JP3828684B2 - Tractor-mounted backhoe hydraulic system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hydraulic system for a tractor-mounted backhoe.
[0002]
[Prior art]
For example, Japanese Patent Application Laid-Open No. 9-9713 discloses a work vehicle (so-called T · L · B) in which a front loader is attached to the front portion of a tractor and a backhoe is attached to the rear portion of the tractor.
This T / L / B is equipped with a main circuit (main line) that feeds (feeds and discharges) hydraulic oil from the pump driven by the engine to hydraulically operate the front loader and backhoe. ing.
[0003]
[Problems to be solved by the invention]
In a tractor-mounted backhoe, when the backhoe is mounted on the tractor, there is no need to hydraulically drive a hydraulic device having a lift arm provided to the tractor, while when the backhoe is mounted on the tractor, the hydraulic device is hydraulically operated. Since it is driven, it is provided with hydraulic pressure switching means for switching the hydraulic pressure from the main hydraulic circuit to the control valve of the backhoe and the control valve of the hydraulic device.
[0004]
The conventional hydraulic switching means is provided in the return circuit from the backhoe to the tractor, and the hydraulic system having the lift arm is hydraulically driven even when the backhoe is mounted. In this state, the backhoe is mounted. When the hydraulic system is driven, there is interference between the lift arm and the backhoe components, so the backhoe should be mounted far away from the tractor (away from the front and back to eliminate interference with the lift arm). There must be.
[0005]
This means that as the size of the backhoe increases, the rear wheel load (particularly during traveling with the backhoe lifted up) increases and running stability is lacking, so it is necessary to install the backhoe close to the tractor. It was contrary to the current situation.
Accordingly, the present invention has an object of enabling the backhoe to be mounted close to the tractor by shutting off the supply of hydraulic oil to the hydraulic device and preventing the lift arm from being hydraulically driven when the backhoe is mounted. It is.
[0006]
[Means for Solving the Problems]
In the present invention, a back hoe B is detachably mounted on a tractor T having a hydraulic device 10 having a lift arm 10A for lifting and lowering a work implement, and the back hoe B is mounted on the back hoe B. In order to achieve the above-mentioned object, the following technical means are taken for the valves having the valves 30 to 34 for controlling the hydraulic equipment.
[0007]
That is, the hydraulic system for a tractor-mounted backhoe according to the present invention attaches the backhoe B to the tractor T having the hydraulic device 10 having the lift arm 10A for controlling the lifting / lowering of the work implement in a detachable manner. In the case where the backhoe B has valves 30 to 34 for controlling the hydraulic equipment installed in the backhoe B,
When the backhoe B is mounted on the tractor T, the hydraulic switching device 60 is provided so that the hydraulic device 10 is not hydraulically driven. The hydraulic switching device 60 controls the hydraulic oil path from the main pump 36 by controlling the hydraulic device 10. There is a switching spool 60A and a hydraulic outlet 40A for switching on the upstream side of the valve 10B, and the switching spool 60A blocks the pressure oil from the main pump 36 to the control valve 10B of the hydraulic device 10. A position for sending the pressure oil from the main pump 36 to the valves 30 to 34 of the backhoe B via the coupler 40B that can be joined and separated from the hydraulic outlet 40A, and a control valve for the hydraulic device 10 to send the pressure oil from the main pump 36 a portion of pressure oil along with the 10B can be feeding through the coupler 40B is freely switched to the feeding position capable to valve 30 to 34 of the backhoe B, this Pressure oil liquid feed to the control valve 10B is cut off from the main pump 36 is supplied to the valve 30 to 34 of the backhoe B of the hydraulic device 10 by the pressure switching spool 60A is a valve 30 to 34 of the backhoe B After passing, it is configured to return to the hydraulic oil tank without being supplied to the control valve 10B of the hydraulic device 10 (Claim 1).
[0008]
Further, in claim 1, the hydraulic pressure switching means 60 is provided so as to be switchable from the rear of the tractor T (claim 2).
With this configuration, when the backhoe B is moved and mounted on the tractor T, the hydraulic pressure is not supplied to the control valve 28 side of the backhoe B unless the hydraulic pressure to the hydraulic device 10 is cut off (to the hydraulic device 10). Therefore, when the backhoe B is mounted, the hydraulic device 10 cannot be hydraulically driven, and the backhoe B can be mounted close to the tractor T. .
[0009]
Therefore, when the tractor T travels (moves) with the rotor L and the backhoe B being lifted and held in T, L, and B, the front-rear weight balance becomes good and traveling stability can be ensured, and the overall length is shortened. Because it is possible, for example, not only can it be transported by a 10,000 pound trailer, but also the driver's seat 11 of the tractor T can be transferred to the loader working position (forward operation) and the backhoe working position (rear driving operation) while sitting It became.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In FIG. 4 which shows the whole working vehicle 1 to which the hydraulic circuit according to the present invention is applied and in FIG. 1 which shows the entire configuration of the hydraulic circuit S, the working vehicle 1 includes a left and right front wheel 2 and a left and right rear wheel. An example of a so-called TLB work vehicle composed of a two-shaft, four-wheel tractor T having three, a front loader L attached to the front portion of the tractor T, and a backhoe B attached to the rear portion of the tractor T Yes.
[0011]
The left and right front wheels 2 of the tractor T can be steered by a power steering 4, and the vehicle body 5 of the tractor T is configured by connecting a clutch housing 6 and a transmission case 7 in the front and rear. The hydraulic oil tank 8 is shared by the clutch housing 6 and the gear mission 9 is incorporated in the transmission case 7 as a transmission system.
[0012]
A hydraulic device 10 having a lift arm 10A for raising and lowering a working machine such as a rotary tiller is installed on the upper surface of the rear part of the vehicle body 5. On the hydraulic device 10, the operation can be changed in the front-rear direction. A seat 11 is provided, and a reinforcing frame 12 that extends in the front-rear direction and is fixed to the vehicle body 5 is provided on the left and right sides of the vehicle body 5.
The front loader L includes left and right booms 14 whose bases are pivotally supported on the left and right masts 13 and a bucket 15 provided at the tip of the boom 14. The front loader L is operated by a pair of left and right boom cylinders 16 and 17. (Driving) is possible.
[0013]
The backhoe B includes a mounting frame 18 detachably attached to the rear part of the tractor vehicle body 5, and a swing bracket 19 provided in the frame 18 is provided with a boom 20 and an arm 22 having a bucket 21 so as to be bent. The swing bracket 19 can be driven (operated) by the left and right swing cylinders 23, the boom 20 can be driven by the boom cylinder 24, the arm 22 can be driven by the arm cylinder 25, and the bucket 21 can be driven by the bucket cylinder 26, and can be configured to include a pair of left and right stabilizers 27. ing.
[0014]
The stabilizer 27 and the cylinders 23 to 26 can be controlled by the valves 29 to 34 shown in FIG. 1 in the control box 28 when the driver's seat 11 is turned backward.
In the hydraulic circuit S shown in FIG. 1, pumps 35, 36, and 37 driven by the engine M suck the hydraulic oil stored in the hydraulic oil tank (substantially the vehicle body) T through the filter 38 and pump 35. The liquid can be fed to each drive unit (cylinder, etc.) through.
[0015]
The first pump 35 is for the power steering 4, and the second pump (main pump) 36 passes a directional control valve 39, and part of the oil is supplied to the control valve 40 of the hydraulic device 10 and the remaining oil. Can be fed to the control valve 41 and the horizontal control valve 42 of the front loader L.
The third pump 37 can send liquids to the control valves 29 to 34 in the control box 28 of the backhoe B via a directional control valve 43 and a coupler 43A that can be joined and separated, and the main pump 36 is supplied via a directional control valve 39. is sent to the control valve 40 of the hydraulic device 10, and is capable of feeding the valve control box 28 via a future portion of the oil from the hydraulic pressure takeoff port 40A joined detachably coupler 40B.
[0016]
That is, the hydraulic system (hydraulic circuit) according to the present invention includes left and right swing cylinders 23 that swing the boom 20 of the backhoe B mounted on the tractor T in the left-right direction as shown in FIGS. 1, 3, and 4. And a control valve 29 for controlling the swing cylinder 23, and an independent swing circuit 37A for supplying and discharging hydraulic oil from the dedicated third pump 37 to the control valve 29.
[0017]
More specifically, as shown in FIG. 2, the control for controlling each of the boom cylinder 24, the pair of stabilizer cylinders 27, the arm cylinder 25, and the bucket cylinder 26 on the downstream side of the control valve 29 that controls the swing cylinder 23. The valves 30, 31, 32, 33, and 34 are connected in a parallel arrangement.
Furthermore, a front loader L is mounted on the tractor T, and control valves 41 and 42 for controlling the cylinders 16 and 17 of the boom and bucket of the front loader L are provided. The control valves 41 and 42 are supplied and discharged by the main pump 36. The hydraulic oil to be diverted is diverted by the direction control valve 39 and is merged downstream of the control valve 29 for controlling the swing cylinder 23.
[0018]
Referring to FIGS. 1 and 3, the relationship between the power steering 4 and the hydraulic transmission 8 is illustrated. The power steering 4 switches the rotary valve 4B by rotating the handle 4A and moves the power cylinder 4D to the left and right by the controller 4C. The left and right front wheels 2 can be steered by expanding and contracting to R and L, and includes a relief valve 4E, a check valve 4F, and the like.
[0019]
The hydraulic transmission 8 includes a variable displacement hydraulic pump 8A driven by the engine M and a fixed displacement hydraulic motor 8B connected by a closed circuit 8C and a charge pump 8D driven by the engine M. The charge pump 8D can suck in the hydraulic oil in the tank T through the filter 44 and supply the leak from the closed circuit 8C through the filter 45.
[0020]
Further, an oil cooler 46 is provided on the downstream side of the charge circuit in the hydraulic transmission 8. As shown in FIG. 5, the return gear from the oil cooler 46 is included in the gear mission 9 via the first pipe 47. In addition to returning to the transmission case 7, the flow is divided and returned to the clutch housing 6 having the hydraulic transmission 8 through the second pipe 48 branched from the first pipe 47.
[0021]
Referring to FIG. 5, the first pump 35 and the second pump 36 are mounted on the front wheel bearing base 49 together with the oil cooler 46, and the third pump 37 is mounted on the side portion of the engine M.
The first to third pumps 35 to 37 suck the hydraulic oil (for lubrication and cooling) in the mission case 7 through the pipe 49 through the double filter 38 and the power steering controller 4C and the loader port block 50 through the pipes 50A and 50B. The operation hydraulic pressure from the controller 4C can be supplied to the power cylinder 4D via the pipes 51A and 51B, and the charge pump 8D in the hydraulic transmission 8 communicates with the charge port via the suction pipe 52. The return oil from the controller 4C communicates with the charge port via the pipe 54 to the suction side of the charge circuit (see FIG. 3).
[0022]
The oil cooler 46 is provided on the lower side of the charge circuit via a pipe 55, and the return oil of the oil cooler 46 is lubricated or cooled to the clutch housing 6 and the transmission case 7 via the first and second pipes 47 and 48. Each of them is divided and recirculated for use, and the return circuit (pipe 54) of the power steering 4 is connected to the suction circuit 52 (charge port) of the charge pump in the hydraulic transmission 8.
[0023]
In FIG. 3, the hydraulic transmission 8 includes a high-pressure relief valve 56, a charge relief valve 57, a relief valve 58 provided in a pilot pipeline, a direction control valve 59, a spring-loaded double acting cylinder 60, and the like.
In FIG. 5, the front axle that supports the front wheel 2 so as to be steerable via the king pin is supported by the front wheel bearing stand 49 and the like via the center pin.
[0024]
According to the hydraulic circuit S configured as described above, the return oil from the oil cooler 46 provided downstream of the charge circuit is diverted through the first pipe 47 and the second pipe 48 and the front mission section (hydraulic mission) 8) The clutch housing 6 having an internal structure and the transmission case 7 having a rear transmission (gear transmission 9) are recirculated (divided) to lubricate and cool the respective parts to form a hydraulic oil tank T. The hydraulic oil can be circulated as a whole to prevent a local temperature rise of the hydraulic oil and to prevent early deterioration of the hydraulic oil.
[0025]
Further, since the return oil of the power steering 4 is connected to the suction side of the charge pump 8D via the pipe 54 and joined to the transmission case 7 by the pipe 52, the amount of return oil from the power steering 4 is A, the charge When the suction oil amount of the pump 8D is B, when A> B, the oversupply oil amount is returned to the tank (mission case 7) by the pipe 52, the charge oil temperature can be lowered, and the oil circulation performance in the entire circuit On the other hand, when B> A, the shortage of supply to the charge port is compensated, so that the loss horsepower of the charge pump 8D can be reduced.
[0026]
That is, the flow rate balance is maintained even when the flow rate of the power steering system fluctuates (for example, charging to the closed circuit 8C of the hydraulic mission is stopped during the relief operation or the amount of supplied oil changes due to a decrease in volumetric efficiency of the pump 8A). Thus, the loss horsepower can be reduced by the charge pump.
3 and 6-8, there is shown a detailed such as a hydraulic device 10 and the reinforcing frame 12 has a directional control valve 43 and the hydraulic takeout port 40A of.
[0027]
The hydraulic oil from the third pump 37 dedicated to the swing (priority) is sent to the direction control valve 43 for the control valve 29 for controlling the left and right swing cylinders 23 via a delivery pipe (swing circuit) 37A. The valve 43 is mounted as shown in FIG. 8 on the right side front portion of the casing in the hydraulic apparatus 10 having the left and right lift arms 10A.
[0028]
As shown in FIG. 8, the hydraulic pressure switching block 43B of the directional control valve 43 includes a switching spool 43D and a relief valve 43E for switching the hydraulic pressure by the operating tool 43C, and a pair of connection ports 43F and 43G having couplers 43A and 43A. One is for the inlet port (import connection port) and the other is for the tank port (out port connection port). When working with the backhoe B attached to the tractor T, the swing circuit (delivery pipe) 37A is used. The oil from the dedicated pump 37 is sent to the direction control valve 43 through the oil, and the oil from the direction control valve 43 is sent to the swing valve 29 through the coupler 43A and the connection ports 43F, 43G. The boom 20 swings in the horizontal direction around the swing axis by swinging each of the Single operation because the supply amount of oil into cylinder 23 is constant, it is the same operability in a simultaneous operation can be obtained.
[0029]
On the other hand, when the backhoe B is removed from the tractor T, the operation tool 43C is used to switch the switching spool 43D so as to have an unloading function. It can be.
That is, by operating the operating tool 43C and switching the spool 43D to have an unloading function as shown in FIG. 8, the relief valve 43E can set a system relief pressure different from the main circuit, and the connection ports 43F, 43G When the backhoe B is removed by configuring the service port according to the above, it can be used for a wide range of applications as a hydraulic supply source (service port) for other hydraulic equipment. At this time, the relief valve 43E can be replaced by a cartridge system or the like, for example. By doing so, a wider range of applications can be accommodated.
[0030]
The return oil from the switching block (direction control valve) 43B is returned to the tank (tractor vehicle body) T via the pipe 43H.
5 to 8, a switching valve means (direction control valve) 43 having a service port capable of setting a system relief pressure different from that of the main circuit is mounted on the right side of the hydraulic device 10 mounted on the tractor vehicle body 5. However, a hydraulic pressure switching means 60 is mounted on the left side of the hydraulic device 10.
[0031]
That is, an oil passage switching block (hydraulic switching means) 60 is provided on the hydraulic delivery side (supply side) of the hydraulic device 10 and the backhoe B.
This switching means 60 is configured such that the supply piping 39A of the directional control valve 39 shown in FIG. 3 is connected to the backhoe B side and the hydraulic device 10 side by the switching spool 60A on the upstream side of the control valve (position control valve) 10B in the hydraulic device 10. The hydraulic pressure can be switched freely.
[0032]
That is, as shown in FIGS. 5 to 7, a switching block 60B is detachably mounted on the left side front surface portion of the hydraulic housing 10C constituting the hydraulic device 10, and a hydraulic outlet 40A is provided in the block 60B. The switching spool can be switched between when the hydraulic pressure from the main pump 36 is supplied to the control box 28 of the backhoe B by the coupler 40B and when the hydraulic pressure from the pump 36 is supplied to the control valve 10B of the hydraulic equipment 10. The switching spool 60A can be switched by an operating tool 60D having a knob 60C extending rearward on the left side surface of the hydraulic housing 10C.
[0033]
The switching spool 60A is supported by the block 60B so as to be rotatable about a horizontal axis, and the tip (front end) of a rod-like operation tool 60D is pivoted by a pin or the like on an arm 60E provided at the end of the spool 60A. The hydraulic pressure from the pipe 39A can be switched between the control valve 10B side of the hydraulic device 10 and the control valve 28 side of the backhoe B. The position A1 of the solid line knob 60C in FIG. On the other hand, the position A2 removes the backhoe B, and the hydraulic device 10 allows a working machine other than the backhoe to be moved up and down via a three-point link or the like. 3P use is shown respectively.
[0034]
That is, conventionally, the hydraulic pressure switching means 60 is provided in the return oil path from the backhoe to the tractor, and this is a hydraulic circuit that can operate the hydraulic device 10 even when the backhoe is mounted.
In this conventional example, when the backhoe B is mounted, the lift arm 10A can move up and down, so that the backhoe B is separated rearward from the tractor vehicle body 5 so as not to interfere with the vertical movement of the arm 10A (front-rear spacing). In this case, the weight balance of the TLB becomes poor and the stability during running is lacking, or the total length of the TLB becomes long and cannot be transported by, for example, a 10,000 pound trailer. It was.
[0035]
On the other hand, according to the hydraulic pressure switching means 60 described above, when the backhoe B is mounted, a hydraulic circuit is provided so that the hydraulic device 10 does not move. Therefore, the backhoe B can be mounted close to the tractor vehicle body 5. Thus, the problem of the switching means of the conventional example is solved.
That is, when the backhoe B is detachably attached to the tractor T having the hydraulic device 10 having the lift arm 10A, the hydraulic pressure that prevents the hydraulic device 10 from being hydraulically driven when the backhoe B is attached to the tractor T. The switching means 60 is provided. The hydraulic pressure switching means 60 is provided so as to be switchable from the rear of the tractor T, and either one of the control valve 10B in the hydraulic device 10 and the control valve 28 in the backhoe B is hydraulically operated. It can be switched to supply
[0036]
Although the embodiment of the present invention is as described above, the hydraulic switching means 60 can be freely designed, for example, mounted in the opposite direction, and the rated flow rate of the first pump 35 is 22.5 l / min. The rated flow rate of the pump (main pump) 36 is 47.9 l / min, and the rated flow rate of the third pump (swing dedicated (priority) pump) 37 is 27.7 l / min, but other flow rates are set. It is also possible.
[0037]
The hydraulic device 10 may be configured to raise and lower the lift arms 10A individually or simultaneously with a hydraulic cylinder.
[0038]
【The invention's effect】
As described above in detail, according to the present invention, the backhoe cannot be mounted unless the hydraulic pressure to the hydraulic device is cut off, and therefore, the backhoe can be mounted close to the tractor and the front-rear weight balance can be appropriately adjusted. Yes, and the overall length can be shortened.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a hydraulic circuit in the present invention.
FIG. 2 is a circuit diagram of a backhoe and a loader in a hydraulic path in the present invention.
FIG. 3 is a circuit diagram of a hydraulic device and power steering in a hydraulic path according to the present invention.
FIG. 4 is an overall side view showing a TLB as a working machine to which the present invention is applied.
FIG. 5 is a plan view showing an outline of hydraulic piping.
FIG. 6 is a rear view of the TLB.
FIG. 7 is a side view showing hydraulic pressure switching means between the backhoe and the hydraulic device.
FIG. 8 is a plan view showing switching means between backhoe hydraulic pressure and service port hydraulic pressure.
[Explanation of symbols]
1 T ・ L ・ B
T tractor B backhoe L front loader 10 hydraulic device 60 hydraulic pressure switching means

Claims (2)

A backhoe (B) is detachably attached to a tractor (T) having a hydraulic device (10) having a lift arm (10A) for lifting and lowering the work implement, and the backhoe (B) In what has the valve | bulb (30-34) which controls the hydraulic equipment with which the backhoe (B) was equipped,
When the backhoe (B) is mounted on the tractor (T), the hydraulic device (10) is provided with a hydraulic pressure switching means (60) that does not hydraulically drive. The hydraulic pressure switching means (60) includes a main pump (36). A switching spool (60A) and a hydraulic outlet (40A) for switching the path of pressure oil from the upstream side of the control valve (10B) of the hydraulic device (10). The switching spool (60A) The backhoe (B) is connected to the control valve (10B) of the apparatus (10) through a coupler (40B) that can cut off the pressure oil from the main pump (36) and can be joined to and separated from the hydraulic outlet (40A). The pressure oil from the main pump (36) can be sent to the valves (30 to 34) and the pressure oil from the main pump (36) to the control valve (10B) of the hydraulic device (10). And some pressure oil La (40B) is freely switched to the liquid feed can be located in the valve (30 to 34) of the backhoe (B) via a control valve of the hydraulic device (10) by the hydraulic switching spool (60A) (10B) pressurized oil from the valve (30 to 34) to the supplied main pump (36) of the liquid feed is interrupted to backhoe (B), after passing through the valve (30 to 34) of the backhoe (B) The tractor-mounted backhoe hydraulic system is configured to return to the hydraulic oil tank without being supplied to the control valve (10B) of the hydraulic device (10).   The hydraulic system for a tractor-mounted backhoe according to claim 1, wherein the hydraulic pressure switching means (60) is provided so as to be switchable from the rear of the tractor (T).

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