JP2000266159A - Hydraulic coupling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce drag torque without exerting influence on actuation of a lockup clutch by arranging throttling in a hydraulic circuit for supplying a hydraulic fluid at engaging/releasing time of a casing and a turbine by the lockup clutch. SOLUTION: In a hydraulic circuit, a throttling 75 is arranged in a downstream side passage 69 from a solenoid directional control valve 67. This throttling 75 is arranged in the hydraulic circuit for supplying a hydraulic fluid at engaging/releasing time of a casing and a turbine 43 by a lockup clutch 50 for circulating the hydraulic fluid to thereby largely reduce hydraulic fluid quantity supplied to an inside chamber 40b by passing through an outside chamber 40a of a hydraulic coupling to reduce fluid pressure for confining the hydraulic fluid in an operating chamber 4a formed of a pump 42 and the turbine 43 so that the hydraulic fluid in the operating chamber 4a easily flows out to thereby reduce transmission torque, that is, drag torque at idling operation time of a diesel engine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid coupling device for transmitting a rotating torque of a prime mover, and more particularly to an improvement of a fluid coupling device having a lock-up clutch.

[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 (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 the pump and the casing. A turbine disposed in the formed chamber so as to face the pump, the turbine being mounted on an output shaft arranged on the same axis as the input shaft. Such a fluid coupling device is provided with a lock-up clutch that frictionally engages the casing and the turbine to directly connect the two. The lock-up clutch includes a clutch disc provided with a clutch facing that is disposed between the casing and the turbine and forms an outer chamber between the casing and the inner chamber between the casing 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 circulating in the inner chamber and the working chamber formed by the pump and the turbine. In order to operate the lock-up clutch of such a fluid transmission device to frictionally engage the casing with the turbine (hereinafter referred to as lock-up clutch ON), the transmission torque, the diameter of the clutch disk, the clutch facing material, and the like are used. It is necessary to apply a considerably high fluid pressure to be determined. On the other hand, when the friction engagement between the casing and the turbine is released (hereinafter referred to as lock-up clutch OFF), the fluid pressure acting when the lock-up clutch is ON is removed, and the lock-up is performed to prevent clutch facing drag. Apply fluid pressure in the opposite direction to when the clutch is ON.

[0003]

In the fluid coupling provided in 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, when the input shaft is rotating and the output shaft is stopped, it has a drag torque due to its characteristics. This drag torque sets the design point of the fluid coupling to the rotational speed ratio at which the efficiency is maximized, that is, the rotational speed ratio between the pump and the turbine from 0.95 to 0.9.
In eighth place, it will be quite 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. This drag torque increases as the fluid pressure of the circulating working fluid increases.Therefore, in order to reduce the drag torque, it is conceivable to decrease the fluid pressure of the circulating working fluid. When the operating pressure of the lock-up clutch is insufficient, lock-up is impossible in the worst case. Therefore, the hydraulic pressure of the working fluid must be set to a pressure at which the operating pressure does not become insufficient when the lock-up clutch is ON.

[0004] 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 affecting the operation of a lock-up clutch. It is in.

[0005]

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 disposed in a chamber formed by the pump and the casing, opposed to the pump, and mounted on an output shaft disposed on the same axis as the input shaft; A lock-up clutch provided between the casing and a clutch disk for forming an outer chamber between the casing and the turbine and forming an inner chamber between the casing and the turbine, and for engaging or disengaging the casing and the turbine; And a working fluid circulating means for circulating working fluid to the working chamber formed by the outer chamber, the inner chamber, and the pump and the turbine. The working fluid circulating means includes a relief valve for adjusting the working fluid supplied from the fluid pressure source to a predetermined fluid pressure, and a circulation path of the working fluid adjusted to the predetermined fluid pressure by the relief valve. A directional control valve for controlling, and a throttle disposed in a fluid circuit for supplying a working fluid controlled by the directional control valve when the lock-up clutch disengages the casing and the turbine, A fluid coupling device is provided.

[0006]

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 (fluid coupling) device to which the present invention is applied is disposed between an automobile engine and a friction clutch. The drive device in the illustrated embodiment includes an internal combustion engine 2 as a prime mover, a fluid coupling device 4 and a 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.

A 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.

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.
The clutch facing 52 is mounted on the surface facing the clutch facing 1. An annular recess 53 is formed in the outer peripheral portion of the clutch disc 51 on the inner chamber 40b side, and a plurality of damper springs 55 supported by support pieces 54 in the recess 53 at predetermined intervals. It is arranged. 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.
The output side retainer 57 attached to the third 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 circulating means described later is formed by the pump 42 and the turbine 43.
When the clutch disk 51 flows from the inner space 40b to the outer chamber 40a through the inner chamber 40b, the clutch disc 51 is pressed to the left in FIG. Engage (lock-up clutch ON). Therefore,
The casing 41 and the turbine 43 are provided with a clutch facing 52, a clutch disc 51, an input side retainer 56,
The power transmission is directly connected via the damper spring 55 and the output side retainer 57. 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. Working chamber 4a formed by turbine 43
When the clutch disk 51 circulates in FIG.
At the right side, the clutch disc 51
The clutch facing 52 mounted on the casing 4
1 is not in frictional engagement, and therefore, the transmission connection between the casing 41 and the turbine 43 is released.

The fluid coupling device 4 in the illustrated embodiment has a hydraulic pump 60 as a fluid pressure 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 rotatably supported by a bearing 490 on a cylindrical support portion 620 of the pump housing 62 formed so as to surround the output shaft 46. 2 and 3
As shown in the figure, a working fluid passage 460 is provided on the output shaft 46 in connection with a working fluid circulating means described later, and a working fluid passage 461 is provided between the output shaft 46 and the cylindrical support portion 620. Is provided. One end of the passage 460 communicates with the outer chamber 40a at one end thereof and opens at the left end face in the drawing of the output shaft 46, and the other end thereof communicates with a radial passage 462 opening at the outer peripheral surface of the output shaft 46. . Also,
The passage 461 is configured to communicate the working chamber 4 a formed by the pump 42 and the turbine 43 with a 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 into the passage 66 is connected to the passage 68 or the passage 46 that communicates with the communication hole 621 through an electromagnetic direction control valve 67 that controls a circulation path of the working fluid.
It is supplied to a passage 69 communicating with the second. Electromagnetic directional control valve 6
In the state shown in FIG. 2 in which the power supply 7 is deenergized (OFF), the working fluid discharged into the passage 66 receives the passage 69, the passage 462, the passage 460, the outer chamber 40a, the inner chamber 40b, and the pump as indicated by arrows. The working chamber 4 a formed by the turbine 42 and the turbine 43, the passage 461, the communication hole 621, the passage 6
8. Circulated to the reserve tank 65 through the return passage 70, the cooler 71 and the passage 72. When the working fluid circulates as shown by the arrow in FIG. 2, the lockup clutch 50 does not frictionally engage as described above because the fluid pressure in the outer chamber 40a is higher than the fluid pressure in the inner chamber 40b. On the other hand, when the electromagnetic directional control valve 67 is urged (ON), the state shown in FIG. 3 is reached, and the working fluid discharged into the passage 66 passes through the passage 68, the communication hole 621, the passage 461, and the pump 42 as shown by arrows. Working chamber 4 formed by turbine 43
a, inner chamber 40b, outer chamber 40a, passage 460, passage 4
62, a passage 69, a return passage 70, a cooler 71, and a passage 72 circulate to the reserve tank 65. When the working fluid circulates as shown by the arrow in FIG. 3, 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 frictionally engages as described above.

In the fluid circuit in the illustrated embodiment, a relief passage 7 connecting the passage 66 and the reserve tank 65 is provided.
The relief valve 74 is provided in the relief passage 73. The relief valve 74 is set at a valve opening pressure of, for example, 6 kg / cm 2, which is a fluid pressure required for the clutch facing 52 mounted on the clutch disk 51 to be pressed by the casing 41 and frictionally engaged when the lock-up clutch is ON. Passage 6
When the working fluid pressure in 6 exceeds 6 kg / cm 2, the working fluid is returned to the reserve tank 65 via the relief passage 73. In the illustrated fluid circuit, a throttle 75 is provided in a passage 69 downstream of the electromagnetic directional control valve 67.
Are arranged. The throttle 75 is provided in a fluid circuit that supplies the working fluid when the engagement between the casing 41 and the turbine 43 by the lock-up clutch 50 in which the working fluid circulates is released as indicated by an arrow in FIG.

Next, the friction clutch 8 will be described (see FIG. 1). 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 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, An input shaft of a transmission without transmission), a driven plate 86 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, and a driven plate 86 Plate 87 that presses against the flywheel 82 and a diaphragm spring 88 that urges the pressure plate 87 toward the flywheel 82.
A release bearing 89 which engages the inner end of the diaphragm spring 88 to operate the diaphragm spring 88 with the intermediate portion as a fulcrum 881; and a clutch release fork 90 for operating the release bearing 89 in the axial direction. ing. In the state shown in the drawing, the friction clutch 8 having the above-described structure is operated by the spring force of the diaphragm spring 88.
7 is pressed toward the clutch drive plate 82, so that the clutch facing 85 mounted on the driven plate 86
Is transmitted to the transmission shaft 83 through 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.
The diaphragm spring 88 is actuated as shown by a two-dot chain line in the figure, and the power transmission from the clutch drive plate 82 to the driven plate 86 is cut off by releasing the pressing force on the pressure plate 87.

The fluid coupling device in the illustrated embodiment is configured as described above, and its operation will be described below. First, a state in which the diesel engine 2 is performing an idling operation will be described. 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. 2 as described above. 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, and the pump 42 formed integrally with the casing 41 rotates. I'm sullen. 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. 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. However, in the illustrated embodiment, the electromagnetic directional control valve 6
Since the throttle 75 is disposed in the passage 69 downstream of the valve 7, the fluid pressure in the fluid circuit from the hydraulic pump 60 to the throttle 75 increases, and a part of the working fluid during this time is supplied from the relief valve 74 to the reserve valve 74. It is discharged to the tank 65. As a result, the amount of working fluid supplied to the inner chamber 40b through the outer chamber 40a of the fluid coupling is greatly reduced, and the hydraulic pressure for containing the working fluid in the working chamber 4a formed by the pump 42 and the turbine 43 is reduced. And the working fluid in the working chamber 4a easily flows out. Accordingly, the efficiency of filling the working chamber 4a with the working fluid is reduced, so that the transmission torque, that is, the drag torque during the idling operation of the diesel engine 2 is reduced.

Next, a description will be given of a state where the diesel engine 2 is operated at a rotation speed higher than the idling rotation and the driving torque is transmitted by the fluid coupling. 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
As described above, the power is transmitted to the casing 41 of the fluid coupling 4 via the drive plate 44. Since the casing 41 and the pump shell 421 of the pump 42 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. Note that, even when the drive torque is transmitted by the fluid coupling, the working fluid is supplied to the fluid coupling through the passage 69. Therefore, the throttle 7 arranged in the passage 69
5, the hydraulic pump 60 stops the throttle 75
The hydraulic pressure of the hydraulic circuit up to this point increases, and a part of the working fluid during this time is discharged from the relief valve 74 to the reserve tank 65. However, when the rotation speed of the diesel engine 2 increases, the discharge amount of the hydraulic pump 60 increases. Therefore, when the discharge limit from the relief valve 74 is exceeded, the flow rate of the working fluid supplied to the fluid coupling increases rapidly with the increase in the fluid pressure between the hydraulic pump 60 and the throttle 75. Therefore, the pump 4
Since the efficiency of filling the working fluid into the working chamber 4a formed by the turbine 2 and the turbine 43 increases, and the torque transmission efficiency of the fluid coupling increases, there is no problem in torque transmission during high engine speed. Therefore, by setting the throttle amount of the throttle 75 in accordance with the flow characteristics of the hydraulic pump 60,
The drag torque can be reduced during idling operation of the engine, and a fluid coupling with good torque transmission efficiency can be obtained during high engine rotation.

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. The fluid pressure of the working fluid at this time is adjusted to 6 kg / cm 2 by the relief valve 74. In a state where the working fluid is circulated in the direction indicated by the arrow in FIG. 3, the pressure on the inner chamber 40b side is higher than the pressure on the outer chamber 40a as described above, and the clutch disk 51 is moved to the left in FIGS. The clutch facing 52 mounted on the clutch disc 51 is pressed by the casing 41 to frictionally engage (lock-up clutch ON). As a result, the casing 41 and the turbine 43 are directly transmission-coupled via the clutch facing 52, the clutch disk 51, the input side retainer 56, the damper spring 54, 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. When the lock-up clutch is ON, the working fluid is circulated in the direction shown by the arrow in FIG. 3 as described above, and the passage 69 in which the throttle 75 is provided is on the return circuit side of the working fluid, and the supply of the working fluid is performed. Since the passage 68 on the circuit side is not restricted, the efficiency of filling the working fluid into the fluid coupling increases, and the fluid pressure in the fluid coupling also easily rises. Accordingly, the pressing force for frictionally engaging the clutch facing 52 mounted on the clutch disc 51 with the casing 41, that is, the lockup efficiency can be improved. For this reason, the capacity of the working fluid circulation means can be reduced as compared with the conventional one.

[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, the throttle is provided in the fluid circuit for supplying the working fluid when the casing is disengaged from the turbine, so that the amount of the working fluid supplied to the fluid coupling is reduced. Then, the fluid pressure for containing the working fluid in the working chamber formed by the pump and the turbine decreases, and the working fluid in the working chamber easily flows out.
Therefore, the efficiency of filling the working chamber with the working fluid is reduced, and the transmission torque, that is, the drag torque during the idling operation of the prime mover is reduced. Further, in the fluid coupling device according to the present invention, when the lock-up clutch is ON, the restrictor is on the return circuit side of the working fluid, so that the efficiency of filling the working fluid into the fluid coupling increases, and the fluid pressure in the fluid coupling easily increases. Therefore, lock-up efficiency 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 and showing a lock-up clutch OFF state.

FIG. 3 is an explanatory diagram showing an operation state of a working fluid circulation unit of the fluid coupling device shown in FIG. 1 and showing a lock-up clutch ON state.

[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 disk 54: Support piece 55: Damper spring 56: Input side retainer 57: Output side retainer 60: Hydraulic pump 62: Pump housing 65: Reserve tank 67: Electromagnetic Direction control valve 71: Cooler 74: Relief valve 75: Restrictor 8: Friction clutch 80: Clutch housing 82: Clutch drive plate 83: Power transmission shaft 84: Clutch hub 85: Clutch facing 86: Driven Rate 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 disposed on the same axis as the input shaft, and an outer chamber formed between the casing and the turbine, and an outer chamber formed between the turbine and the turbine. A lock-up clutch for engaging or disengaging the casing and the turbine between the clutch disc and an inner chamber, and an operation formed by the outer chamber, the inner chamber, the pump, and the turbine; A working fluid circulating means for circulating a working fluid in the chamber, wherein the working fluid circulating means is a working fluid supplied from a fluid pressure source. A relief valve that adjusts to a predetermined fluid pressure, a directional control valve that controls a circulation path of a working fluid adjusted to a predetermined fluid pressure by the relief valve, and engagement between the casing and the turbine by the lock-up clutch And a throttle disposed in a fluid circuit for supplying a working fluid controlled by the direction control valve when released.