JP2013241974A - Continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress energy loss and stably maintain a hydraulic pressure in a hydraulic chamber in a continuously variable transmission controlled by hydraulic pressure.
SOLUTION: A belt including a primary hydraulic chamber 32 provided in a primary pulley 10 and a secondary hydraulic chamber 42 provided in a secondary pulley 20 that generate thrust to push movable sheaves 12 and 22 toward fixed sheaves 11 and 21. In the continuously variable transmission 5, the primary hydraulic chamber 32 and the secondary hydraulic chamber 42 are communicated with each other by oil passages 82 and 83 that form a closed circuit. The reserve hydraulic chamber 63 for sucking or discharging the pressure oil is changed and is connected to the closed circuit.
[Selection] Figure 2

Description

  The present invention relates to a continuously variable transmission that continuously changes a gear ratio, and more particularly to a continuously variable transmission in which the gear ratio is controlled by hydraulic pressure.

  For example, in Patent Document 1, in a hydraulic control device for a V-belt type continuously variable transmission, a line pressure obtained by regulating a discharge pressure from a first oil pump by a pressure regulating valve is applied to a driving pulley and a one-way valve. The structure supplied to the oil chamber of the driven pulley is disclosed. Further, in the hydraulic circuit on the pulley side closed by the one valve, a second oil pump is provided between the oil chamber of the drive pulley and the oil chamber of the driven pulley.

  Patent Document 2 discloses that in a shift control device for a belt-type continuously variable transmission, a primary oil chamber and a secondary oil chamber are connected via a hydraulic motor pump, and the hydraulic oil flowing through the hydraulic motor pump. An arrangement is disclosed in which the amount is adjusted and shifted.

  Further, in Patent Document 3, the amount of pressure oil held in the first hydraulic chamber of the first pulley is kept constant, and when pressure oil leakage occurs, the pressure held in the first hydraulic chamber. A control device for a belt-type continuously variable transmission configured to increase the amount of oil is disclosed.

JP-A-4-157256 JP 2001-330113 A JP 2010-139029 A

  The devices described in Patent Documents 1, 2, and 3 described above each supply a hydraulic pressure to narrow the belt winding groove to change the gear ratio or increase the belt clamping pressure. By discharging pressure oil from the hydraulic chamber to the drain location, the width of the belt winding groove is expanded or the belt clamping pressure is reduced. In other words, since the hydraulic pressure boosted by the oil pump is eventually discharged to the drain location that is at atmospheric pressure, when the belt winding groove is narrowed again or the clamping pressure is increased again, The pressure oil whose pressure has been increased to this pressure is supplied again. Thus, since it is the structure which discharges the pressure oil which pressure | voltage-rised, energy loss may become large.

  In addition, by disposing an oil pump between the hydraulic chambers and causing the pressure oil to flow back and forth between the hydraulic chambers, the amount of pressure oil that has been increased can be reduced. However, even if the structure of each hydraulic chamber is the same, the increase in the volume of one hydraulic chamber does not necessarily match the decrease in the volume of the other hydraulic chamber. This is considered to be caused by the deformation of the movable sheave constituting the pulley or the hydraulic chamber that applies hydraulic pressure to the movable sheave. Conventionally, no technology has been developed to cope with such deviations in the volume change of each hydraulic chamber, and there is room to develop a new technology that suppresses energy loss and stably maintains the hydraulic pressure of each hydraulic chamber. there were.

  For this reason, when the hydraulic circuit that connects the primary hydraulic chamber and the secondary hydraulic chamber is closed, the sum of the volumes of the hydraulic chambers is reduced in order to reduce the change in the amount of pressure oil in the closed circuit. There is room to consider.

  Therefore, the present invention has been made paying attention to the above technical problem, and reduces the change in the amount of pressure oil in the hydraulic circuit communicating between the hydraulic chambers, thereby reducing the energy consumed at the time of shifting. An object of the present invention is to provide a continuously variable transmission.

  In order to achieve the above object, the invention according to claim 1 is characterized in that a pair of pulleys around which a belt is wound approach a fixed sheave integrated with a rotation shaft provided in parallel with each other and the fixed sheave. A movable sheave that is fitted to move in the axial direction so as to be separated from each other, and is provided in a primary hydraulic chamber and a secondary pulley that are provided in a primary pulley that generates a thrust that pushes the movable sheave toward the fixed sheave. In the continuously variable transmission having the secondary hydraulic chamber, the primary hydraulic chamber and the secondary hydraulic chamber are communicated by a closed circuit, and the volume changes according to a deviation in the volume change amount of these hydraulic chambers. A pre-hydraulic chamber for sucking or discharging pressure oil is connected to the closed circuit.

  The invention according to claim 2 is the continuously variable transmission according to claim 1, wherein the primary hydraulic chamber and the secondary hydraulic chamber are connected via a reversible pump.

  According to a third aspect of the present invention, in the second aspect of the present invention, the preliminary hydraulic chamber is connected to the pulley provided with any one of the hydraulic chambers via a cam mechanism, and the groove width of the pulley. The continuously variable transmission is configured such that the volume is changed on the basis of a change in the speed.

  According to the first aspect of the present invention, when changing the transmission gear ratio, it is not necessary to supply new pressure oil in the closed circuit. For this reason, energy consumed by the oil pump can be reduced, and fuel consumption is improved. Can be made. Furthermore, since the pressure oil is not discharged from the closed circuit to the drain location at the time of shifting, the energy efficiency corresponding to the amount of oil that is no longer drained can be improved.

  According to the second aspect of the present invention, since the closed circuit including the primary hydraulic chamber, the secondary hydraulic chamber, and the auxiliary hydraulic chamber is formed, the reversible pump stabilizes the hydraulic pressure in the primary hydraulic chamber and the hydraulic pressure in the secondary hydraulic chamber. Can be maintained.

  According to the invention of claim 3, the force by which the pulley moves back and forth in the axial direction can be applied as the force for changing the volume of the auxiliary hydraulic chamber via the cam mechanism. That is, the volume of the auxiliary hydraulic chamber can be changed based on the mechanical force.

1 is a skeleton diagram schematically showing a power transmission path of a vehicle equipped with a belt type continuously variable transmission according to an embodiment of the present invention. It is the figure which showed typically the hydraulic device, the reserve cylinder mechanism, and cam mechanism which were connected to the belt-type continuously variable transmission. It is the figure which showed typically an example of the cam mechanism connected with the reserve cylinder mechanism and the primary pulley. FIG. 5 is a diagram showing volume changes in a primary hydraulic chamber, a secondary hydraulic chamber, and a reserve hydraulic chamber provided in a closed circuit when a gear ratio changes.

  Hereinafter, the present invention will be described based on specific examples. The continuously variable transmission according to the present invention makes a hydraulic circuit that connects a hydraulic chamber provided in a driving pulley and a hydraulic chamber provided in a driven pulley a closed circuit and a pressure in one hydraulic chamber. The gear ratio is controlled by supplying oil to the other hydraulic chamber. That is, a reversible pump configured to supply pressure oil in one hydraulic chamber to the other hydraulic chamber without changing the amount of oil in the closed circuit is provided, and a spare communicated with the hydraulic chamber of the pulley A hydraulic chamber is provided. Therefore, the oil amount in the closed circuit is made constant, the volumes of the hydraulic chambers are changed, and the speed ratio of the continuously variable transmission is changed.

  First, a belt type continuously variable transmission according to an embodiment of the present invention will be described in detail with reference to FIG. FIG. 1 is a skeleton diagram schematically showing a power transmission path of a vehicle equipped with the belt type continuously variable transmission 5 of this embodiment. The belt type continuously variable transmission 5 is disposed in a power transmission path from the power source 1 of the vehicle to the drive wheels 8. The power source 1 serving as the starting point of the power transmission path is mainly composed of an internal combustion engine such as a gasoline engine or a diesel engine or a motor, and is configured such that the output is controlled based on an output operation such as an accelerator operation. Has been. The power output from the power source 1 is transmitted to a transmission mechanism 3 such as a torque converter or a forward / reverse switching mechanism connected via an output shaft 2 of the power source 1. For example, when the transmission mechanism 3 is a forward / reverse switching mechanism, the rotational direction of the power is switched between forward and reverse by switching the rotational direction of the rotating element constituting the forward / reverse direction. A primary shaft 4, which is a rotation shaft on the input side of the belt type continuously variable transmission 5, is connected to the output side of the transmission mechanism 3, and the belt type continuously variable transmission 5 from the transmission mechanism 3 via the primary shaft 4. Power is transmitted to.

  The belt-type continuously variable transmission 5 includes a pair of primary shafts 4 and secondary shafts 6 that are parallel to each other, a primary pulley 10 that is provided on the primary shaft 4 and rotates integrally with the primary shaft 4, and a secondary shaft. An endless belt 51 is wound around a pair of pulleys that are provided at 6 and that include a secondary pulley 20 that rotates integrally with the secondary shaft 6. Specifically, a groove having a V-shaped cross section formed by an inclined surface in which the fixed sheaves 11 and 21 integrated with the shafts 4 and 6 and the movable sheaves 12 and 22 movably in the axial direction face each other ( A belt 51 is wound around the (V-groove).

  The belt 51 may be a so-called wet belt or a dry belt. For example, as the belt 51, a metal belt constituted by a plurality of elements and a laminated ring, a dry composite belt constituted by a tension band having a core wire which is a resin tension member and an element, or resin power transmission There is a rubber belt having a core wire as a part.

  The primary pulley 10 is fixedly movable with a fixed sheave 11 integrated with the primary shaft 4, and is slidably fitted in the primary shaft 4 and slidable in the axial direction so as to approach or separate from the fixed sheave 11. And a sheave 12. The fixed sheave 11 and the movable sheave 12 are formed so as to protrude in the radial direction, and surfaces facing each other are formed in a tapered shape. That is, a V-groove is formed in which the fixed sheave 11 and the movable sheave 12 face each other. A V groove formed by the fixed sheave 11 and the movable sheave 12 forms a groove width in the primary pulley 10, and a belt 51 is wound around the V groove. Therefore, when the primary pulley 10 around which the belt 51 is wound around the V groove rotates, the inclined surfaces of the sheaves 11 and 12 are frictionally engaged with each other by contact with the belt 51 to generate a frictional force. Based on this, power is transmitted from the primary pulley 10 to the belt 51.

  Further, the primary pulley 10 is provided with a hydraulic actuator 30 as a thrust applying mechanism that applies a thrust to the movable sheave 12 toward the fixed sheave 11 in the axial direction. The hydraulic actuator 30 includes a hydraulic chamber that accommodates pressure oil in a liquid-tight state, and generates a thrust that changes the groove width of the primary pulley 10 by the hydraulic pressure in the hydraulic chamber. The thrust generated by the hydraulic actuator 30 is applied to the movable sheave 12. Therefore, the hydraulic actuator 30 is configured to push the movable sheave 12 in the axial direction toward the fixed sheave 11 side by the hydraulic pressure in the hydraulic chamber. Therefore, in the primary pulley 10, the groove width of the primary pulley 10 is changed and the belt winding diameter is changed as the movable sheave 12 to which thrust is applied from the hydraulic actuator 30 moves back and forth in the axial direction. It is configured.

  The secondary pulley 10 is a fixed sheave 21 integrated with the secondary shaft 6, and a movable sheave that is fitted to the secondary shaft 6 and is slidable in the axial direction so as to approach or separate from the fixed sheave 21. 22. The fixed sheave 21 and the movable sheave 22 are formed so as to protrude in the radial direction, and the surfaces facing each other are formed in a tapered shape. That is, the V-groove is formed by the inclined surfaces where the fixed sheave 11 and the movable sheave 12 face each other. A V groove formed by the fixed sheave 21 and the movable sheave 22 forms a groove width in the secondary pulley 20, and a belt 51 is wound around the V groove. Therefore, when the belt 51 wound around the V-groove of the secondary pulley 20 operates as the primary pulley 10 rotates, the inclined surfaces of the sheaves 21 and 22 are frictionally engaged by the contact with the belt 51 to generate frictional force. And the power is transmitted from the belt 51 to the secondary pulley 20 based on the frictional force.

  Further, the secondary pulley 20 is provided with a hydraulic actuator 40 as a thrust applying mechanism that applies a thrust to the movable sheave 22 toward the fixed sheave 21 in the axial direction. The hydraulic actuator 40 includes a hydraulic chamber that accommodates pressure oil in a liquid-tight state, and generates a thrust that changes the groove width of the secondary pulley 20 by the hydraulic pressure in the hydraulic chamber. The thrust generated by the hydraulic actuator 40 is applied to the movable sheave 22. Therefore, the hydraulic actuator 40 is configured to push the movable sheave 22 in the axial direction toward the fixed sheave 21 side by the hydraulic pressure in the hydraulic chamber. Therefore, the secondary pulley 20 is configured to generate a belt clamping pressure when the movable sheave 22 to which thrust is applied from the hydraulic actuator 40 is pushed toward the fixed sheave 21 in the axial direction. The belt clamping pressure is a force that clamps the belt 51 around which the secondary pulley 20 is wound around the V-groove.

  That is, the belt-type continuously variable transmission 5 changes the belt winding diameter of the primary pulley 10 and the belt winding diameter of the secondary pulley 20 and changes the ratio of the winding diameters, thereby changing the gear ratio γ. It is comprised so that it may change continuously. As described above, the belt-type continuously variable transmission 5 in the power transmission path changes the speed ratio γ to increase or decrease the torque, and the increased or decreased torque is transmitted to the output-side secondary shaft 6. The secondary shaft 6 is connected to a drive shaft 7 and a drive wheel 8 via a differential gear (not shown). Therefore, the power after the torque increase / decrease output from the belt type continuously variable transmission 5 is transmitted to the drive wheels 8 via the secondary shaft 6 and the drive shaft 7, and a drive force is generated in the drive wheels 8.

  Although not shown, a vehicle equipped with the belt type continuously variable transmission 5 is provided with an electronic control unit (ECU) as a controller for controlling the belt type continuously variable transmission 5. This electronic control unit is composed of a processing unit (CPU), a storage unit (RAM and ROM), and a microcomputer mainly having an input / output interface.

  For the electronic control unit, the engine speed, vehicle speed, vehicle acceleration, accelerator pedal operation state, brake pedal operation state, brake pedal force, primary shaft 4 rotation speed, secondary shaft 6 rotation speed, drive shaft The sensor signal for detecting the rotational speed of 7, the rotational speed of the drive wheel 8, and the like is input. That is, the electronic control unit is configured to be able to detect an upshift request and a downshift request.

  Various data are stored in the storage device of the electronic control device together with various control programs. Therefore, a signal for controlling the belt type continuously variable transmission 5 is output from the electronic control unit based on a signal input to the electronic control unit and stored data. For example, an instruction signal obtained as a result of performing predetermined processing based on an upshift request, a downshift request, or the like is output to the belt type continuously variable transmission 5. Specifically, the hydraulic pressure or oil amount control of the hydraulic actuator 30 of the belt type continuously variable transmission 5 is performed based on the downshift request, and the hydraulic pressure in the hydraulic chamber 32 is decreased or increased to move the movable sheave 12 in the axial direction. Is moved back and forth to increase or decrease the groove width of the primary pulley 10 to downshift or upshift.

  Next, referring to FIG. 2, in the belt-type continuously variable transmission 5 that changes the gear ratio γ by controlling the hydraulic pressure in the hydraulic chamber, the primary hydraulic actuator 30 and the secondary hydraulic actuator 40 are operated. The hydraulic device to be operated will be described. FIG. 2 is a diagram schematically showing a hydraulic apparatus 100 that operates the hydraulic actuator 30 and the hydraulic actuator 40 together with a cross-sectional view of the belt-type continuously variable transmission 5. In the hydraulic device 100, the oil stored in the oil pan 106 is sucked and pressurized by the oil pump 101 and discharged to the oil passage 81, and the pressure oil pumped through the oil passage 81 is included in the hydraulic actuator 30. The primary hydraulic chamber 32 and the secondary hydraulic chamber 42 included in the hydraulic actuator 40 are supplied.

  The primary hydraulic chamber 32 is provided on the back side opposite to the inclined surface of the movable sheave 12, and is a space formed by the plunger 31 fitted to the primary shaft 4, the movable sheave 12, and the primary shaft 4. is there. The primary hydraulic chamber 32 is filled with pressure oil in a liquid-tight state by a sealing material provided between the movable sheave 12 and the plunger 31 and a sealing material provided between the movable sheave 12 and the primary shaft 4. It is sealed to be. That is, the primary hydraulic chamber 32 is formed in a piston structure so that the volume in the primary hydraulic chamber 32 is changed and the amount of pressure oil filled in the primary hydraulic chamber 32 is changed.

  The secondary hydraulic chamber 42 is provided on the back side opposite to the inclined surface of the movable sheave 22, and is a space formed by the plunger 41 fitted to the secondary shaft 6, the movable sheave 22, and the secondary shaft 6. It is. The secondary hydraulic chamber 42 is filled with pressure oil in a liquid-tight state by a sealing material provided between the movable sheave 22 and the plunger 41 and a sealing material provided between the movable sheave 22 and the secondary shaft 6. It is sealed to be. That is, the secondary hydraulic chamber 42 is formed in a piston structure, and is configured so that the volume in the secondary hydraulic chamber 42 can be changed and the amount of pressure oil filled in the secondary hydraulic chamber 42 can be changed. Note that an elastic body such as a coil spring that biases the movable sheave 22 in the axial direction may be provided in the secondary hydraulic chamber 42.

  Therefore, in the hydraulic circuit formed by the hydraulic apparatus 100, the oil pump 101 is a supply source of pressure oil. The oil pump 101 is driven based on the rotational movement of the output shaft 2, or is driven based on an output from a driving source different from the power source 1 for driving the oil pump 101 such as an electric motor, A suction port for sucking the stored oil and a discharge port for discharging the pressure oil raised in pressure in the oil passage 81 are provided. Specifically, the oil sucked into the oil pump 101 from the suction port is boosted to the discharge pressure based on the change in the volume of the gap as a rotating member such as a gear or rotor provided in the oil pump 101 rotates. It is pumped to the path 81.

  The hydraulic circuit is provided with a pressure increasing valve 102 and a pressure reducing valve 103 as control valves that function as pressure control valves. The pressure increasing valve 102 is provided between an oil passage 81 on the oil pump 101 side and an oil passage 82 on the belt-type continuously variable transmission 5 side, and pressure oil on the relatively high-pressure oil passage 81 side is supplied to the oil passage 82. It is configured to supply. Note that a line pressure valve (not shown) is provided in the oil passage 81, that is, between the oil pump 101 and the pressure increasing valve 102, and the hydraulic pressure adjusted to the line pressure by the line pressure valve is supplied to the pressure increasing valve 102. It may be configured as follows.

  On the other hand, the pressure reducing valve 103 is provided between the oil passage 82 on the belt-type continuously variable transmission 5 side and the oil passage 84 on the oil pan 106 side, and the oil pressure on the oil passage 82 side is relatively high. It is configured to discharge. The oil passage 84 connected to the discharge port of the pressure reducing valve 103 communicates with the oil pan 106, and the pressure oil discharged from the pressure reducing valve 103 flows through the oil passage 84 and is stored in the oil pan 106. It is configured as follows.

  The pressure increasing valve 102 and the pressure reducing valve 103 functioning as control valves in the hydraulic circuit are configured to be able to control the valve opening operation or the valve closing operation. For example, the operation of the on-off valve is electrically controlled, and the valve closing state or the valve opening state can be maintained regardless of the oil pressure in the hydraulic circuit. Accordingly, by closing the pressure increasing valve 102 and the pressure reducing valve 103, the hydraulic circuit on the belt type continuously variable transmission 5 side can be closed from the pressure increasing valve 102 and the pressure reducing valve 103. . That is, the amount of pressurized oil in the closed circuit can be kept constant. Specifically, the amount of oil in the closed circuit formed by the oil passage 83 connected to the hydraulic actuator 30 of the primary pulley 10 and the oil passage 82 connected to the hydraulic actuator 40 of the secondary pulley 20 is constant. It is configured to be able to keep. In addition, since the hydraulic apparatus 100 in this embodiment is in a state where there is no leakage from the constituent members forming the closed circuit, the amount of pressure oil in the closed circuit is assumed to be constant.

  The oil passage 82 on the belt type continuously variable transmission 5 side is configured to communicate with the secondary hydraulic chamber 42. In the hydraulic circuit, an oil passage 83 is provided as an oil passage on the belt-type continuously variable transmission 5 side and connected to the oil passage 82 and formed to communicate with the primary hydraulic chamber 32. That is, as illustrated in FIG. 2, the oil passage 82 communicated with the secondary hydraulic chamber 42 and the oil passage 83 communicated with the primary hydraulic chamber 32 are connected via the reversible pump 104.

  The reversible pump 104 is driven based on the output from the motor 105 that is the drive source of the reversible pump 104, and at least one of the two ports is connected to the oil passage 83 on the primary hydraulic chamber 32 side, The other port is configured to be connected to an oil passage 82 on the secondary hydraulic chamber 42 side. In other words, the hydraulic device 100 is configured such that pressure oil is reversibly discharged to the oil passage 82 on the secondary hydraulic chamber 42 side and the oil passage 83 on the primary hydraulic chamber 32 side by the reversible pump 104.

  For example, the pressure oil sucked from one of the ports serving as the suction port is rotated from the other port serving as the discharge port based on a change in the volume of the gap as a rotating member such as a gear or a rotor included in the reversible pump 104 rotates. It is configured to be discharged. Further, the reversible pump 104 is configured to close the port by stopping the driving of the motor 105 so as to block the oil passage 83 on the primary hydraulic chamber 32 side and the oil passage 82 on the secondary hydraulic chamber 42 side. It is configured. Therefore, the oil passage 82 and the oil passage 82 closed by the pressure increasing valve 102 and the pressure reducing valve 103 are configured to be connected or disconnected by the reversible pump 104. The motor 105 only needs to have a configuration that can be driven and controlled, and may be a drive source for the reversible pump 104.

  In addition, a reserve cylinder mechanism 60 configured to change the volume of the reserve hydraulic chamber 63 formed by the cylinder 61 and the piston 62 is connected to the oil passage 83 on the primary hydraulic chamber 32 side. That is, the primary hydraulic chamber 32 and the auxiliary hydraulic chamber 63 are communicated with each other by the oil passage 83. Therefore, the auxiliary hydraulic chamber 63 is configured to be connected to or disconnected from the secondary hydraulic chamber 42 via the reversible pump 104.

  Further, the reserve cylinder mechanism 60 is connected to the primary pulley 10 via the cam mechanism 70, and a load that changes the volume of the reserve hydraulic chamber 63 from the cam mechanism 70 based on the change in the groove width of the primary pulley 10. It is configured to be acted on. Specifically, the cam mechanism 70 is configured to operate based on the movement of the movable sheave 12 of the primary pulley 10 that moves back and forth in the axial direction.

  Here, with reference to FIG. 3, it demonstrates based on the specific example of the cam mechanism 70. FIG. FIG. 3 is a diagram schematically illustrating an example of the cam mechanism 70. The cam mechanism 70 is configured so that a connecting member 76 that is integrally connected to the movable sheave 12 and a cam 73 that is connected via a bearing 75 can rotate relative to the movable sheave 12. That is, the cam 73 receives the movement of the movable sheave 12 moving back and forth in the axial direction via the connecting member 76, and moves back and forth in the axial direction together with the movable sheave 12.

  The cam 73 is formed with an inner peripheral cam surface 73a and an outer peripheral cam surface 73b with which the cam follower 71 connected to the connecting member 72 abuts. The cam surface 73a is formed with a convex cross section, and acts on the connecting member 72 in the radial direction toward the outer peripheral side. The cam surface 73b is formed with a concave cross section, and the connecting member 72 is radially inward. It is comprised so that the load which goes to the circumference side may act. That is, the cam 73 connected via the connecting member 76 based on the movable sheave 12 moving back and forth in the axial direction moves back and forth in the axial direction, and the connecting member 72 moves back and forth in the radial direction via the cam follower 71. Be made. In other words, the connecting member 72 is configured to function as a driven node according to the movement of the cam 73.

  The connecting member 72 is connected to a piston 62 that changes the volume of the auxiliary hydraulic chamber 63. In the preliminary cylinder mechanism 60 illustrated in FIG. 3, the cylinder 61 is fixed to a case (not shown). Therefore, the volume of the auxiliary hydraulic chamber 63 is changed based on the change in the groove width of the primary pulley 10. Although not illustrated, as a modification of the preliminary cylinder mechanism 60, when the cylinder 61 is configured to move back and forth in the radial direction, the connecting member 72 may be connected to the cylinder 61. That is, the cylinder 61 may be configured to slide on the piston 62 fixed to the housing or the like to change the volume of the preliminary hydraulic chamber 63 based on the back and forth movement of the connecting portion 72 in the radial direction. .

  For example, when the cam follower 71 and the connecting member 72 are operated by a load from the cam surface 73a of the cam 73, the connecting member 72 is moved outward in the radial direction, and the volume of the auxiliary hydraulic chamber 63 is reduced. That is, a load for discharging the pressure oil in the auxiliary hydraulic chamber 63 to the oil passage 83 is applied to the auxiliary cylinder mechanism 60 from the movable sheave 12 via the cam mechanism 70. Note that the load acting on the auxiliary cylinder mechanism 60 from the cam surface 73a via the connecting member 72 is not limited to the case of acting to decrease the volume of the auxiliary hydraulic chamber 63, but the volume of the auxiliary hydraulic chamber 63 increases. You may act so that it may suppress.

  On the other hand, when the cam follower 71 and the connecting member 72 are operated by a load from the cam surface 73b of the cam 73, the connecting member 72 is moved inward in the radial direction, and the volume of the auxiliary hydraulic chamber 63 is increased. That is, a load for sucking the pressure oil in the oil passage 83 from the movable sheave 12 through the cam mechanism 70 into the auxiliary hydraulic chamber 63 is applied to the auxiliary cylinder mechanism 60. The cam 73 may be formed on the outer peripheral side of the movable sheave 12 over the entire circumference, or may be configured to be slidable in the axial direction by a rail 74 provided at a predetermined location. That is, the cam surfaces 73 a and 73 b may be formed so as to surround the outer peripheral side of the primary pulley 10. Further, the cam follower 71 may be configured to come into contact with the cam surfaces 73a and 73b while rotating as the cam 73 moves back and forth in the axial direction.

  Next, referring to FIG. 4, when the hydraulic circuit including the secondary side oil passage 82 and the primary side oil passage 83 is a closed circuit, the transmission ratio γ and the volumes of the hydraulic chambers 32, 42, and 63 are determined. The relationship with change will be described. Here, a description will be given assuming that the volume of the primary hydraulic chamber 32 is the volume A, the volume of the secondary hydraulic chamber 42 is the volume B, and the volume of the auxiliary hydraulic chamber 63 is the volume C. Further, since the amount of pressure oil in the closed circuit is kept constant in a state where there is no leakage, as illustrated in FIG. 4, the volume S which is the sum of the volumes of all the hydraulic chambers 32, 42, 63 is In a fixed state, the volumes A, B, and C of the hydraulic chambers 32, 42, and 63 change in volume.

  When the gear ratio γ is decreased from a relatively large gear ratio to a small gear ratio, the belt winding diameter of the primary pulley 10 is increased and the belt winding diameter of the secondary pulley 20 is reduced. Therefore, the volume A of the primary hydraulic chamber 32 is increased to narrow the groove width of the primary pulley 10, and the volume B of the secondary hydraulic chamber 42 is decreased to increase the groove width of the secondary pulley 20. That is, the reversible pump 104 is driven so as to circulate the pressure oil from the oil passage 82 to the oil passage 83 so as to send the pressure oil in the secondary hydraulic chamber 42 into the primary hydraulic chamber 32.

  On the other hand, when the speed ratio γ is increased from a relatively small speed ratio to a large speed ratio, the belt winding diameter of the primary pulley 10 is reduced and the belt winding diameter of the secondary pulley 20 is increased. Accordingly, since the groove width of the primary pulley 10 is enlarged, the volume A of the primary hydraulic chamber 32 is reduced, and the groove width of the secondary pulley 20 is reduced, so that the volume B of the secondary hydraulic chamber 42 is increased. That is, the reversible pump 104 is driven so as to circulate the pressure oil from the oil passage 83 to the oil passage 82 so as to send the pressure oil in the primary hydraulic chamber 32 into the secondary hydraulic chamber 42.

  As illustrated in FIG. 4, the total volume (A + B) of the volume A of the primary hydraulic chamber 32 and the volume B of the secondary hydraulic chamber 42 changes as the speed ratio γ is changed. The total volume (A + B) changes as a result of deviations in the volume changes of the hydraulic chambers 32 and 42 in accordance with the gear ratio γ. Specifically, when changing the gear ratio γ, the belt winding diameter of the primary pulley 10 and the belt winding diameter of the secondary pulley 20 are different, so that the stroke change amount of the movable sheave 12 and the stroke of the movable sheave 22 are different. Deviation from the amount of change occurs. The stroke change amount is a distance that the movable sheaves 12 and 22 move in the axial direction when the speed ratio γ of the belt type continuously variable transmission 5 is changed from one speed ratio to another speed ratio. Note that there may be a deviation in the amount of volume change due to deformation of the hydraulic chambers 32 and 42.

  Therefore, when shifting from a predetermined gear ratio toward the gear ratio γ = 1, as illustrated in FIG. 4, the volume change amount ΔA of the primer hydraulic chamber 32 and the volume change amount ΔB of the secondary hydraulic chamber 42 Deviation decreases. That is, the volume C of the auxiliary hydraulic chamber 63 decreases. On the other hand, when the speed ratio γ is increased or decreased from the speed ratio γ = 1, the deviation between the volume change amount ΔA of the primary hydraulic chamber 32 and the volume change amount ΔB of the secondary hydraulic chamber 42 increases. Therefore, since the total volume (A + B) of the volume A of the primary hydraulic chamber 32 and the volume B of the secondary hydraulic chamber 42 changes as the speed ratio γ changes, the difference in the total volume (A + B) is corrected. The volume C of the auxiliary hydraulic chamber 63 is increased or decreased.

The volume C of the reserve hydraulic chamber 63 is changed so that the minimum volume C _min is obtained when the gear ratio γ = 1 and the maximum volume C _max is obtained when the gear ratio γ _max or γ _min . Therefore, the maximum volume _{B max} and the same volume of the maximum volume _{A max} and the secondary hydraulic chamber 42 of the primary hydraulic chamber 32, the minimum volume _{B min} and the same volume of minimum volume _{A min} and the secondary hydraulic chamber 42 of the primary hydraulic chamber 32 It is comprised so that. When the gear ratio γ = 1, the volume A of the primary hydraulic chamber 32 and the volume B of the secondary hydraulic chamber 42 are the same, and the total volume (A + B) is the maximum total volume (A + B) _max .

In other words, when the movable sheave 12 slides away from the fixed sheave 11 as the hydraulic pressure in the primary hydraulic chamber 32 decreases, the spare cylinder mechanism 60 moves from the cam mechanism 70 to the predetermined speed ratio range X. In this case, a load for reducing the volume of the auxiliary hydraulic chamber 63 is applied, and a load for increasing the volume of the auxiliary hydraulic chamber 63 is applied in a gear ratio range Y different from the predetermined gear ratio range X. That is, even when the hydraulic pressure in the primary oil passage 83 decreases, a load that causes the hydraulic oil in the oil passage 83 to be sucked into the auxiliary hydraulic chamber 63 is applied to the auxiliary hydraulic chamber 63 via the cam mechanism 70. The volume can be increased. For example, the speed ratio range X is the minimum speed ratio γ _min ≦ X <1, and the speed ratio range Y is 1 <Y ≦ the maximum speed ratio γ _max .

  On the other hand, when the movable sheave 12 slides in the direction approaching the fixed sheave 11 as the hydraulic pressure in the primary hydraulic chamber 32 increases, the reserve cylinder mechanism 60 moves from the cam mechanism 70 in a different gear ratio range Y. A load that reduces the volume of the auxiliary hydraulic chamber 63 is applied, and a load that suppresses an increase in the volume of the auxiliary hydraulic chamber 63 is applied in the predetermined gear ratio range X. That is, even when the oil pressure of the primary side oil passage 83 increases, a load is applied to discharge the pressure oil in the auxiliary hydraulic chamber 63 to the oil passage 83 via the cam mechanism 70, and in a certain gear ratio range. The spare hydraulic chamber 63 is configured so that the volume thereof can be reduced.

  The belt-type continuously variable transmission according to the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the object of the present invention. For example, the belt type continuously variable transmission according to the present invention may be a wet type belt type continuously variable transmission or a dry type belt type continuously variable transmission.

  DESCRIPTION OF SYMBOLS 1 ... Power source, 4 ... Primary shaft, 5 ... Belt type continuously variable transmission, 6 ... Secondary shaft, 10 ... Primary pulley, 20 ... Secondary pulley, 30 ... Hydraulic actuator, 32 ... Primary hydraulic chamber, 40 ... Hydraulic actuator, 42 ... Secondary hydraulic chamber, 51 ... Belt, 60 ... Preliminary cylinder mechanism, 61 ... Cylinder, 62 ... Piston, 63 ... Preliminary hydraulic chamber, 70 ... Cam mechanism, 71 ... Cam follower, 72 ... Connecting member, 73 ... Cam, 81, DESCRIPTION OF SYMBOLS 82,83 ... Oil path, 100 ... Hydraulic device, 101 ... Oil pump, 102 ... Pressure increasing valve, 103 ... Pressure reducing valve, 104 ... Reversible pump, 105 ... Motor.

Claims (3)

A pair of pulleys around which a belt is wound are a fixed sheave integrated with a rotation shaft provided in parallel with each other, and a movable fitting fitted so as to move in the axial direction so as to approach or separate from the fixed sheave. In a continuously variable transmission that includes a primary hydraulic chamber provided in a primary pulley and a secondary hydraulic chamber provided in a secondary pulley, each of which includes a sheave, and that generates a thrust that pushes the movable sheave toward the fixed sheave.
The primary hydraulic chamber and the secondary hydraulic chamber are communicated by a closed circuit,
A continuously variable transmission, wherein a spare hydraulic chamber that changes its volume in accordance with a deviation of a change in volume of these hydraulic chambers and sucks or discharges pressure oil is connected to the closed circuit.   The continuously variable transmission according to claim 1, wherein the primary hydraulic chamber and the secondary hydraulic chamber are connected via a reversible pump.   The preliminary hydraulic chamber is connected to the pulley provided with any one of the hydraulic chambers via a cam mechanism, and the volume is changed based on a change in the groove width of the pulley. The continuously variable transmission according to claim 2, wherein the continuously variable transmission is provided.

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