JPH02159451A - Continuously variable transmission for vehicle - Google Patents

Abstract

PURPOSE:To prevent a belt from slipping when a vehicle reverses by controlling the line pressure working on a pulley when a vehicle reverses with the reverse rotation of an impeller to be higher than the line pressure for forward movement with the turbine impeller rotation in the normal direction. CONSTITUTION:When a brake mechanism 42 engages with a brake side casing 60, a direct engagement clutch 62 engages with the brake mechanism 42 in linked motion and the rotation of a stator impeller 44 is stopped. As a result, oil flow is reversed with the blade of the impeller 44 and oil flows in from the back side of a turbine impeller 48 and the impeller 48 rotates in the opposite direction to that of a pump impeller 40. At the time a vehicle reverses with the reverse rotation of the impeller 48, a line pressure PR to be exerted on a drive side pulley 4 for example is made higher by a specified value than a line pressure PF for the forward movement of the vehicle with the normal rotation of the impeller 48. This makes it possible to prevent a belt from slipping even if a torque difference is produced at the time of forward or reverse movement with a torque converter 50 by compensating the torque difference with the line pressure.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a continuously variable transmission for a vehicle, and in particular to a continuously variable transmission for a vehicle, and in particular, to prevent belt slippage when the turbine impeller of a torque converter rotates in reverse and the vehicle moves backward. The present invention relates to a continuously variable transmission for vehicles.

[Conventional technology]

In a vehicle, a transmission is interposed between an internal combustion engine and drive wheels. This transmission changes the driving force and running speed of the drive wheels in accordance with the widely varying running conditions of the vehicle, thereby making full use of the performance of the internal combustion engine. The transmission includes, for example, a fixed pulley part fixed to a rotating shaft and a movable pulley part attached to the rotating shaft so as to be able to approach and separate from the fixed pulley part. By decreasing or increasing the groove width using hydraulic pressure, the rotation radius of the belt wrapped around the pulley is decreased or increased, power is transmitted, and the gear ratio (
There is a continuously variable transmission that changes the belt ratio.

As such a continuously variable transmission, for example, Japanese Patent Application Laid-Open No. 59-2
It is disclosed in Japanese Patent Application Laid-open No. 22659 and Japanese Patent Application Laid-Open No. 59-219555. The method described in Japanese Patent Application Laid-Open No. 59-222659, when controlling line pressure according to the gear ratio,
The sensor shoe of the feedback sensor is brought into sliding contact with the side of the belt opposite the movable pulley, and when the sliding contact part wears out, the line pressure is set to a high level, thereby increasing the pressure on the pulley to prevent belt slippage. It is to be ensured. In addition, what is described in Japanese Patent Application Laid-Open No. 59-219555 is
The pressure receiving part of the slider piston is supplied with hydraulic pressure that applies a force to the slider piston that does not exceed the biasing force of the spring,
This reduces the pressing force acting on the lever from the slider piston, reduces the surface pressure of each contact part and sliding part, and reduces wear of each part.

Furthermore, some continuously variable transmissions are equipped with a torque converter that changes the rotational direction of the belt to move the vehicle forward or backward. This torque converter has a pump impeller connected to the internal combustion engine, a stator impeller whose rotation is prevented by a brake mechanism, and a turbine impeller connected to the pulley. By allowing or blocking, the turbine impeller rotates forward or backward, changing the rotation direction of the belt, thereby moving the vehicle forward or backward.

[Problem that the invention seeks to solve]

By the way, in a continuously variable transmission equipped with a torque converter, the line pressure applied to each pulley is adjusted to
Regardless of whether the vehicle was in reverse, the accelerator opening, engine speed, gear ratio of the continuously variable transmission, etc. were determined as control factors.

However, when the turbine impeller is rotated in the opposite direction to move the vehicle backwards, the flow path of the oil that has passed through the pump impeller and stator impeller and reaches the turbine impeller is changed again by the blades of the turbine impeller and pumped Returning to the impeller,
The output torque from the torque converter increases. At this time, as mentioned above, if the line pressure acting on the pulley is constant regardless of whether the vehicle is moving forward or backward, a difference will occur in the torque converter when moving forward or backward, resulting in the belt slipping. There is this inconvenience.

[Purpose of the invention]

Therefore, the purpose of this invention is to eliminate the above-mentioned disadvantages.
By controlling the line pressure applied to the pulley when the turbine impeller rotates in reverse and the vehicle moves backwards to a predetermined level higher than the line pressure when the turbine impeller rotates forward and the vehicle moves forward, the vehicle To provide a continuously variable transmission for a vehicle that can prevent a belt from slipping by properly adjusting line pressure applied to a pulley depending on when the vehicle is moving forward or backward.

[Means for solving problems]

In order to achieve this object, the present invention hydraulically reduces or increases the groove width between the fixed pulley part and the movable pulley part attached to the fixed pulley part so as to be able to move toward and away from the fixed pulley part. In continuously variable transmissions for vehicles that control speed change to change the gear ratio by decreasing or increasing the rotation radius of a belt wrapped around both pulleys, rotation is prevented by a pump impeller and a brake mechanism connected to the internal combustion engine side. A torque converter is provided, which has a stator impeller and a turbine impeller connected to the pulley side, and allows the turbine impeller to rotate in forward and reverse directions by allowing or blocking the rotation of the stator impeller, and A control means is provided for controlling the line pressure applied to the pulley when the vehicle rotates in reverse and the vehicle moves backward to a predetermined level higher than the line pressure when the turbine impeller rotates forward and the vehicle moves forward. It is characterized by:

[Effect]

According to the configuration of the present invention, the control means applies line pressure to be applied to the pulley when the turbine impeller rotates in the reverse direction and the vehicle moves backward, and to a line pressure that acts on the pulley when the turbine impeller rotates in the forward direction and the vehicle moves forward. The pressure is controlled to a predetermined level higher than the pressure.

Thereby, the line pressure applied to the pulley can be adjusted depending on when the vehicle is moving forward or backward, and the belt can be prevented from slipping.

〔Example〕

Embodiments of the present invention will be described in detail and specifically below based on the drawings.

1 to 9 show embodiments of this invention. In the figure, 2 is a continuously variable transmission for a vehicle, 4 is a driving pulley, 6 is a driven pulley, and 8 is a belt. The drive-side pulley 4 includes a drive-side fixed pulley piece 14 fixed to the drive-side shaft I2 in the pulley-side housing 10, and a drive-side fixed pulley piece 14 fixed to the drive-side shaft I2, and a drive-side shaft 12 that is movable in the axial direction of the drive-side shaft 12 but not rotatable.
A drive side movable pulley piece 16 is attached to the drive side movable pulley piece 16, and the oil is guided to a drive side oil chamber 20 formed by a drive side housing 18 arranged on the back side of the drive side movable pulley piece 16. Drive side movable pulley part 16 by oil pressure
is moved in the axial direction of the drive side shaft 12, and the drive side a22 between the drive side fixed pulley piece 14 and the drive side movable pulley piece 14 is moved in the axial direction of the drive side shaft 12.
This is to increase or decrease the width of

Further, the driven side pulley 6 includes a driven side fixed pulley part 26 fixed to the driven side shaft 24, and a driven side fixed pulley part 26 that is movable in the axial direction of the driven side shaft 24 but is attached to the driven side shaft 24 so as not to rotate. The driven side movable pulley piece 28 has a driven side movable pulley piece 28, and the oil is guided to a driven side oil chamber 32 formed by a driven side housing 30 disposed on the back side of the driven side movable pulley piece 28. This oil pressure moves the driven side movable pulley piece 28 in the axial direction of the driven side shaft 24, and the driven side movable pulley piece 28 is moved between the driven side fixed pulley piece 26 and the driven side movable pulley piece 28. This is to increase or decrease the width of a34. Further, a pressing spring 36 is contracted in the driven side oil chamber 32 and presses the driven side movable pulley piece 28 in the direction of expansion of the driven side oil chamber 32 .

A belt 8 is disposed in the drive side groove 22 of the drive side boob IJ 4 and the driven side groove 34 of the driven side pulley 6, and this belt 8 is tensioned between the drive side pulley 4 and the driven side pulley 6. There is.

Inside the housing 38 on the internal combustion engine side of the continuously variable transmission 2, there are a pump impeller 40 connected to the internal combustion engine (not shown) side, a stator impeller 44 whose rotation is prevented by a brake mechanism 42, and a pulley side. It has a turbine impeller 48 fixed to an output side shaft 46 connected to the drive side shaft 12, and by allowing or blocking the rotation of the stator impeller 44, the turbine impeller 48 is rotated in forward and reverse directions. 46 can be rotated in forward and reverse directions, and a torque converter 50 is provided to change the direction of rotation of the heald 8. That is, a drive plate 54 that drives the torque converter 50 is fixed to an internal combustion engine side shaft 52 that is connected to the internal combustion engine. The torque converter 50 includes the pump impeller 40, the stator impeller 44, and the turbine impeller 48 in a converter-side housing 56. Pump impeller 40 is connected to drive plate 54 via converter-side housing 56 . Further, the stator impeller 44 is connected to the pulley side housing 10 and the converter side housing 5 via a first communication body 58.
The brake mechanism 42 is connected to the brake mechanism 42 provided on the inner surface of the brake side casing 60 located between the brake parts 6 and 6. Thereby, the stator impeller 44 can be locked to and separated from the brake side casing 60 depending on the operating state of the brake mechanism 42. Furthermore, a direct coupling clutch 62 is disposed within the converter housing 56 and is capable of engaging and separating the converter housing 56 and the turbine impeller 48 .

In other words, this direct coupling clutch 62 can directly couple the internal combustion engine side shaft 52 and the output side shaft 64.

Further, the other end of the output shaft 46 to which the turbine impeller 48 is fixed is supported by a bearing 64 . Further, a second connecting body 66 is fixed to this output side shaft 46, and this second connecting body 66 is connected to a neutral clutch 68.

This neutral clutch 68 is operated by oil pressure, and disconnects and disconnects the relationship between the output side shaft 46 and the drive side shaft 12. As a result, the turbine impeller 48 can be connected to and connected to the drive-side fixed pulley piece 14 by the neutral clutch 68. That is, the neutral clutch 68 is connected to the turbine impeller 4
The power transmitted from 8 to the output shaft 46 is transferred to the drive pulley 4
, and connects the subsequent power transmission device via the driven pulley 6.
It separates and creates neutrality.

The turbine impeller 48 of the torque converter 50 rotates forward and backward as shown in FIG. 4.5. That is, when the brake mechanism 42 is separated from the brake-side casing 60, the stator impeller 440 is allowed to rotate, oil passes between the blades of the stator impeller 44, and the turbine impeller 48 is moved in the same direction as the pump impeller 40. , that is, rotate it in the forward direction (see Figure 4). On the other hand, when the brake mechanism 42 is locked to the brake side casing 60, the rotation of the stator impeller 44 is prevented, and the direction of the kinetic energy of the oil sent out from the pump impeller 48 is fixed. The rotation direction of the turbine impeller 48 becomes opposite to that of the pump impeller 40 (
(See Figure 5). Therefore, since changes in the forward and reverse rotation of the output shaft 46 fixed to the turbine impeller 48, that is, changes in the rotational direction of the belt 8, are both performed via the turbine impeller 48, the neutral clutch 68 is not engaged.・It is possible to maintain the drive/neutral state by separating.

Furthermore, the converter housing 56 integrated with the pump impeller 48 is directly connected to the oil pump 70, so that the oil pump 70 is directly driven by the internal combustion engine shaft 52.

Further, the brake mechanism 42 includes a brake piston 72 operated by hydraulic pressure and a brake piston 72 operated by hydraulic pressure.
The operation is controlled by an actuation mechanism 76 consisting of an actuation ring 74 which is actuated by the movement of the actuator.

The continuously variable transmission 2 performs speed change control so as to continuously change a gear ratio that decreases or increases the rotation radius of a belt 8 wound around a driving pulley 4 and a driven pulley 6.

Further, a reduction drive gear 78 is fixed to the driven shaft 6, and a reduction driven gear 82 is fixed to the support shaft 80 or meshes with the reduction drive gear 78. Further, a final drive gear 84 is fixed to this support shaft 80, and a final gear 88 of a differential unit 86 is attached to this final drive gear 84.
It meshes with the This differential unit 86 is in communication with the wheels (not shown).

In addition, in the continuously variable transmission 2, when the turbine impeller 48 rotates in reverse and the vehicle moves backward, the turbine impeller 48 rotates in the forward direction to apply line pressure to the drive pulley 4, for example, so that the vehicle moves forward. A control means 90 is provided for controlling the line pressure to a predetermined value higher than the actual line pressure. That is, as shown in FIG.
It controls the operation of a line pressure regulating valve 96 provided in the middle of a hydraulic circuit (not shown). The forward/backward movement determination unit 92 is a forward/backward movement detection means such as a pressure sensor that detects the oil pressure state or a rotation direction detection sensor that electrically detects reverse rotation of the turbine impeller 48 or the output shaft 46. The line pressure setting section 94 also includes a central processing unit (C
It determines whether the vehicle is moving forward or backward from the forward/reverse determination unit 92, and sets the forward line pressure PF in the case of forward movement, while setting the forward line pressure PF to a predetermined value higher than the forward line pressure PF in the case of reverse movement. This is to set the reverse line pressure PR. This reverse line pressure P11 is set to a predetermined value higher than the forward line pressure PF in order to compensate for the difference in torque of the torque converter 50.

Next, the operation of this embodiment will be explained.

When the internal combustion engine operates, the internal combustion engine side shaft 52 rotates, and as the internal combustion engine side shaft 52 rotates, the drive plate 5 rotates.
4 rotates and drives the torque converter 50.

In this torque converter 50, the actuating ring 72 is moved by the movement of the brake piston 72 which is operated by oil pressure.
The brake mechanism 42 connects to the brake side casing 6 via 4.
In the case of separation from 0, the direct coupling clutch 62 is also in a separated state and the stator impeller 44 is in a rotating state, and oil passes through between the blades of the stator impeller 44 and acts on the blades of the turbine impeller 48. , thereby causing the turbine impeller 48 to rotate in the same direction as the pump impeller 40, that is, in the forward direction (see FIG. 4). This causes the vehicle to move forward.

On the other hand, when the brake mechanism 42 is engaged with the brake side casing 60, the direct coupling clutch 62 is connected to the brake mechanism 4.
2, the platform is in a stopped state, and the stator impeller 44
Since the rotation of the stator impeller 44 is stopped, the oil flows into the stator impeller 44.
The rotation of the turbine impeller 48 is reversed by the rotation direction of the pump impeller 40 , and the oil flows in from the back side of the blade of the turbine impeller 48 . (See Figure 5). This causes the vehicle to move backward.

At this time, the control means 90 sets the line pressure as shown in the flowchart of FIG. That is, in FIG. 7, in step 2, the forward/reverse motion determining section 92 determines whether or not the vehicle is moving forward.
01), if step 20J is YES for forward movement, set the forward line pressure PF in the line pressure setting section 94 (step 202), and output a signal of this forward line pressure PFO value to the line pressure regulating valve 96. , controls the operation of this line pressure regulating valve 96.

On the other hand, in the case of NO in step 201 other than moving forward, it is determined whether the vehicle is in neutral or not (step 203), and YES in neutral.
In the case of ES, the process returns to step 202 and the forward line pressure pF is set.

In addition, if it is not neutral in step 203, that is, in the case of No in reverse, the reverse line pressure PR is set to a predetermined higher value than the forward line pressure PF (step 204), and the value of this reverse line pressure pi+ is set. A signal is output to the line pressure regulating valve 96 to control the operation of the line pressure regulating valve 96.

Also, at this time, the oil pump 70 is connected to the internal combustion engine side shaft 52.
The oil pan absorbs oil from an oil pan (not shown) and supplies it to the torque converter 50 and other parts.

The continuously variable transmission 2 includes a drive side groove 2 of the drive side pulley 4.
2 and the width of the driven side groove 34 of the driven side pulley 6, the rotation radius of the belt 8 is decreased or increased, and the speed ratio is changed steplessly.

As a result, the power of the internal combustion engine is input from the internal combustion engine shaft 52, and the forward and reverse rotation directions of the belt 8 are determined by the rotation direction of the turbine impeller 48 of the torque converter 50.
Drive side pulley 4, belt 8, driven side pulley 6,
The signal then passes through a reduction drive gear 78, a reduction driven gear 82, a final drive gear 84, and a final gear 88, and then is branched by a differential unit 86 and transmitted to each wheel.

By the way, in this embodiment, the turbine impeller 48
For example, the line pressure PR applied to the drive pulley 4 is made higher than the line pressure PF when the turbine impeller 48 rotates forward and the vehicle moves forward when the turbine impeller 48 rotates in the forward direction and the vehicle moves backward. Therefore, even if there is a difference in the torque during forward movement and backward movement in the torque converter 50, this difference in torque can be compensated for by the line pressure, and the belt can be prevented from slipping.

In addition, in FIG. 8, the relationship between the input/output ratio (e) between the output rotation speed and the input rotation speed in the fluid coupling and the torque ratio (1) is explained. In this case, the torque ratio (1) is constant. is maintained.

In addition, in FIG. 9, the relationship between the human output ratio (e) and the torque ratio (1) in the torque converter 50 is explained,
In this case, for example, when the input/output ratio (e) goes from zero to 0.5, the torque ratio decreases from 2, and the input/output ratio (e)
is from 0.5 to 1, the torque ratio decreases from 1 to zero.

〔Effect of the invention〕

As is clear from the above detailed description, according to the present invention,
A control means is provided for controlling the line pressure applied to the pulley when the turbine impeller rotates in reverse and the vehicle moves backward to a predetermined level higher than the line pressure when the turbine impeller rotates forward and the vehicle moves forward. As a result, the line pressure applied to the pulley can be appropriately adjusted depending on when the vehicle is moving forward or backward, and the belt can be prevented from slipping.

[Brief explanation of the drawing]

1 to 9 show examples of the present invention, FIG. 1 is a schematic explanatory diagram of a continuously variable transmission equipped with a fluid coupling, and FIG. 2 is a detailed diagram of a continuously variable transmission equipped with a fluid coupling. , FIG. 3 is a shaft layout diagram of the continuously variable transmission, FIG. 4 is an explanatory diagram with the turbine impeller rotating in the forward direction, and FIG. 5 is an explanatory diagram with the turbine impeller rotating in the reverse direction. FIG. 6 is an explanatory diagram of the control means and the line pressure regulating valve, FIG. 7 is a flowchart explaining the operation of this embodiment, and FIG. 8 is a diagram showing the relationship between the input/output ratio and the torque ratio in the fluid coupling. FIG. 9 is a diagram showing the relationship between the input/output ratio and the torque ratio in the torque converter. In the figure, 2 is a continuously variable transmission, 4 is a driving pulley, 6 is a driven J side pulley, 8 is a belt, 40 is a pump blade, 4
2 is a brake mechanism, 44 is a stator impeller, 46 is an output side shaft, 48 is a turbine impeller, 50 is a torque converter, 60 is a brake side casing, 62 is a direct coupling clutch,
64 is a bearing, 68 is a neutral clutch, 70 is an oil pump, 76 is an operating mechanism, 90 is a control means, 92 is a forward/reverse motion determining section, 94 is a line pressure setting section, and 96 is a line pressure regulating valve.

Claims (1)

[Claims] 1. The groove width between the fixed pulley piece and the movable pulley piece attached to the fixed pulley piece so as to be able to move toward and away from the fixed pulley piece is increased or decreased by hydraulic pressure, and the belt that is wound around the two pulleys is rotated. In a continuously variable transmission for a vehicle that performs speed change control to change the speed ratio by decreasing or increasing the radius, a pump impeller connected to the internal combustion engine side, a stator impeller whose rotation is prevented by a brake mechanism, and a stator impeller connected to the pulley side are connected. A torque converter is provided, the turbine impeller is configured to rotate in the reverse direction by allowing or blocking the rotation of the stator impeller, and the turbine impeller rotates in the reverse direction, causing the vehicle to move backward. The vehicle is equipped with a control means for controlling the line pressure applied to the pulley to a predetermined value higher than the line pressure when the turbine impeller rotates forward and the vehicle moves forward. gearbox.