JP2000257695A - Fluid coupling device - Google Patents

Abstract

(57) [Problem] To provide a fluid coupling device capable of reducing drag torque without insufficient operating pressure of a lock-up clutch. A fluid coupling device includes a casing, a pump attached to the casing, a turbine disposed opposite the pump, and an outer chamber disposed between the casing and the turbine. A lock-up clutch having a clutch disk formed therein and forming an inner chamber with the turbine. The lock-up clutch engages the casing and the turbine when the working fluid flows from the outer chamber through the inner chamber to the working chamber, and engages the casing with the turbine when the working fluid flows from the working chamber through the inner chamber to the outer chamber. It is configured to be released.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a fluid coupling device for transmitting a rotational torque of a motor.

[0002]

2. Description of the Related Art Fluid couplings have been conventionally used as power transmission couplings for ships and industrial machines. The fluid coupling includes a casing connected to a crankshaft (input shaft as a fluid coupling) of a prime mover, for example, a diesel engine, a pump disposed opposite to the casing and attached to the casing, a pump and a casing. And a turbine mounted on the output shaft disposed coaxially with the input shaft in the chamber formed by the pump. Further, a lock-up clutch for frictionally engaging the casing and the turbine is provided between the casing and the turbine. The lock-up clutch includes a clutch disk disposed between the casing and the turbine, the clutch disk forming an outer chamber between the casing and the turbine, and forming an inner chamber between the turbine and the turbine, and is formed by the pump and the turbine. The casing and the turbine are configured to frictionally engage with each other by a pressure difference between the inner chamber side and the outer chamber side of the working fluid flowing from the working chamber through the inner chamber to the outer chamber. When the frictional engagement between the casing and the turbine by the lock-up clutch is released, the working fluid is circulated from the outer chamber through the inner chamber so as to flow to the working chamber formed by the pump and the turbine. Is higher than the fluid pressure in the inner chamber. When such a fluid coupling is installed in, for example, a drive device of a vehicle, it is generally operatively connected to a transmission via a friction clutch.

[0003]

In the above-mentioned fluid coupling mounted on the drive device of the vehicle, the engine is driven while the vehicle is stopped and the transmission gear of the transmission is engaged, that is, the input shaft is rotated and the output shaft is rotated. In a stopped state, it has a drag torque due to its characteristics. This drag torque is
When the design point of the fluid coupling is set to a rotational speed ratio at which the maximum efficiency is obtained, that is, a rotational speed ratio between the pump and the turbine is about 0.95 to 0.98, the value becomes considerably large. If the drag torque is large, the idling operation of the engine becomes extremely unstable, and this unstable rotation causes abnormal vibration in the drive system. In addition, the large drag torque causes deterioration of fuel efficiency during idling operation.

One of the causes of the increase in the drag torque is due to the operation of the lock-up clutch. That is, the load in the working chamber formed by the pump and the turbine increases due to the drag torque, and the working fluid pressure increases. Further, the torque transmitted by the fluid coupling is generated by the working fluid circulating in the working chamber, and in principle, the pressure is higher on the outer peripheral side. Further, the pressure on the outer peripheral side increases due to the centrifugal force of the working fluid due to the rotation of the pump. However, in the conventional fluid coupling,
When the lock-up clutch is not actuated as in the idling operation of the engine, the working fluid is configured to flow from the outer chamber to the working chamber formed by the pump and the turbine through the inner chamber as described above. Therefore, the circulating working fluid flows into the working chamber from the outer peripheral side where the pressure is high, so that the circulation of the working fluid is restricted and the working fluid pressure in the working chamber further increases. On the other hand, it is conceivable to lower the pressure of the working fluid to be supplied in order to reduce the drag torque, but if the pressure of the supplied working fluid is reduced, the working pressure of the lock-up clutch becomes insufficient, and in the worst case, the lock-up cannot be performed. Becomes

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and a main technical problem thereof is to provide a fluid coupling device capable of reducing drag torque without insufficient operating pressure of a lock-up clutch. It is in.

[0006]

According to the present invention, in order to solve the above-mentioned main technical problems, a casing connected to an input shaft and a casing disposed opposite to the casing and attached to the casing are provided. A pump, a turbine provided in a chamber formed by the pump and the casing, opposed to the pump, and attached to an output shaft arranged coaxially with the input shaft; and A clutch disk disposed between the casing and the casing to form an outer chamber and an inner chamber between the casing and the turbine, wherein a fluid pressure difference between the outer chamber and the inner chamber causes the casing and the turbine to rotate. And a working fluid circulating hand for circulating working fluid to a working chamber formed by the outer chamber, the inner chamber, and the pump and the turbine. Wherein the lock-up clutch engages the casing and the turbine when the working fluid flows from the outer chamber through the inner chamber to the working chamber, and the working fluid transfers the working fluid to the working chamber. A fluid coupling device configured to disengage the casing from the turbine when flowing from the casing to the outer chamber through the inner chamber.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a fluid coupling device constructed in accordance with the present invention will be described below in more detail with reference to the accompanying drawings.

FIG. 1 shows an embodiment of a drive device in which a fluid coupling device constructed according to the present invention is disposed between an automobile engine and a friction clutch. The drive device in the illustrated embodiment is an internal combustion engine 2 as a prime mover.
And the fluid coupling device 4 and the friction clutch 8 configured according to the present invention. The internal combustion engine 2 is a diesel engine in the illustrated embodiment, and a pump side, described later, of the fluid coupling device 4 is attached to an end of the crankshaft 21.

The fluid coupling device 4 includes a diesel engine 2
Is provided in a fluid coupling housing 40 attached to a housing 22 mounted on the housing 22 by fastening means such as bolts 23. Fluid coupling device 4 in illustrated embodiment
Includes a casing 41, a pump 42, and a turbine 43.

The casing 41 is mounted on the outer peripheral portion of a drive plate 44 in which the inner peripheral portion is mounted on the crankshaft 21 with bolts 24 by means of fastening means such as bolts 441 and nuts 442. A ring gear 45 for starting is engaged with the drive gear of a starter motor (not shown) on the outer periphery of the drive plate 44.

The pump 42 is provided to face the casing 41. The pump 42 includes a bowl-shaped pump shell 421 and a plurality of impellers 422 radially arranged in the pump shell 421. The pump shell 421 is fixed to the casing 41 by welding or the like. Installed. Accordingly, the pump shell 421 of the pump 42 is connected to the crankshaft 21 via the casing 41 and the drive plate 44. For this reason, the crankshaft 21 functions as an input shaft of the fluid coupling device 4.

The turbine 43 is disposed in a chamber formed by the pump 42 and the casing 41 so as to face the pump 42. The turbine 43 includes a bowl-shaped turbine shell 431 disposed to face the pump shell 421 of the pump 42, and a plurality of runners 432 radially disposed in the turbine shell 431. . The turbine shell 431 is attached to a turbine hub 47 spline-fitted to an output shaft 46 disposed on the same axis as the crankshaft 21 as the input shaft by welding or other fixing means.

[0013] The fluid coupling device 4 in the illustrated embodiment.
Is provided with a lock-up clutch 50 for directly drivingly connecting the casing 41 and the turbine 43. The lock-up clutch 50 includes a clutch disk 51 that is disposed between the casing 41 and the turbine 43 and forms the outer chamber 40a with the casing 41 and forms the inner chamber 40b with the turbine 43. . The clutch disk 51 has an inner peripheral edge supported on the outer periphery of the turbine hub 47 so as to be relatively rotatable and slidable in the axial direction, and has an annular portion formed on the outer peripheral portion so as to project rightward in the drawing. A friction surface 511 is provided.
A plurality of friction disks 52 are mounted on the outer peripheral portion of the clutch disk 51 at positions facing the friction surface 511 so as to be movable in the left-right direction in the figure. The plurality of friction plates 53 mounted on the reference numeral 41 are alternately arranged. Further, on the inner peripheral side of the friction surface 511 of the clutch disk 51,
An annular concave portion 512 is formed, and a plurality of damper springs 55 supported by the support pieces 54 are arranged in the concave portion 512 at predetermined intervals. On both sides of the plurality of damper springs 55, an input-side retainer 56 attached to the clutch disk 51 is provided so as to protrude therefrom, and between the damper springs 55 is attached to a turbine shell 431 of the turbine 43. The output side retainer 57 is provided to protrude.

The lock-up clutch 50 in the illustrated embodiment is configured as described above, and its operation will be described. When the pressure of the working fluid in the inner chamber 40b is higher than the pressure of the working fluid in the outer chamber 40a, that is, the working fluid supplied by the working fluid circulating means described later is formed by the pump 42 and the turbine 43.
a, the clutch disc 51 is pressed to the left in FIG. 1 so that the friction plates 52 and 53 are frictionally engaged with each other. Therefore, the transmission connection between the casing 41 and the turbine 43 is released. On the other hand, when the pressure of the working fluid in the outer chamber 40a is higher than the pressure of the working fluid on the inner chamber 40b side, that is, the working fluid supplied by the working fluid circulating means described later passes from the outer chamber 40a to the pump 42 through the inner chamber 40b. When circulating in the working chamber 4a formed by the turbine 43, the clutch disk 51 is pressed rightward in FIG. 1, so that the annular friction surface 511 has the plurality of friction plates 52 and the plurality of friction plates 52. In order to press the friction disk 53, both friction disks are frictionally engaged. Therefore, the casing 41 and the turbine 43 are
Friction disc 52 and friction disc 53, clutch disc 51,
It is directly driven and connected via an input side retainer 56, a damper spring 55, and an output side retainer 57.

The fluid coupling device 4 in the illustrated embodiment is provided with a hydraulic pump 60 as a hydraulic operating source of a working fluid circulating means described later. The hydraulic pump 60 is mounted on the fluid coupling housing 40 by a fixing means such as a bolt 61 and is disposed on the pump housing 62. The hydraulic pump 60 is configured to be rotationally driven by a pump hub 48 attached to a pump shell 421 of the pump 42. The pump hub 48 is provided with a bearing 490 on a cylindrical support portion 620 of the pump housing 62 formed so as to surround the output shaft 46.
It is rotatably supported by. As shown in FIGS. 2 and 3, a working fluid passage 460 is provided in the output shaft 46 in association with a working fluid circulating means to be described later, and a space between the output shaft 46 and the cylindrical support portion 620 is provided. Is provided with a working fluid passage 461. Passage 460
One end thereof is open at the left end face in the drawing of the output shaft 46 and communicates with the outer chamber 40a, and the other end communicates with a radial passage 462 opening at the outer peripheral surface of the output shaft 46.
Further, the passage 461 is configured to communicate the working chamber 4 a formed by the pump 42 and the turbine 43 with the communication hole 621 provided in the cylindrical support 620.

Next, the working fluid circulating means for circulating the working fluid through the fluid coupling will be described with reference to FIGS. The working fluid circulating means includes a reserve tank 65 for containing a working fluid.
The working fluid inside is discharged into the passage 66 by the hydraulic pump 60. The working fluid discharged to the passage 66 is supplied to the passage 68 communicating with the communication hole 621 or the passage 69 communicating with the passage 462 via the electromagnetic direction control valve 67. In the state shown in FIG. 2 in which the electromagnetic direction control valve 67 is deenergized (OFF), the working fluid discharged into the passage 66 flows through the passage 68, the communication hole 621, and the passage 4 as indicated by arrows.
61, working chamber 4a formed by pump 42 and turbine 43, inner chamber 40b, outer chamber 40a, passage 46
0, passage 462, passage 69, return passage 70, cooler 71
And is circulated to the reserve tank 65 through the passage 72. When the working fluid circulates as shown by the arrow in FIG. 2, the fluid pressure in the inner chamber 40b is higher than the fluid pressure in the outer chamber 40a, so that the lock-up clutch 50 does not frictionally engage as described above. On the other hand, when the electromagnetic direction control valve 67 is energized (ON), the state shown in FIG. 3 is established, and the working fluid discharged into the passage 66 is supplied to the passage 69 and the passage 4 as indicated by arrows.
62, passage 460, outer chamber 40a, inner chamber 40b, working chamber 4 formed by pump 42 and turbine 43
a, passage 461, communication hole 621, passage 68, return passage 7
0, and is circulated to the reserve tank 65 through the cooler 71 and the passage 72. When the working fluid circulates as shown by the arrow in FIG. 3, the fluid pressure in the outer chamber 40a is higher than the fluid pressure in the inner chamber 40b.
0 frictionally engages as described above. In the fluid circuit in the illustrated embodiment, the passage 66 and the reserve tank 65 are provided.
Are provided, and a relief valve 74 is disposed in the relief passage 73. The valve opening pressure of the relief valve 74 is set to, for example, 6 kg / cm 2. When the working fluid pressure in the passage 66 exceeds 6 kg / cm 2, the working fluid is returned to the reserve tank 65 via the relief passage 73. As described above, the fluid circuit in the illustrated embodiment is configured as an open circuit.

Next, the friction clutch 8 will be described. The friction clutch 8 includes a clutch housing 80 mounted on the fluid coupling housing 40 by bolts 81.
It is arranged in. The friction clutch 8 in the illustrated embodiment includes a flywheel 82 mounted on the output shaft 46 of the fluid coupling, and a transmission shaft 83 disposed on the same axis as the output shaft 46 (in the illustrated embodiment, And a driven plate 8 attached to a clutch hub 84 spline-fitted to the transmission shaft 83 and having a clutch facing 85 mounted on an outer peripheral portion thereof.
6, a pressure plate 87 that presses the driven plate 86 against the clutch drive plate 82, a diaphragm spring 88 that urges the pressure plate 87 toward the flywheel 82, and an inner end of the diaphragm spring 88 A release bearing 89 for operating the diaphragm spring 88 with the middle portion as a fulcrum 881 and a clutch release fork 90 for operating the release bearing 89 in the axial direction are provided. The friction clutch 8 thus configured is
In the state shown in the figure, the pressure plate 87 is pressed toward the clutch drive plate 82 by the spring force of the diaphragm spring 88, so that the clutch facing 85 mounted on the driven plate 86 is pressed against the clutch drive plate 82 and the fluid flows. The power transmitted to the output shaft 46 of the joint is transmitted to the transmission shaft 83 via the clutch drive plate 82 and the driven plate 86. When shutting off this power transmission,
The clutch release fork 90 is operated by supplying hydraulic pressure to a slave cylinder (not shown).
1 is moved to the left in FIG. 1, the diaphragm spring 88 is actuated as shown by a two-dot chain line in the figure, and the pressing force on the pressure plate 87 is released. Power transmission is shut off.

The drive device equipped with the fluid coupling device in the illustrated embodiment is configured as described above, and its operation will be described below. First, diesel engine 2
Is operated at a rotation speed equal to or higher than the idling rotation, and the drive torque is transmitted by the fluid coupling. In this case, the electromagnetic direction control valve 67 of the working fluid circulation means is deenergized (OFF), and the working fluid is circulated in the direction indicated by the arrow in FIG. The driving force generated on the crankshaft 21 (input shaft) of the diesel engine 2 is transmitted to the casing 41 of the fluid coupling 4 via the drive plate 44. Casing 41 and pump 4
Since the two pump shells 421 are integrally formed, the pump 42 is rotated by the driving force. When the pump 42 rotates, the working fluid in the pump 42 flows toward the outer periphery along the impeller 422 by centrifugal force, and flows into the turbine 43 as indicated by an arrow. The working fluid flowing into the turbine 43 flows toward the center and returns to the pump 42 as indicated by an arrow. As described above, the working fluid in the working chamber 4a formed by the pump 42 and the turbine 43 circulates in the pump 42 and the turbine 43, so that the driving torque of the pump 42 is transmitted to the turbine 43 through the working fluid. Is transmitted. Turbine 4
The driving force transmitted to the third side is transmitted to the output shaft 46 via the turbine shell 431 and the turbine hub 47, and further transmitted to a transmission (not shown) via the friction clutch 8.

Next, a state in which the diesel engine 2 is performing an idling operation will be described. In this case as well, the electromagnetic direction control valve 67 of the working fluid circulating means is deenergized (OFF), and the working fluid is circulated in the direction indicated by the arrow in FIG. The driving force generated on the crankshaft 21 (input shaft) of the diesel engine 2 is transmitted to the casing 41 of the fluid coupling device 4 via the drive plate 44 as described above, and is formed integrally with the casing 41. The pump 42 is rotated. At this time, when the transmission gear (not shown) is engaged and the friction clutch 8 is connected, the drag torque is generated because the output shaft 46 is stopped and the turbine 42 is stopped. Due to this drag torque, the working chamber 4 formed by the pump 42 and the turbine 43
The load in “a” increases, and the working fluid pressure increases. The torque transmitted by the fluid coupling is generated by the working fluid circulating in the working chamber 4a formed by the pump 42 and the turbine 43 as shown by the arrow in the drawing. Become. Further, the pressure on the outer peripheral side increases due to the centrifugal force of the working fluid due to the rotation of the pump 42. Therefore, the pump 42 and the turbine 43
If the working fluid circulating means is formed such that the working fluid in the working chamber 4a formed by the above flows out and circulates from the outer peripheral side, the working fluid in the working chamber 4a easily flows out. However, in the illustrated embodiment, when the lock-up clutch 50 is not operated, the working fluid is circulated as indicated by an arrow in FIG. 2 and flows out from the outer peripheral side of the working chamber 4a formed by the pump 42 and the turbine 43. As a result, the working fluid in the working chamber 4a flows out positively. That is, in the illustrated embodiment, a circulating flow of the working fluid is formed to assist the outflow of the working fluid in the working chamber 4a formed by the pump 42 and the turbine 43 by the drag torque. Accordingly, the efficiency of filling the working chamber 4a with the working fluid is reduced, so that the drag torque during the idling operation of the diesel engine 2 is reduced.

Next, a state in which the lock-up clutch 50 is operated to directly connect the casing 41 and the turbine 43 to transmit the driving torque will be described. In this case, the electromagnetic direction control valve 67 of the working fluid circulating means is energized (ON), and the working fluid is circulated in the direction indicated by the arrow in FIG. Therefore, as described above, the pressure of the working fluid in the outer chamber 40a is higher than the pressure of the working fluid in the inner chamber 40b, and the clutch disk 51 is pressed rightward in FIGS. Presses the plurality of friction disks 52 and the plurality of friction disks 53, so that both friction disks are frictionally engaged. As a result, the casing 4
1 and the turbine 43 are directly driven and connected via friction disks 52 and 53, a clutch disk 51, an input side retainer 56, a damper spring 55, and an output side retainer 57. Accordingly, the driving force generated on the crankshaft 21 (input shaft) of the diesel engine 2 is transmitted to the output shaft 46 via the drive plate 44, the casing 41, the lock-up clutch 50, the turbine 43, and the turbine hub 47, and further, The power is transmitted to a transmission (not shown) via the friction clutch 8. In the illustrated embodiment, since the drag torque can be reduced as described above, it is not necessary to reduce the supply pressure of the working fluid in order to reduce the drag torque, so that the operating pressure of the lock-up clutch becomes insufficient. Never.

[0021]

As described above, the fluid coupling device according to the present invention has the following functions and effects.

That is, in the fluid coupling device according to the present invention, when the working fluid flows from the outer chamber to the working chamber through the inner chamber, the lock-up clutch engages the casing and the turbine, and the working fluid passes from the working chamber to the inner chamber. Since the engagement between the casing and the turbine by the lock-up clutch is released when flowing into the outer chamber, the working fluid that assists the outflow of the working fluid in the working chamber to the outside when the drag torque is generated. Since a circulating flow is formed and the efficiency of filling the working chamber with the working fluid is reduced, drag torque during idling operation of the engine is reduced. Therefore, the idling operation of the engine can be performed smoothly, occurrence of abnormal vibration can be prevented, and fuel consumption during idling operation can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a driving device equipped with a fluid coupling device configured according to the present invention.

FIG. 2 is an explanatory diagram showing an operation state of a working fluid circulation unit of the fluid coupling device shown in FIG. 1, in which a lock-up clutch is not operated.

FIG. 3 is an explanatory diagram showing an operation state of a working fluid circulating means of the fluid coupling device shown in FIG. 1, in which a lock-up clutch is operated.

[Explanation of symbols]

 2: Internal combustion engine 21: Crankshaft 4: Fluid coupling 40: Fluid coupling housing 41: Casing 42: Pump 421: Pump shell 422: Impeller 43: Turbine 431: Turbine shell 432: Runner 44: Drive plate 45: Ring gear 46: Output Shaft 47: Turbine hub 48: Pump hub 50: Lock-up clutch 51: Clutch disc 52: Friction disc 53: Friction disc 54: Supporting piece 55: Damper spring 56: Input retainer 57: Output retainer 60: Hydraulic pump 62: Pump Housing 65: Reserve tank 67: Electromagnetic direction control valve 71: Cooler 74: Relief valve 8: Friction clutch 80: Clutch housing 82: Clutch drive plate 83: Transmission shaft 84: Clutch hub 85: Clutch facing 6: driven plate 87: pressure plate 88: the diaphragm spring 89: the release bearing 90: clutch release fork

Claims (1)

[Claims] 1. A casing connected to an input shaft, a pump disposed opposite to the casing and attached to the casing, and a pump disposed in a chamber formed by the pump and the casing opposite to the pump. A turbine mounted on an output shaft arranged on the same axis as the input shaft; and an outer chamber formed between the casing and the turbine, the outer chamber being formed between the turbine and the turbine. A lock-up clutch that includes a clutch disc that forms an inner chamber between the casing and the turbine by a fluid pressure difference between the outer chamber and the inner chamber; and a lock-up clutch that engages the outer chamber, the inner chamber, and the pump. A working fluid circulating means for circulating a working fluid to a working chamber formed by the turbine. Engage the casing and the turbine when fluid flows from the outer chamber through the inner chamber to the working chamber, and engages the casing and the turbine when working fluid flows from the working chamber through the inner chamber to the outer chamber. The fluid coupling device is configured to release the engagement of the fluid coupling device.