JP6943204B2 - Power transmission device - Google Patents

Description

The present invention relates to a power transmission device.

In Patent Document 1, as a power transmission device, a first power transmission path for transmitting power by meshing gears and a second power transmission path for transmitting power by a belt-type continuously variable transmission are provided in parallel. Things are disclosed. Further, this power transmission device is for belt traveling which is engaged when power is transmitted by the first power transmission path with a gear traveling clutch and a synchro mechanism which are engaged when power is transmitted by the second power transmission path. It has a clutch.

In addition, the hydraulic control circuit of the belt-type stepless transmission includes an SLP solenoid valve for adjusting the primary sheave pressure, which is the hydraulic pressure for adjusting the gear ratio to be supplied to the movable sheave of the primary pulley, and the movable sheave of the secondary pulley. It is provided with an SLS solenoid valve for adjusting the secondary sheave pressure, which is the hydraulic pressure for adjusting the belt pinching pressure supplied to the engine. Further, the oil pressure for switching the engagement and disengagement of the lockup clutch is adjusted by the SLU solenoid valve, and the synchronization engagement pressure for switching the engagement and disengagement of the synchronization mechanism is adjusted by the SLG solenoid valve. It is said. Further, the SLP solenoid valve is connected to a sequence valve capable of switching between a normal position and a failure position via an oil passage.

Then, in the power transmission device disclosed in Patent Document 1, when there is a request to switch the sequence valve, the sequence valve is switched to the failure position by the SLP solenoid valve, and the output of the SLP solenoid valve is increased. It is disclosed that the primary sheave pressure is adjusted by the SLG solenoid valve.

Japanese Unexamined Patent Publication No. 2017-048898

However, since the SLG solenoid valve also controls the synchro engagement pressure at the same time, if the oil pressure of the SLG solenoid valve is lowered in order to adjust the primary sheave pressure, an engagement failure of the synchro mechanism may occur.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a power transmission device capable of achieving both reduction of primary sheave pressure and engagement of a synchronization mechanism.

In order to solve the above-mentioned problems and achieve the object, the power transmission device according to the present invention comprises a torque converter having a lockup clutch that transmits power from a drive source via a hydraulic oil, and the torque converter. The first power transmission path for transmitting the power of the above to the output shaft via the gear mechanism and the first power transmission path are provided in parallel, and the power from the torque converter is transmitted via a belt-type stepless transmission. A power transmission including a second power transmission path for transmitting to the output shaft, a first clutch and a synchronization mechanism for connecting and disconnecting the first power transmission path, and a second clutch for connecting and disconnecting the second power transmission path. In the apparatus, at least the SLP solenoid valve capable of supplying the primary sheave pressure to the primary pulley of the stepless transmission, the SLG solenoid valve capable of supplying at least the engagement pressure to the synchronization mechanism, and the SLP solenoid valve are supplied. A sequence valve capable of switching between a normal position and a failure position by flood control is provided, and when there is a request to switch the sequence valve to the failure position, the synchronization mechanism by the SLG solenoid valve is provided. After the engagement is completed, the sequence valve is switched to the failure position by the SLP solenoid valve, and the primary sheave pressure is reduced by the SLG solenoid valve within a range in which the synchronization mechanism is not released. It is a feature.

In the power transmission device according to the present invention, a high pressure is required for the engagement of the synchro mechanism, but a low pressure is also possible for maintaining the engaged state. Therefore, in order to adjust the primary sheave pressure. Even if the oil pressure of the SLG solenoid valve is lowered, the engaged state of the synchronization mechanism can be maintained. As a result, it is possible to achieve both the reduction of the primary sheave pressure and the engagement of the synchro mechanism.

FIG. 1 is a skeleton diagram showing a schematic configuration of a power transmission device according to an embodiment. FIG. 2 is a block diagram showing a power transmission device and an engine control system. FIG. 3 is a flowchart showing a procedure for hydraulic control when the SLU solenoid valve fails.

Hereinafter, an embodiment of the power transmission device according to the present invention will be described. The present invention is not limited to the present embodiment.

FIG. 1 is a skeleton diagram showing a schematic configuration of a power transmission device 1 according to an embodiment. The power transmission device 1 transmits torque (power) from the engine 2, which is a driving force source for traveling, toward the drive wheels 7L and 7R. The power transmission device 1 includes a torque converter 3, a forward / backward switching device 4, a belt-type continuously variable transmission 5, a gear mechanism 6, an output shaft 8 provided with an output gear 81, a differential device 9, and the like.

The power transmission device 1 is provided in parallel with a first power transmission path that transmits power by meshing gears and a second power transmission path that transmits power by a continuously variable transmission 5. Specifically, in the first power transmission path, the torque output from the engine 2 is input to the turbine shaft 31 via the torque converter 3, and this torque is transmitted from the turbine shaft 31 to the forward / backward switching device 4 and the gear mechanism 6. It is transmitted to the output shaft 8 via the output shaft 8. On the other hand, in the second power transmission path, the torque input to the turbine shaft 31 is transmitted to the output shaft 8 via the continuously variable transmission 5. Then, the power transmission path is switched between the first power transmission path and the second power transmission path according to the traveling state of the vehicle.

The engine 2 is, for example, a multi-cylinder gasoline engine, and is configured to be capable of outputting a driving force for traveling. The engine 2 can control operating states such as a throttle opening (intake air amount), a fuel injection amount, and an ignition timing of a throttle valve provided in an intake passage.

The torque converter 3 includes a pump impeller 32 connected to the crankshaft of the engine 2 and a turbine impeller 33 connected to the forward / reverse switching device 4 via the turbine shaft 31. Further, the torque converter 3 is provided with a lockup clutch 34, and the pump impeller 32 and the turbine impeller 33 rotate integrally when the lockup clutch 34 is completely engaged.

The forward / backward switching device 4 includes a forward clutch (gear traveling clutch) C1, a reverse brake B1, and a double pinion type planetary gear device 41. The carrier 42 of the planetary gear device 41 is integrally connected to the turbine shaft 31 and the input shaft 51 of the continuously variable transmission 5, the ring gear 43 is selectively connected to the housing 11 via the reverse brake B1, and the sun gear 44 is It is connected to the small diameter gear 61. Further, the sun gear 44 and the carrier 42 are selectively connected via the forward clutch C1. The forward clutch C1 and the reverse brake B1 are both hydraulic friction engagement elements that are frictionally engaged by a hydraulic actuator.

The gear mechanism 6 includes a small-diameter gear 61 and a large-diameter gear 63 that meshes with the small-diameter gear 61 and is provided on the first counter shaft 62 so as to be relatively non-rotatable. An idler gear 64 is provided around the same rotation axis as the first counter shaft 62 so as to be rotatable relative to the first counter shaft 62. Further, a synchronization mechanism S1 for selectively connecting and disconnecting the first counter shaft 62 and the idler gear 64 is provided. The synchronization mechanism S1 includes a first gear 65 formed on the first counter shaft 62, a second gear 66 formed on the idler gear 64, and a spline capable of meshing with the first gear 65 and the second gear 66. It includes a toothed hub sleeve 67. By fitting the hub sleeve 67 with the first gear 65 and the second gear 66, the first counter shaft 62 and the idler gear 64 are connected.

The idler gear 64 is meshed with an input gear 68 having a diameter larger than that of the idler gear 64. The input gear 68 is provided so as not to rotate relative to the output shaft 8 arranged on the rotation axis common to the rotation axis of the secondary pulley 53 of the continuously variable transmission 5. The output shaft 8 is rotatably arranged around the center of the rotation shaft, and the input gear 68 and the output gear 81 are provided so as to be relatively non-rotatable. When the forward clutch C1 and the synchro mechanism S1 are both engaged and the belt traveling clutch C2 described later is released, the torque of the engine 2 passes through the turbine shaft 31, the forward / backward switching device 4 and the gear mechanism 6. Then, the first power transmission path transmitted to the output shaft 8 is formed.

The continuously variable transmission 5 is provided on a power transmission path between the input shaft 51 and the output shaft 8 connected to the turbine shaft 31. The continuously variable transmission 5 is a transmission belt wound between the primary pulley 52, which is an input side member provided on the input shaft 51, the secondary pulley 53, which is an output side member, and the primary pulley 52 and the secondary pulley 53. 54 is provided, and power is transmitted via a frictional force between the primary pulley 52 and the secondary pulley 53 and the transmission belt 54.

The primary pulley 52 has a fixed sheave 52a fixed to the input shaft 51, a movable sheave 52b provided so as not to rotate relative to the input shaft 51 and to move in the axial direction, and between them. It is provided with a primary side hydraulic actuator 52c that generates a thrust for moving the movable sheave 52b in order to change the V-groove width. Further, the secondary pulley 53 has a fixed sheave 53a, a movable sheave 53b provided so that it cannot rotate relative to the fixed sheave 53a and can move in the axial direction, and a V-groove width between them. It includes a secondary hydraulic actuator 53c that generates thrust to move the movable sheave 53b to change.

In the continuously variable transmission 5, the actual gear ratio γ can be continuously changed by changing the V-groove width of the primary pulley 52 and the secondary pulley 53 and changing the hook diameter (effective diameter) of the transmission belt 54. It has become.

Further, a belt traveling clutch C2 is provided between the continuously variable transmission 5 and the output shaft 8 to selectively disconnect and disconnect between them. The belt traveling clutch C2 is a hydraulic friction engagement element that is frictionally engaged by a hydraulic actuator. When the belt traveling clutch C2 is engaged and the forward clutch C1 is released, the torque of the engine 2 is transmitted to the output shaft 8 via the input shaft 51 and the continuously variable transmission 5. 2 Power transmission paths are formed.

The output gear 81 is meshed with a large diameter gear 92 fixed to the second counter shaft 91. The second counter shaft 91 is provided with a small diameter gear 94 that meshes with the differential ring gear 93 of the differential device 9. The differential device 9 is composed of a well-known differential mechanism.

Then, in the vehicle equipped with the power transmission device 1, gear traveling in which power is transmitted via the first power transmission path and belt traveling in which power is transmitted via the second power transmission path can be performed. It is possible.

When the gear is running, the forward clutch C1 and the synchronization mechanism S1 are engaged, and the belt running clutch C2 and the reverse brake B1 are released.

Specifically, when the forward clutch C1 is engaged, the carrier 42 of the planetary gear device 41 and the sun gear 44 rotate integrally. As a result, the small diameter gear 61 rotates at the same rotation speed as the turbine shaft 31. Further, when the synchronization mechanism S1 is engaged, the first counter shaft 62 and the idler gear 64 are connected and rotate integrally. Therefore, the first power transmission path is established by engaging the forward clutch C1 and the synchro mechanism S1, and the torque of the engine 2 is the torque converter 3, the turbine shaft 31, the forward / backward switching device 4, the gear mechanism 6, and the like. It is transmitted to the output shaft 8 and the output gear 81 via the idler gear 64 and the input gear 68. Further, the torque transmitted to the output gear 81 is transmitted to the left and right drive wheels 7L and 7R via the large diameter gear 92, the small diameter gear 94, and the differential device 9.

Here, gear running is selected in the low vehicle speed region. The gear ratio when power is transmitted by the first power transmission path is set to a value larger than the maximum gear ratio γmax of the continuously variable transmission 5. That is, the gear ratio in the first power transmission path is set to a value that does not hold in the continuously variable transmission 5. Then, when the vehicle speed V is increased and the vehicle speed is removed from the low vehicle speed region, the belt traveling is switched to.

When the belt travels, the belt traveling clutch C2 is engaged, and the forward clutch C1, the reverse brake B1 and the synchronization mechanism S1 are released.

Specifically, since the secondary pulley 53 and the output shaft 8 are connected by engaging the belt traveling clutch C2, the secondary pulley 53, the output shaft 8 and the output gear 81 rotate integrally. Therefore, the second power transmission path is established by engaging the belt traveling clutch C2, and the torque of the engine 2 passes through the torque converter 3, the turbine shaft 31, the input shaft 51, and the continuously variable transmission 5. It is transmitted to the output shaft 8 and the output gear 81. Further, the torque transmitted to the output gear 81 is transmitted to the left and right drive wheels 7L and 7R via the large diameter gear 92, the small diameter gear 94 and the differential device 9.

When moving backward, the reverse brake B1 and the synchronization mechanism S1 are engaged, and the belt traveling clutch C2 and the forward clutch C1 are released. In this case, since the small diameter gear 61 is rotated in the direction opposite to the rotation direction of the turbine shaft 31, the reverse rotation is caused by the left and right drive wheels 7L via the gear mechanism 6, the idler gear 64, the input gear 68, and the like. It is transmitted to 7R.

FIG. 2 is a block diagram showing a control system of the power transmission device 1 and the engine 2. The ECU 100 includes, for example, a so-called microprocessor including a CPU, ROM, RAM, an input / output interface, and the like. The ECU 100 executes output control of the engine 2, gear ratio control of the continuously variable transmission 5, belt pinching pressure control, control of switching the power transmission path of the power transmission device 1, and the like.

The ECU 100 has a signal representing the engine rotation speed Ne, which is the rotation speed of the engine 2 per unit time detected by the engine rotation speed sensor 110, and the rotation of the primary pulley 52 detected by the primary rotation speed sensor 111 per unit time. A signal representing the primary rotation speed Nin, which is a number, a signal representing the secondary rotation speed Nss, which is the rotation speed per unit time of the secondary pulley 53 detected by the secondary rotation speed sensor 112, and a signal detected by the output shaft rotation speed sensor 113. A signal representing the output shaft rotation speed Now, which is the number of rotations of the output shaft 8 corresponding to the vehicle speed V per unit time, a signal representing the throttle opening θth of the throttle valve detected by the throttle sensor 114, and an accelerator opening sensor 115. A signal indicating the accelerator opening Acc, which is the amount of operation of the accelerator pedal as the detected acceleration request amount of the driver, and the brake-on-bon indicating the state in which the foot brake, which is a regular brake detected by the foot brake switch 116, is operated. A signal representing the above, a signal representing the lever position Psh of the shift lever detected by the lever position sensor 117, and the like are supplied. Further, the ECU 100 sequentially calculates the actual gear ratio γ (Nin / Nss) established in the continuously variable transmission 5 based on, for example, the primary rotation speed Nin and the secondary rotation speed Nss.

Further, from the ECU 100, the engine output control command signal Se for output control of the engine 2, the hydraulic control command signal Scvt for hydraulic control related to the shift of the continuously variable transmission 5, and the power transmission path of the power transmission device 1 are switched. A forward / backward switching device 4 (forward clutch C1, reverse brake B1), a belt traveling clutch C2, a synchro mechanism S1, a hydraulic control command signal Sswt to the lockup clutch 34, and the like are output.

Specifically, as the engine output control command signal Se, a throttle signal for controlling the opening and closing of the throttle valve of the engine 2, an injection signal for controlling the amount of fuel injected from the injector, and ignition of the spark plug. An ignition timing signal or the like for controlling the timing is output.

Further, as the hydraulic control command signal Scvt, a command signal for driving an SLP solenoid valve (not shown) for adjusting the primary sheave pressure supplied to the primary side hydraulic actuator 52c and a secondary sheave pressure supplied to the secondary side hydraulic actuator 53c are used. A command signal or the like for driving the SLS solenoid valve (not shown) for adjusting the pressure is output to the flood control circuit 12.

The primary sheave pressure is a flood control for adjusting the gear ratio of the continuously variable transmission 5. The secondary sheave pressure is a flood control for adjusting the belt pinching pressure. That is, in the gear ratio control of the continuously variable transmission 5, the gear ratio γ of the continuously variable transmission 5 is controlled so as to be a target gear ratio calculated based on the accelerator opening degree Acc, the vehicle speed V, and the like. At this time, the primary sheave pressure and the secondary sheave pressure so as to achieve the target gear ratio of the continuously variable transmission 5 in which the operating point of the engine 2 is on the optimum fuel consumption line while preventing the belt slip of the continuously variable transmission 5 from occurring. Is regulated. From the ECU 100, a command signal of the primary instruction hydraulic pressure for achieving the target primary sheave pressure and a command signal of the secondary instruction hydraulic pressure for achieving the target secondary sheave pressure are output to the hydraulic control circuit 12. Then, the SLP solenoid valve operates according to the command signal of the primary instruction hydraulic pressure, and the SLS solenoid valve operates according to the command signal of the secondary instruction hydraulic pressure.

Further, as the hydraulic control command signal Sswt, each linear solenoid valve that controls the hydraulic pressure supplied to the hydraulic actuators of the forward clutch C1, the reverse brake B1, the belt traveling clutch C2, the synchro mechanism S1 and the lockup clutch 34 is used. A command signal or the like for driving is output to the flood control circuit 12.

The hydraulic control circuit 12 includes, for example, an SL1 solenoid valve that controls the operation of the forward clutch C1, an SL2 solenoid valve that controls the operation of the belt traveling clutch C2, an SLG solenoid valve that controls the operation of the synchronization mechanism S1. It includes a sequence valve that can switch between the normal side, which is the normal position, and the fail side, which is the failure position.

The SL1 solenoid valve is provided for adjusting the hydraulic pressure for switching the engagement and disengagement of the forward clutch C1 and operates in response to a command signal output from the ECU 100. The SL2 solenoid valve is provided for adjusting the hydraulic pressure for switching the engagement and disengagement of the belt traveling clutch C2, and operates in response to a command signal output from the ECU 100. The SLG solenoid valve is provided for adjusting the hydraulic pressure for switching the engagement and disengagement of the synchronization mechanism S1, and operates in response to a command signal output from the ECU 100. The sequence valve is provided to secure the limp home.

For example, if the SLU solenoid valve fails on the side that engages the lockup clutch 34, the engine may stall when the vehicle is stopped. Therefore, hydraulic control is performed to avoid the engine stall. Specifically, the oil pressure adjusted by the SLP solenoid valve is increased, and this oil pressure is supplied to the sequence valve to switch the sequence valve to the fail side. Along with this, hydraulic control is supplied from the SLG solenoid valve to the lockup control valve (hydraulic supply on the lockup release side), and the lockup clutch 34 is operated on the release side. As a result, engine stall can be avoided.

When the sequence valve is on the normal side, the SLP solenoid valve controls the primary sheave pressure and switches the sequence valve, and the SL2 solenoid valve controls the oil supply supplied to the belt traveling clutch C2 and suppresses the switching of the sequence valve. The SLG solenoid valve controls the synchro pressure. On the other hand, when the sequence valve is on the fail side, the SLP solenoid valve controls the primary sheave pressure and switches the sequence valve, the SL2 solenoid valve suppresses the switching of the sequence valve, and the SLG solenoid valve controls the synchro pressure and switches the primary sheave. It reduces the pressure and releases the lockup clutch.

Here, if the oil pressure of the SLP solenoid valve is increased in order to switch the sequence valve from the normal side to the fail side, the primary sheave pressure rises too much, so the SLG solenoid valve reduces the primary sheave pressure. However, the SLG solenoid valve controls the synchro engagement pressure at the same time, and if the primary sheave pressure is reduced, an engagement failure of the synchro mechanism S1 may occur. Therefore, in the power transmission device 1 according to the embodiment, after the synchronization mechanism S1 is engaged by the SLG solenoid valve, the primary sheave pressure is reduced within a range in which the synchronization mechanism S1 is not released.

FIG. 3 is a flowchart showing a procedure for hydraulic control when the SLU solenoid valve fails.

First, when the ECU 100 detects that a solenoid valve failure that makes it impossible to travel, for example, a failure of the SLU solenoid valve has occurred and a sequence valve switching request is generated (step S1), the synchronization mechanism S1 by the SLG solenoid valve Engagement is performed (step S2). After that, the ECU 100 determines whether the engagement of the synchronization mechanism S1 is completed (step S3). When it is determined that the engagement of the synchronization mechanism S1 is not completed (No in step S3), the ECU 100 waits until the engagement of the synchronization mechanism S1 is completed (step S4). On the other hand, when it is determined that the engagement of the synchronization mechanism S1 is completed (Yes in step S3), the ECU 100 sweeps down the oil pressure of the SL2 solenoid valve (step S5).

Next, the ECU 100 performs torque reduction according to the torque capacity of the belt traveling clutch C2 (step S6). After that, the oil pressure of the SL2 solenoid valve drops to the switchable pressure of the sequence valve, and it is determined whether the sweep down of the oil pressure of the SL2 solenoid valve is completed (step S7). When it is determined that the sweep-down of the oil pressure of the SL2 solenoid valve is not completed (No in step S7), the ECU 100 waits until the oil pressure of the SL2 solenoid valve drops to the sequence valve switchable pressure (step S8). On the other hand, when it is determined that the sweep-down of the oil pressure of the SL2 solenoid valve is completed (Yes in step S7), the ECU 100 sweetens up the oil pressure of the SLP solenoid valve from the normal side to the fail side of the sequence valve by the SLP solenoid valve. Switching to is started (step S9).

After that, the ECU 100 determines whether the oil pressure of the SLP solenoid valve rises to the sequence valve switching pressure and the sequence valve switching is completed (step S10). When it is determined that the sequence valve switching is not completed (No in step S10), the ECU 100 waits until the oil pressure of the SLP solenoid valve rises to the sequence valve switching pressure (step S11). On the other hand, when it is determined that the switching of the sequence valve is completed (Yes in step S10), the ECU 100 reduces the primary sheave pressure and releases the lockup clutch 34 by the SLG solenoid valve (step S12). , Ends a series of controls.

As described above, in the power transmission device 1 according to the embodiment, after the engagement of the synchronization mechanism S1 is completed by the SLG solenoid valve, the sequence valve is switched from the normal side to the fail side by the SLP solenoid valve, and the synchronization is performed by the SLG solenoid valve. The primary sheave pressure is reduced within a range in which the mechanism S1 is not released. As a result, a high pressure is required for the engagement of the synchro mechanism S1, but once the synchro mechanism S1 is engaged, the engaged state of the synchro mechanism S1 can be maintained even if the primary sheave pressure is reduced, so that the primary sheave pressure can be maintained. It is possible to achieve both the depressurization of the above and the engagement of the synchronization mechanism S1.

1 Power transmission device 12 Hydraulic control circuit 34 Lockup clutch 100 ECU
C1 Forward clutch C2 Belt running clutch S1 Sync mechanism

Claims (1)

A torque converter with a lockup clutch that transmits power from the drive source via hydraulic fluid,
A first power transmission path that transmits power from the torque converter to the output shaft via a gear mechanism, and
A second power transmission path provided in parallel with the first power transmission path and transmitting power from the torque converter to the output shaft via a belt-type continuously variable transmission.
The first clutch and the synchro mechanism that connect and disconnect the first power transmission path,
With the second clutch that connects and disconnects the second power transmission path,
In a power transmission device equipped with
At least an SLP solenoid valve capable of supplying primary sheave pressure to the primary pulley of the continuously variable transmission, and
At least an SLG solenoid valve capable of supplying engagement pressure to the synchronization mechanism,
A sequence valve that can switch between the normal position and the failure position by the oil supply supplied from the SLP solenoid valve.
Is equipped with
When there is a request to switch the sequence valve to the failure position, after the engagement of the synchronization mechanism by the SLG solenoid valve is completed, the sequence valve is switched to the failure position by the SLP solenoid valve. A power transmission device characterized in that the primary sheave pressure is reduced by the SLG solenoid valve within a range in which the synchronization mechanism is not released.

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