JP6292057B2 - Hydraulic supply device for vehicles - Google Patents

Description

  The present invention relates to a vehicular hydraulic pressure supply device, and more particularly, to removal of bubbles mixed in hydraulic oil.

  A transmission mechanism that shifts the power from the drive source and outputs it to the output shaft, a mechanical oil pump driven by the drive source, and an electric oil driven by an electric motor provided in parallel to the mechanical oil pump A hydraulic control circuit is realized that includes a pump and a check valve that is provided in a discharge oil passage of the electric oil pump and prevents the oil discharged from the mechanical oil pump from flowing into the electric oil pump side. . For example, the hydraulic pressure supply device described in Patent Document 1 is an example.

JP 2007-139060 A JP 2006-046610 A JP 2005-054684 A

  By the way, the oil in the hydraulic control circuit has a low viscosity when the oil temperature increases, and the amount of oil to be stirred increases, so that the oil tends to contain bubbles. When the oil containing bubbles is sucked and discharged by the oil pump, the oil is supplied to the hydraulic chamber constituting the hydraulic engagement device of the transmission mechanism, and the bubbles are accumulated in the hydraulic chamber. As a result, an air cushion is formed, and even if the oil pressure is supplied to the oil chamber, there is a possibility that the engagement of the engagement device (hegitation) or engagement shock may occur due to the presence of the air cushion. On the other hand, a technique is known in which a protrusion is provided on the lip portion of the piston constituting the hydraulic engagement device, and air bubbles are discharged from the gap between the protrusion and the case. Because it may occur, it was not an optimal measure.

  The present invention has been made against the background of the above circumstances, and the object of the present invention is to provide a vehicle that can suppress the slack of gear shifting and engagement shock by suppressing bubbles accumulated in the oil chamber of the transmission mechanism. An object of the present invention is to provide a hydraulic pressure supply device.

In order to achieve the above object, the gist of the first invention is that: (a) a transmission mechanism portion in which engagement and disengagement of an engagement device are selectively executed by supplying oil; A connected oil passage, a mechanical oil pump driven by a drive source, an electric oil pump provided in parallel to the mechanical oil pump, driven by an electric motor, and discharged from the mechanical oil pump Oil is supplied, the first discharge oil passage communicating with the oil passage connected to the transmission mechanism portion, the oil discharged from the electric oil pump is supplied, and the first discharge oil A second discharge oil passage connected to the passage; and provided in the second discharge oil passage to prevent the oil discharged from the mechanical oil pump from flowing into the electric oil pump side; A vehicle hydraulic pressure supply device comprising: a check valve that allows oil discharged from an oil pump to flow toward the first discharge oil passage; and (b) the first valve that is in contact with the outer peripheral surface of the check valve. The two discharge oil passages are composed of members having a coefficient of thermal expansion higher than that of the members constituting the check valve, and (c) when the oil temperature of the oil exceeds a predetermined temperature, the outer peripheral surface of the check valve and the A gap is formed between the second discharge oil passage and (d) air bubbles are discharged to the oil passage closer to the electric oil pump than the check valve of the second discharge oil passage. For this purpose, a drain hole is formed.

  When the oil temperature is high, bubbles tend to be included when the oil is stirred. On the other hand, the second discharge oil passage in contact with the outer peripheral surface of the check valve is composed of a member having a higher coefficient of thermal expansion than the member constituting the check valve. A gap is formed between the second discharge oil passage and the check valve, and the bubbles are discharged to the electric oil pump side from the check valve of the second discharge oil passage through the gap. It is discharged from a drain hole formed in the oil passage. Accordingly, since the supply of bubbles to the speed change mechanism is suppressed, it is possible to suppress the slack of the speed change caused by the air cushion and the engagement shock.

It is a figure which shows roughly the structure of the hydraulic supply apparatus for vehicles which supplies a hydraulic pressure to the transmission mechanism part to which this invention was applied. It is sectional drawing explaining the structure of the non-return valve of FIG. 1 in detail. The state at the time of high temperature is shown in the check valve of FIG. It is a figure which shows the area | region where the minimum air discharge amount determined by a clearance gap and a non-return valve fitting length is ensured.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios, shapes, and the like of the respective parts are not necessarily drawn accurately.

  FIG. 1 is a diagram schematically showing a configuration of a vehicle hydraulic pressure supply device 10 (hereinafter referred to as a hydraulic pressure supply device) that supplies hydraulic pressure to a transmission mechanism 8 to which the present invention is applied. The hydraulic pressure supply device 10 includes a mechanical oil pump 14 driven by an engine 12 and an electric oil pump 18 driven by an electric motor 16 in parallel. Oil (ATF) stored in the oil pan 22 is supplied to a suction oil passage 26 of the mechanical oil pump 14 and the electric oil pump 18 via a strainer 24. The hydraulic pressure supply device 10 sucks up the oil stored in the oil pan 22 from the suction oil passage 26 by driving at least one of the mechanical oil pump 14 and the electric oil pump 18 provided in parallel, and supplies the oil to the transmission mechanism unit 8. A hydraulic pressure is generated as a source pressure to be supplied.

  The transmission mechanism unit 8 includes a plurality of clutches C (engagement devices) and brakes B (engagement devices) that are hydraulic friction engagement devices, and these clutches and brakes are selectively engaged or released. Thus, the gear is shifted to a predetermined gear position. These clutches and brakes are each provided with a hydraulic chamber to which hydraulic pressure (engagement pressure) is supplied, and the hydraulic pressure adjusted with the hydraulic pressure supplied from the hydraulic pressure supply device 10 as the original pressure is supplied into the hydraulic chamber, Engagement and release of the clutch C and the brake B are selectively performed.

  A mechanical oil pump 14 is a known oil pump that is connected to an output shaft of an engine 12 that is an internal combustion engine such as a gasoline engine or a diesel engine, and generates hydraulic pressure by being driven to rotate as the engine 12 is driven. It is. The electric oil pump 18 is a known oil pump that is connected to the output shaft of the electric motor 16 and generates hydraulic pressure by being driven to rotate as the electric motor 16 is driven. The engine 12 corresponds to the drive source of the present invention.

  As shown in FIG. 1, the mechanical oil pump 14 and the electric oil pump 18 are arranged in parallel between the strainer 24 and the transmission mechanism unit 8. The hydraulic pressure supply device 10 includes a suction oil passage 26 that supplies the oil sucked up from the oil pan 22 to the mechanical oil pump 14 or the electric oil pump 18, and a first oil supplied from the mechanical oil pump 14. A discharge oil passage 28 and a second discharge oil passage 30 to which oil discharged from the electric oil pump 18 is supplied are provided. The intake oil passage 26 is connected to the strainer 24 on the upstream side (oil pan 22 side) and branches on the way to the downstream side (transmission mechanism unit 8 side), so that the mechanical oil pump 14 and the electric oil pump 18 are separated. It is connected to the. The first discharge oil passage 28 is in communication with the output oil passage 32 connected to the transmission mechanism unit 8. The second discharge oil passage 30 is connected to the first discharge oil passage 28. The output oil passage 32 corresponds to the oil passage connected to the speed change mechanism portion of the present invention.

  The hydraulic pressure supply device 10 includes a check valve 34 and a drain mechanism 36 in the second discharge oil passage 30. FIG. 2 is a cross-sectional view illustrating the structure of the check valve 34 in detail. Note that the lower side of the second discharge oil passage 30 in FIG. 2 is connected to the electric oil pump 18, and the upper side is connected to the first discharge oil passage 28. Therefore, in FIG. 2, the lower side is the upstream side of the hydraulic pressure supply device 10, and the upper side is the downstream side of the hydraulic pressure supply device 10.

  As shown in FIG. 2, the check valve 34 is provided in the second discharge oil passage 30 formed in the case 38. The check valve 34 includes a cylindrical first body 44 in which the flow path 42 of the second discharge oil passage 30 is formed, and one end in the flow direction of the first body 44 (downstream side, upper side in FIG. 2). ) Connected to the cylindrical second body 46, a ball 48 built in the second body 46 and having a diameter larger than the diameter of the flow path 42, and a ball built in the second body 46 in a preloaded state. Coil spring 50 that presses 48 toward the first body 44 side.

  The first body 44 and the second body 46 cannot be moved relative to each other when the claws formed on the shaft end portions of the first body 44 and the second body 46 are fitted. A stepped portion 52 in which the diameter of the circular cross section of the flow path changes is formed in the second body 46, and a surface perpendicular to the flow direction of the stepped portion 52 is in contact with one end of the coil spring 50. It touches. The other end of the coil spring 50 is in contact with the ball 48, and the ball 48 is pressed against the shaft end portion of the first body 44 by the coil spring 50.

  In the check valve 34 configured as described above, when the oil is discharged from the electric oil pump 18 and the oil pressure on the upstream side of the check valve 34 becomes higher than the oil pressure on the downstream side, the upstream side oil pressure is increased. The ball 48 is moved away from the first body 44 against the pressing force of the coil spring 50 by the oil pressure of the oil. Therefore, as shown in FIG. 2, the check valve 34 is opened, and the oil discharged from the electric oil pump 18 is allowed to flow out to the first discharge oil passage 28 side.

  On the other hand, when the discharge from the electric oil pump 18 is stopped and the oil pressure on the upstream side of the check valve 34 of the second discharge oil passage 30 becomes equal to or lower than the oil pressure on the downstream side, the pressing force of the coil spring 50 As indicated by a broken line 2, the ball 48 is brought into contact with the shaft end portion of the first body 44. Thereby, the check valve 34 is closed, and the flow of oil in the second discharge oil passage 30 from the downstream side to the upstream side is prevented. That is, the oil discharged from the mechanical oil pump 14 is prevented from flowing into the electric oil pump 18 side.

  In the present embodiment, since the mechanical oil pump 14 is driven while the engine 12 is being driven, the electric oil pump 18 is operated while the required amount of oil is secured in the transmission mechanism 8 by the mechanical oil pump 14. Stopped. At this time, in the second discharge oil passage 30, the oil pressure on the downstream side with respect to the check valve 34 is higher than the oil pressure on the upstream side, and the oil in the second discharge oil passage 30 is transferred to the electric oil pump 18. The force acts in the direction toward the side (upstream side), but at that time, the check valve 34 is closed to prevent the flow.

  Further, the mechanical oil pump 14 driven by the engine 12 is stopped while the motor is running to drive the vehicle by the electric motor. At this time, when the electric oil pump 18 is driven, the oil discharged from the electric oil pump 18 is supplied to the second discharge oil passage 30, and the oil is supplied to the transmission mechanism unit 8 through the check valve 34. The

  As described above, the check valve 34 is provided in the second discharge oil passage 30, prevents the oil discharged from the mechanical oil pump 14 from flowing into the electric oil pump 18, and the electric oil pump 18. Allowed to flow out to the first discharge oil passage 28 side.

  In the second discharge oil passage 30 of the present embodiment, the thermal expansion coefficient A of the case 38 forming the oil passage is equal to the thermal expansion coefficient B of the members (first body 44, second body 46) constituting the check valve 34. A larger value is set (A> B). That is, the case 38 in which the second discharge oil passage 30 is formed is configured by a member having a higher thermal expansion coefficient than the first body 44 and the second body 46 that constitute the check valve 34. Here, at the time of low temperature (low oil temperature), there is almost no influence due to the difference in thermal expansion coefficient, and as shown in FIG. 2, the inner peripheral surface 40 of the case 38 and the outer peripheral surface 45 of the first body 44 Between the two is in contact. That is, the state between the check valve 34 and the case 38 is sealed.

  On the other hand, at a high temperature (high oil temperature), the increase in the radial dimension of the second discharge oil passage 30 formed in the case 38 due to the difference in thermal expansion causes the check valve 34 (the first body 44, the first oil pressure). As shown in FIG. 3, a gap C <b> 1 is formed between the outer peripheral surface 45 of the first body 44 and the inner peripheral surface 40 of the case 38.

  By the way, when the oil reaches a high oil temperature, the viscosity also decreases, and bubbles (aeration) are mixed in the oil when the oil stored in the oil pan 22 is stirred with a predetermined gear. When the oil mixed with aeration is sucked up by the hydraulic pressure supply device 10, the inside of the hydraulic control circuit from the hydraulic pressure supply device 10 to the speed change mechanism portion 8 is completely sealed (sealed), so that the aeration is discharged to the outside. Without reaching the hydraulic chambers of the clutch C and the brake B of the transmission mechanism 8, aeration is accumulated in the oil chamber. When the engagement of the clutch C and the brake B is started in this state, the air accumulated in the oil chamber becomes a cushion, and there is a possibility that shifting (shading) or shifting shock occurs.

  In contrast, in the check valve 34 of the present embodiment, a gap C1 is formed between the outer peripheral surface 45 of the first body 44 of the check valve 34 and the inner peripheral surface 40 of the case 38 at high temperatures. Therefore, although the check valve 34 is closed when the mechanical oil pump 14 is driven, the aeration in the oil passes through the gap C1 and is upstream of the check valve 34 as shown by the arrow in FIG. It is discharged to the side (electric oil pump 18 side). That is, the check valve 34 allows a part of the oil to flow upstream, so that the aeration in the second discharge oil passage 30 is discharged upstream of the check valve 34. Therefore, the inflow of aeration to the transmission mechanism unit 8 side is suppressed.

  Further, the aeration discharged to the upstream side of the check valve 34 of the second discharge oil passage 30 is provided on the upstream side (electric oil pump 18 side) of the check valve 34 of the second discharge oil passage 30. It is discharged through a drain hole 54 for discharging aeration formed vertically above the drain mechanism 36. Therefore, the aeration is suitably discharged from the hydraulic pressure supply device 10. In addition, the ball is disposed vertically above the drain hole 54 of the drain mechanism 36, thereby preventing air from entering from the outside.

  Next, a method for calculating the gap C1 necessary for discharging aeration will be described. First, a minimum temperature (oil temperature) T0 at which aeration is confirmed is experimentally obtained, and various flow rates to be described later are calculated based on the temperature T0. When the flow rate of oil flowing between the gaps C1 is Q1, the consumption flow rate of the transmission mechanism 8 (hydraulic circuit) is Q2, the actual discharge flow rate of the mechanical oil pump 14 is Q3, and the aeration discharge flow rate is Q4, the following formula (1 ) Is determined so that the maximum dimension C1max of the gap C1 is determined.

Here, the flow rate Q1 flowing through the gap C1max is calculated by the following equation (2). In equation (2), d corresponds to the diameter of the oil passage formed in the case 38 into which the check valve 34 is inserted (see FIG. 3), and P _L represents the hydraulic pressure (original pressure) of the mechanical oil pump 14. Correspondingly, η1 corresponds to the viscosity of the oil at the temperature T0, and h1 corresponds to the length of the first body 44 in the axial direction (flow direction) (check valve fitting length). The aeration discharge flow rate Q4 is calculated by the following equation (3). Here, the viscosity η2 of the oil including aeration is calculated by the following equation (4) which is publicly known (see EINSTEIN 1906, 1911). In the equation (4), φ corresponds to the oil particle volume density and is a value obtained in advance. Then, substituting Equation (2) and Equation (3) into Equation (1) and rearranging the maximum dimension C1max gives the following Equation (5), and the Equation (5) calculates the maximum dimension C1max of the gap C1. Further, the minimum dimension C1min of the gap C1 is determined by extracting a formation region in which the minimum aeration discharge amount (minimum air discharge amount) is secured within the design constraints (check valve arrangement space, supplyable flow rate, etc.). The The minimum dimension C1min is set in consideration of restrictions due to fitting tolerances of the check valve 34.

Q1 + Q2 + Q4 <Q3 (1)
Q1 = πdC1 ³ maxP _L / (12η1h1) (2)
Q4 = πdC1 ³ maxP _L / (12η2h1) (3)
η2 / η1 = 1 + φ (4)
C1max <{12h1 (Q3-Q2) / πdP _L (1 / η2-1 / η1)} ^1/3 (5)

  FIG. 4 shows the relationship between the clearance C1 and the check valve fitting length h1 and the region where the minimum air discharge amount is secured, which is obtained based on the above calculation formula. In FIG. 4, the horizontal axis indicates the check valve fitting length h1, and the lower limit value hmin and the upper limit value hmax are set in consideration of design constraints (such as space). The vertical axis indicates the gap C1. In addition, the hatched area indicates an established range area in which the minimum air discharge amount is ensured. Note that FIG. 4 is obtained based on the lowest temperature T0 at which aeration is confirmed.

  As shown in FIG. 4, the air discharge amount increases as the check valve fitting length h1 increases, and the air discharge amount increases as the gap C1 increases. The check valve 34 is set to dimensions (h1, C1) that are within the range of formation in FIG. 4 in consideration of design constraints, and the case 38 and the gap 38 are formed so that the gap C1 is formed at a high temperature (temperature T0). The material of the check valve 34 (first body 44, second body 46) is selected. As a result, a material is selected in which the thermal expansion coefficient A of the case 38 is higher than the thermal expansion coefficient B of the check valve 34 (first body 44, second body 46). As a result, a check valve 34 is obtained from which aeration is suitably discharged at high temperatures. In addition, since the gap C1 is set to the maximum dimension C1max or less, a decrease in hydraulic pressure due to the formation of the gap C1 is also suppressed.

  As described above, according to the present embodiment, the oil is likely to contain bubbles when the oil temperature is high. On the other hand, the second discharge oil passage 30 in contact with the outer peripheral surface 45 of the check valve 34 is composed of a member having a higher thermal expansion coefficient than the first body 44 constituting the check valve 34, A gap C1 is formed between the second discharge oil passage 30 and the check valve 34 at a high oil temperature, and the oil containing the bubbles passes through the gap C1 and the check valve 34 of the second discharge oil passage 30. The oil is discharged further to the electric oil pump 18 side, and is further discharged from the drain hole 54 formed in the second discharge oil passage 30. Accordingly, since the supply of bubbles to the speed change mechanism portion 8 is suppressed, it is possible to suppress the looseness of the speed change caused by the air cushion and the engagement shock.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this invention is applied also in another aspect.

  The above description is only an embodiment, and the present invention can be implemented in variously modified and improved forms based on the knowledge of those skilled in the art.

8: Transmission mechanism 12: Engine (drive source)
14: Mechanical oil pump 16: Electric motor 18: Electric oil pump 28: First discharge oil passage 30: Second discharge oil passage 32: Output oil passage (oil passage connected to the transmission mechanism)
34: Check valve 44: First body (member constituting the check valve)
54: Drain hole B: Brake (engagement device)
C: Clutch (engagement device)

Claims (1)

A transmission mechanism that selectively engages and disengages the engagement device by supplying oil, an oil passage that is connected to the transmission mechanism, a mechanical oil pump that is driven by a drive source, and An electric oil pump provided in parallel to the mechanical oil pump and driven by an electric motor; and the oil passage supplied with the oil discharged from the mechanical oil pump and connected to the transmission mechanism Provided in the first discharge oil passage, the second discharge oil passage connected to the first discharge oil passage, and the second discharge oil passage supplied with oil discharged from the electric oil pump The oil discharged from the mechanical oil pump is prevented from flowing into the electric oil pump, and the oil discharged from the electric oil pump is prevented from flowing out toward the first discharge oil passage. And a check valve for capacity, a hydraulic pressure supply device for a vehicle comprising,
The second discharge oil passage in contact with the outer peripheral surface of the check valve is composed of a member having a higher coefficient of thermal expansion than a member constituting the check valve,
When the oil temperature of the oil is equal to or higher than a predetermined temperature, a gap is formed between the outer peripheral surface of the check valve and the second discharge oil passage,
The vehicle hydraulic pressure supply device, wherein a drain hole for discharging air bubbles is formed in the oil passage closer to the electric oil pump than the check valve of the second discharge oil passage.

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