JP2008189210A - Power takeoff speed change mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact and inexpensive PTO (Power Take-off) speed change mechanism capable of improving efficiency of the energy to be transmitted to an oil pump of a working machine by changing the output rotation of the PTO. <P>SOLUTION: The PTO mechanism for transmitting the power of a prime mover taken out of the PTO mechanism to an oil pump of a working machine comprises a first shaft with first gears connected to each other in series being arranged therearound, a second shaft with a one-way clutch and a fourth gear being integrally rotated, and a third shaft with a second gear and a third gear being arranged thereon. When the number of rotation of the prime mover is below a predetermined value, the rotation of the first shaft is transmitted to the oil pump via the one-way clutch and the second shaft; and when the number of rotation of the prime mover exceeds the predetermined value, the rotation of the first shaft is transmitted to the oil pump via the clutch, the first gear, the second gear, the third shaft, the third gear, the fourth gear and the second shaft. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a PTO transmission mechanism that changes gears without interrupting power of a prime mover taken out by a power take-off (PTO) mechanism by a combination of a clutch, a gear, and a one-way clutch.

  Oil pumps for work machines such as winches, cranes, compressors, etc. for work vehicles such as tractors, fire trucks, garbage trucks, dump trucks, vacuum trucks, tow trucks, aerial work platforms, crane trucks, cold trucks, refrigeration trucks and truck mixers The transmission is provided with a PTO device that extracts the power of the prime mover for driving the motor. The power extracted by the PTO device, for example, the rotational speed of the prime mover, is transmitted to the oil pump at a constant speed.

  For example, an oil pump used in a working machine such as a truck-mounted crane or an arm roll is driven by the power of a prime mover transmitted through a PTO device. Such a working machine generally employs a small pump whose capacity is matched to the torque generated in the idling region of the prime mover. When increasing the operating speed of the work machine, it is necessary to increase the output speed of the PTO mechanism in order to increase the discharge amount of the oil pump. However, when the speed of the prime mover is increased, the output of the prime mover is excessive. Not only is energy efficiency worse, but also increases noise. In addition, since most of the work machines are used in a stopped state, a rise in the water temperature and oil temperature of the prime mover due to heat generated by rotation cannot be suppressed by the traveling wind, and the load on the prime mover is large. Although it is possible to increase the pump discharge volume by increasing the pump size, it is necessary to select a pump capacity that matches the torque generated in the idling area of the prime mover. There is.

  Furthermore, in truck cranes, one oil pump that uses a prime mover as a power source is usually used. In order to suppress the output of the prime mover, two oil pumps are connected in series, and the discharge amount from the oil pump is electronically controlled. Therefore, only one oil pump is used during low-speed work, and the combined discharge amount of the two oil pumps is used during high-speed work. However, in order to apply this structure to a working machine equipped with a conventional oil pump, it is necessary to replace the oil pump set, and the replacement cost is high. . Moreover, the installation space wider than the conventional oil pump storage space of a working machine is required, and it cannot apply with the conventional working machine.

In addition, by using a plunger pump, it is possible to increase the discharge amount of the oil pump without changing the output rotational speed of the prime mover. However, the plunger pump is expensive, and from the viewpoint of cost to the work vehicle. The possibility of practical application in work vehicles is low.
“U-CAN ECO” on the Furukawa Unic Corporation website (URL: http://www.furukawaunic.co.jp/product/unic_u-can-eco.htm)

  Therefore, an object of the present invention is to reduce the energy efficiency transmitted to the oil pump of the work machine by shifting the PTO output rotation according to the torque increase of the prime mover without interrupting the power of the prime mover taken out by the PTO device. An object of the present invention is to provide a PTO transmission mechanism that is improved and compact and inexpensive.

  In order to solve the above-mentioned problems, the present inventor has made extensive researches, and when the rotational speed of the prime mover exceeds a predetermined value between the prime mover and the oil pump, the PTO can be engaged by shifting the clutch. We have found that by providing a speed change mechanism, it is possible to make a compact and inexpensive PTO speed change mechanism that can transmit power to the oil pump of the work machine without changing the power of the prime mover, and further research has been conducted. As a result, the present invention has been completed.

That is, the present invention is a PTO transmission mechanism that transmits the power of a prime mover taken out by a power take-off (PTO) mechanism to an oil pump of a work machine,
A first shaft, a one-way clutch and a second shaft, each connected in series;
A third shaft juxtaposed on an axis different from the first shaft, the one-way clutch and the second shaft;
A first gear arranged around the first shaft;
A fourth gear arranged around the second shaft and rotating integrally with the second shaft;
A second gear and a third gear which are arranged around the third shaft at axial intervals and rotate integrally with the third shaft;
A clutch that is arranged around the first shaft and moves together with the first shaft and the first gear only when the rotation of the first shaft exceeds a predetermined value;
When the rotational speed of the prime mover is below a predetermined value, the rotation of the first shaft is transmitted to the oil pump via the one-way clutch and the second shaft,
When the rotational speed of the prime mover exceeds a predetermined value, the rotation of the first shaft causes the oil pump to pass through the clutch, the first gear, the second gear, the third shaft, the third gear, the fourth gear, and the second shaft. The PTO transmission mechanism is transmitted to

The present invention also relates to the PTO transmission mechanism, wherein the clutch is integrated with the first gear and / or the one-way clutch is integrated with the fourth gear.
Furthermore, the present invention relates to the PTO speed change mechanism, wherein the clutch is a centrifugal clutch, an electromagnetic clutch or a multi-plate clutch.

The present invention also relates to an oil pump system in which the PTO transmission mechanism is incorporated.
Furthermore, the present invention relates to a work vehicle equipped with the oil pump system.
The present invention also relates to the work vehicle, which is a tractor, a fire truck, a garbage truck, a dump truck, a vacuum truck, a tow truck, an aerial work vehicle, a crane truck, a cold truck, a freezer truck, or a truck mixer.

According to the PTO transmission mechanism of the present invention, when the rotational speed of the prime mover is lower than the predetermined value, the rotation is transmitted to the oil pump of the work equipment via the first shaft, the one-way clutch, and the second shaft, and the rotational speed of the prime mover When the clutch exceeds the predetermined value and the clutch is engaged, the rotation of the first shaft causes the oil to pass through the clutch, the first gear, the second gear, the third shaft, the third gear, the fourth gear, and the second shaft. By transmitting to the pump, the power of the prime mover is not interrupted and the speed is changed in accordance with the increase in the rotational torque of the prime mover. Therefore, the output of the prime mover can be efficiently converted to hydraulic pressure by the oil pump, and the desired oil The number of revolutions of the prime mover that drives the oil pump for obtaining the discharge amount can be suppressed to be lower than the conventional one. Further, by suppressing the rotational speed to a low level, it is possible to reduce fuel consumption and CO ₂ emission, to reduce noise, and to reduce the load on the prime mover due to the heat generated by the rotation. .

  Furthermore, the PTO transmission mechanism of the present invention is applied to an oil pump whose capacity is matched to the torque generated in the idling region of a conventional prime mover without increasing the capacity or number of pumps or changing the type of pump. Thus, the rotational speed of the prime mover that drives the oil pump can be kept low. In addition, since the number of parts is small, it can be compacted and the installation space can be reduced. And since it is a simple structure, there are few processes for manufacturing and it can hold down manufacturing cost low. Further, since the structure is simple, there are few failures and no periodic replacement parts other than the clutch plate and gear oil are generated, so that the maintenance cost can be kept low.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a first embodiment.
The PTO transmission mechanism in this embodiment includes a first shaft 1 that passes through the first clutch 5 that moves integrally with the centrifugal clutch 2 and is connected to the one-way clutch 3 only when the centrifugal clutch 2 is engaged. The second shaft 4 connected to the one-way clutch 3 and having the fourth gear 8 disposed around is connected in series. Further, the second gear 6 and the third gear 7 that are arranged around the third shaft 9 with an axial interval and rotate together with the third shaft 9 are respectively connected to the first gear 5 and the fourth gear 8. Meshing. The one-way clutch 3 is configured to transmit power from the prime mover to the oil pump between the first shaft 1 and the second shaft 4 while blocking power transmission in the reverse direction. Further, since the fourth gear 8 is fixed to the second shaft 4, it is interlocked with the rotation of the second shaft 4.

  The number of teeth and the pitch of the first gear 5 to the fourth gear 8 are not particularly limited, but the gear ratio (second gear / first gear) between the first gear 5 and the second gear 6 and the third gear 7 and the fourth gear 4 are not limited. The number of teeth and the pitch for increasing the number of rotations transmitted through the first gear 5 to the fourth gear 8 are set so that the gear ratio with the gear 8 (fourth gear / third gear) is less than 1, respectively. It is preferable that the second gear 6 has fewer teeth than the first gear 5 and the fourth gear 8 has fewer teeth than the third gear 7. Specifically, for example, when the total reduction ratio of the transmission gear ratio (second gear / first gear) and the transmission gear ratio (fourth gear / third gear) is 0.5, the number of revolutions of the prime mover is kept at half. The same power as that conventionally transmitted via the shaft aa ′ can be transmitted to the oil pump of the working machine. The material of the gear is not particularly limited, but in order to reduce the frictional force, a combination of different types is preferable, and a material with a smaller gear is harder than a gear with a larger gear.

The PTO transmission mechanism is provided between a PTO device that extracts a part of the power of a prime mover (not shown) and an oil pump of a working machine that is driven by the power extracted by the PTO device.
The power extracted by the PTO device is transmitted to the first shaft 1, and this power is transmitted to the second shaft 4 through the one-way clutch 3 at a constant speed and further to the oil pump. The work machine is driven at the same speed as the power extracted by the PTO device.
When the rotational speed of the prime mover exceeds a predetermined value, the centrifugal clutch 2 is engaged, and the centrifugal clutch 2 and the first gear 5 rotate at the same speed as the first shaft 1 by the power extracted by the PTO device. The power is transmitted to the second gear 6 meshed with the first gear 5 and to the third gear 7 and the fourth gear 8 meshed with the third gear 7 via the third shaft 9. , Gear ratio of the first gear 5 and the second gear 6 (second gear / first gear) and gear ratio of the third gear 7 and the fourth gear 8 (fourth gear / third gear) Then, the oil pump is transmitted to the second shaft 4 interlocked with the fourth gear 8, and the oil pump is driven by the increased rotational speed. The rotational difference between the first shaft 1 and the second shaft 4 generated at this time is adjusted by the one-way clutch 3.

In this way, the oil pump can be driven at a rotational speed increased with respect to the rotational speed of the prime mover as compared with the conventional case where the oil pump is driven at a constant speed, so that energy efficiency is improved. . That is, when the value exceeds the predetermined value, it is possible to obtain a desired power at a lower rotational speed than when the oil pump is driven at a constant speed, so that the load on the prime mover is small, the fuel consumption amount and The amount of CO ₂ emission can be reduced, the noise can be reduced, and the load caused by the heat generated by the rotation of the prime mover can be reduced.

  Further, by using the centrifugal clutch 2, no special clutch operation is required, and the mechanism can be simplified. That is, if there is a space for mounting the PTO transmission mechanism between the PTO device and the work machine of the existing work vehicle, it can be attached to the existing work vehicle.

Next, a second embodiment will be described with reference to FIG.
The PTO speed change mechanism in this embodiment is the same as that of the first embodiment except that the centrifugal clutch 2 is integrated with the first gear 5 and the one-way clutch 3 is also integrated with the fourth gear 8. By adopting such a structure, further downsizing is possible.

  Further, as the third embodiment, by using an electromagnetic clutch instead of the centrifugal clutch in the first and second embodiments, a more accurate gear shift that matches the torque characteristics of various prime movers becomes possible.

Furthermore, a fourth embodiment will be described.
The PTO speed change mechanism in the present embodiment is the one in which the centrifugal clutch is a multi-plate clutch in the first embodiment, and includes a mechanism for fastening the multi-plate clutch by the discharge pressure from the oil pump. In such a structure, the multi-plate clutch is fastened via a release cylinder that operates when the rotation of the prime mover increases and the discharge pressure of the oil pump exceeds a predetermined pressure, and the multi-plate clutch and the first gear are connected by the PTO device. The extracted power rotates at the same speed as the first shaft. The power is transmitted to the second gear meshed with the first gear and through the third shaft to the third gear and the fourth gear meshed with the third gear. The power is transmitted to the first gear and the first gear. The gear ratio is changed by the gear ratio between the second gear (second gear / first gear) and the gear ratio between the third gear and the fourth gear (fourth gear / third gear) and transmitted to the second shaft. The oil pump is driven by the increased power.
In this way, the oil pump can be driven at a rotational speed increased with respect to the rotational speed of the prime mover as compared with the conventional case where the oil pump is driven at a constant speed, so that energy efficiency is improved. The same effect as in the first embodiment described above can be obtained.

Further, as a fifth embodiment, a PTO speed change with the same configuration as that of the third embodiment except that the multi-plate clutch and the first gear are integrated and the one-way clutch and the fourth gear are integrated. The mechanism. By adopting such a structure, further downsizing is possible.
Further, in the fourth and fifth embodiments, by providing a flow rate adjusting mechanism between the oil pump and the release cylinder, it is possible to control the engagement timing of the multi-plate clutch, that is, the shift timing.

  Furthermore, as a sixth embodiment, by changing the multi-plate clutch used in the fourth and fifth embodiments to one that is fastened by external input, more accurate gear shifting that matches the torque characteristics of various prime movers is possible. Is possible. For example, in the third and fourth embodiments, the multi-plate clutch is electronically controlled while the multi-plate clutch is fastened by the discharge pressure from the oil pump.

In the seventh embodiment, the number of shifts can be increased by combining a plurality of PTO transmission mechanisms of the present invention.
In each of the above embodiments, an example in which the present invention is applied between a PTO device and an oil pump has been described. However, the present invention can be incorporated in an oil pump.

  Further, in each of the above embodiments, the example in which the present invention is applied between the PTO device and the oil pump has been described. However, the present invention can be incorporated in a vehicle transmission.

According to the PTO transmission mechanism of the present invention, when the rotational speed of the prime mover is lower than the predetermined value, the rotation is transmitted to the oil pump of the work equipment via the first shaft, the one-way clutch, and the second shaft, and the rotational speed of the prime mover When the clutch exceeds the predetermined value and the clutch is engaged, the rotation of the first shaft causes the oil to pass through the clutch, the first gear, the second gear, the third shaft, the third gear, the fourth gear, and the second shaft. Because it is transmitted to the pump, the power of the prime mover is not interrupted, and the speed is changed in accordance with the increase in the rotational torque of the prime mover. Therefore, the output of the prime mover can be efficiently converted to hydraulic pressure by the oil pump, and the desired oil discharge The number of revolutions of the prime mover that drives the oil pump for obtaining the quantity can be kept lower than the conventional one. Further, by suppressing the rotational speed to a low level, it is possible to reduce fuel consumption and CO ₂ emission, to reduce noise, and to reduce the load on the prime mover due to heat generated by the rotation.

It is a figure which shows the whole structure of the 1st Embodiment of this invention. It is a figure which shows the whole structure of the 2nd Embodiment of this invention.

Explanation of symbols

1 First shaft 2 Centrifugal clutch 3 One-way clutch 4 Second shaft 5 First gear 6 Second gear 7 Third gear 8 Fourth gear 9 Third shaft

Claims (6)

A PTO transmission mechanism that transmits the power of the prime mover taken out by a power take-off (PTO) mechanism to an oil pump of a work machine,
A first shaft, a one-way clutch and a second shaft, each connected in series;
A third shaft juxtaposed on an axis different from the first shaft, the one-way clutch and the second shaft;
A first gear arranged around the first shaft;
A fourth gear arranged around the second shaft and rotating integrally with the second shaft;
A second gear and a third gear which are arranged around the third shaft at axial intervals and rotate integrally with the third shaft;
A clutch that is arranged around the first shaft and moves together with the first shaft and the first gear only when the rotation of the first shaft exceeds a predetermined value;
When the rotational speed of the prime mover is below a predetermined value, the rotation of the first shaft is transmitted to the oil pump via the one-way clutch and the second shaft,
When the rotational speed of the prime mover exceeds a predetermined value, the rotation of the first shaft causes the oil pump to pass through the clutch, the first gear, the second gear, the third shaft, the third gear, the fourth gear, and the second shaft. The PTO transmission mechanism is transmitted to the PTO.   2. The PTO transmission mechanism according to claim 1, wherein the clutch is integral with the first gear and / or the one-way clutch is integral with the fourth gear.   The PTO transmission mechanism according to claim 1 or 2, wherein the clutch is a centrifugal clutch, an electromagnetic clutch, or a multi-plate clutch.   An oil pump system in which the PTO transmission mechanism according to claim 1 is incorporated.   A work vehicle comprising the oil pump system according to claim 4.   The work vehicle according to claim 5, wherein the work vehicle is a tractor, a fire truck, a garbage truck, a dump truck, a vacuum car, a tow truck, an aerial work vehicle, a crane car, a cold truck, a refrigerated car, or a truck mixer.

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