JP2008002604A - Driving mechanism for tilting truck box of dump motor lorry - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make improvements such as circumventing failure such as seizure of a hydraulic pump or the like and an interference between the hydraulic pump and the other parts by means of integrating various types of hydraulic valves with a hydraulic cylinder in a dump motor lorry. <P>SOLUTION: A truck box 4 is mounted on a lorry body 2 in such a manner as to enable backward tilting. There are provided a hydraulic pump 13 for pressure-feeding a working oil going out of an oil tank 11 and a hydraulic valve 12. The working oil is pressure-fed to the hydraulic cylinder 15 and thereby the truck box is tilted by a hydraulic cylinder 15. Among the above hydraulic valves, at least a directional control valve and a check valve are provided separately from the hydraulic pump, while the directional control valve 18 and the check valve 27 are provided integrally with the hydraulic cylinder. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a drive device for tilting a cargo box of a dump vehicle for carrying and discharging gravel, sand, earth and the like used for various construction works.

  Dump vehicles are used to efficiently carry and discharge gravel, sand, and soil used in various construction works. The dump vehicle is provided with a packing box, and the packing box is configured to be tiltable by a hydraulic unit (see, for example, Patent Document 1).

  In such a hydraulic unit, as shown in FIG. 3, a direction switching valve 100, a check valve 101 and a flow rate adjusting valve 103 are built in a casing 107 of a hydraulic pump 105. Thus, by integrating the various hydraulic valves and the hydraulic pump 105, the hydraulic parts can be reduced in size.

The hydraulic cylinder 110 for inclining the packing box 108 is connected to various integrated hydraulic valves and the hydraulic pump 105 by external piping, high-pressure rubber hoses 111a and 111b, etc., and the hydraulic oil in the oil tank 112 is The hydraulic pump 105 feeds the pressure to the hydraulic cylinder 110.
JP 2002-160574 A

  However, the conventional hydraulic unit has the following drawbacks. When the hydraulic pump 105 is driven in a state where the direction switching valve 100 is in the neutral position or the lowered position, the hydraulic oil discharged from the hydraulic pump 105 circulates in the neutral circulation path 108 provided in the casing 107. Such a hydraulic valve-integrated pump has a drawback that the oil temperature is likely to rise due to pipe resistance or the like because the neutral circulation path 108 is short and the amount of circulating oil is small. Therefore, when used in this state for a long time, the hydraulic pump 105 may be seized.

  Further, by integrating and miniaturizing the various hydraulic valves and the hydraulic pump 105, the direction switching valve 100 and the various bolts fastened to the casing 107 are close to each other. Therefore, the casing 107 is distorted by tightening the bolts, the spool hole in which the spool shaft of the direction switching valve 100 is slidably mounted is distorted into an ellipse, and the spool shaft and the spool hole interfere with each other to operate the spool. There is a problem that power increases.

  The present invention integrates various hydraulic valves in a dump vehicle into a hydraulic cylinder so as to avoid problems such as seizure of the hydraulic pump and avoid interference between the hydraulic pump and other parts. Let it be an issue.

  The present invention has been made in order to solve the above-described problem, and includes a hydraulic pump and a hydraulic valve that are mounted on a vehicle body so that the cargo box can be tilted rearward, and that pumps hydraulic oil from an oil tank. In the drive device for tilting the cargo box of a dump vehicle in which the cargo box is tilted by the hydraulic cylinder by being pumped to the hydraulic cylinder, at least the direction switching valve and the check valve among the hydraulic valves are the hydraulic pump. And the direction switching valve and the check valve are provided integrally with the hydraulic cylinder.

  The hydraulic valve and hydraulic cylinder of the present invention are preferably formed of a single casing.

  The direction switching valve and the check valve are provided integrally with the hydraulic cylinder. When the hydraulic valve includes the direction switching valve and the check valve, the direction switching valve and the check valve are connected to the hydraulic cylinder. Or a hydraulic valve including the direction switching valve and the check valve and a hydraulic cylinder are integrally fixed by means such as a bolt.

  Since the various hydraulic valves in the dump vehicle are integrated with the hydraulic cylinder, the present invention has an advantage that problems such as seizure of the hydraulic pump can be avoided and interference between the pump and other parts can be avoided.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  1 to 2 show an embodiment according to the present invention. FIG. 2 shows a dump vehicle according to the present invention. The dump vehicle 1 has a cab 3 at the front portion of the vehicle body 2 and is mounted with a load box 4 that can be tilted rearward at the rear portion. A tilting device 5 is provided between the two. The upper part of the rear saddle door 6 is pivotally supported at the rear part of the packing box 4, and the lower part of the rear saddle door 6 is releasably secured by a securing device (not shown).

  Further, the vehicle body 2 is provided with a power take-out device 8 that takes out power from the engine 7, a power transmission device 9, a hydraulic pump 13, and an oil tank 11.

  FIG. 1 shows a hydraulic circuit of a hydraulic unit that operates the packing box 4. The power of the engine 7 is transmitted to the hydraulic pump 13 via the power take-out device 8 and the power transmission device 9. In the tilting device 5, a hydraulic cylinder 15 that tilts the cargo box 4 and a hydraulic valve 12 that operates the hydraulic cylinder 15 are integrally configured. The hydraulic cylinder 15 and the hydraulic valve 12 are supported so as to be rotatable with respect to the vehicle body 2 so as to be inclined according to the inclination angle of the cargo box 4.

  The hydraulic valve 12 includes a direction switching valve 18 in which a spool shaft 19 is slidably mounted in a spool hole formed in the casing 17. By changing the position of the spool shaft 19, the direction switching valve 18 can be changed to a neutral position 18a at the center, an up position 18b on the left side, and a down position 18c on the right side. The tilting operation of the cargo box 4 can be stopped at the neutral position 18a, the cargo box 4 can be tilted at the raised position 18b, and the cargo box 4 can be lowered at the lowered position 18c.

  The hydraulic pump 13 is connected to a suction-side oil passage 20 a that sucks the hydraulic oil in the oil tank 11 and a discharge-side oil passage (discharge-side line) 20 b that supplies the hydraulic oil to the tilting device 5.

  The casing 17 is formed with various flow paths including a main flow path 21, a return flow path 22, a neutral circulation flow path 23, and a sub flow path 25. The main oil passage 21 is connected to the discharge side line 20 b of the hydraulic pump 13. The neutral circulation channel 23 divides the working oil from the main channel 21 and circulates it to the return channel 22 via the direction switching valve 18.

  The sub flow path 25 allows the main flow path 21 and the direction switching valve 18 to communicate with each other and is connected to the high pressure side oil chamber 15 </ b> A of the hydraulic cylinder 15. The main flow path 21 is provided with a check valve 27 that restricts the back flow toward the hydraulic pump 13, and the sub flow path 25 is provided with a flow rate adjusting valve (throttle valve) 28.

  The hydraulic valve 12 and the hydraulic cylinder 15 may be integrally formed with a single casing (the hydraulic cylinder 15 includes the direction switching valve 18, the check valve 27, and the flow rate adjustment valve 28). Alternatively, a casing separate from the casing of the hydraulic cylinder 15 and the casing 17 of the hydraulic valve 12 may be integrally fixed by a fixing means such as a bolt.

  The low pressure side oil chamber 15 </ b> B of the hydraulic cylinder 15 and one end of the return flow path 22 are connected by a return oil path 29. The other end of the return flow path 22 is connected to a return side line 30 that returns the hydraulic oil to the oil tank 11.

  Each flow path 21, 22, 23, 25 can be formed by simply making a hole in the casing 17 and the shortest distance can be selected, so that the whole can be made very compact. In addition, since the direction switching valve 18, the check valve 27, and the flow rate adjustment valve 28 are integrally provided on the hydraulic cylinder 15 side, a large circulation path can be obtained as shown by a virtual line in FIG. 1 without adding complicated piping. 32 is formed.

  Next, operation | movement of the cargo box 4 of the dump vehicle 1 which consists of the said structure is demonstrated.

  First, at the work site, the hydraulic pump 13 is operated via the power take-out device 8, the switching valve 18 is switched to the raised position 18b, the hydraulic cylinder 5 is extended, and the cargo box 4 is tilted. At this time, the hydraulic oil in the oil tank 11 flows through the suction side oil passage 20a, the discharge side line 20b, the main oil passage 21, and the sub flow passage 25 and is supplied to the high pressure side oil chamber 15A of the hydraulic cylinder 15.

  When the cargo box 4 reaches a predetermined inclination angle, the direction switching valve 18 is switched to the neutral position 18a to stop the tilting of the cargo box 4. Meanwhile, the hydraulic oil discharged from the hydraulic pump 13 and flowing through the discharge side line 20 b passes through the neutral circulation oil passage 23 and the switching valve 18, returns to the oil tank 11 through the return side line 30, and is sucked from the oil tank 11. . At this time, the hydraulic oil circulation path 32 in the neutral circulation is long and the amount of the circulating oil is large, so that the oil temperature hardly rises due to pipe resistance or the like. Therefore, even when used in this state for a long time, the hydraulic pump 13 can be prevented from seizing.

  When the switching valve 18 is operated to the lowered position 18c, the cargo box 4 can be lowered to the storage position. When the hydraulic pump 13 is driven in the lowered position 18 c, the hydraulic oil passes through the neutral circulation oil passage 23 and the switching valve 18 and returns to the oil tank 11 through the return line 30. Even in such a case, the oil temperature hardly rises and the pump can be prevented from seizing.

  Further, in the dump vehicle 1 according to the present embodiment, the switching valve 18 and the hydraulic pump 13 are separated from each other to be separate parts, and the directional switching valve and various bolts are not close to each other due to integration and miniaturization as in the past. For this reason (for example, the number of bolts close to the direction switching valve 18 can be reduced), the distortion of the casing due to the tightening of the bolts distorts the spool hole into an ellipse, and the spool shaft and the hole interfere with each other to reduce the spool operating force. The problem of becoming larger can also be solved.

  In recent years, due to compliance with exhaust gas regulations, the number of vehicle parts has increased and the parts have been concentrated around the hydraulic pump, but the hydraulic valve is separated from the hydraulic pump. It can be increased by as much as possible, and the problem of interference with other vehicle parts can be solved.

  Since the hydraulic pump can be used as a single unit, it can be easily changed from a dedicated one for dump vehicles to a commercial product, and options such as the discharge amount and rotation direction can be expanded and a more appropriate design can be achieved.

  Conventionally, the inspection of the amount of internal oil leakage at the neutral position is performed separately for the hydraulic valve built in the hydraulic pump and the hydraulic cylinder, but both can be inspected at once.

It is a figure which shows the hydraulic circuit of the hydraulic unit for inclining a cargo box applied to the dump vehicle in this Embodiment. It is a side view showing a schematic structure of a dump vehicle. It is a figure which shows the hydraulic circuit of the conventional hydraulic unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Dump vehicle 2 Car body 4 Cargo box 5 Tilt device 12 Hydraulic valve 13 Hydraulic pump 15 Hydraulic cylinder 17 Valve casing 18 Directional switching valve 27 Check valve 28 Flow control valve

Claims (2)

  A cargo box is mounted on the vehicle body so as to be able to tilt backward, and includes a hydraulic pump and a hydraulic valve that pump hydraulic fluid from an oil tank. The hydraulic cylinder is pumped to the hydraulic cylinder so that the cargo box is In the dump vehicle tilting drive device for a dump vehicle that is tilted, at least the direction switching valve and the check valve of the hydraulic valve are separated from the hydraulic pump, and the direction switching valve and the check valve are A drive device for tilting a cargo box of a dump vehicle, wherein the drive device is provided integrally with a hydraulic cylinder.   2. The drive device for tilting a cargo box of a dump vehicle according to claim 1, wherein the hydraulic valve and the hydraulic cylinder are formed of a single casing.

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