JP2010159821A - Wet clutch cooling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize the cooling effect of a wet clutch. <P>SOLUTION: A clutch cooling oil path in which a cooling oil of a clutch plate 12 is circulated is subject to a close circuit independent from a work machine oil path in which a hydraulic oil to be supplied to the work machine is circulated. On the clutch cooling oil path, a hydraulic pump 20 separated from a hydraulic pump for work machine is provided. The hydraulic pump 20 provided on the clutch cooling oil path rotates corresponding to rotation of an engine, sucks a cooling oil stored in a clutch housing and discharges it to a cooler 30. The cooling oil is cooled by the cooler 30 and returns into the clutch housing 11. Thus, the cooling oil for cooling the clutch plate 12 is separated from the hydraulic oil to be supplied to the work machine, thereby preventing it from affecting the operation of the work machine in cooling a wet clutch 10. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wet clutch cooling device that cools a clutch plate with cooling oil, and more particularly to an independent closed circuit for a clutch cooling oil passage for circulating cooling oil.

  A work vehicle equipped with a hydraulic working machine, such as a forklift, raises and lowers a fork by supplying hydraulic oil to a lift cylinder, and tilts a mast by supplying hydraulic oil to a tilt cylinder. Steering, brakes and clutches are also driven by hydraulic oil. The work vehicle travels by transmitting engine power to drive wheels via a power train such as a clutch, transmission, drive axle or the like.

  The main work of a forklift is not a long-distance driving but a cargo handling work within a certain area, so forklifts are often switched between running and stopping compared to ordinary vehicles. Is done frequently. Thus, the forklift frequently uses the clutch, and the temperature of the clutch plate is likely to rise. For this reason, wet clutches are used in forklifts to extend the life of the clutch plates.

  The wet clutch is provided with an input / output side clutch plate in the clutch housing and storing cooling oil for cooling the clutch plate. The clutch plate is provided with fins, and a cooling oil recovery port connected to the clutch cooling oil passage is provided in the clutch housing. When the fin rotates according to the rotation of the clutch plate, the cooling oil is scraped up by the fin. When the scooped-up cooling oil reaches the position of the cooling oil recovery port, the cooling oil is discharged from the cooling oil recovery port to the outside of the clutch housing and circulates through the clutch cooling oil passage. And heat is dissipated during circulation.

  Conventionally, hydraulic oil supplied to each cylinder such as a lift cylinder has been used as the cooling oil, and the hydraulic oil tank for clutch cooling stores the hydraulic oil together with the oil path for the work machine such as the lift cylinder. It is connected to the. In other words, the same hydraulic oil is used in the lift cylinder or tilt cylinder and the wet clutch, and the hydraulic oil is exchanged between the lift cylinder or tilt cylinder and the wet clutch via the hydraulic oil tank. It can be said that there is.

  Conventionally, a wet clutch cooling device is configured as described above.

  However, the conventional wet clutch cooling device has the following problems.

  Generally, when the clutch is repeatedly connected and disconnected, the clutch plate is worn and dust is generated. In the case of a wet clutch, this dust enters the cooling oil. After the cooling oil is collected in the tank, a part of the cooling oil is supplied as hydraulic oil to the working machine oil passage. When the working oil mixed with dust is supplied to each cylinder, the dust accumulates in each cylinder. When the amount of accumulated dust increases, the movement of each cylinder worsens, which adversely affects the operation of forks, masts, brakes, and the like.

  Further, since the cooling oil dissipates heat in the hydraulic oil tank, the heat balance of the hydraulic oil itself is affected, and this also affects the operation of the fork, mast, brake, and the like.

  The present invention has been made in view of such a situation, and a first problem to be solved is to prevent the operation of the work machine from being affected by the cooling of the wet clutch.

  Further, although the cooling oil is recovered according to the rotation of the fins attached to the clutch plate, the rotation of the clutch plate is not stable in the first place. For this reason, the recovery amount of the cooling oil increases when the clutch plate rotates at a high speed, but the recovery amount of the cooling oil decreases when the clutch plate rotates at a low speed. As a result, the heat of the cooling oil cannot be sufficiently dissipated, and the cooling of the wet clutch itself may be insufficient.

  The present invention has been made in view of such a situation, and a second problem to be solved is to stabilize the recovered amount of cooling oil and stabilize the cooling effect of the wet clutch.

Therefore, the present invention provides
Wet clutch cooling, which is disposed in a power train of a work vehicle that drives a hydraulic working machine with hydraulic oil and has a clutch plate and a cooling oil for cooling the clutch plate in a clutch housing, and cools the cooling oil. In the device
A clutch cooling oil passage for circulating the cooling oil outside the clutch housing and cooling the cooling oil;
Further, the clutch cooling oil passage is a closed circuit independent of a working machine oil passage for circulating hydraulic oil supplied to the hydraulic working machine.

The present invention also provides:
A cooler is provided in the clutch cooling oil passage.

The present invention also provides:
A hydraulic pump is provided in the oil passage for cooling the clutch.

The present invention also provides:
A hydraulic pump, a cooler, and a relief valve are provided in the clutch cooling oil passage,
Communicating the inside of the clutch housing and the suction port of the hydraulic pump;
The discharge port of the hydraulic pump communicates with the oil inlet of the relief valve and the oil inlet of the cooler,
The oil outlet of the relief valve and the outlet of the cooler are communicated with the inside of the clutch housing.

The present invention also provides:
The rotating shaft of the hydraulic pump is connected to the output shaft of the engine.

The present invention also provides:
The clutch cooling oil passage is provided with a dust removing unit that removes dust in the cooling oil.

The present invention also provides:
A wet clutch disposed in a power train of a work vehicle that drives a hydraulic working machine by hydraulic oil discharged from a piston pump and having a clutch plate and a cooling oil for cooling the clutch plate in the clutch housing; In the wet clutch cooling device that cools
A clutch cooling oil passage for circulating the cooling oil outside the clutch housing and cooling the cooling oil;
Further, the clutch cooling oil passage is a closed circuit independent of a working machine oil passage through which hydraulic oil is circulated by the piston pump.

  According to the present invention, the clutch cooling oil passage through which the cooling oil of the clutch plate circulates is formed as a closed circuit independent of the working oil passage through which the hydraulic oil supplied to the working machine circulates. The clutch cooling oil passage is provided with a hydraulic pump different from the hydraulic pump for the working machine. The hydraulic pump provided in the clutch cooling oil passage rotates according to the rotation of the engine, sucks the cooling oil stored in the clutch housing, and discharges it to the cooler. The cooling oil is cooled by the cooler and returns to the clutch housing. Thus, the cooling oil for cooling the clutch plate is separated from the hydraulic oil supplied to the working machine.

  If a filter is provided in any of the clutch cooling oil passages, dust contained in the cooling oil can be removed. If a relief valve is provided in parallel with the cooler, the cooler can be protected even if the cooling oil becomes high pressure.

  Moreover, when a piston pump is provided in the working machine oil passage, oil mixed with bubbles is not supplied to the piston pump.

According to the present invention, since the clutch cooling oil passage is provided as a closed circuit independent of the work implement oil passage, the cooling oil for cooling the clutch plate does not flow through the work implement oil passage. It does not flow into each cylinder. For this reason, the dust generated from the clutch is not mixed in each cylinder for the work implement, and the operation of the work implement is not adversely affected. Further, the cooling oil does not radiate heat to the hydraulic oil, and the heat balance of the hydraulic oil is not adversely affected.
Further, according to the present invention, the cooling oil is sucked and discharged by the hydraulic pump and supplied to the cooler. Since the supply amount of the cooling oil to the cooler is stabilized by using the hydraulic pump, the cooling efficiency of the cooling oil is improved as compared with the conventional case.

The circuit diagram which shows the oil path for clutch cooling in the wet clutch cooling device which concerns on this embodiment. The figure which shows simply arrangement | positioning of each component in the wet clutch cooling device which concerns on this embodiment.

  Embodiments of the present invention will be described below with reference to the drawings.

  In this embodiment, the forklift provided with the wet clutch in the power train between an engine and a driving wheel is assumed as a work vehicle.

FIG. 1 is a circuit diagram showing an oil passage for clutch cooling in the wet clutch cooling device according to the present embodiment. In general, a forklift operates each working machine such as a fork, mast, steering, brake, and clutch with hydraulic oil, and has a working machine oil passage through which the hydraulic oil circulates. The clutch cooling oil passage shown in FIG. 1 is a closed circuit independent of the working machine oil passage. For this reason, the working machine oil passage is not shown in FIG.
The clutch cooling oil passage according to the present embodiment includes a wet clutch 10, a hydraulic pump 20, a cooler 30, a relief valve 40, a line filter 50, and pipe lines 71 to 74.

  The wet clutch 10 includes a clutch plate 12 on the input side and the output side, and a cooling oil 13 that cools the clutch plate 12 inside the clutch housing 11. Furthermore, the strainer 14 which can flow out the cooling oil 13 inside the clutch housing 11 out of the clutch housing 11 is provided.

  The strainer 14 is connected to the suction port of the hydraulic pump 20 provided outside the clutch housing 11 through a pipe 71. The discharge port of the hydraulic pump 20 is connected to the oil inlet of the cooler 30 and the oil inlet of the relief valve 40 via a pipeline 72 that branches in the middle. The oil outlet of the cooler 30 and the oil outlet of the relief valve 40 are connected to the oil inlet of the line filter 50 via a pipe line 73 that joins on the way. The oil outlet of the line filter 50 is connected to the inside of the clutch housing 11 via a pipe line 74.

  The drive shaft 2 of the engine 1 is connected to an input side clutch plate 12 provided in the clutch housing 11. The belt 3 is wound around the drive shaft 2 of the engine 1 and the rotary shaft 21 of the hydraulic pump 20, whereby the drive shaft 2 of the engine 1 and the rotary shaft 21 of the hydraulic pump 20 are connected. In addition, a hydraulic pump is also provided in an oil passage for a work machine (not shown), and a belt is wound around the rotary shaft of the hydraulic pump and the drive shaft 2 of the engine 1, thereby The rotary shaft of the hydraulic pump is connected.

  The hydraulic pump 20 only needs to be able to circulate the cooling oil 13 in the oil passage for clutch cooling, and does not require a large capacity. The hydraulic pump 20 can be a gear pump, a piston pump, or a vane pump. Among these, it is desirable to use a gear pump. This is because the gear pump not only has a simple structure and is inexpensive, but also is particularly difficult to be affected by bubbles contained in oil, so-called aeration. A small motor or the like may be provided as a power source for the hydraulic pump 20, but it is desirable to use the engine 1 in consideration of installation space and cost. The cooler 30 can be either water-cooled or air-cooled.

  In this embodiment, the strainer 14 and the line filter 50 are provided in the oil passage for cooling the clutch, but only one of them may be provided, or another filter such as a suction strainer (suction filter) or a return filter may be provided. May be provided. Although it is desirable to provide a filter in the clutch cooling oil passage as in this embodiment, the filter is not essential from the viewpoint of cooling the cooling oil.

  Further, if the heat of the cooling oil 13 is not so high, the clutch cooling oil passage has a certain length, and the cooling oil 13 can sufficiently dissipate heat while flowing through the clutch cooling oil passage, the cooler 30 Is not necessary.

  FIG. 2 is a diagram simply showing the arrangement of each component in the wet clutch cooling device according to the present embodiment. 2A is a plan view and FIG. 2B is a side view.

  A clutch housing 11 is disposed in front of the engine 1. A suction strainer 14 is attached to the lower portion of the clutch housing 11. A drive shaft 2 extends in a substantially horizontal direction behind the engine 1, and a fan 4 is attached to an end of the drive shaft 2. A cooler 30 is disposed behind the fan 4 so as to face the fan 4. A hydraulic pump 20, a relief valve 40, and a line filter 50 are disposed on one side of the engine 1. Although not shown in order to make the drawing easy to see, a pipe 71 is arranged on one side of the engine 1 and between the suction strainer 14 and the hydraulic pump 20, and the hydraulic pump 20, the cooler 30 and the relief valve 40. Between the cooler 30 and the relief valve 40 and the line filter 50, and a pipe line 74 between the line filter 50 and the clutch housing 11. Be placed.

  Returning to FIG. 1 again, the operation of the wet clutch cooling device according to the present embodiment will be described.

  When the drive shaft 2 is rotated by the operation of the engine 1, the clutch plate 12 is rotated. When the clutch plates 12 on the input side and the output side generate heat due to friction, the cooling oil 13 stored in the clutch housing 11 absorbs the heat of the clutch plate 12.

  The power of the engine 1 is transmitted to the rotary shaft 21 of the hydraulic pump 20 via the drive shaft 2 and the belt 3, and the hydraulic pump 20 rotates. When the hydraulic pump 20 rotates, the cooling oil 13 stored in the clutch housing 11 passes through the strainer 14 and flows through the pipe 71. As the cooling oil 13 passes through the strainer 14, it is filtered to remove dust. The cooling oil 13 is sucked from the suction port of the hydraulic pump 20 and discharged from the discharge port. The cooling oil 13 discharged from the hydraulic pump 20 flows through the pipe line 72 and reaches the cooler 30. The cooling oil 13 is cooled by the endothermic action of the cooling fluid or gas in the cooler 30 while flowing through the cooler 30. The cooling oil 13 discharged from the cooler 30 flows through the pipe 73, passes through the line filter 50, further flows through the pipe 74, and returns to the clutch housing 11. When the cooling oil 13 passes through the line filter 50, it is filtered again to remove dust. As described above, the cooling oil 13 circulates in the clutch cooling oil passage.

  By the way, when the hydraulic pump 20 rotates in a state where the viscosity of the cooling oil 13 is high, for example, under a low temperature condition, the high-pressure cooling oil 13 flows into the cooler 30. The cooler 30 has a pressure resistance, and when the cooling oil 13 exceeding the pressure resistance flows into the cooler 30, the cooler 30 may be damaged. Therefore, as shown in FIG. 1, a relief valve 40 is provided in parallel with the cooler 30, and a pressure sufficiently lower than the pressure resistance of the cooler 30 is set as the set pressure of the relief valve 40. In this case, when the cooling oil 13 flowing through the pipe line 72 becomes equal to or higher than the set pressure of the relief valve 40, the relief valve 40 opens, and a part of the cooling oil 13 in the pipe line 72 passes through the relief valve 40 and passes through the pipe line 73. To leak. As a result, the cooler 30 is protected.

  According to the present embodiment, the clutch cooling oil passage is provided as a closed circuit independent of the work implement oil passage, so that the cooling oil for cooling the clutch plate does not flow through the work implement oil passage. It does not flow into each cylinder. For this reason, the dust generated from the clutch is not mixed in each cylinder for the work implement, and the operation of the work implement is not adversely affected. Further, the cooling oil does not radiate heat to the hydraulic oil, and the heat balance of the hydraulic oil is not adversely affected.

  Further, according to the present embodiment, the cooling oil is sucked and discharged by the hydraulic pump and supplied to the cooler. Since the supply amount of the cooling oil to the cooler is stabilized by using the hydraulic pump, the cooling efficiency of the cooling oil is improved as compared with the conventional case.

  Further, according to the present embodiment, the cooling oil is forcibly cooled by the cooler, so that the cooling oil is efficiently cooled.

  Moreover, according to this embodiment, since the dust contained in the cooling oil is removed by the filter, the service life of the cooling oil is extended.

  Further, according to the present embodiment, since the relief valve is provided in parallel with the cooler, the cooler is protected even when the cooling oil discharged from the hydraulic pump is at a high pressure as in the low temperature start.

  The wet clutch cooling device according to the present embodiment is also suitable for use when the hydraulic pump provided in the working machine oil passage is a piston pump.

  When the cooling oil in the clutch housing is made to flow up with the fins attached to the clutch plate when flowing the cooling oil in the clutch housing as in the conventional case, the cooling oil is agitated, and bubbles are generated in the cooling oil itself. It becomes easy to mix. Compared to gear pumps, piston pumps are more susceptible to such aeration.

  According to the present embodiment, the clutch cooling oil passage is originally provided as a closed circuit independent of the work implement oil passage, so that the piston pump provided in the work implement oil passage can suck oil mixed with bubbles. Disappear.

1 ... engine, 2 ... drive shaft, 3 ... belt,
10 ... wet clutch, 11 ... clutch housing, 12 ... clutch plate,
13 ... Cooling oil, 14 ... Strainer,
20 ... Hydraulic pump, 30 ... Cooler, 40 ... Relief valve, 50 ... Line filter

Claims (7)

Wet clutch cooling, which is disposed in a power train of a work vehicle that drives a hydraulic working machine with hydraulic oil and has a clutch plate and a cooling oil for cooling the clutch plate in a clutch housing, and cools the cooling oil. In the device
A clutch cooling oil passage for circulating the cooling oil outside the clutch housing and cooling the cooling oil;
Furthermore, the clutch cooling oil passage is a closed circuit independent of a working machine oil passage for circulating hydraulic oil supplied to the hydraulic working machine. The wet clutch cooling device according to claim 1, further comprising a cooler in the clutch cooling oil passage. The wet clutch cooling device according to claim 1, wherein a hydraulic pump is provided in the clutch cooling oil passage. A hydraulic pump, a cooler, and a relief valve are provided in the clutch cooling oil passage,
Communicating the inside of the clutch housing and the suction port of the hydraulic pump;
The discharge port of the hydraulic pump communicates with the oil inlet of the relief valve and the oil inlet of the cooler,
The wet clutch cooling device according to claim 1, wherein an oil outlet of the relief valve and an outlet of the cooler are communicated with the inside of the clutch housing. The wet clutch cooling device according to claim 3 or 4, wherein a rotation shaft of the hydraulic pump is connected to a drive shaft of an engine. The wet clutch cooling device according to claim 1, further comprising a dust removing unit that removes dust in the cooling oil in the clutch cooling oil passage. A wet clutch disposed in a power train of a work vehicle that drives a hydraulic working machine by hydraulic oil discharged from a piston pump and having a clutch plate and a cooling oil for cooling the clutch plate in the clutch housing; In the wet clutch cooling device that cools
A clutch cooling oil passage for circulating the cooling oil outside the clutch housing and cooling the cooling oil;
Further, the clutch cooling oil passage is a closed circuit independent of a working machine oil passage through which hydraulic oil is circulated by the piston pump.

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