JP2000337473A - Fluid coupling device - Google Patents

Abstract

(57) [Problem] To provide a fluid coupling device that can reduce drag torque without impairing a torque transmission function. SOLUTION: A fluid coupling having a casing, a pump attached to the casing, a turbine arranged opposite to the pump, and a casing and turbine formed from a working chamber formed by the pump and turbine. And a working fluid circulating means for circulating the working fluid through the chamber to be operated, wherein the working fluid circulating means is disposed in a circuit connecting the working chamber with a fluid pressure working source for circulating the working fluid. Provided with an installed electromagnetic switching valve. The electromagnetic switching valve selectively operates in a state in which the fluid pressure operating source communicates with the working chamber and a state in which the communication between the fluid pressure operating source and the working chamber is cut off and the working chamber is communicated with the atmosphere.

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, industrial machines, and automobiles. The fluid coupling includes a casing connected to a crankshaft (an 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, and a pump opposed to the pump. And a turbine mounted on an output shaft which is arranged on the same axis as the input shaft.

[0003] A fluid coupling including a lock-up clutch between the casing and the turbine for frictionally engaging the casing and the turbine has also been proposed. The lock-up clutch includes a clutch disk disposed between the casing and the turbine and forming an outer chamber between the casing and the turbine and forming an inner chamber between the turbine 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.

[0004] When the above-described fluid coupling is mounted on, for example, a drive device of a vehicle, the fluid coupling is generally operatively connected to a manual transmission via a friction clutch, and the fluid coupling is directly operatively connected to an automatic transmission.

[0005]

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.

In order to reduce the drag torque, it is conceivable to reduce the pressure of the working fluid circulating through the fluid coupling. However, when the pressure of the working fluid is reduced, the filling efficiency of the fluid coupling is reduced, so that the pressure at the time of high rotation is reduced. The transmission torque also decreases. In a fluid coupling provided with a lock-up clutch, the operating pressure of the lock-up clutch is insufficient, and in the worst case, lock-up is impossible.

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 that can reduce drag torque without impairing the torque transmission function. Another technical problem is that in a fluid coupling with a lock-up clutch,
Without running out of operating pressure of the lock-up clutch,
An object of the present invention is to provide a fluid coupling device that can reduce drag torque.

[0008]

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 fluid coupling comprising: a pump; a turbine disposed in a chamber formed by the pump and the casing so as to face the pump; and a turbine mounted on an output shaft disposed coaxially with the input shaft. And a working fluid circulating means for circulating working fluid from a working chamber formed by the turbine through a chamber formed by the casing and the turbine. Switching means disposed in a circuit connecting the fluid pressure working source for circulating fluid and the working chamber, the switching means comprising the fluid working source and the working chamber; And a fluid coupling device selectively operating in a state in which communication between the fluid pressure operating source and the working chamber is interrupted and a state in which the working chamber is connected to the atmosphere. You.

In the return passage of the working fluid supplied to the working chamber, it is desirable to provide a switching valve provided with a throttle.
The switching valve has a normal passage and a throttle passage. When the switching means communicates the fluid pressure operating source with the working chamber, the return passage communicates with the normal passage. When the communication between the operation source and the operation chamber is interrupted and the operation chamber is communicated with the atmosphere, the return passage is selectively operated to communicate with the throttle passage.

[0010] In order to solve the above-mentioned other technical problems, a casing connected to an input shaft, a pump disposed opposite to the casing and attached to the casing, a pump and the casing are provided. A fluid coupling having a turbine disposed in the formed chamber opposite the pump and mounted on an output shaft coaxial with the input shaft, and disposed between the casing and the turbine; A clutch disk forming an outer chamber with the casing and forming an inner chamber with the turbine,
A lock-up clutch for engaging the casing and the turbine by a fluid pressure difference between the outer chamber and the inner chamber; and a working fluid in a working chamber formed by the outer chamber, the inner chamber, and the pump and the turbine. And a working fluid circulating means for circulating the working fluid.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. The working fluid circulation means is configured to disengage the casing from the turbine when the working fluid flows from the working chamber through the inner chamber to the outer chamber, and the working fluid circulation means is configured to circulate the working fluid. Switching means disposed in a circuit connecting the fluid pressure operation source and the operation chamber,
The switching means is selectively connected to a state in which the fluid pressure operating source communicates with the working chamber and a state in which communication between the fluid pressure operating source and the working chamber is interrupted and the working chamber is communicated with the atmosphere. The fluid coupling device is provided.

[0011]

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
Is provided with a fluid coupling 400 having a casing 41, a pump 42 and a turbine 43.

The casing 41 is mounted on an outer peripheral portion of a drive plate 44 in which an inner peripheral portion is mounted on the crankshaft 21 with bolts 24 by 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 disposed 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 provided to face the pump 42. The turbine 43 is connected to the pump 42
And a plurality of runners 432 radially disposed in the turbine shell 431. The bowl-shaped turbine shell 431 is disposed opposite the pump shell 421.
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.

The fluid coupling device 4 in the illustrated embodiment
Is provided with a working fluid circulating means 6 for circulating working fluid from a working chamber 4a formed by the pump 42 and the turbine 43 through a chamber 400a formed by the casing 41 and the turbine 43. The working fluid circulation means 6 includes a hydraulic pump 60 as a fluid pressure working source. 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 rotatably supported by a bearing 490 on a cylindrical support 620 of the pump housing 62 which is formed so as to surround the output shaft 46. In addition, as shown in FIGS. 2 and 3, the output shaft 46 is provided with a working fluid passage 460 in association with the working fluid
A passage 461 for the working fluid is provided between the cylindrical support 620 and the cylindrical support 620. One end of the passage 460 is open at the left end face in the figure of the output shaft 46 and communicates with the chamber 400 a formed by the casing 41 and the turbine 43, and the other end is open at the outer peripheral surface of the output shaft 46. In communication with the direction passage 462. 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, an embodiment of the working fluid circulating means 6 will be described with reference to FIGS. The working fluid circulating means 6 has a reserve tank 65 for containing the working fluid, and the working fluid in the reserve tank 65 is discharged to the passage 661 by the hydraulic pump 60. The working fluid discharged into the passage 661 is supplied to the electromagnetic switching valve 67 (V
It is supplied to the passage 662 communicating with the communication hole 621 through 1). The electromagnetic switching valve 67 (V1) is de-energized (OF
F) in the state shown in FIG.
When the urging (ON) is performed, the communication between the passage 661 and the passage 662 is cut off, and the passage 662 is communicated to the atmosphere via the filter 68 as shown in FIG. It is configured. Therefore, the electromagnetic switching valve 67 (V
When 1) is de-energized (OFF), the hydraulic pump 6
The working fluid discharged into the passage 661 by the pressure chamber 0 is formed by the passage 662, the communication hole 621, the passage 461, the working chamber 4a formed by the pump 42 and the turbine 43, the casing 41 and the turbine 43 as shown by arrows in FIG. 400a, passage 460, passage 46 formed by
2. Circulated to the reserve tank 65 through the return passage 663, the cooler 69 and the passage 664. On the other hand, when the electromagnetic switching valve 67 (V1) is energized (ON), the communication between the passage 661 and the passage 662 is cut off as shown in FIG.
The working fluid discharged into the passage 661 by the hydraulic pump 60 is returned to the reserve tank 65 via a relief valve 70 provided in a relief passage 665 connecting the passage 661 and the reserve tank 65. The relief valve 70 has a valve opening pressure set to, for example, 6 kg / cm 2, and has a passage 661.
When the working fluid pressure exceeds 6 kg / cm 2, the working fluid is returned to the reserve tank 65 via the relief passage 665. In the state shown in FIG. 3 in which the electromagnetic switching valve 67 is energized (ON), the working fluid discharged from the hydraulic pump 60 is not supplied to the fluid coupling. The working fluid in the working chamber 4a formed by the above-mentioned is formed into a chamber 40 formed by the casing 41 and the turbine 43 by centrifugal force.
Since the exhaust gas is discharged to the side 0a and returned to the reserve tank 65 through the passage 462, the return passage 663, the cooler 69, and the passage 664, the inside of the working chamber 4a becomes negative pressure. At this time,
Since the passage 662 communicates with the atmosphere through the filter 68 by the electromagnetic switching valve 67 (V1), air is sucked.

The fluid coupling device 4 in the illustrated embodiment
Has a control means 100 for controlling the electromagnetic switching valve 67 of the working fluid circulation means 6. The control means 100
Central processing unit (CPU) configured by a microcomputer and performing arithmetic processing according to a control program
101, a read only memory (ROM) 102 for storing a control program, a readable and writable random access memory (RAM) 103 for storing calculation results and the like, and an input interface 104 and an output interface 105. Detection signals from a vehicle speed detection sensor 111 for detecting the running speed of the vehicle, an accelerator sensor 112 for detecting the amount of depression of an accelerator pedal, and the like are input to the input interface 104 of the control means 100 configured as described above. Also, the output interface 105
, A control signal is output to the electromagnetic switching valve 67 (VI).

Next, the friction clutch 8 will be described with reference to FIG.
This will be described with reference to FIG. The friction clutch 8 is provided in a clutch housing 80 mounted on the fluid coupling housing 40 by bolts 81. The friction clutch 8 in the illustrated embodiment is connected to the output shaft 46 of the fluid coupling.
, A transmission shaft 83 (in the illustrated embodiment, an input shaft of a transmission (not shown)) disposed on the same axis as the output shaft 46, and a spline fit to the transmission shaft 83. A driven plate 86 attached to the combined clutch hub 84 and having a clutch facing 85 mounted on an outer periphery thereof; a pressure plate 87 for pressing the driven plate 86 against the clutch drive plate 82; A diaphragm spring 88 that urges the diaphragm spring 82 toward
Release bearing 8 which engages with the inner end of the bearing 8 and operates the diaphragm spring 88 with the middle part as a fulcrum 881.
9 and a clutch release fork 90 for operating the release bearing 89 in the axial direction. In the friction clutch 8 configured as described above, the pressure plate 87 is moved by the spring force of the diaphragm spring 88 in the state shown in the drawing.
2, the clutch facing 85 mounted on the driven plate 86 is pressed by the clutch drive plate 82, and the output shaft 4 of the fluid coupling is pressed.
6 is transmitted to the transmission shaft 83 via the clutch drive plate 82 and the driven plate 86. To interrupt this power transmission, hydraulic pressure is supplied to a slave cylinder (not shown) to operate the clutch release fork 90, and the release bearing 89 is moved to the left in FIG. 1, so that the diaphragm spring 88 is indicated by a two-dot chain line in FIG. By operating as shown, by releasing the pressing force on the pressure plate 87,
Driven plate 8 from clutch drive plate 82
6 is shut off.

The drive device equipped with the fluid coupling device 4 in the illustrated embodiment is configured as described above, and its operation will be described below with reference to the drag torque control flowchart shown in FIG. The control means 100
First, in step S1, the traveling speed (V) of the vehicle is set to zero (0) based on the detection signal from the vehicle speed detection sensor 111.
That is, it is checked whether the vehicle has stopped. If the vehicle speed (V) is not zero (0) in step S1, the control means 100 determines that the vehicle is running and there is no need to perform drag torque control, and proceeds to step S2 to switch the electromagnetic switching valve 67 (V1). De-energize (OFF). Solenoid switching valve 6
When 7 (V1) is deenergized (OFF), the working fluid discharged to the passage 661 by the hydraulic pump 60 as described above is circulated in the direction indicated by the arrow in FIG. In this state, 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 400 via the drive plate 44. Pump shell 4 of casing 41 and pump 42
Since the pump 21 is integrally formed, the pump 42 is rotated by the driving force. When the pump 42 rotates, the working fluid in the pump 42 is centrifugally moved to the impeller 4.
It flows toward the outer periphery along 22 and flows into the turbine 43 side as shown by the 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 on the pump 42 side is transmitted through the working fluid to the turbine 43a.
Transmitted to the side. The driving force transmitted to the turbine 43 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.

If the vehicle speed (V) is zero (0) in step S1, the control means 100 proceeds to step S3, and based on the detection signal from the accelerator sensor 112, the depression amount (AP) of the accelerator pedal is set to zero (AP). 0) That is, it is checked whether the accelerator pedal is released. In step S3, the accelerator pedal depression amount (AP)
Is not zero (0), the control means 100 determines that the engine is not in the idling state and there is no need to perform drag torque control, and proceeds to step S2 to deactivate (OFF) the electromagnetic switching valve 67 (V1). . If the depression amount (AP) of the accelerator pedal is zero (0) in step S3, that is, if the accelerator pedal is released, the control means 100 determines that the engine is idling and it is necessary to perform drag torque control. Proceeding to step S4, the electromagnetic switching valve 67 (V1) is energized (ON). When the electromagnetic switching valve 67 (V1) is energized (ON), the communication between the passage 661 and the passage 662 is cut off as shown in FIG. 3, and the passage 662 communicates with the atmosphere via the filter 68. As described above, air is sucked by the negative pressure generated due to the discharge of the working fluid in the working chamber 4a formed by the pump 42 and the turbine 43 by centrifugal force. When this air is sucked into the working chamber 4a formed by the pump 42 and the turbine 43, the working chamber 4a
Since the amount of working fluid in the inside decreases, the drag torque sharply decreases. As described above, in order to reduce the drag torque of the fluid coupling when the vehicle speed (V) is zero (0) and the accelerator pedal is released, the electromagnetic switching valve 67 (V1) is energized (ON). If so, the control means 100 returns to step S1, and the vehicle speed (V) is no longer zero (0) (the vehicle is in a running state), or the depression amount (AP) of the accelerator pedal is no longer zero (0) in step S3. (The accelerator pedal is depressed)
In this case, it is determined that the engine is not in the idling state, and the routine proceeds to step S2, and the electromagnetic switching valve 67 (V1)
Is turned off (OFF).

Next, another embodiment of the working fluid circulating means 6 will be described with reference to FIGS. The embodiment shown in FIGS. 5 and 6 is a switching valve 71 having a throttle in the return passage 663 in the embodiment of FIGS. 2 and 3 described above.
Is arranged. In the embodiment shown in FIGS. 5 and 6, the switching valve 71 is the electromagnetic switching valve 67 (V1)
And are formed integrally. The embodiment shown in FIGS. 5 and 6 is substantially the same as the embodiment shown in FIGS. 2 and 3 except for the electromagnetic switching valve 67 (V1) and the switching valve 71.
The same members are denoted by the same reference numerals, and description thereof will be omitted.
The switching valve 71 includes a normal passage 711 and a throttle passage 712, and the electromagnetic switching valve 67 (V1) is deenergized (OF).
F) in the state shown in FIG.
2 communicates with the return passage 663, and the electromagnetic switching valve 67 (V1)
6 is energized (ON), the normal passage 711 communicates with the return passage 663. Therefore, the electromagnetic switching valve 67 (V1) is deenergized (OF).
F), the working fluid circulating in the direction indicated by the arrow in FIG. 5 is returned to the reserve tank 65 through the throttle passage 712 of the switching valve 71. Therefore, the filling efficiency of the working fluid supplied to the fluid coupling 400 can be increased, the efficiency of the fluid coupling 400 during normal operation can be improved, and the return from the drag torque control can be quickened. Can be. On the other hand, in the drag torque control in which the electromagnetic switching valve 67 (V1) is biased (ON), the return passage 663 is communicated with the normal passage 711 as shown in FIG. When the working fluid in the working chamber 4a formed by the pump 42 and the turbine 43 is discharged by centrifugal force, the discharge speed of the working fluid can be increased, and the above-mentioned air can be efficiently sucked. .

Next, another embodiment of the fluid coupling device 4 will be described with reference to FIGS. The embodiment shown in FIGS. 7 to 10 is provided with a lock-up clutch 50 for directly transmitting and connecting the casing 41 and the turbine 43 to the fluid coupling device 4 shown in FIGS. With the attachment of the clutch 50, the electromagnetic direction control valve 72 (V2) is provided between the passage 661 of the working fluid circulation means 6 and the electromagnetic switching valve 67 (V1).
Since other configurations are substantially the same as those of the above-described embodiments of FIGS. 1 to 3, the same members are denoted by the same reference numerals, and description thereof will be omitted. The lock-up clutch 50 in the embodiment shown in FIGS. 7 to 10 is provided between the casing 41 and the turbine 43 to form an outer chamber 40 a between the casing 41 and the inner chamber 40 b between the turbine 43 and the turbine 43. Are provided. 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. Friction surface 51
1 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, the friction surface 511 of the clutch disc 51
On the inner peripheral side, an annular concave portion 512 is formed,
A plurality of damper springs 55 supported by the support pieces 54 are arranged at predetermined intervals in the recesses 512. This plurality of damper springs 5
An input-side retainer 56 attached to the clutch disk 51 protrudes from both sides of the clutch disk 51, and the turbine 43 is disposed between the damper springs 55.
The output-side retainer 57 attached to the turbine shell 431 is disposed so as 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 circulation means 6 is formed by the pump 42 and the turbine 43 as shown in FIG. When the fluid flows from the working chamber 4a to the outer chamber 40a through the inner chamber 40b, the clutch disk 51 is pressed to the left in FIGS. 7 and 8, so that the plurality of friction disks 52 and the plurality of friction disks 52 are pressed. The disc 53 does not frictionally engage with the board 53, and thus 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 in the inner chamber 40b, that is, the working fluid supplied by the working fluid
When circulating from the outer chamber 40a through the inner chamber 40b to the working chamber 4a formed by the pump 42 and the turbine 43 as shown by 0, the clutch disk 51 is pressed rightward in FIGS. Therefore, since the annular friction surface 511 presses the plurality of friction plates 52 and the plurality of friction plates 53, the two friction plates are frictionally engaged. Therefore, the casing 41 and the turbine 43 are directly driven and connected via the friction disks 52 and 53, the clutch disk 51, the input-side retainer 56, the damper spring 55, and the output-side retainer 57.

The working fluid circulating means 6 in the embodiment shown in FIGS. 7 to 10 is disposed between the passage 661 of the working fluid circulating means shown in FIGS. 1 to 3 and the electromagnetic switching valve 67 (V1). And an electromagnetic directional control valve 72 (V2). This electromagnetic directional control valve 72 (V2) is de-energized (OF
F) When performed, as shown in FIGS. 8 and 9,
The passage 611 connected to the hydraulic pump 60 and the electromagnetic switching valve 6
7 (V1) through a passage 666,
The passage 663 is connected to the cooler 69 by the passage 66.
It is communicated with 7. Also, the electromagnetic directional control valve 72 (V2)
When energized (ON), as shown in FIG. 10, the passage 611 connected to the hydraulic pump 60 communicates with the passage 663, and the passage 666 connected to the electromagnetic switching valve 67 (V1) connects Passage 667 connected to vessel 69
Is communicated with. The electromagnetic switching valve 67 (V1) and the electromagnetic direction control valve 72 (V2) are controlled by the control means 100 in the embodiment shown in FIGS.

The fluid coupling device in the embodiment shown in FIGS. 7 to 10 is configured as described above, and its operation will be described below. First, a state in which the 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 will be described. In this case, the electromagnetic direction control valve 72 of the working fluid circulation means 6
(V2) is deenergized (OFF), the electromagnetic switching valve 67 (V1) is deenergized (OFF), and the working fluid is circulated in the direction indicated by the arrow in FIG. The state shown in FIG. 8 is the same as the state shown in FIG. 2 in the embodiment shown in FIGS. That is, when the casing 41 and the pump 42 are rotated by the crankshaft 21 (input shaft) of the diesel engine 2, the working fluid in the pump 42 flows toward the outer periphery along the impeller 422 due to centrifugal force, as indicated by the arrow. And the driving torque of the pump 42 is transmitted to the turbine 43 via the working fluid. The driving force transmitted to the turbine 43 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. When the working fluid is circulated in the direction indicated by the arrow in FIG. 8, the clutch disc 51 is pressed to the left in FIGS. 7 and 8 as described above. 52 and a plurality of friction plates 5
3 is not in frictional engagement, and therefore, the transmission connection between the casing 41 and the turbine 43 is released.

Next, a state in which the diesel engine 2 is performing an idling operation will be described. In this case, as shown in FIG. 9, the electromagnetic direction control valve 72 (V2) of the working fluid circulation means 6 is deenergized (OFF), and the electromagnetic switching valve 67 (VI) is energized (ON). ) Is done.
When the electromagnetic switching valve 67 (V1) is energized (ON), FIG.
As shown in FIG. 7, the communication between the passage 666 and the passage 662 is cut off, and the passage 662 communicates with the atmosphere via the filter 68. The air is sucked by the negative pressure generated because the working fluid is discharged by centrifugal force. When this air is sucked into the working chamber 4a formed by the pump 42 and the turbine 43, the amount of working fluid in the working chamber 4a decreases, so that the drag torque sharply decreases.

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 72 (V2) of the working fluid circulation means is energized (ON), and the electromagnetic switching valve 67 (V1) is deenergized (OFF). It is circulated in the direction indicated by the arrow. Therefore, as described above, the pressure of the working fluid in the outer chamber 40a is
The clutch disk 51 is pressed to the right in FIGS. 7 and 10 because the pressure is higher than the pressure of the working fluid on the side, and the annular friction surface 511 presses the plurality of friction disks 52 and the plurality of friction disks 53. Therefore, the two friction plates are frictionally engaged. As a result, the casing 41 and the turbine 43 are directly transmission-coupled via the friction disks 52 and 53, the clutch disk 51, the input-side retainer 56, the damper spring 55, and the 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 addition,
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. Absent.

[0030]

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, the working fluid circulating means for circulating the working fluid is provided in a circuit connecting the working chamber formed by the fluid working source, the pump and the turbine. Since switching means for selectively operating between a state in which the source and the working chamber are connected to each other and a state in which the communication between the fluid pressure working source and the working chamber is cut off and the working chamber is connected to the atmosphere is provided, the fluid coupling is provided. When the engine that drives the engine is idling, the switching means cuts off the communication between the fluid pressure operating source and the working chamber and connects the working chamber to the atmosphere, thereby sucking air into the working chamber so that the amount of working fluid in the working chamber is reduced. And the drag torque can be sharply 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.

Further, according to the present invention, since the drag torque can be reduced without reducing the fluid pressure of the working fluid circulated through the fluid coupling as described above, in the fluid coupling provided with the lock-up clutch, The operating pressure of the lock-up clutch does not become insufficient.

[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 circulating means of the fluid coupling device shown in FIG. 1, in which a driving torque is transmitted by a fluid coupling.

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, and illustrating an operation state of the engine that drives the fluid coupling during an idling operation.

FIG. 4 is a flowchart showing an operation of drag torque control by control means provided in the fluid coupling device shown in FIG. 1;

FIG. 5 is a view showing another embodiment of the working fluid circulating means of the fluid coupling device shown in FIG. 1, and is a diagram illustrating a state in which a driving torque is transmitted by a fluid coupling.

6 is an explanatory diagram showing an operation state of the working fluid circulating means shown in FIG. 5, and illustrating an operation state of the engine that drives the fluid coupling during an idling operation.

FIG. 7 is a cross-sectional view showing another embodiment of a drive device equipped with a fluid coupling device configured according to the present invention.

8 is an explanatory diagram showing an operation state of a working fluid circulating means of the fluid coupling device shown in FIG. 7, in which a driving torque is transmitted by a fluid coupling. FIG.

9 is an explanatory diagram showing an operation state of a working fluid circulation unit of the fluid coupling device shown in FIG. 7, and illustrating an operation state of the engine that drives the fluid coupling during an idling operation. FIG.

FIG. 10 is an explanatory diagram showing an operation state of a working fluid circulation unit of the fluid coupling device shown in FIG. 7, in which a lock-up clutch is operated.

[Explanation of symbols]

 2: Internal combustion engine 21: Crankshaft 4: Fluid coupling device 40: Fluid coupling housing 41: Casing 42: Pump 400: Fluid coupling 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 side retainer 57: Output side retainer 6: Working fluid circulation means 60: Hydraulic pump 62: Pump housing 65: Reserve tank 67: Electromagnetic switching valve (V1) 68: Filter 69: Cooler 70: Relief valve 71: Switching valve 72: Electromagnetic direction control valve (V3) 8: Friction clutch 80: crack Housing 82: Clutch drive plate 83: Transmission shaft 84: Clutch hub 85: Clutch facing 86: Driven plate 87: Pressure plate 88: Diaphragm spring 89: Release bearing 90: Clutch release fork 100: Control means 111: Vehicle speed detection sensor 112: Accelerator sensor

Claims (5)

[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 fluid coupling having a turbine mounted on an output shaft disposed coaxially with the input shaft, and formed by the casing and the turbine from a working chamber formed by the pump and the turbine. A working fluid circulating means for circulating the working fluid through the chamber, wherein the working fluid circulating means is disposed in a circuit connecting the working chamber with a fluid pressure working source for circulating the working fluid. Switching means provided, wherein the switching means disconnects communication between the fluid pressure operating source and the working chamber, and disconnects communication between the fluid pressure operating source and the working chamber. A fluid coupling device, wherein the fluid chamber is selectively operated to bring the working chamber into communication with the atmosphere. 2. The fluid coupling device according to claim 1, further comprising a switching valve provided with a throttle in a return passage of the working fluid supplied to the working chamber. 3. The switching valve has a normal passage and a throttle passage, and a state in which the return passage communicates with the normal passage when the switching means communicates the fluid pressure operating source with the working chamber. And the switching means selectively operates to interrupt communication between the fluid pressure operating source and the working chamber and to connect the return passage to the throttle passage when the working chamber is connected to the atmosphere. The fluid coupling device according to claim 2, wherein: 4. The fluid coupling device according to claim 3, wherein said switching valve is configured integrally with said switching means. 5. 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 fluid coupling having a turbine mounted on an output shaft disposed on the same axis as the input shaft, and an outer chamber formed between the casing and the turbine disposed between the casing and the turbine. A lock-up clutch for engaging the casing with the turbine by a fluid pressure difference between the outer chamber and the inner chamber; and a lock-up clutch for engaging the casing with the turbine by a fluid pressure difference between the outer chamber and the inner chamber. A fluid coupling device comprising a chamber and a working fluid circulating means for circulating a working fluid into a working chamber formed by the pump and the turbine; A clutch engages the casing and the turbine when working fluid flows from the outer chamber through the inner chamber to the working chamber, and engages the casing when working fluid flows from the working chamber through the inner chamber to the outer chamber. And the turbine are disengaged from each other, and the working fluid circulating means is provided with a switching device disposed in a circuit connecting the working chamber and a fluid pressure working source for circulating working fluid. Means for connecting the fluid pressure operating source to the working chamber, and disconnecting the communication between the fluid pressure operating source and the working chamber and connecting the working chamber to the atmosphere. And a fluid coupling device that selectively operates in a state.