JP2004125103A - Belt-type continuously variable transmission system for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a belt type continuously variable transmission system for preventing belt slide from occurring even if a high pressure, where pressure is not regulated, operates by the failure of a clutch pressure regulation means. <P>SOLUTION: The belt type continuously variable transmission system for vehicles has a belt type continuously variable transmission means having a primary pulley 21 at an input side, where a groove width changes according to oil pressure; a secondary pulley 22 at an output side, where a groove width changes according to the oil pressure; and a belt 23 that is wound around the primary pulley 21 and the secondary pulley 22 while a pulley contact radius changes according to the groove width. The belt type continuously variable transmission system comprises a clutch means 20 for interrupting rotation from an engine for inputting to the primary pulley 21; a clutch pressure adjusting means 35 that supplies oil pressure to the clutch means 20, and controls the disconnection of the clutch means 20 by regulating the supply oil pressure; and an oil pressure rapid increase prevention means for preventing a rapid increase in the oil pressure that is supplied from the clutch pressure adjusting means 35 to the clutch means 20. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt type continuously variable transmission system for a vehicle, which is suitably used for a power transmission system for transmitting rotation of a motor of an automobile or the like to drive wheels.
[0002]
[Prior art]
2. Description of the Related Art As a transmission system mounted on an automobile or the like, a so-called belt-type continuously variable transmission system for a vehicle has been conventionally known. This belt-type continuously variable transmission system for a vehicle includes a primary pulley that inputs the rotation of the engine, a secondary pulley that outputs the rotation to the drive wheels, and is sandwiched between the primary pulley and the secondary pulley, and transmits the rotation of the primary pulley to the secondary pulley. The ratio of the contact radius (effective radius) (pulley ratio) of the primary pulley and the secondary pulley sandwiching the V belt (pulley ratio) is adjusted to adjust the ratio of the input and output rotation speeds (speed ratio). Is what you do.
[0003]
As described above, in the vehicle belt-type continuously variable transmission system, the V-belt is held between the primary pulley and the secondary pulley. However, if the V-belt slips, the life of the V-belt may be shortened. Various proposals have been made for preventing slippage. For example, when the range is selected from the D range to the L range, or when the range is selected from the L range to the D range, by temporarily increasing the line pressure, the force of the primary pulley and the secondary pulley to clamp the V belt is reduced. An attempt is made to prevent the V-belt from slipping by increasing the height (for example, see Patent Document 1).
[0004]
[Patent Document 1]
JP-A-63-31833 (page 3)
[0005]
[Problems to be solved by the invention]
By the way, a clutch unit for interrupting the rotation of the engine is provided between the engine and the primary pulley. The clutch unit is supplied with a hydraulic pressure that has passed through the line pressure adjusting device and has been reduced in pressure by the clutch pressure adjusting device. The hydraulic pressure is used to connect and disconnect the clutch plate.
[0006]
However, if the clutch pressure adjusting device fails, the hydraulic pressure output from the line pressure adjusting device may be supplied to the clutch unit without being reduced. Then, when the clutch is engaged, the clutch plate comes into contact in a very short time, and the primary pulley is rotated at a stroke. Then, the V-belt may slip due to the force at that time.
[0007]
The present invention has been made in view of such a conventional problem, and is intended for a vehicle that does not cause the V-belt to slip even if the clutch pressure adjusting device breaks down. It is an object of the present invention to provide a belt-type continuously variable transmission system.
[0008]
[Means for Solving the Problems]
The present invention solves the above problem by the following means. Note that, for easy understanding, reference numerals corresponding to the embodiments of the present invention are given, but the present invention is not limited thereto.
[0009]
A first invention provides an input-side primary pulley (21) whose groove width changes according to oil pressure, an output-side secondary pulley (22) whose groove width changes according to oil pressure, and the primary pulley (21). And a belt (23) wound around the secondary pulley (22) and having a pulley contact radius that varies according to the groove width. A clutch means (20) for intermittently inputting rotation from the engine and inputting to the primary pulley (21); and supplying a hydraulic pressure to the clutch means (20), and adjusting the supplied hydraulic pressure to thereby provide the clutch means. (20) clutch pressure adjusting means (35) for controlling the on / off state, and the hydraulic pressure supplied from the clutch pressure adjusting means (35) to the clutch means (20) rises rapidly. Characterized in that it comprises a hydraulic jump prevention means for preventing the.
[0010]
According to a second aspect of the present invention, in the first aspect, the hydraulic pressure sudden rise prevention means includes a throttle () for reducing a cross-sectional area of a flow path of a hydraulic pressure supplied from the clutch pressure adjustment means (35) to the clutch means (20). 37).
[0011]
In a third aspect based on the first or second aspect, the hydraulic pressure abrupt rise prevention means includes an accumulator (temporarily storing hydraulic pressure supplied from the clutch pressure adjusting means (35) to the clutch means (20)). 38).
[0012]
In a fourth aspect based on any one of the first to third aspects, a hydraulic pressure is supplied to the primary pulley (21) and the secondary pulley (22) in accordance with an engine speed to change a belt torque capacity. And a control unit (40) for causing the control unit to perform the control.
[0013]
[Action / Effect]
According to the first aspect of the present invention, the sudden increase in the hydraulic pressure supplied to the clutch means input to the primary pulley while the rotation from the engine is intermittently provided is provided. Even if the pressure adjusting device fails, the clutch torque can be suppressed lower than the belt torque capacity, and belt slippage can be prevented.
[0014]
According to the second aspect, since the sudden increase in hydraulic pressure has the throttle, even if the amount of oil supplied to the clutch increases rapidly, the amount of increase in clutch pressure can be kept low.
[0015]
According to the third aspect of the present invention, since the sudden increase in hydraulic pressure has the accumulator, the clutch pressure can be increased with time.
[0016]
According to the fourth aspect, since the hydraulic pressure is supplied to the primary pulley and the secondary pulley in accordance with the engine speed, the belt slip can be more reliably prevented by changing the belt torque capacity. In addition, since the pulley pressure is not increased more than necessary when the engine is running at a low speed, the effect of improving fuel efficiency and the effect of not causing an insufficient oil supply to the clutch can be expected.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings and the like.
(1st Embodiment)
FIG. 1 is a schematic configuration diagram showing a belt type continuously variable transmission system for a vehicle according to the present invention.
[0018]
The belt-type continuously variable transmission system 1 for a vehicle includes a clutch unit 10, a belt-type continuously variable transmission unit 20, a hydraulic pressure adjusting unit 30, a control unit 40, a torque converter (hereinafter abbreviated as "torque converter" as appropriate) 50. , And the rotation of the engine 60 is reduced and transmitted to the drive wheels 70.
[0019]
The clutch unit 10 includes a planetary gear 11 that switches a power transmission path between the engine 60 side and the primary pulley 21 side, a forward clutch 12, and a reverse brake 13, and uses a hydraulic pressure supplied from a clutch pressure adjusting device 35 to The forward clutch 12 is engaged when the vehicle is moving forward, the reverse brake 13 is engaged when the vehicle is moving backward, and both the forward clutch 12 and the reverse brake 13 are released at the neutral position (neutral or parking). The clutch pressure adjusting device 35 adjusts the hydraulic pressure (forward clutch pressure, reverse brake pressure) supplied to the forward clutch 12 and the reverse brake 13 according to a command from the control unit 40 to control the engagement state.
[0020]
The forward clutch 12 and the reverse brake 13 are exclusively engaged. During forward travel (range signal = D range), the forward clutch pressure is supplied to fasten the forward clutch 12, and the reverse brake pressure is connected to the drain. Release the reverse brake 13. On the other hand, when reversing (range signal = R range), the forward clutch pressure is connected to the drain, the forward clutch 12 is released, the reverse brake pressure is supplied, and the reverse brake 13 is engaged. At the neutral position (range signal = N range), the forward clutch pressure and the reverse brake pressure are connected to the drain, and both the forward clutch 12 and the reverse brake 13 are released.
[0021]
The belt-type continuously variable transmission unit 20 includes a primary pulley 21, a secondary pulley 22, and a V-belt 23.
[0022]
The primary pulley 21 is an input shaft side pulley for inputting the rotation of the engine 60. The primary pulley 21 has a fixed conical plate 21a that rotates integrally with the input shaft 21c, a V-shaped pulley groove disposed opposite to the fixed conical plate 21a, and a hydraulic pressure acting on the primary pulley (hereinafter, referred to as a primary pulley 21). And a movable conical plate 21b that can be displaced in the axial direction by “primary pressure”. The rotation speed of the primary pulley 21 is detected by a primary pulley rotation speed sensor 41.
[0023]
Secondary pulley 22 transmits the rotation transmitted by V-belt 23 to drive wheels 70 via idler gears and differential gears. The secondary pulley 22 includes a fixed conical plate 22a that rotates integrally with the output shaft 22c, a V-shaped pulley groove disposed opposite to the fixed conical plate 22a, and a hydraulic pressure acting on the secondary pulley (hereinafter, referred to as a secondary pulley). A movable conical plate 22b that can be displaced in the axial direction according to “secondary pressure”). The pressure receiving area of the secondary pulley and the pressure receiving area of the primary pulley are equal or almost equal. The rotation speed of the secondary pulley 22 is detected by a secondary pulley rotation speed sensor 42. The vehicle speed is calculated from the rotation speed of the secondary pulley 22.
[0024]
V-belt 23 is wound around primary pulley 21 and secondary pulley 22, and transmits the rotation of primary pulley 21 to secondary pulley 22.
[0025]
The hydraulic pressure adjusting unit 30 includes a hydraulic pump 31, a line pressure adjusting device 32, a primary pressure adjusting device 33, a secondary pressure adjusting device 34, and a clutch pressure adjusting device 35.
[0026]
The hydraulic pump 31 is driven by the engine 60 to pump oil.
[0027]
The line pressure adjusting device 32 adjusts the pressure of the oil pressure-fed from the hydraulic pump 31 to a predetermined line pressure according to the operation state according to a command (for example, a duty signal) from the control unit 40.
[0028]
The primary pressure adjusting device 33 is a device that controls the primary pressure, and includes, for example, a solenoid, a servo link and a step motor that constitute a mechanical feedback mechanism.
[0029]
The secondary pressure adjusting device 34 is controlled by a command from the control unit 40, and further reduces the line pressure adjusted by the line pressure adjusting device 32 to adjust the line pressure to a predetermined secondary pressure according to the operation state.
[0030]
The clutch pressure adjusting device 35 adjusts the hydraulic pressure from the line pressure adjusting device 32 as a base pressure based on the hydraulic pressure command value of the control unit 40, supplies the adjusted hydraulic pressure to the clutch unit 10, and controls the disc spring 38a. The provided forward clutch 12 and reverse brake 13 are engaged or released. The disc spring 38a plays a role in relieving sudden engagement in the forward clutch 12 and the reverse brake 13.
[0031]
The hydraulic pressure of the clutch pressure adjusting device 35 is supplied to the clutch unit 10 through a clutch pressure supply pipe 36. A throttle 37 and an accumulator 38 are provided in the course of the clutch supply pipe 36. The throttle 37 narrows the cross-sectional area of the pipeline of the clutch supply pipe 36 to limit transmission of clutch pressure. The accumulator 38 temporarily stores the high-pressure fluid inside the clutch supply pipe 36, and transmits the high-pressure fluid to the active part as needed to perform work.
[0032]
The control unit 40 includes a vehicle speed signal of a secondary pulley rotation speed sensor 42, a range signal of an inhibitor switch 43 responsive to a shift lever, an accelerator pedal depression amount signal of an accelerator pedal 44, an engine rotation speed signal of an engine 60 (or an engine control device), and the like. The hydraulic pressure command value is determined based on the operating state and the driving operation of and the clutch pressure adjusting device 35 is instructed. Note that the inhibitor switch 43 shows an example of selecting one of forward (D range), neutral position = neutral (N range), and backward (R range).
[0033]
Further, the control unit 40 controls the clutch pressure adjusting device 35 to adjust the hydraulic pressure supplied to the forward clutch 12 and the reverse brake 13 to control the forward clutch pressure and the reverse brake pressure, thereby controlling the engaged state of the clutch. .
[0034]
The control unit 40 further includes input torque information, a ratio between the rotation speed of the primary pulley and the rotation speed of the secondary pulley (gear ratio), a position selected by the inhibitor switch 43, a vehicle speed (secondary pulley rotation speed), and an accelerator pedal depression amount. , Read signals of oil temperature, oil pressure, etc., determine a target gear ratio, calculate primary pressure and secondary pressure target pressures for realizing the target gear ratio, and correct the target pressure as necessary. By controlling the line pressure adjusting device 32, the primary pressure adjusting device 33, and the secondary pressure adjusting device 34 so as to meet the target pressure, the hydraulic pressure supplied to the primary pulley 21 and the secondary pulley 22 is adjusted, and the movable cone plate is adjusted. The primary pulley 21 and the secondary pulley 21b are reciprocated in the direction of the rotation axis. Changing the second pulley groove width. Then, the V-belt 23 moves on the primary pulley 21 and the secondary pulley 22, the contact radius of the V-belt 23 with the primary pulley 21 and the secondary pulley 22 is changed, and the gear ratio is controlled.
[0035]
The rotation of the engine 60 is input to the belt-type continuously variable transmission unit 20 via the torque converter 50 and the clutch unit 10, and is transmitted from the primary pulley 21 to the drive wheel 70 via the V-belt 23 and the secondary pulley 22.
[0036]
When the accelerator pedal is depressed or the shift is changed in the manual mode, the control unit 40 displaces the movable conical plate 21b of the primary pulley 21 and the movable conical plate 22b of the secondary pulley 22 in the axial direction, and The gear ratio is continuously changed by changing the contact radius.
[0037]
Further, the control unit 40 controls the fuel injection amount and the throttle opening of the engine 60 to control the engine torque and the rotation speed.
[0038]
The torque converter 50 is a device that is provided between the engine 60 and the clutch unit 10 and that transmits the rotational torque of the engine 60 by the flow of oil contained therein.
[0039]
Assuming the engine speed Ne, the torque converter capacity coefficient τ, and the torque converter torque ratio t, the input torque T _{in to} the torque converter 50 and the output torque T _out from the torque converter 50 are
T _in = τ × Ne ²
T _out = τ × Ne ² × t
Is represented by Thus, the transmission torque of the torque converter 50 is determined by the engine speed.
[0040]
FIG. 2 is a diagram showing a state change of the clutch unit before and after a shift change (N → D) when the hydraulic pressure from the line pressure adjusting device is directly supplied to the clutch unit. The horizontal axis represents time, and the vertical axis represents rotation speed (FIG. 2A), torque (FIG. 2B), and clutch pressure (FIG. 2C). Also, in the drawing, the solid line indicates the present embodiment (a case where a throttle and an accumulator are provided in the middle of the path of the clutch supply pipe, and further a disc spring is provided for the forward clutch and the reverse brake), and a broken line indicates a conventional product (the clutch supply pipe (A case where a stop and an accumulator are not provided in the middle of the route).
[0041]
The effect of the present embodiment will be described based on FIG.
[0042]
In the conventional product, when the range is changed from the N range to the D range, the clutch pressure sharply rises (FIG. 2C), the clutch torque rises sharply, and the peak torque is the belt torque capacity (the power can be transmitted without the belt slipping). It can be seen that the maximum torque has been exceeded (FIG. 2 (B)). In addition, it can be seen that the rotation speed of the difference between the turbine rotation and the primary pulley rotation falls in a shorter time than the solid line (FIG. 2A).
[0043]
On the other hand, in the present embodiment, when the range is changed from the N range to the D range, first, the amount of increase in the clutch pressure is suppressed to a low level (FIG. 2C). This is due to the action of the throttle 37 provided on the way of the clutch supply pipe 36. Further, thereafter, the clutch pressure gradually increases with time (FIG. 2C). This is due to the action of the accumulator 38 provided on the way of the clutch supply pipe 36 and the disc spring 38a provided on the forward clutch 12 and the reverse brake 13. Since the clutch pressure changes in this manner, the rise of the clutch torque becomes gentle, and the peak torque is suppressed to be lower than the belt torque capacity (FIG. 2 (B)), and the difference between the turbine rotation and the primary pulley rotation is reduced. It can be seen that the number of rotations decreases over time as compared with the broken line (FIG. 2A).
[0044]
As described above, according to the present embodiment, since the throttle 37 and the accumulator 38 are provided in the middle of the path of the clutch supply pipe 36, the clutch pressure adjusting device should fail and the hydraulic pressure from the line pressure adjusting device 32 should be directly applied. Even when the clutch torque is supplied to the clutch unit 10, the clutch torque can be suppressed lower than the belt torque capacity. As described above, since the clutch torque is always lower than the belt torque capacity, belt slippage can be prevented.
[0045]
(2nd Embodiment)
In the present embodiment, if the forward range or the reverse range is selected from the neutral range, the line pressure is changed according to the engine speed at that time, and the primary pulley pressure and the secondary pulley pressure are also changed at the engine speed at that time. By increasing the belt torque capacity as the hydraulic pressure according to the number, it is intended to more reliably prevent belt slippage. Hereinafter, an outline of a controller control method which is particularly important in the present embodiment will be described.
[0046]
FIG. 3 is a flowchart illustrating a control method according to the second embodiment.
[0047]
In step S1, the process is started when the forward range or the reverse range is selected from the neutral range.
[0048]
In step S2, the engine speed and the oil temperature are measured.
[0049]
In step S3, a line pressure, a primary pulley pressure, and a secondary pulley pressure are calculated based on the engine speed and the oil temperature. Specifically, a diagram as shown in FIG. 4 is prepared for each temperature, and the determination is made based on the diagram. Then, the line pressure adjusting device 32, the primary pressure adjusting device 33, and the secondary pressure adjusting device 34 are adjusted so that the line pressure, the primary pulley pressure, and the secondary pulley pressure are obtained.
[0050]
In step S4, when the predetermined time has elapsed and it is determined that belt slippage cannot occur, the process ends.
[0051]
FIG. 4 is a graph showing the relationship between the oil pressure and the torque capacity with respect to the engine speed at a certain oil temperature. The horizontal axis represents the engine speed, the vertical axis represents the torque capacity (FIG. 4A), and the hydraulic pressure (FIG. 4A). (B)).
[0052]
In the present embodiment, as shown in FIG. 4B, as the engine speed increases, the energy required for clutch engagement increases, and as a result, the clutch pressure and the peak torque at the time of clutch engagement, that is, the line pressure, etc. Will be higher. This is because the higher the engine speed, the greater the shock at the time of clutch engagement. Therefore, the line pressure and the like are to be increased in advance. Note that FIG. 4B shows a line pressure limit that can be generated, which is determined from the engine speed and the oil temperature, and the line pressure is naturally lower than that. When the line pressure and the like are determined, the belt torque capacity is obtained from the line pressure and the like. The belt torque capacity changes as shown in FIG. Further, based on the belt torque capacity, the clutch engagement peak torque is determined to be smaller than the belt torque capacity (FIG. 4A). Then, a clutch pressure that can realize the clutch engagement peak torque is determined. The clutch pressure is shown in FIG.
[0053]
According to the present embodiment, when the neutral range is selected from the forward range or the reverse range, the line pressure, the primary pulley pressure, and the secondary pulley pressure are increased as the hydraulic pressure according to the engine speed at that time, so that the belt torque capacity is increased. In addition to the effects of the first embodiment, belt slippage can be more reliably prevented.
[0054]
Without being limited to the embodiments described above, various modifications and changes can be made within the scope of the technical idea, and it is apparent that they are equivalent to the present invention.
[0055]
For example, in the second embodiment, the end of step S4 is determined based on whether a predetermined time has elapsed. For example, the rotation speed of the clutch turbine is measured, and the rotation speed is determined as the rotation speed of the primary pulley. The processing may be terminated when the state matches.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a belt type continuously variable transmission system for a vehicle according to the present invention.
FIG. 2 is a diagram showing a state change of a clutch unit before and after a shift change (N → D) when hydraulic pressure from a line pressure adjusting device is directly supplied to a clutch unit.
FIG. 3 is a flowchart illustrating a control method according to a second embodiment.
FIG. 4 is a diagram showing a relationship between an oil pressure and a torque capacity with respect to an engine speed at a certain oil temperature.
[Explanation of symbols]
DESCRIPTION OF REFERENCE NUMERALS 1 vehicle belt type continuously variable transmission system 10 clutch unit 20 belt type continuously variable transmission unit 21 primary pulley 22 secondary pulley 23 V-belt 30 hydraulic adjustment unit 31 hydraulic pump 32 line pressure adjustment device 33 primary pressure adjustment device 34 secondary pressure adjustment device 35 Clutch pressure adjusting device 40 Control unit 50 Torque converter 60 Engine 70 Drive wheel

Claims (4)

An input-side primary pulley whose groove width changes according to the oil pressure,
An output-side secondary pulley whose groove width changes according to the oil pressure,
A belt-type continuously variable transmission system for a vehicle, comprising: a belt-type continuously variable transmission unit including a belt wound around the primary pulley and the secondary pulley, and having a pulley contact radius that varies according to the groove width,
Clutch means for intermittently inputting rotation from the engine to the primary pulley;
Supplying a hydraulic pressure to the clutch means, a clutch pressure adjusting means for controlling the on / off of the clutch means by adjusting the supplied hydraulic pressure,
A belt-type continuously variable transmission system for a vehicle, comprising: a sudden increase in hydraulic pressure that prevents a sudden increase in hydraulic pressure supplied from the clutch pressure adjusting means to the clutch means. 2. The belt-type continuously variable transmission for a vehicle according to claim 1, wherein the sudden increase in hydraulic pressure has a throttle that reduces a cross-sectional area of a flow path of hydraulic pressure supplied from the clutch pressure adjusting means to the clutch means. system. The belt type continuously variable vehicle according to claim 1 or 2, wherein the hydraulic pressure sudden rise preventing means has an accumulator for temporarily storing hydraulic pressure supplied from the clutch pressure adjusting means to the clutch means. Transmission system. 4. The control device according to claim 1, further comprising a control unit configured to supply a hydraulic pressure to the primary pulley and the secondary pulley according to an engine speed to change a belt torque capacity. 5. Belt-type continuously variable transmission system for vehicles.

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