JP2004316832A - Hydraulic control device of continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic control device of a continuously variable transmission capable of improving fuel consumption by reducing load on an engine while securing necessary hydraulic pressure and flow. <P>SOLUTION: This hydraulic control device of the continuously variable transmission controlling a V-belt continuously variable speed-change mechanism comprises a line pressure circuit system in which a main pump driven by the engine is used as a hydraulic pressure source and which supplies pulley hydraulic pressure and the other hydraulic circuit system in which at least a hydraulic pressure drained from the line pressure circuit system is used as a hydraulic pressure source and which supplies a hydraulic pressure to a fluid electric device and a forward/reverse movement switching mechanism. The control device also comprises a sub pump driven by an electric motor, and the sub pump is connected to the other hydraulic circuit system through a check valve which allows only the supply of hydraulic pressure from the sub pump side. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hydraulic control device for a continuously variable transmission, and more particularly to a hydraulic control device for a belt-type continuously variable transmission.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a hydraulic control device for a V-belt type continuously variable transmission, a technique described in Patent Literature 1 is known. In this technique, a single oil pump driven by an engine supplies hydraulic pressure to a pulley holding a belt, a fluid electric device, a forward / reverse switching mechanism, and various lubricating parts. At this time, since the hydraulic pressure for the pulley requires the highest hydraulic pressure, the hydraulic circuit uses the drain pressure of the pressure regulator valve for adjusting the hydraulic pressure for the pulley as the hydraulic pressure for other devices and mechanisms.
[0003]
[Patent Document 1]
JP-A-7-259939 (see pages 4 and 5).
[0004]
[Problems to be solved by the invention]
However, the above-described prior art has the following problems. That is, in the belt-type continuously variable transmission, the required hydraulic pressure for the pulley is much higher than the hydraulic pressure for other devices and mechanisms, and even when the drain pressure of the pressure regulator valve is used, The hydraulic pressure is supplied higher than necessary for the mechanism and mechanism. Therefore, as a whole, an oil pump having a size that discharges an originally unnecessary flow rate is provided under each traveling condition, which causes a problem that fuel efficiency is deteriorated.
[0005]
In particular, although the hydraulic pressure for the pulley needs to be high, the flow rate is only a part of the valve leak amount and the shift flow rate during shifting. On the other hand, the capability required of the oil pump is required to discharge a high oil pressure while securing a flow rate to another circuit system, and thus has a problem that fuel efficiency is deteriorated.
[0006]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and a hydraulic pressure of a continuously variable transmission capable of improving fuel efficiency by reducing engine load while securing necessary hydraulic pressure and flow rate. It is an object to provide a control device.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, in a hydraulic control apparatus for a continuously variable transmission that controls a V-belt type continuously variable transmission mechanism, a sub-pump driven by an electric motor is provided, and the sub-pump and another hydraulic circuit system are connected. By connecting via a check valve that allows only hydraulic pressure supply from the sub-pump side, the above problem has been solved.
[0008]
Effect of the Invention
In the present invention, the main pump driven by the engine supplies only the pulley pressure that is high in hydraulic pressure, and the flow rate of low hydraulic pressure is supplied by the sub-pump, so that the main pump can have the minimum necessary pump size. As a result, the engine load can be reduced. In addition, since the hydraulic pressure drained from the line pressure circuit system is used as a hydraulic source for another hydraulic circuit system, it is possible to reduce or stop the electric motor when the sub-pump does not need to be driven. Consumption can be reduced.
[0009]
As described above, since the electric power is converted from the rotational energy of the engine by the alternator, it is possible to reduce unnecessary energy consumption by executing the necessary minimum electric pump drive in each traveling condition, and thereby reducing the use of the vehicle. Fuel efficiency can be improved.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0011]
(Embodiment 1)
FIG. 1 is a diagram illustrating a control system of an automatic transmission including a belt-type continuously variable transmission 3 (hereinafter, referred to as CVT) according to the first embodiment.
[0012]
1 is a torque converter, 2 is a lock-up clutch, 3 is a CVT, 4 is a primary speed sensor, 5 is a secondary speed sensor, 6 is a hydraulic control valve unit, 8 is a main pump driven by an engine, and 9 is CVT control. The unit 10 is an accelerator opening sensor, and 11 is an oil temperature sensor.
[0013]
A torque converter 1 is connected to the engine output shaft as a rotation transmission mechanism, and a lock-up clutch 2 that directly connects the engine and the CVT 3 is provided. The output side of the torque converter 1 is connected to the ring gear 21 of the forward / reverse switching mechanism 20. The forward / reverse switching mechanism 20 includes a planetary gear mechanism including a ring gear 21 connected to the engine output shaft 12, a pinion carrier 22, and a sun gear 23 connected to the transmission input shaft 13. The pinion carrier 22 is provided with a reverse brake 24 for fixing the pinion carrier 22 to the transmission case, and a forward clutch 25 for integrally connecting the transmission input shaft 13 and the pinion carrier 22.
[0014]
A primary pulley 30 a of the CVT 3 is provided at an end of the transmission input shaft 13. The CVT 3 includes the primary pulley 30a, the secondary pulley 30b, a belt 34 that transmits the rotational force of the primary pulley 30a to the secondary pulley 30b, and the like. The primary pulley 30a is provided with a fixed conical plate 31 that rotates integrally with the transmission input shaft 13, and is arranged opposite to the fixed conical plate 31 to form a V-shaped pulley groove, and the primary pulley 30a is shifted by hydraulic pressure acting on the primary pulley cylinder chamber 33. The movable conical plate 32 is movable in the axial direction of the machine input shaft 13.
[0015]
The secondary pulley 30b is provided on the driven shaft 38. The secondary pulley 30 b has a fixed conical plate 35 that rotates integrally with the driven shaft 38, a V-shaped pulley groove that is disposed to face the fixed conical plate 35, and that is driven by hydraulic pressure acting on the secondary pulley cylinder chamber 37. And a movable conical plate 36 that can move in the axial direction.
[0016]
A drive gear (not shown) is fixed to the driven shaft 38, and the drive gear drives a drive shaft reaching wheels (not shown) via a pinion, a final gear, and a differential device provided on the idler shaft.
[0017]
The rotational force input from the engine output shaft 12 to the CVT 3 as described above is transmitted to the CVT 13 via the torque converter 1 and the forward / reverse switching mechanism 20. The rotational force of the transmission input shaft 13 is transmitted to the differential via a primary pulley 30a, a belt 34, a secondary pulley 30b, a driven shaft 38, a driving gear, an idler gear, an idler shaft, a pinion, and a final gear.
[0018]
At the time of the power transmission as described above, the movable conical plate 32 of the primary pulley 30a and the movable conical plate 36 of the secondary pulley 30b are moved in the axial direction to change the contact position radius with the belt 34, so that the primary pulley 30a The rotation ratio with the secondary pulley 30b, that is, the gear ratio, can be changed. Such control of changing the width of the V-shaped pulley groove is performed by hydraulic control of the primary pulley cylinder chamber 33 or the secondary pulley cylinder chamber 37 via the CVT control unit 9.
[0019]
The CVT control unit 9 includes a throttle opening TVO from the throttle opening sensor 10, an oil temperature f in the transmission from the oil temperature sensor 11, a primary rotation speed Npri from the primary rotation speed sensor 4, and a signal from the secondary rotation speed sensor 5. The secondary rotation speed Nsec, the pulley clamp pressure from the pulley clamp pressure sensor 14, and the like are input. The control signal is calculated based on the input signal, and the control signal is output to the hydraulic control valve unit 6.
[0020]
An accelerator opening, a gear ratio, an input shaft speed, a primary oil pressure, and the like are input to the hydraulic control valve unit 6, and shift control is performed by supplying control pressure to the primary pulley cylinder chamber 33 and the secondary pulley cylinder chamber 37. .
[0021]
FIG. 2 is a circuit diagram illustrating a hydraulic circuit of the belt-type continuously variable transmission according to the first embodiment.
[0022]
Reference numeral 40 denotes a pressure regulator valve that regulates the discharge pressure of the main pump 8 supplied from the oil passage 41 as a line pressure (pulley clamp pressure). An oil passage 42 is connected to the oil passage 41 and supplies a pulley clamping pressure for clamping the belt 34 to the primary pulley cylinder chamber 33 and the secondary pulley cylinder chamber 37 of the CVT 3.
[0023]
Reference numeral 50 denotes a clutch regulator valve 50 that regulates the hydraulic pressure drained from the pressure regulator valve 40 as a clutch engagement pressure. The hydraulic pressure adjusted by the clutch regulator valve 50 is supplied to the forward clutch 25 or the reverse brake 24 via the oil passage 51 by the manual valve 60 responsive to the select lever selected by the driver.
[0024]
70 is a torque converter regulator valve that regulates the hydraulic pressure drained from the clutch regulator valve 50 as the supply pressure of the torque converter 1. The oil pressure adjusted by the torque converter regulator valve 50 is supplied to the lock-up control valve 80 via an oil passage 72 connected to the oil passage 71. The lock-up control valve 80 is regulated by the hydraulic pressure output from the torque converter regulator valve 70 via the oil passage 73 to control the engagement state of the torque converter 1 and the lock-up clutch 2.
[0025]
The oil pressure drained from the lock-up control valve 80 is collected from the oil passage 81 via the cooler 82 through each lubricating portion and into the oil pan.
[0026]
In the hydraulic circuit of the belt-type continuously variable transmission 3 according to the first embodiment, a sub-pump 90 driven by an electric motor 91 is provided as a sub-pump 90 that operates based on a command signal from the CVT control unit 9. I have. The discharge side of the sub-pump 90 is connected to the oil passage 71 via a one-way valve 93 that allows only the output from the sub-pump 90 side.
[0027]
Further, a hydraulic pressure sensor 94 for detecting the hydraulic pressure of the oil passage 71 is provided, and outputs a hydraulic pressure signal to the CVT control unit 9.
[0028]
Hereinafter, the operation of the above configuration will be described.
(Reduction of pump energy)
FIG. 6 is a diagram showing a relationship between a hydraulic pressure and a flow rate required for each traveling state in the related art. In general, the maximum set hydraulic pressure of a belt-type continuously variable transmission requires two to three times the hydraulic pressure in order to generate a pulley thrust, compared to a normal stepped transmission. It is about the leak amount and the shifting oil amount. On the other hand, other parts such as the engagement pressure of the forward clutch 25 or the reverse brake 24, the torque converter pressure for the torque converter 1 and the lock-up clutch 2, the lubrication pressure for lubricating the sliding portion between the belt and the pulley, the differential, and the like. Does not require much hydraulic pressure. In other words, the required flow rate and the required oil pressure are different for each part.
[0029]
FIG. 3 is a diagram illustrating a relationship between a hydraulic pressure and a flow rate required for each traveling state in the hydraulic control device for the continuously variable transmission according to the first embodiment. For example, the maximum hydraulic pressure Pmax required when the engine is fully opened (when the throttle is fully opened and the engine starts rotating after the engine speed is sufficiently increased) is the same as the conventional configuration, but the hydraulic pressure shared by the torque converter 1 and each lubricating portion is not changed. Is supplied by the sub pump 90, the required maximum flow rate fmax required for the main pump 8 can be reduced from the conventional flow rate Fmax.
[0030]
However, the sub pump 90 is driven by the electric motor 91, and the maximum hydraulic pressure required for the sub pump 90 is Psmax, and the maximum flow rate is fsmax. This electric power gives a load such as an alternator to the engine. In consideration of the power generation efficiency for the motor, it is possible to reduce the energy loss corresponding to the area represented by the product of the oil pressure and the flow rate, that is, the energy loss for the region A in FIG. 3 (corresponding to claim 1).
[0031]
Further, the provision of the hydraulic pressure sensor 94 makes it possible to determine whether or not the hydraulic pressure needs to be supplied by the sub-pump 90, thereby reliably reducing power consumption without driving the sub-pump 90 unnecessarily. (Corresponding to claim 2).
[0032]
(Embodiment 2)
FIG. 4 is a circuit diagram illustrating a hydraulic circuit of the belt-type continuously variable transmission according to the second embodiment. Since the basic configuration is the same as that of the first embodiment, only different points will be described.
In the hydraulic circuit of the belt-type continuously variable transmission 3 according to the second embodiment, the discharge side of the sub-pump 90 is connected to the oil passage 51 via a one-way valve 93 that allows only the output from the sub-pump 90 side. The oil passage 51 is a circuit that regulates the hydraulic pressure drained from the pressure regulator valve 40 by the clutch regulator valve 50 and supplies it to the forward clutch 25 and the reverse brake 24. Further, a hydraulic pressure sensor 94 for detecting the hydraulic pressure of the oil passage 51 is provided, and outputs a hydraulic pressure signal to the CVT control unit 9.
[0033]
FIG. 5 is a diagram illustrating a relationship between a hydraulic pressure and a flow rate required for each traveling state in the hydraulic control device for the continuously variable transmission according to the second embodiment. That is, the hydraulic control device according to the second embodiment has a configuration in which the clutch engagement pressure can be supplied by the sub-pump 90 as necessary. For this reason, the maximum hydraulic pressure Psmax required for the sub-pump 90 is slightly higher than in the first embodiment, but is within the range of low hydraulic pressure, and there is no need to make the sub-pump 90 so large. Further, although the area in which the power generation efficiency for the motor is considered increases, the energy loss for the area A can be reduced as described in the first embodiment.
[0034]
Further, the hydraulic pressure sensor 94 according to the second embodiment can detect the clutch engagement pressure. As a result, the clutch engagement pressure can be freely controlled, and the power consumption can be reliably reduced according to the traveling state without driving the sub-pump 90 unnecessarily. ).
[0035]
(Clutch engagement control during idle stop control)
Next, a case where the hydraulic control device for the continuously variable transmission according to the second embodiment is applied to an idle stop vehicle will be described. When the vehicle stops and a predetermined stop condition is met, an idle stop vehicle that is configured to automatically stop the engine to save fuel, reduce exhaust emissions, or reduce noise is already in practical use. Has been In such a vehicle, when the engine stops, the main pump 8 driven by the engine stops. For example, the oil supplied to the forward clutch 25 also drops out of the oil passage, and the hydraulic pressure decreases. Would. Therefore, when the engine is restarted, the forward clutch 25 to be engaged during forward running is also disengaged from the engaged state. If the engine is not quickly engaged, the accelerator pedal is depressed in a so-called neutral state, and there is a possibility that the forward clutch 25 is engaged with the engine blown up and an engagement shock is generated.
[0036]
Therefore, at the time of idling stop, the sub-pump 90 is driven to secure the engagement pressure of the forward clutch 25, thereby preventing the engagement shock and achieving a smooth start (corresponding to claim 4).
[Brief description of the drawings]
FIG. 1 is a system diagram illustrating an overall configuration of a belt-type continuously variable transmission according to a first embodiment.
FIG. 2 is a circuit diagram illustrating a hydraulic circuit of the continuously variable transmission according to the first embodiment.
FIG. 3 is a diagram illustrating a relationship between a required hydraulic pressure and a flow rate of the pump according to the first embodiment.
FIG. 4 is a circuit diagram illustrating a hydraulic circuit of the continuously variable transmission according to the first embodiment.
FIG. 5 is a diagram illustrating a relationship between a required hydraulic pressure and a flow rate of the pump according to the first embodiment.
FIG. 6 is a diagram illustrating a relationship between a required hydraulic pressure and a flow rate of a pump in the related art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Torque converter 2 Lock-up clutch 3 Belt-type continuously variable transmission 4 Primary speed sensor 5 Secondary speed sensor 6 Hydraulic control valve unit 8 Main pump 9 Control unit 10 Throttle opening sensor 11 Oil temperature sensor 12 Engine output shaft 13 Shift Machine input shaft 14 pulley clamp pressure sensor 20 forward / reverse switching mechanism 21 ring gear 22 pinion carrier 23 sun gear 24 reversing brake 25 forward clutch 40 pressure regulator valve 50 clutch regulator valve 50 torque converter regulator valve 60 manual valve 70 torque converter regulator valve 80 lock-up control Valve 90 Sub-pump 91 Electric motor 93 One-way valve 94 Oil pressure sensor

Claims (4)

A main pump driven by the engine is used as a hydraulic pressure source, and a line pressure circuit system for supplying a pulley hydraulic pressure, and at least a hydraulic pressure drained from the line pressure circuit system is used as a hydraulic pressure source. And a hydraulic control system for a continuously variable transmission that controls a V-belt type continuously variable transmission mechanism.
A sub-pump driven by an electric motor is provided,
A hydraulic control device for a continuously variable transmission, wherein the sub-pump and the other hydraulic circuit system are connected via a check valve that allows only hydraulic pressure supply from the sub-pump side. The hydraulic control device for a continuously variable transmission according to claim 1,
Hydraulic pressure detecting means for detecting the hydraulic pressure of a hydraulic circuit system connected to the sub-pump,
A hydraulic control device for a continuously variable transmission, comprising: motor drive control means for controlling the drive of the electric motor according to the detected hydraulic pressure. The hydraulic control device for a continuously variable transmission according to claim 2,
A hydraulic control device for a continuously variable transmission, wherein the hydraulic pressure detecting means is a coupling pressure detecting means for detecting a coupling pressure of the forward / reverse switching mechanism. The hydraulic control device for a continuously variable transmission according to any one of claims 1 to 3,
When a predetermined condition is satisfied, idle stop control means for stopping idling of the engine,
A hydraulic control device for a continuously variable transmission, comprising: motor drive control means for controlling the drive of the electric motor during idle stop.

Images