JP2011121460A - Traveling device of working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide improved reliability of a working vehicle by enabling the working vehicle to travel at crawling speed that is slower than the usual minimum traveling speed without changing any structures in a conventional traveling power transmission system and external power extraction system. <P>SOLUTION: In the working vehicle V in which working equipment 15 is mounted, a motor 20 for crawling speed traveling is driven by a hydraulic pump 14 for crawling speed traveling that is driven by an engine 1 through a flywheel PTO 12, thus enabling the working vehicle V to travel at the crawling speed by the hydraulic motor 20 through a transmission 4. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a traveling device for a work vehicle equipped with a work device, and more particularly, to a traveling device for a work vehicle that can travel at a low speed that is lower than the original minimum traveling speed of the vehicle as necessary.

  In general, in a work vehicle in which power is taken out from a power take-off system connected to a traveling engine via a PTO (power take-off device) and the work equipment mounted on the chassis is driven by this power, the work equipment Is driven at a high speed by the engine, but various operations may be performed with the work equipment while traveling at a low speed that is lower than the vehicle's original minimum travel speed. In the case of a work vehicle equipped with a device, a high engine speed is required to drive the feeding device, but the work vehicle is lower than the original minimum traveling speed so that the feeding operation can be continued while the vehicle is running. The vehicle is driven at a slow speed.

  By the way, as this work vehicle, what is shown in FIG. 3 is conventionally known. In this system, a propeller shaft that transmits power from a traveling engine to left and right drive wheels (left and right rear wheels) via a clutch and transmission is divided into a front side and a back side, and a switchable shaft is provided between them. A speed reducer is interposed, and the power of the drive side propeller shaft is transmitted to the driven side propeller shaft via the speed reducer so that the work vehicle travels at a low speed, and the engine is operated via the flywheel PTO. A hydraulic pump for driving the device can be driven.

However, in the conventional work vehicle,
(1) Since the vehicle's original driving power transmission system will be greatly modified, the reliability of the vehicle will be reduced.

  (2) Excessive deceleration by the speed reducer may exceed the allowable additional torque of the power transmission system such as the propeller shaft, differential gear, and rear axle.

  (3) The vehicle type is limited because it is necessary to secure a space for installing the speed reducer near the propeller shaft.

  (4) When a large truck is adopted as a work vehicle, the speed reducer for a high-power engine is required to have high strength, which leads to an increase in the size and weight of the speed reducer.

  (5) Since the slow speed reducer is not commercially available, it must be manufactured independently, resulting in a significant cost increase.

  There are various problems such as.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a novel traveling device for a work vehicle that can solve the above-described problems.

In order to achieve the above object, according to the first aspect of the present invention, an output shaft of a traveling engine is connected to a propeller shaft via a clutch and a transmission, and an output side of the propeller shaft is connected to a differential gear and a rear axle. In the traveling device of the work vehicle that is linked to and connected to the left and right drive wheels,
A working hydraulic pump and a low speed traveling hydraulic pump are connected to the output shaft of the engine via a flywheel PTO, and a low speed traveling hydraulic motor is connected to the transmission via a transmission side PTO. While the work equipment mounted on the work vehicle is driven by the pump, the slow-speed traveling motor is driven by the slow-speed traveling hydraulic pump, and the work vehicle can travel at low speed via the transmission by the slow-speed traveling hydraulic motor. This is the first feature.

  In order to achieve the above object, according to a second aspect of the present invention, in the first aspect of the present invention, the slow running speed of the work vehicle is controlled by a hydraulic control of the slow running hydraulic motor and a shift of the transmission. The second feature is that it can be changed by gear selection.

  Furthermore, in order to achieve the object, the invention according to claim 3 is the invention according to claim 1 or 2, wherein the work vehicle can be moved backward by reverse rotation control of the slow-speed traveling hydraulic motor or reverse operation of the transmission. This is the third feature.

  Furthermore, in order to achieve the above object, a fourth aspect of the present invention is the one according to the first, second or third aspect, wherein the propeller shaft, the differential is controlled by controlling the operating pressure of the hydraulic oil from the slow speed hydraulic pump. A fourth feature is that power exceeding the allowable additional torque is not applied to the power transmission system such as the gear and the rear axle.

  According to the inventions described in the claims, the work vehicle can be driven at a slow speed lower than the original minimum traveling speed without remodeling the conventional traveling power transmission system, external power take-out system and other structures at all. In addition, high reliability can be secured, and the traveling device can be provided at a low price.

Plan view of the traveling device of the work vehicle during normal traveling Plan view of the traveling device of the work vehicle at low speed traveling Plan view of a conventional work vehicle traveling device

  Embodiments of the present invention will be specifically described below based on the embodiments of the present invention illustrated in the accompanying drawings.

  In FIGS. 1 and 2, a traveling engine 1 for the vehicle V is mounted on the front portion of the work vehicle V, and the power of the engine 1 is transmitted to the left and right drive wheels (left and right rear wheels) via a normal traveling power transmission system PD. Wheel) 10, 10. The traveling power transmission system PD is connected to the rear end of the output shaft (crankshaft) 2 of the engine 1 to turn on / off the power of the engine 1, and is connected to the output end of the clutch 3 to connect the engine 1. A transmission 4 that changes the rotational speed of the transmission 4, a propeller shaft 6 connected to the transmission output shaft 5 of the transmission 4, and a differential gear 7 connected to the rear end of the propeller shaft 6. The left and right axles 8 and 8 of the left and right drive wheels 10 and 10 are coupled to the output ends.

  The flywheel 11 directly connected to the rear end of the output shaft (crankshaft) 2 of the engine 1 is connected to the working hydraulic pump 13 and the slow-speed traveling hydraulic pump 14 via the flywheel PTO 12 to operate the engine 1. Therefore, the pumps 13 and 14 can be driven regardless of whether the clutch 3 is on or off. The hydraulic fluid passage 16 connected to the output port of the work hydraulic pump 13 is connected to the input port of the drive hydraulic motor 17 of the work equipment 15 mounted on the work vehicle V.

  The transmission 4 is connected to a slow speed hydraulic motor 20 via a transmission side PTO 19, and an input port of the slow speed hydraulic motor 20 is connected to the low speed hydraulic pump via a hydraulic oil passage 21. 14, the hydraulic pressure from the hydraulic pump 14 is supplied to the low-speed traveling hydraulic motor 20 via the hydraulic oil passage 21, and as shown in FIG. When the motor is off, the power from the slow running hydraulic motor 20 is transmitted from the transmission side PTO 19 to the transmission 4, and from the transmission output shaft 5 through the propeller shaft 6, the differential gear 7 and the rear axles 8, 8, the left and right drive wheels ( The left and right rear wheels) 10 and 10 are transmitted to the work vehicle V at a low speed. In this case, by controlling the operating pressure of the hydraulic oil from the slow speed hydraulic pump 14, power exceeding the allowable additional torque is not applied to the power transmission system such as the propeller shaft 6, the differential gear 7 and the rear axle 8.

  Next, the operation of this embodiment will be described.

  As shown in FIG. 1, during normal travel of the work vehicle V, the power of the engine 1 is transmitted to the left and right drive theory 10, 10 via the travel power transmission system PD by turning on the clutch 3. Normal shift control is performed by the shift operation. During normal travel of the work vehicle V, the power of the engine 1 is transmitted to the work hydraulic pump 13 and the slow speed travel pump 14 via the flywheel PTO 12 regardless of whether the clutch is on or off. The vehicle V can drive the work equipment 15 mounted thereon while traveling, and the drive speed of the work equipment 15 can be changed by speed control of the engine 1 and hydraulic control of the hydraulic motor 17. In addition, although the slow speed hydraulic pump 14 is in a driving state, the hydraulic oil is not supplied to the slow speed hydraulic motor 20.

  Next, in order to travel the work vehicle V at a low speed, as shown in FIG. 2, after the clutch 3 is turned off, the high-pressure hydraulic oil discharged from the high-speed hydraulic pump 14 is operated by operating the low-speed travel hydraulic pump 14. The motor 20 is supplied to the slow speed running motor 20 through the motor 21. The power of the hydraulic motor 20 is transmitted to the transmission 4 via the transmission side PTO 19, and the shift output therefrom is transmitted to the propeller shaft 6 and transmitted to the left and right rear axles 8 and 8 via the differential gear 7. The drive wheels 10 are driven to rotate.

  Accordingly, the rotational speeds of the left and right drive wheels 10 and 10 are lower than the minimum rotational speed by the shift control of the transmission 4 during normal traveling, and the work vehicle V is slightly slower than the normal minimum speed traveling. It is possible to run. On the other hand, the work hydraulic pump 13 is always driven regardless of the on / off operation of the clutch 3, and the work equipment 15 is driven by the working hydraulic pressure therefrom.

  Therefore, the work vehicle V can perform work by the work equipment 15 while traveling at a low speed.

  The slow running speed of the work vehicle V can be freely changed by adjusting the hydraulic flow rate of the slow running hydraulic motor 20 and selecting the gear of the transmission 4.

  Further, the backward movement of the work vehicle V can be performed by the reverse rotation control of the slow-speed traveling hydraulic motor 20 or the reverse operation of the transmission 4.

  Furthermore, by controlling the operating pressure of the hydraulic oil from the slow speed hydraulic pump, power exceeding the allowable additional torque is not applied to the power transmission system such as the propeller shaft, the differential gear, and the rear axle.

  As described above, according to this embodiment, since it is possible to travel at a speed lower than the normal minimum traveling speed without adding any structural change to the conventional traveling power transmission system and the external power extraction system, The reliability of the work vehicle V can be increased, and the cost of the traveling device for the work vehicle can be greatly reduced.

  As mentioned above, although the Example of this invention was described, this invention is not limited to the Example, A various Example is possible within the claim of this invention.

1 ... Engine 2 ... Output shaft (crankshaft)
3 ... Clutch 4 ... Transmission 6 ... Propeller shaft 7 ... Differential gear 8 ...・ ・ ・ ・ ・ ・ Rear axle 10 ・ ・ ・ ・ ・ ・ ・ ・ ・ Driving wheel (rear wheel)
12 ... Flywheel PTO
13 ················ Work hydraulic pump 14 ························································································・ Transmission side PTO
20 ········ Low-speed traveling hydraulic motor V ············ Work vehicle

Claims (4)

The output shaft (2) of the traveling engine (1) is connected to the propeller shaft (6) via the clutch (3) and the transmission (4), and the output side of the propeller shaft (6) is connected to the differential gear (7). In a traveling device for a work vehicle that is linked and connected to the left and right drive wheels (10, 10) via the rear axle (8),
A working hydraulic pump (13) and a low speed traveling hydraulic pump (14) are connected to the output shaft (2) of the engine (1) via a flywheel PTO (12), and the transmission (4) is connected to the transmission (4). A low speed traveling hydraulic motor (20) is connected via a side PTO (19), and the work hydraulic pump (13) drives the work equipment (15) mounted on the work vehicle (V), while the fine speed is set. The slow-speed traveling motor (20) is driven by the traveling hydraulic pump (14), and the work vehicle (V) can travel at a very low speed via the transmission (4) by the slow-speed traveling hydraulic motor (20). A traveling device for a work vehicle, characterized in that   The slow running speed of the work vehicle (V) can be changed by hydraulic control of the slow running hydraulic motor (20) and transmission gear selection of the transmission (4). A traveling device for a work vehicle as described.   The work vehicle (V) according to claim 1 or 2, characterized in that the work vehicle (V) can be moved backward by reverse rotation control of the slow-speed traveling hydraulic motor (20) or reverse operation of the transmission (4). Traveling device.   Power exceeding the allowable additional torque is applied to the power transmission system such as the propeller shaft (6), the differential gear (7), and the rear axle (8) by controlling the operating pressure of the hydraulic oil from the slow speed hydraulic pump (14). The traveling device for a work vehicle according to claim 1, 2 or 3, wherein the traveling device is not provided.

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