JP2012219977A - Hydraulic control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic control device for a vehicle capable of effectively using heat generated by a torque converter and easily and early increasing oil temperature during cold time.SOLUTION: The hydraulic control device for the vehicle having a continuously variable transmission 12 and the torque converter 6 with a lockup mechanism includes: normal oil passages 11, 14 supplying oil discharged from an oil pump 3 and supplied to the torque converter 6 to an oil supply portion 13 and then recirculating the oil to the oil pump 3; a directly connecting oil passage 15 directly recirculating oil supplied to the torque converter 6 to the oil pump 3; a selector valve 10 selectively switching a flowing destination of the oil discharged from the torque converter 6 to the normal oil passages 11, 14 or the directly connecting oil passage 15; and switching control means 10, 16 operating the selector valve 10 to switch the oil flowing destination to the directly connecting oil passage 15 when an oil temperature is lower than a prescribed temperature predetermined as a threshold value.

Description

  The present invention relates to a hydraulic control device for supplying oil to a transmission mounted on a vehicle and various devices related to the transmission, and more particularly to a vehicle equipped with a continuously variable transmission and a torque converter with a lock-up mechanism. The present invention relates to a hydraulic control device.

  Oil is supplied as control hydraulic pressure or lubricating oil to a transmission mounted on a vehicle and various power transmission devices such as a torque converter and a differential case. Normally, the lower the oil temperature, the greater the viscosity of the oil, so the viscosity of the oil increases immediately after starting or when the oil temperature is low at low temperatures, resulting in a decrease in oil pressure response or loss due to viscous resistance. It gets bigger. In view of this, devices and systems have been developed for the purpose of improving the oil pressure responsiveness and reducing loss by increasing the oil temperature early.

  An example of an apparatus for the purpose of quickly raising the oil temperature as described above is described in Patent Document 1. The drive control device for a transmission oil pump described in Patent Document 1 uses a mechanical oil pump that is driven by an engine and an electric oil pump that is driven by an electric motor as a hydraulic pressure source, and a control valve unit that has an ATF. An oil temperature sensor for detecting the oil temperature of the oil, an ATF warmer communicating with the downstream of the control valve unit via an oil passage, and an electric oil pump upstream of the control valve unit And an oil path switching unit that can selectively communicate with the downstream oil path, and a control unit that controls the oil path switching unit and the electric motor. When the oil temperature is equal to or lower than the low oil temperature judgment value, the oil path switching unit is operated to connect the electric oil pump to the downstream oil path, and the electric oil pump is driven to remove the oil. It is configured to supply to the ATF warmer.

  Further, Patent Document 2 discloses that a torque converter provided between an internal combustion engine and an automatic transmission is engaged and operated according to the oil pressure of the engagement side oil chamber and the release side oil chamber of the torque converter. An invention relating to a control device for a vehicle on which a lockup clutch is mounted is described. The device described in Patent Document 2 includes a lockup switching valve that supplies oil to either the engagement-side oil chamber or the release-side oil chamber of the torque converter and discharges the oil from the other, and a release-side oil chamber And a lockup control valve for adjusting the slip amount of the lockup clutch by adjusting the pressure of oil discharged through the lockup switching valve. And in this patent document 2, the control of turning on the lock-up switching valve and turning off the lock-up control valve at the time of running / stopping at low oil temperature, the hydraulic circuit of the torque converter is controlled. A configuration is described in which oil that is shut off and warmed by the torque converter is prevented from being cooled outside the torque converter, and heat loss of oil during running and stopping at low oil temperatures is reduced. ing.

JP 2006-307950 A JP 2010-127380 A

  In the device described in Patent Document 1, when the oil temperature is low, the electric oil pump and the ATF warmer are directly connected via an oil passage on the downstream side, and the electric oil pump Driven. Therefore, the oil discharged from the electric oil pump is directly supplied to the ATF warmer without going through the control valve unit, so that the temperature of the oil at a low temperature can be raised quickly.

  However, the conventional oil temperature raising means such as the ATF warmer described in Patent Document 1 generally uses the heat generated in the engine as a heat source. Until the temperature is raised, the temperature raising effect of the oil by the temperature raising means may not be expected.

  Further, in the device described in Patent Document 2 described above, attention is focused on the heat generated inside the torque converter. Generally, in the converter region where the lock-up clutch does not operate, the torque converter causes oil agitation and shear between the pump impeller and the stator or between the turbine runner and the stator. Heat is generated by friction. Therefore, in the hydraulic circuit including the torque converter, the amount of heat generated by the torque converter is usually the largest. Therefore, it is conceivable to raise the temperature of oil during cold using heat generated by the torque converter.

  However, in the conventional configuration as shown in FIG. 4, for example, the oil discharged from the torque converter passes through oil supply parts such as a continuously variable transmission belt and a pulley and a differential case, an oil pan, a strainer, and the like. Recirculated to oil pump. For this reason, the oil whose temperature has been raised by the heat of the torque converter radiates heat when passing through these oil supply parts and oil pan, and the oil temperature is lowered. In other words, the conventional configuration cannot effectively use the heat generated by the torque converter.

  On the other hand, the device described in the above-mentioned Patent Document 2 is configured to suppress that the oil heated up by the heat of the torque converter is discharged to the outside of the torque converter and dissipated. Yes. However, although the device described in Patent Document 2 also pays attention to the heat generated by the torque converter, it is configured to actively raise the temperature of the oil using the heat of the torque converter. However, there is still room for improvement in order to effectively use the heat generated by the torque converter and to raise the temperature of the oil easily and quickly.

  The present invention has been made paying attention to the above technical problem, and without using a temperature raising means or a special heating means using heat generated by the engine as a heat source at a low temperature or cold immediately after starting. An object of the present invention is to provide a vehicle hydraulic control device that can effectively use heat generated in a torque converter and easily and quickly raise the temperature of oil.

  In order to achieve the above object, an invention according to claim 1 provides a continuously variable transmission, a torque converter with a lockup mechanism, oil to the continuously variable transmission, the lockup clutch, and the torque converter. In the hydraulic control apparatus for a vehicle including a hydraulic circuit for supplying and discharging, the hydraulic circuit supplies oil discharged from an oil pump and supplied to the torque converter from the torque converter to oil in each part of the continuously variable transmission. A normal oil passage that recirculates to the oil pump after being supplied to the supply site, a direct oil passage that recirculates the oil supplied to the torque converter directly from the torque converter to the oil pump, and is discharged from the torque converter Switching for selectively switching the flow destination of the oil between the normal oil passage and the direct oil passage And a switching control means for operating the switching valve to switch the flow destination of the oil to the directly connected oil path when the oil temperature of the oil is lower than a predetermined temperature set as a threshold value. It is characterized by being.

  According to a second aspect of the present invention, in the first aspect of the present invention, the hydraulic circuit is provided between the oil pump and the torque converter so as to set engagement / release of the lockup clutch. A lockup control valve for controlling the oil temperature, and an oil temperature sensor provided between the oil pump and the lockup control valve, wherein the switching control means is based on the oil temperature detected by the oil temperature sensor. Means for determining switching between the normal oil passage and the direct oil passage.

  According to the first aspect of the present invention, when the oil temperature is low and the viscosity is high, the oil supplied from the oil pump to the torque converter is discharged from the torque converter, and then another oil supply site or oil is supplied. It will be returned directly to the oil pump without going through the pan. Therefore, it is possible to suppress the decrease in the oil temperature due to heat dissipation when the oil whose temperature is increased inside the torque converter circulates in the hydraulic circuit, and to increase the temperature of the oil by effectively using the heat generated in the torque converter. It is possible to easily increase the temperature of the oil when it is cold. As a result, the loss due to the viscous resistance of the oil can be reduced, and consequently the fuel consumption of the vehicle can be improved.

  According to the second aspect of the present invention, the lockup control valve and the oil temperature sensor are provided in the directly connected hydraulic circuit that is switched between the oil pump and the torque converter by switching to the directly connected oil passage when cold. It is done. Therefore, it is possible to increase the temperature of the oil during the cold by actively and effectively using the heat generated in the torque converter. As a result, by promoting the temperature rise of the oil, the oil temperature can be raised to the lockup permission oil temperature in the lockup mechanism of the torque converter at an early stage, and the frequency of the lockup state by the lockup mechanism can be increased. In this respect, the fuel efficiency of the vehicle can be improved.

It is a figure which shows typically the structure of the hydraulic control apparatus by this invention. It is a schematic diagram for demonstrating the friction loss characteristic by the viscous resistance of the oil in a continuously variable transmission and a torque converter. It is a schematic diagram for demonstrating the friction loss characteristic by the viscous resistance of the oil in an oil pump. It is a figure which shows typically the structure of the conventional hydraulic control apparatus.

  Next, the present invention will be described with reference to specific examples. FIG. 1 schematically shows an example of a vehicle hydraulic control apparatus that is a subject of the present invention and that is equipped with a continuously variable transmission and a torque converter with a lock-up mechanism. The hydraulic circuit C of the hydraulic control device shown in FIG. 1 sucks oil from the oil pan 1 with an oil pump 3 through a strainer 2 and the like, and the hydraulic pressure generated by the oil pump 3 The oil is supplied to the torque converter 6 via a lock-up control valve 5 provided in the middle of the oil passage 4. That is, the hydraulic circuit C is configured to generate a hydraulic pressure by the oil pump 3 and supply the torque converter 6 with oil as control hydraulic pressure or lubricating oil. An oil temperature sensor 7 for detecting the oil temperature of the oil flowing in the oil passage 4 is provided between the oil pump 3 and the lockup control valve 5 and in the vicinity of the discharge port 3o of the oil pump 3. It has been.

  The torque converter 6 is a torque converter with a so-called lock-up mechanism provided with a lock-up clutch 8. By engaging the lock-up clutch 8, the torque converter 6 is mechanically connected directly. Is possible. The engagement / release state of the lock-up clutch 8 is controlled by hydraulic pressure in accordance with the traveling state of the vehicle such as the vehicle speed and the engine speed, as in the known lock-up mechanism of the torque converter. That is, the engagement / release operation of the lockup clutch 8 is controlled based on the control hydraulic pressure supplied and discharged from the lockup control valve 5 described above.

  If the oil temperature during the hydraulic control of the engagement / release operation of the lock-up clutch 8 is low, the viscosity of the oil increases, so the responsiveness of the hydraulic control decreases and the clutch engagement / release operation is appropriate. May not be done. Therefore, the lockup permission oil temperature is set so that the engagement / release operation of the lockup clutch 8 is performed under an oil temperature equal to or higher than a predetermined temperature that does not hinder its operation. This lock-up permission oil temperature is appropriately set in advance in consideration of the properties of the oil to be used, the structure of the device, and the like.

  The hydraulic circuit C discharges the oil supplied to the torque converter 6 as described above from the torque converter 6 after passing through the inside of the torque converter 6, that is, between the pump impeller and the turbine runner. The discharged oil is supplied to the oil supply portion 13 of each part of the belt type continuously variable transmission 12 through the oil passage 9, the switching valve 10 and the oil passage 11 communicating with the discharge portion 6 o of the torque converter 6. It is configured. Then, the oil supplied to the oil supply portion 13 is returned to the oil pan 1 via the oil passage 14. Therefore, the hydraulic circuit C supplies the oil discharged from the oil pump 3 and supplied to the torque converter 6 to the oil supply portion 13 from the torque converter 6 via the oil passage 9 and the oil passage 11, It is configured to recirculate to the oil pump 3 through the passage 14, the oil pan 1, the strainer 2, and the like.

  The belt used in the belt type continuously variable transmission 12 may be, for example, a pressing type belt constituted by a large number of elements and rings, or a chain structure continuously variable transmission belt. It may be.

  The switching valve 10 is configured to selectively communicate one suction port 10i and one of the two discharge ports 10a and 10b. In the hydraulic circuit C, as described above, An oil passage 9 is communicated with the suction port 10i, and an oil passage 11 is communicated with one discharge port 10a. An oil passage 15 is communicated with the other discharge port 10b. As described above, one end of the oil passage 15 communicates with the discharge portion 6o of the torque converter 6 via the switching valve 10 and the oil passage 9, and the other end communicates with the suction port 3i of the oil pump 3. Has been. That is, the oil passage 15 is an oil passage for returning the oil supplied to the torque converter 6 directly from the torque converter 6 to the oil pump 3, and functions as a direct oil passage in the present invention. .

  In contrast, the oil passage 11 and the oil passage 14 described above normally supply oil discharged from the oil pump 3 and supplied to the torque converter 6 from the torque converter 6 via the oil passage 9 and the oil passage 11. The oil passage for feeding back to the oil pump 3 through the oil passage 14, the oil pan 1, the strainer 2 and the like after being supplied to the oil supply portion 13, and functions as a normal oil passage in the present invention. is there.

  An electronic control unit (ECU) for electrically controlling the operation of each part of the hydraulic circuit C configured as described above, specifically, the operation of the lockup control valve 5 and the switching valve 10 described above. 16 is provided. The electronic control device 16 is configured mainly by a microcomputer as an example, and performs an operation according to a predetermined program based on input data and data stored in advance, and controls the lockup control valve 5 and the switching valve 10. It is configured to execute control of an operation state of a solenoid valve or the like for operating. For this electronic control unit 16, for example, a detection signal from a rotation speed sensor (not shown) or a vehicle speed sensor (not shown) for detecting the rotation speed of the oil temperature sensor 7 or each rotation member described above. Is entered.

  Therefore, the hydraulic control apparatus according to the present invention including the hydraulic circuit C described above can control the switching operation of the switching valve 10 based on the oil temperature detected by the oil temperature sensor 7. That is, according to the temperature of the oil discharged from the oil pump 3, the flow destination of the oil discharged from the torque converter 6 is selected as the oil passage 11, the oil supply portion 13, the oil passage 14, and the oil passage 15. Can be switched automatically. For example, in consideration of the above-described lock-up permission oil temperature, friction loss due to oil viscosity resistance, and the like, by setting a reference temperature as a threshold value in advance, the oil temperature in the hydraulic circuit C is lower than the reference value. In the case of low, the switching valve 10 can set the communication destination of the oil passage 9 to the oil passage 15 or switch to connect the discharge portion 6o of the torque converter 6 and the suction port 3i of the oil pump 3 directly.

  For example, as shown in FIGS. 2 and 3, in the oil supply portion 13 and the torque converter 6 in the belt type continuously variable transmission 12 such as a belt and a pulley, there is almost no temperature dependency of friction loss due to oil viscous resistance. On the other hand, in the oil pump 3, the temperature dependence of the friction loss due to the viscous resistance of the oil is large. That is, in the oil pump 3, when the oil temperature is low and the oil viscosity is high, the friction loss due to the viscosity resistance of the oil also increases. Therefore, when the oil temperature is low and the viscosity of the oil is cold, the exhaust portion 6o of the torque converter 6 and the suction port 3i of the oil pump 3 are directly connected by the oil passage 15 as described above. The oil warmed by the heat generated by the oil can be directly recirculated to the oil pump 3 without circulating the oil supply part 13 or the oil pan 1, and the temperature of the oil in the hydraulic circuit C during the cold is efficiently raised. be able to. As a result, it is possible to effectively reduce the loss due to the viscous resistance of oil in the oil pump 3 in particular.

  Although not shown, oil can be supplied to the oil supply portion 13 from a system different from the hydraulic circuit C. For example, oil can be supplied to the oil supply portion 13 from a hydraulic system that is regulated by a secondary regulator valve (not shown). Therefore, even when the flow destination of the oil discharged from the torque converter 6 is switched to the oil passage 15 in the cold state as described above, the oil is supplied to the oil supply portion 13 from another system. So there is no shortage of oil.

  As described above, according to the hydraulic control device of the present invention, the oil supplied from the oil pump 3 to the torque converter 6 is discharged from the torque converter 6 when the oil temperature is low and the viscosity is high. Thereafter, the oil is directly returned to the oil pump 3 without going through the oil supply part 3 or the oil pan 1. Therefore, it is possible to prevent the oil whose temperature has been raised inside the torque converter 3 from radiating heat when it flows through the oil supply part 3 or the oil pan 1 and the oil temperature is lowered. Therefore, the oil whose temperature has been raised inside the torque converter 3 can significantly suppress a decrease in the oil temperature due to heat radiation when circulating through the hydraulic circuit C. Further, the heat generated in the torque converter 6 can be effectively used to raise the temperature of the oil, and the temperature rise of the oil during cold can be easily promoted.

  Further, a lockup control valve 5 and an oil temperature sensor 7 are provided in a directly connected hydraulic circuit formed between the oil pump 3 and the torque converter 6 by switching to the oil passage 15 when cold. Therefore, the heat generated in the torque converter 6 can be positively and effectively used to promote the temperature rise of the oil during the cold time, and thereby the oil temperature in the hydraulic circuit C can be reduced. The oil temperature can be raised to the lockup permission oil temperature for the lockup clutch 8 at an early stage. As a result, the frequency of the direct connection state of the torque converter 6 by engaging the lockup clutch 8 can be increased, and as a result, the fuel consumption of the vehicle can be improved.

  DESCRIPTION OF SYMBOLS 3 ... Oil pump, 5 ... Lock-up control valve, 6 ... Torque converter, 7 ... Oil temperature sensor, 8 ... Lock-up clutch, 10 ... Switching valve, 11, 14 ... Oil path (normal oil path), 12 ... Continuously Transmission: 13 ... Oil supply site, 15 ... Oil passage (directly connected oil passage), 16 ... Electronic control unit (ECU), C ... Hydraulic circuit.

Claims (2)

Hydraulic control device for a vehicle including a continuously variable transmission, a torque converter with a lockup mechanism, a hydraulic circuit for supplying and discharging oil to and from the continuously variable transmission, the lockup clutch, and the torque converter In
The hydraulic circuit includes a normal oil path that supplies oil discharged from an oil pump and supplied to the torque converter to the oil pump after being supplied from the torque converter to an oil supply portion of each part of the continuously variable transmission, A direct oil path for recirculating the oil supplied to the torque converter directly from the torque converter to the oil pump, and a flow destination of the oil discharged from the torque converter are selected as the normal oil path and the direct oil path A switching valve that automatically switches,
When the oil temperature of the oil is lower than a predetermined temperature that is predetermined as a threshold value, the oil supply apparatus includes switching control means for operating the switching valve to switch the oil flow destination to the directly connected oil path. Vehicle hydraulic control device.
The hydraulic circuit is provided between the oil pump and the torque converter and controls a hydraulic pressure for setting engagement / release of the lockup clutch, and the oil pump and the lockup An oil temperature sensor provided between the control valve and
2. The vehicle hydraulic pressure according to claim 1, wherein the switching control unit includes a unit that determines switching between the normal oil passage and the direct oil passage based on an oil temperature detected by the oil temperature sensor. Control device.

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