JP2017155888A - Lubrication device of drive system of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To immediately increase a circulation amount of oil to an oil reservoir 21, and to suppress the mixing of air bubbles into the oil caused by the suction of air when the suction of the air occurs at the supply of the oil to a region which is necessary to be lubricated or cooled by scooping up the oil by an oil pump 4 from the oil reservoir 21 of a machine chamber R1, in a drive system (transaxle 1) of a vehicle.SOLUTION: A flow rate control valve 5 whose valve-opening degree is changed according to the hydraulic pressure of a discharge oil passage 43 from an oil pump 4 is arranged at a reflux oil passage 44 of oil to an oil reservoir 21 from an oil storage chamber such as, for example, a catch tank 40, and when the hydraulic pressure is lowered to prescribed hydraulic pressure P2 or lower, and it is thought that air bubbles are mixed, the value-opening degree is increased, and a reflux volume of the oil is increased.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a drive system lubrication device such as a transmission of a vehicle, and relates to an apparatus for pumping oil from an oil reservoir in a machine room in which a gear mechanism is accommodated.

  2. Description of the Related Art Conventionally, in a transmission mounted on a vehicle, oil is pumped from an oil reservoir provided at the bottom of a casing by an oil pump and supplied to a lubrication site such as a clutch or a bearing. For example, in the transmission described in Patent Document 1, the oil reservoir (oil reservoir) is partitioned by a partition wall from the first partition corresponding to the bottom of the machine chamber in which the gear mechanism is housed. The oil pump is divided into second compartments, and the suction ports of the oil pump are opened in the first and second compartments, respectively.

  In addition, a float valve is provided at the suction port of the first section so that it can be opened and closed following the oil level. If the oil level becomes high, the suction port is opened to suck in the oil. Therefore, the oil level is lowered. This reduces oil agitation resistance by rotating parts such as gears and clutches, and also suppresses foaming of the agitated oil. On the other hand, if the oil level of the first section is lowered, the suction port is closed by the float valve, so that air can be prevented from being sucked together with the oil.

  Further, the suction port of the second section is always open, but the oil supplied to the control body of the transmission and the oil cooled by the oil cooler are recirculated to the second section. Since the oil is always filled with oil during the steady running of the vehicle, there is no fear that the oil level becomes low and air is sucked in along with the oil from the suction port.

JP 2011-27142 A

  However, in the conventional example, the oil in the first section having a low oil level does not flow to the second section beyond the partition wall. Therefore, even if the suction ports are opened in both sections as described above, If the amount of oil sucked is not always properly balanced, the amount of oil stored in each section cannot be maintained at a desired amount, which may lead to unexpected problems.

  That is, for example, when the engine is cold, the operation of the oil pump starts with no oil remaining in the control body of the transmission, and the oil in the first and second compartments is sucked in at a stroke. As a result, in the second section in which the float valve is not provided in the suction port, the height of the oil level is lowered at a stretch, and there is a possibility that air is sucked together with the oil from the suction port.

  At this time, in the first section, the height of the oil level is maintained by the float valve. However, since this oil level is lower than the partition wall, the oil does not flow into the second section. For this reason, in the second section, the oil level is lowered until the oil recirculates through the control body, the oil cooler, etc., and the air suction continues. As a result, bubbles are mixed into the oil discharged from the oil pump, causing problems such as a decrease in hydraulic pressure.

  In view of such circumstances, an object of the present invention is to immediately increase the amount of oil to be recirculated to the oil reservoir when air inhalation occurs as described above, thereby suppressing the mixing of bubbles into the oil. .

  In order to achieve the above object, in the lubricating device according to the present invention, a flow control valve is provided in the oil return oil passage to the oil reservoir, and the pressure of the oil discharged from the oil pump becomes a predetermined value or less. When it was considered that bubbles were included, the amount of oil reflux was immediately increased.

  Specifically, the present invention is a lubrication apparatus in which oil is pumped up by an oil pump from an oil reservoir in a machine room in which a gear mechanism of a drive system of a vehicle is housed, and supplied to a predetermined portion requiring lubrication or cooling. A discharge oil passage communicating with the discharge port of the oil pump, and a reflux oil passage through which at least a part of the oil supplied to the predetermined portion returns to the oil reservoir through an oil storage chamber. ing.

  As a feature of the present invention, the reflux oil passage is provided with a flow rate control valve whose degree of valve opening varies according to the oil pressure of the discharge oil passage, and the oil pressure of the discharge oil passage contains bubbles in the oil. If the predetermined hydraulic pressure is less than the predetermined hydraulic pressure, the degree of opening of the flow rate control valve is greater than when the predetermined hydraulic pressure is exceeded.

  Due to the above-mentioned invention specific matters, the oil level of the oil sump in the machine room is moderately high during normal times such as during steady running of the vehicle, and there is no fear of air being sucked in along with the oil, and the oil is discharged from the oil pump. The oil is essentially free of bubbles. Therefore, when the hydraulic pressure exceeds a predetermined hydraulic pressure, the degree of opening of the flow rate control valve in the return oil passage is reduced, and the amount of oil returned to the oil reservoir is reduced. Thereby, the height of the oil level of the oil reservoir is maintained at an appropriate level, and the oil stirring resistance by the gear mechanism is reduced.

  On the other hand, if for some reason the oil level in the oil reservoir temporarily drops and air is sucked in along with the oil from the suction port, bubbles are mixed into the oil discharged from the oil pump, and the oil pressure drops. To do. When the hydraulic pressure falls below the predetermined hydraulic pressure, the degree of opening of the flow control valve in the reflux oil passage increases accordingly, so that the amount of oil recirculated to the oil reservoir increases and the oil level rises quickly. As a result, inhalation of air is suppressed.

  That is, according to the present invention, the oil level height of the oil sump in the machine room can be suitably maintained during normal times, the oil stirring resistance by the gear mechanism can be reduced, and the oil level height can be lowered for some reason. If air is sucked in, the amount of oil that is immediately returned to the oil reservoir can be increased to prevent air bubbles from entering the oil.

  As an example, the flow control valve may be configured to operate by receiving the hydraulic pressure of the discharge oil passage as a pilot hydraulic pressure, or an electromagnetic valve may be used. In this case, a sensor for detecting the oil pressure in the discharge oil passage may be provided, and the flow rate control valve may be operated by a controller that receives a signal from the sensor.

  Specifically, the oil reservoir chamber is specifically provided with another oil reservoir (second compartment) adjacent to the oil reservoir (first compartment) of the machine chamber as in the conventional example (Patent Document 1). Alternatively, when an oil catch tank is provided at a position higher than the oil sump in the machine room, this catch tank may be used.

  As described above, according to the lubrication device for a vehicle drive system according to the present invention, the oil pump is provided with the flow rate control valve in the return oil passage for returning the oil from the oil storage chamber to the oil reservoir in the machine chamber. If the pressure of the oil discharged from the tank drops below a predetermined value, the oil recirculation amount is increased, so that if the air is sucked in, the oil level in the oil reservoir can be raised immediately, Air bubbles can be prevented from entering the oil.

It is explanatory drawing which shows schematic structure of the transaxle of the vehicle which concerns on embodiment. It is a figure which shows typically the structure of the lubrication apparatus of a transaxle, Comprising: It shows about the case where the flow control valve of a recirculation | reflux oil path is near a closed position. It is a graph which shows an example of the relationship between the hydraulic pressure (pilot hydraulic pressure) of a discharge oil path, and the valve opening degree of a flow control valve. FIG. 3 is a view corresponding to FIG. 2 when the flow control valve is fully opened. FIG. 3 is a view corresponding to FIG. 2 according to a modified example in which the flow control valve is a solenoid valve. FIG. 5 is a view corresponding to FIG. 2 according to another embodiment in which a sub-reservoir adjacent to the oil reservoir is provided and used as an oil storage chamber.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, the case where the present invention is applied to the transaxle 1 (drive system) of a hybrid vehicle will be described as an example. However, the present invention is not limited to this, and the present invention is not limited to this, for example, a belt type CVT or a stepped automatic transmission. It can also be applied.

  Although only an outline is shown in FIG. 1, in the present embodiment, the case 2 of the transaxle 1 is formed with a machine room R1 in which the first and second motor generators MG1, MG2 and the gear mechanism 3 are accommodated. In addition, although not shown, an electric chamber for accommodating a controller or the like is also formed. The machine room R1 may be further divided into a motor room in which the motor generators MG1 and MG2 are accommodated and a gear room in which the gear mechanism 3 and the like are accommodated.

  As shown in FIG. 1, four rotation axes C1 to C4 are laid out parallel to each other in the machine room R1, and the first motor generator MG1 is disposed on the first axis C1 among them. In addition, a planetary gear mechanism PG for distributing power from an engine (not shown) is disposed. Further, a counter shaft is disposed on the second axis C2, and the counter gear 32 is engaged with the ring gear 31 of the planetary gear mechanism PG.

  The second motor generator MG2 is disposed on the third axis C3, and a small-diameter gear 33 provided on the output shaft is engaged with the counter gear 32. Further, a differential DF is disposed on the fourth axis C4, and its ring gear 34 (final driven gear) meshes with a final drive gear 35 provided on the counter shaft. The output from the differential DF is transmitted to the drive wheels of the vehicle via a drive shaft (not shown).

  The fourth axis C4, which is the rotational axis of the differential DF, is at the lowest position among the four rotational axes C1 to C4, and the lower part of the ring gear 34 of the differential DF is stored at the bottom of the machine room R1. Soaked in oil (such as ATF). That is, the bottom portion of the case 2 is lowered at the bottom portion of the machine room R1, and functions as an oil reservoir (hereinafter referred to as an oil reservoir 21).

  Then, when the ring gear 34 rotates while the vehicle is running, the oil stored in the oil reservoir 21 is scraped up (shown as an arrow O) and supplied to the parts requiring lubrication such as various gears 31 to 35 and bearings. Later, it flows down to the lower oil reservoir 21. A part of the oil thus scraped up is temporarily stored in a catch tank 40 (oil storage chamber) provided above the first motor generator MG1, and the first motor generator MG1. For example, it is supplied to a portion requiring cooling.

  Furthermore, as schematically shown in FIG. 2, in the present embodiment, the oil pump 4 is disposed so as to pump up oil from the oil reservoir 21 and supply it to the portion requiring lubrication and cooling. The oil pump 4 is driven by, for example, a counter shaft, and a suction oil passage 41 constituted by an oil pipe is connected to the suction port, and the oil in the oil reservoir 21 is sucked through an oil strainer 42. It is like that.

  On the other hand, the upstream end (lower end in FIG. 2) of the discharge oil passage 43 constituted by an oil pipe or the like communicates with the discharge port of the oil pump 4. The discharge oil passage 43 is configured to supply oil to the first and second motor generators MG1 and MG2 via an oil passage (not shown) provided on the side wall of the case 2, for example. In this way, a part of the oil supplied to a portion requiring lubrication or cooling is also temporarily stored in the catch tank 40, and the remaining oil flows down to the lower oil reservoir 21.

  In other words, in the present embodiment, a part of the oil supplied to the portion requiring lubrication or cooling flows into the catch tank 40 as indicated by an arrow in FIG. 2, and is temporarily stored. Yes. As a result, it is possible to suppress the amount of oil flowing down to the oil reservoir 21 from being excessively large and to maintain the height of the oil surface suitably, so that the oil agitation resistance can be reduced.

  Thus, an appropriate amount of oil is recirculated from the catch tank 40 for adjusting the return amount of oil to the oil reservoir 21 through the recirculation oil passage 44. The reflux oil passage 44 is also constituted by an oil pipe or the like, and its upper end passes through the bottom of the catch tank 40, while the lower end of the reflux oil passage 44 is opened downward above the oil reservoir 21 in the machine chamber R1. Yes.

  A flow rate control valve 5 that adjusts the flow rate of oil flowing from the catch tank 40 to the oil reservoir 21 is interposed in the middle of the reflux oil passage 44. The flow control valve 5 of the present embodiment is a spool valve, and the spool 51 is urged toward the fully open position (the left position in FIG. 2) by the pressing force of the spring 52. The flow control valve 5 is connected to the downstream end of a pilot oil passage 45 that branches from the middle of the discharge oil passage 43, and the spool 51 is closed by the oil pressure (pilot oil pressure) (on the right side of FIG. 2). Is biased toward (position).

  And the valve opening degree of the flow control valve 5 changes continuously by the position of the spool 51 changing by the balance of those energizing forces. That is, as shown in an example in FIG. 3, if the pilot hydraulic pressure P supplied from the discharge oil passage 43 (that is, the oil pressure of the discharge oil passage 43) is equal to or higher than the valve closing pressure P1, the flow control valve 5 is closed. If the pilot oil pressure P is less than the valve closing pressure P1, the valve is opened. Thereafter, the lower the pilot oil pressure P, the larger the valve opening degree.

  The spring constant, the free length, and the like of the spring 52 that presses the spool 51 are set so that the valve closing pressure P1 is higher than a predetermined oil pressure P2 when bubbles are included in the oil. Therefore, as shown in FIG. 3, the degree of opening of the flow rate control valve 5 is greater when the pilot oil pressure P is less than or equal to the predetermined oil pressure P2 compared to when the predetermined oil pressure P2 is exceeded.

  Therefore, if the oil discharged from the oil pump 4 does not substantially contain bubbles and the discharge pressure exceeds the predetermined oil pressure P2, the degree of opening of the flow control valve 5 is relatively small, and the recirculation The amount of oil reflux in the oil passage 44 is reduced. On the other hand, if the oil contains bubbles and the oil pressure in the discharge oil passage 43 is equal to or less than the predetermined oil pressure P2, the degree of opening of the flow control valve 5 increases and the amount of oil recirculation increases.

  According to the lubricating device configured as described above, during normal times such as during steady running of the vehicle, for example, the pilot oil pressure P from the discharge oil passage 43 of the oil pump 4 becomes higher than the predetermined oil pressure P2, and in response to this. In the flow rate control valve 5 in the reflux oil passage 44, as shown in FIG. 2, the spool 51 is closer to the closed position, and the degree of valve opening becomes relatively small. As a result, the flow of oil from the catch tank 40 is throttled and its recirculation amount is reduced, so that the oil level of the oil reservoir 21 is maintained so as not to become too high, and the oil stirring resistance by the ring gear 34 is reduced. Can be reduced.

  On the other hand, when the oil level of the oil reservoir 21 is temporarily lowered for some reason and the air is sucked into the oil strainer 42 together with the oil, bubbles are included in the oil discharged from the oil pump 4. The hydraulic pressure decreases. As a result, the pilot hydraulic pressure P to the flow control valve 5 also decreases, so that the spool 51 moves toward the closed position as shown in FIG. 4 and the degree of valve opening increases. Accordingly, the amount of oil recirculated from the catch tank 40 increases, and the oil level of the oil reservoir 21 rises quickly, thereby suppressing air inhalation.

  That is, according to the present embodiment, in the case 2 (machine room R1) of the transaxle 1, the oil level of the oil reservoir 21 can be suitably maintained, and the oil stirring resistance by the ring gear 34 can be reduced. If the oil level temporarily decreases and air suction occurs, the amount of oil recirculated to the oil reservoir 21 can be immediately increased to quickly suppress air suction. Thereby, mixing of the bubble to oil can be controlled.

-Modification-
FIG. 5 shows a modification in which the flow rate control valve 5 is constituted by a solenoid valve (electromagnetic valve) in the above embodiment. In this modified example, the pilot oil passage 45 is not provided, and the spool 51 of the flow control valve 5 is driven by the electromagnetic solenoid 53. Except for this point, the configuration of the modified example is the same as that described above. The same reference numerals are given to the same members, and the description thereof is omitted.

  In this modification, a hydraulic pressure sensor 46 is disposed in the discharge oil passage 43 through which oil is discharged from the oil pump 4, and the signal is input to the controller 6. The controller 6 only needs to control the first and second motor generators MG1 and MG2, for example. The controller 6 operates the electromagnetic solenoid 53 in accordance with the discharge pressure detected by the hydraulic sensor 46, and is similar to the above embodiment. The position of the spool 51 is changed.

  Therefore, in this modification as well, the opening degree of the flow rate control valve 5 is controlled according to the pressure of the oil discharged from the oil pump 4 and the amount of oil recirculated from the catch tank 40 is adjusted as in the above embodiment. As a result, the oil level of the oil reservoir 21 is suitably maintained, the oil stirring resistance by the ring gear 34 is reduced, and the oil recirculation amount to the oil reservoir 21 is immediately increased when the oil level temporarily decreases. It is possible to increase the air intake and quickly suppress the air suction.

-Other embodiments-
The configuration of the present invention is not limited to the above-described embodiment and its modifications, but includes other various forms. That is, in the above-described embodiment and the like, a part of the oil supplied to the motor generators MG1, MG2 and the gear mechanism 3 is temporarily stored in the catch tank 40, and the catch tank 40 passes through the reflux oil passage 44. Although the oil is recirculated to the oil reservoir 21, it is not limited to this.

  That is, for example, as in the conventional example described in Patent Document 1, the sub-reservoir 22 may be partitioned at the bottom of the case 2 of the transaxle 1 so as to be adjacent to the oil reservoir 21, and this may be used as an oil storage chamber. In this case, as shown in FIG. 6, for example, a reflux oil passage 47 is provided so as to penetrate the partition wall 23 between the oil reservoir 21 and the adjacent sub reservoir 22, and oil is supplied from the sub reservoir 22 to the oil reservoir 21. To reflux.

  Then, the downstream end of the pilot oil passage 45 that branches from the middle of the discharge oil passage 43 is connected in the middle of the reflux oil passage 47 by interposing the flow control valve 5 formed of a spool valve in the same manner as in the above embodiment. In this way, the flow control valve 5 operates in accordance with the balance between the urging force of the pilot oil pressure P (hydraulic pressure of the discharge oil passage 43) and the urging force of the spring 52, as in the above embodiment. When the hydraulic pressure becomes equal to or lower than the predetermined hydraulic pressure P2, the degree of opening of the flow control valve 5 increases, and the amount of oil recirculation increases.

  Therefore, as in the above-described embodiment, the oil level of the oil reservoir 21 is suitably maintained, and the oil stirring resistance by the ring gear 34 is reduced. When the oil level temporarily decreases, the oil reservoir 21 is immediately returned. The amount of oil recirculated can be increased, and air inhalation can be quickly suppressed. In this case, the flow control valve 5 may be constituted by a solenoid valve as in the above-described modification.

  In the present invention, since the oil level of the oil reservoir 21 is suitably maintained and the oil agitation resistance by the gear mechanism is reduced, mixing of bubbles into the oil due to air suction can be suppressed. Useful for systems.

1 Transaxle (drive system)
2 Transaxle case 21 Oil reservoir (oil reservoir) at the bottom of the case
3 Gear mechanism 4 Oil pump 5 Flow control valve 40 Catch tank (oil storage chamber)
43 Discharge oil passage 44 Reflux oil passage 46 Hydraulic pressure sensor R1 Machine room in the case of the transaxle

Claims (1)

A lubricating device that pumps up oil by an oil pump from an oil reservoir in a machine room in which a gear mechanism of a vehicle drive system is housed, and supplies the oil to a predetermined portion that requires lubrication or cooling,
A discharge oil passage communicating with a discharge port of the oil pump;
A reflux oil path in which at least a part of the oil supplied to the predetermined part flows back to the oil reservoir through an oil storage chamber,
The reflux oil passage is provided with a flow rate control valve whose degree of valve opening varies according to the oil pressure of the discharge oil passage, and the oil pressure of the discharge oil passage is a predetermined oil pressure when bubbles are included in the oil. If it is below, it is comprised so that a valve opening degree may become large compared with the time of exceeding this predetermined oil_pressure | hydraulic, The lubricating device of the drive system of the vehicle characterized by the above-mentioned.

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