as to move back and forth in the axial direction of the rotary shaft so as to approach and separate from the fixed sheave integrated with the rotary shaft. And a torque cam that generates a thrust force that presses the movable sheave toward the fixed sheave in accordance with torque. When the movable sheave approaches the fixed sheave, the belt is wound around the pulley. In the thrust mechanism of the dry belt type continuously variable transmission where the hanging radius increases,
A hydraulic actuator that is shielded in a liquid-tight state with respect to the dry chamber in which the fixed sheave and the movable sheave and the belt are housed, and in which a piston moves back and forth by oil pressure;
A dry type comprising: a connecting member that connects the piston and the movable sheave and causes the hydraulic sheave to act on the movable sheave as a thrust force that causes the movable sheave to approach the fixed sheave. Thrust mechanism for belt type continuously variable transmission. The dry belt type continuously variable transmission has a casing that forms the dry chamber;
The thrust mechanism of the dry belt type continuously variable transmission according to claim 1, wherein the hydraulic actuator is provided outside the casing. The hydraulic actuator is arranged such that the piston moves back and forth on an extension line of the rotating axis of the rotating shaft,
The rotating shaft is inserted from an end of the insertion hole formed to extend to the inner peripheral side of the portion where the movable sheave is fitted, and from the outer peripheral surface of the portion where the movable sheave is fitted. Having a long hole that reaches the hole and is long in the axial direction,
The connecting member includes a rod that passes through the casing and is inserted into the insertion hole so as to be movable back and forth, and a connecting pin that passes through the elongated hole and connects the rod and the movable sheave. The thrust mechanism of the dry belt type continuously variable transmission according to claim 2.   The said connection pin is comprised so that a torque may be transmitted between the said rotating shaft and the said movable sheave so that a slide may contact the inner surface of the said long hole. Thrust mechanism for dry belt type continuously variable transmission.   The thrust mechanism of the dry belt type continuously variable transmission according to claim 4, wherein a friction coefficient lowering process for reducing a friction coefficient with the connecting pin is performed on an inner surface of the elongated hole. The dry belt type continuously variable transmission is mounted on a vehicle,
The thrust for moving the movable sheave toward the fixed sheave increases when the deceleration of the vehicle is greater than or equal to a predetermined value or when the braking force of the vehicle is greater than or equal to a predetermined braking force. The thrust mechanism of the dry belt type continuously variable transmission according to any one of claims 1 to 5, wherein hydraulic pressure is supplied to the hydraulic actuator.

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