KR20130143581A - Hydraulic drive device for construction machine - Google Patents

Abstract

The object of the present invention is to induce high pressure oil in the flow path portion connecting the valve and the filter to the relief valve by a relatively inexpensive structure even when the filter disposed in the flow path communicating the valve and the relief valve occurs. .
The hydraulic pump 20 and the filling valve 25 supplied with the hydraulic oil of this hydraulic pump 20 through the flow path 26 are provided, and the pressure discharged from the hydraulic pump 20 in this filling valve 25 is carried out. The valve switched according to the oil, for example, the on-off valve 33, the relief valve 34 defining the maximum pressure of the switching pressure of the on-off valve 33, the on-off valve 33 and the relief valve 34 The filter 36 arranged in the communication channel 35 is provided, and the filter 36 is provided in the channel 35 so as to flow the pressure oil from the on-off valve 33 side to the relief valve 34 side. The check valve 37 which permits and prevents the flow of the hydraulic oil from the relief valve 34 side to the on-off valve 33 side is provided.

Description

HYDRAULIC DRIVE DEVICE FOR CONSTRUCTION MACHINE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic drive device for a work machine provided in a work machine such as a wheel shovel and provided with a filter for collecting dust mixed in oil flowing through a flow path.

As this kind of prior art, there exists a thing described in patent document 1. As shown in FIG. The prior art disclosed in this patent document 1 is provided in the upstream flow path of the hydraulic circuit to which the pressurized oil discharged from a hydraulic pump is supplied, and is attached to this filter and the filter which collects the dust mixed in the oil discharged from a hydraulic pump, and this filter. The arrangement provided in the flow path so that the oil may flow from the hydraulic pump side to the hydraulic circuit side, and the check valve which prevents the flow of oil from the hydraulic circuit side to the hydraulic pump side is shown.

In this prior art, oil which has been purified through a filter is supplied to the hydraulic circuit. In addition, when the filter becomes clogged and the oil is difficult to pass through the filter, the oil is supplied to the hydraulic circuit through the check valve attached to the filter because the upstream of the filter becomes high pressure. Thereby, the damage to the whole circuit including the hydraulic pump accompanying clogging of a filter can be prevented.

Although the above-mentioned prior art provided a filter in an upstream side with respect to a hydraulic pump, it is also conventionally well-known that a filter was provided in the downstream hydraulic circuit with respect to a hydraulic pump. That is, the hydraulic circuit downstream of the hydraulic pump includes a valve and a relief valve defining a maximum pressure of the switching pressure of the valve, and collects dust flowing through the flow path in a flow path connecting the valve and the relief valve. The structure provided with the filter is also known conventionally. In this way, the oil flowing through the flow path on the downstream side of the hydraulic pump can be cleaned.

Japanese Utility Model Application Publication No. Hei 6-35607

In the prior art having a structure in which a filter is provided in a hydraulic drive device having a conventionally known configuration, that is, a flow path connecting a valve and a relief valve, there is a problem associated with clogging of the filter. In other words, when the degree of clogging of the filter increases, the flow of oil from the filter side to the relief valve side is restricted, whereby the flow passage portion connecting the valve and the filter gradually becomes a high pressure, and the high pressure is trapped in the flow passage portion. The entire hydraulic circuit including the flow path and the valve may be damaged.

Therefore, in order to prevent such a breakage of the hydraulic circuit, it is conceivable to provide a relief valve between the valve and the filter, and to configure the high pressure to be released from the relief valve when the flow passage portion connecting the valve and the filter becomes high pressure. . However, since the relief valve is generally expensive, if it is comprised so that a relief valve may be provided in this way, the manufacturing cost of the said hydraulic drive apparatus will arise.

The present invention has been made from the above-described actual state in the prior art, and its object is to provide a high pressure of the flow path portion that communicates with the valve and the filter even when clogging occurs in the filter disposed in the flow path that communicates between the valve and the relief valve. It is to provide a hydraulic drive of a working machine that can lead oil to a relief valve by a relatively inexpensive structure.

In order to achieve this object, the hydraulic drive device of the working machine according to the present invention includes a hydraulic pump, a valve which is switched in accordance with the hydraulic oil discharged from the hydraulic pump, and a relief valve that defines the maximum pressure of the switching pressure of the valve. And a hydraulic drive device of a working machine provided with a filter provided in a flow path communicating with the valve and the relief valve, wherein the flow of oil from the valve side to the relief valve side is provided in the flow path in parallel with the filter. And a check valve for preventing the flow of oil from the relief valve side to the valve side.

According to the present invention configured as described above, when a blockage occurs in the filter disposed in the flow path communicating with the valve and the relief valve, and the flow path portion connecting the valve and the filter becomes high pressure, a relatively inexpensive check valve provided in the filter, namely, In general, oil can be induced into the relief valve through a check valve which is cheaper than a relief valve or the like, and the high pressure hydraulic oil can be released by the operation of the relief valve. As a result, high pressure is confined to the flow path portion, and damage to the entire hydraulic circuit including the flow path and the valve can be prevented.

Moreover, the hydraulic drive apparatus of the working machine which concerns on this invention is equipped with the valve in which the oil pressure discharged from the said hydraulic pump is supplied in the said invention, In this valve, the said valve, the said relief valve, the said flow path, the said filter And the check valve.

Moreover, the hydraulic drive apparatus of the working machine which concerns on this invention is equipped with the brake valve and the accumulator which can supply pressure oil to this brake valve in the said invention, The said valve is a filling valve which can supply pressure oil to the said accumulator. The valve is made of an on-off valve capable of relief of the high pressure hydraulic oil when the accumulator pressure of the accumulator is higher than a predetermined pressure.

Moreover, the hydraulic drive apparatus of the working machine which concerns on this invention WHEREIN: In the said invention, the said working machine consists of a wheel shovel, and is provided with the priority valve and the steering valve to which the hydraulic oil discharged from the said hydraulic pump is supplied, While installing a flow path for inducing pressure oil to the filling valve through the privacy valve, a different filter is installed in another flow path that communicates the hydraulic pump and the purity valve, and in the other flow path, the other filter. And a check valve which permits the flow of oil from the hydraulic pump side to the priometry valve side, and prevents the flow of oil from the prioririum valve side to the hydraulic pump side. have.

According to the present invention, a filter is provided in a flow path that communicates the valve and the relief valve. In the flow path described above, a filter is provided in parallel with the filter to allow the flow of oil from the valve side to the relief valve side. Since the check valve which prevents the flow of oil is provided, even if a clogging occurs in the filter, the high pressure oil of the flow path portion connecting the valve and the filter can be led to the relief valve through the relatively low check valve. Thereby, the damage of the whole hydraulic circuit can be prevented, restraining the manufacturing cost of the said hydraulic drive apparatus containing a flow path and a valve, and it can implement the protection of the excellent hydraulic circuit at low cost.

BRIEF DESCRIPTION OF THE DRAWINGS It is a side view which shows the wheel shovel mentioned as an example of the working machine provided with the hydraulic drive apparatus which concerns on this invention.
FIG. 2 is a hydraulic circuit diagram showing a hydraulic drive device according to the present embodiment included in the wheel shovel shown in FIG. 1.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of the hydraulic drive of the working machine which concerns on this invention is described based on drawing.

The working machine with which the hydraulic drive apparatus which concerns on this embodiment is equipped is a wheel shovel, for example. As shown in FIG. 1, the wheel shovel includes a traveling body 1 having a front wheel 2 and a rear wheel 3, a swing body 4 disposed on the traveling body 1, and the swinging body. The work device 5 is rotatably mounted to the sieve 4 in the vertical direction. The work device 5 includes a boom 6 rotatably installed on the swinging structure 4, an arm 7 rotatably provided at the tip of the boom 6, and a tip of the arm 7. It includes a bucket (8) rotatably installed in. The cab 9 is disposed at the front side position on the swinging structure 4, and the counter weight 10 is disposed at the rear side position. The machine room 11 is arrange | positioned between the cab 9 and the counter weight 11, and the main part of the hydraulic drive apparatus which concerns on this embodiment is accommodated in this machine room 11.

As shown in FIG. 2, the hydraulic drive device according to the present embodiment includes a hydraulic pump 20, a priity valve 21 connected to the hydraulic pump 20, and the priity valve 21. Is provided continuously, and the steering valve 22 which supplies a hydraulic oil to the steering cylinder which is not shown in accordance with operation of the steering wheel which is not shown in figure is provided. In addition, the brake valve 23 for supplying pressure oil for braking the front wheels 2 and the rear wheels 3 to a brake device (not shown) according to the depression operation of the brake pedal 23a disposed in the cab 9, and the front wheel ( 2) A pair is provided corresponding to each of the rear wheels 3, and the accumulator 24 which accumulates the hydraulic oil supplied to the brake valve 23, and the flow path 26 are connected to the above-mentioned purity valve 21. It is provided with the filling valve 25 which is communicated through and can supply a hydraulic oil to the accumulator 24. As shown in FIG.

In the flow path 38 which connects the hydraulic pump 20 and the priority valve 21, the filter 28 which collects the dust mixed in the pressurized oil which flows through this flow path 38, and from the hydraulic pump 20 side, The check valve 29 which permits the flow of the pressurized oil to the priority valve 21 side, and prevents the flow of the oil from the priority valve 21 side to the hydraulic pump 20 side is provided in parallel.

Priority valve 21 switches the supply of the hydraulic oil to the steering valve 23 in accordance with the operation of the steering wheel (not shown) and the neutral position 21a1 which is a switching position capable of supplying the hydraulic oil to the accumulator 24. The direction change valve 21a which has the operation position 21a2 which is a position, and the relief valve 21b which defines the maximum pressure of the switching pressure of this direction change valve 21a are included. The relief valve 21b is connected to the tank 27.

The above-mentioned steering valve 22 is supplied to the pump part 22b through the pump part 22b which supplies a hydraulic oil to the steering cylinder which is not shown in figure, and the direction change valve 21a of the priity valve 21. The direction change valve 22a which controls the flow of a hydraulic oil is included. The direction switching valve 22a has a switching position 22a1 that enables supply of pressure oil for forward rotation of the pump portion 22b, and a switching position 22a2 that enables supply of pressure oil for reverse rotation of the pump portion 22b. And a neutral position 22a3 for preventing the supply of pressure oil to the pump portion 22b.

The filling valve 25 mentioned above enables the supply of pressurized oil to each of the accumulators 24, and check valves 30 and 31 which block the flow of the pressurized oil from the accumulator 24 side, and these check valves The check valve 32 which enables supply of the hydraulic oil to the (30, 31) direction and prevents the flow of the hydraulic oil from the check valve 30, 31 side is included. In addition, this filling valve 25 is maintained in the closed position 33a when the pressure of the accumulator 24 is low, and is switched to the open position 33b when the pressure of the accumulator 24 rises to a predetermined pressure. That is, the on / off valve 33 and the relief valve 34 which defines the maximum pressure of the switching pressure of this on / off valve 33 are included. The on-off valve 33 and the relief valve 34 are connected to the tank 27.

Moreover, this filling valve 25 is provided in the flow path 35 which connects the opening-closing valve 33 and the relief valve 34, and the filter 36 which collects the dust mixed in the pressure oil which flows through this flow path 35. ) Is included. Moreover, in this embodiment, the filling valve 25 is provided in the above-mentioned flow path 35 to the filter 36, and the flow of the hydraulic oil from the on-off valve 33 side to the relief valve 34 side is allowed. And the check valve 37 which prevents the flow of the pressurized oil from the relief valve 34 side to the on / off valve 33 side. Such check valve 37 is generally known to be cheaper than a relief valve or the like. In addition, one end portion of the flow path 26 which communicates the above-mentioned priity valve 21 and the filling valve 25 is connected to the outlet port of the direction change valve 21a of the priity valve 21, An end part is connected to the flow path which connects the check valve 32 and the opening / closing valve 33 of the filling valve 25.

According to the present embodiment configured in this manner, when a steering wheel (not shown) is operated, the direction switching valve 22a of the steering valve 22a is switched to any one of the switching positions 22a1 and 22a2, and the priori It becomes the tendency for the direction change valve 21a of the tee valve 21 to switch to the operation position 21a side. Therefore, the considerable amount of the pressurized oil discharged from the hydraulic pump 20 is the operation position 21a2 of the direction change valve 21a of the filter 28 and the priity valve 21, and the direction change valve of the steering valve 22. It is supplied to the pump part 22b via the switching position 22a1 or the switching position 22a2 of 22a, and is also supplied from the pump part 22b to the steering cylinder which is not shown in figure. As a result, the traveling direction of the traveling body 1 is determined. During this time, when the switching pressure of the direction change valve 21a of the priity valve 21 exceeds the set pressure of the relief valve 21b, the relief valve 21b is operated and the high pressure exceeding the set pressure is exceeded. Pressure oil is released into the tank 27 through the relief valve 21b.

In addition, even when the steering wheel (not shown) is operated, a part of the pressure oil discharged from the hydraulic pump 20 is diverted to the direction switching valve 21a of the priity valve 21 depending on the operation amount of the steering wheel. It is supplied to the flow path 26 from the neutral position 21a1 side of the. Therefore, at this time, the pressure accumulation to the accumulator 24 becomes possible.

In addition, in the state in which the steering wheel which is not shown in figure is not operated, the direction switching valve 21a1 of the priority valve 21 is hold | maintained in the neutral position 21a1. Therefore, the pressurized oil discharged from the hydraulic pump 20 is supplied to the filling valve 25 via the switching position 21a1 of the direction change valve 21a1 of the priity valve 21, and the flow path 26. As shown in FIG. At this time, in the state where the accumulator pressure of the accumulator 24 does not become a predetermined pressure, the on-off valve 33 is maintained in the closed position 33a, and the pressure oil of the hydraulic pump 20 is the check valve 32, the check valve It is supplied to each of the accumulators 24 via 30, 31. When each of the accumulators 24 has risen to a predetermined pressure, the opening / closing valve 33 is opened by the switching pressure applied to the portion of the flow path 35 positioned between the opening / closing valve 33 and the filter 36. Is converted to). Thereby, the high pressure hydraulic oil exceeding predetermined pressure is relief | released to the tank 27 via the open position 33b of the open / close valve 33. As shown in FIG. In addition, when the above-mentioned switching pressure exceeds the set pressure of the relief valve 34, the relief valve 34 operates, and the high pressure hydraulic oil exceeding the set pressure supplies the filter 36 and the relief valve 34. Through to tank 26.

In addition, when the brake pedal 23a is depressed when the front wheels 2 and the rear wheels 3 of the traveling body 1 are being driven, the pressure oil of the accumulator 24 passes through the brake valve 23. It is supplied to the brake apparatus which is not shown in figure, braking force is provided to the front wheel 2 and the rear wheel 3, and the traveling body 1 stops.

While the above operation is performed, the dust mixed in the pressurized oil flowing through the flow path 38 is collected by the filter 28 provided in the flow path 38 connected to the hydraulic pump 20, and the hydraulic pump 20 ), Cleanliness of the pressurized oil flowing upstream of this hydraulic circuit, including the purity valve 21, the steering valve 22, the filling valve 25, the accumulator 24, the brake valve 23 and the like. . Moreover, the dust mixed in the pressurized oil which flows through the flow path 35 is collected by the filter 36 provided in the flow path 35 which connects the opening / closing valve 33 of the filling valve 25 and the relief valve 34. Cleaning of the pressurized oil which flows downstream of this hydraulic circuit is performed. That is, by the filter 28 and the filter 36, the pressurized oil which flows through this hydraulic circuit is kept clean, and the priity valve 21, the steering valve 22, the filling valve 25, and the brake valve 23 are kept clean. Good operating performance of each hydraulic device, including) is maintained.

And when clogging occurs in the filter 28 provided in the flow path 38 which connects the hydraulic pump 20 and the priority valve 21, and it becomes difficult for hydraulic oil to pass through this filter 28, The pressurized oil of the pump 20 is supplied to the priority valve 21 through the check valve 29 provided in the filter 28. Therefore, the cleansing function of the pressurized oil flowing through the flow path 38 is weakened, but the desired operation can be continued while preventing the entire hydraulic circuit from being damaged. In addition, clogging occurs in the filter 36 provided in the flow path 35 that connects the opening / closing valve 33 and the relief valve 35 of the filling valve 25 to prevent the oil from passing through the filter 36. When it is, the pressure oil of the flow path 35 located between the on-off valve 33 and the filter 36 is supplied to the relief valve 34 through the check valve 37 provided in the filter 36. Therefore, when the pressure of this pressure oil becomes high pressure exceeding the setting pressure of the relief valve 34, the relief valve 34 is operated and the high pressure pressure oil exceeding the setting pressure is relief | released to the tank 27. FIG. Therefore, the cleansing function of the pressurized oil flowing through the flow path 35 is weakened, but the flow path 35 and the open / close valve 33 by the high pressure pressurized oil which generate | occur | produce in the part of the flow path 35 between the on-off valve 33 and the filter 36 are made. ), Damage to the entire hydraulic circuit including the hydraulic pump 20 can be reliably prevented.

As described above, according to the present embodiment, clogging occurs in the filter 36 disposed in the flow path 35 which communicates the open / close valve 33 and the relief valve 34, thereby preventing the open / close valve 33 and the filter ( When the part of the flow path 35 which connects 36 becomes high, the relatively inexpensive check valve provided in the filter 36, ie, the check valve 37 which is generally cheaper than the relief valve or the like, is transferred to the relief valve 34. By inducing the hydraulic oil, the high pressure hydraulic oil can be released by the operation of the relief valve 34. As a result, as described above, the cleansing function of the pressurized oil by the filter 36 is weakened, but the entire hydraulic circuit is suppressed while the manufacturing cost of the hydraulic drive device including the flow path 35 and the opening / closing valve 33 is increased. Can be prevented from being damaged, and excellent hydraulic circuit protection can be realized at low cost.

Moreover, the said embodiment is the structure which provided the filter 36 and the check valve 37 in parallel with the flow path 35 which communicates the on-off valve 33 and relief valve 34 contained in the filling valve 25. Although it is mentioned, it is good also as a structure which provided the filter and the check valve in parallel to the flow path which connects the direction switching valve 21a and relief valve 21b of the priority valve 21. In such a configuration, it is possible to realize cleaning of the pressurized oil flowing through the flow path connecting the directional valve 33 and the relief valve 21b, and when the filter is clogged, the directional valve 33 and the filter are prevented. The high pressure pressure oil of the flow path portion in contact with the can be guided to the relief valve 21b through the check valve, and the relief valve 21b can be operated to relief the tank 27. That is, damage to the whole hydraulic circuit including the direction change valve 21a, the hydraulic pump 20, etc. can be prevented by providing an inexpensive check valve.

In addition, although the said embodiment has the structure with which the wheel shovel was equipped, this invention is not limited to what is a wheel shovel. For example, you may comprise so that a wheel loader may be provided with this embodiment.

1: traveling body
4: swinging structure
5: Working device
20: hydraulic pump
21: Priority Valve
22: steering valve
23: brake valve
24: Accumulator
25: filling valve (valve)
26: Euro
27 tank
33: on-off valve (valve)
34: relief valve
35 Euro
36 filter (other filter)
37: check valve (other check valve)
38: Euro (other euro)

Claims (4)

A hydraulic pump, a valve switched in accordance with the pressure oil discharged from the hydraulic pump, a relief valve defining a maximum pressure of the switching pressure of the valve, and a filter provided in a flow path connecting the valve and the relief valve. In the hydraulic drive of the working machine,
A check valve is provided in the flow path in parallel with the filter to allow the flow of oil from the valve side to the relief valve side and to block the flow of oil from the relief valve side to the valve side. , Hydraulic drive of working machine. The valve according to claim 1, further comprising a valve to which pressure oil discharged from the hydraulic pump is supplied, wherein the valve, the relief valve, the flow path, the filter, and the check valve are provided. Hydraulic drive of the machine. A brake valve and an accumulator capable of supplying pressure oil to the brake valve,
The valve is composed of a filling valve capable of supplying pressure oil to the accumulator,
The hydraulic drive device of the working machine, characterized in that the valve comprises an on-off valve capable of relief of the high pressure hydraulic oil when the accumulator pressure of the accumulator becomes higher than a predetermined pressure. 4. The work machine according to claim 3, wherein the working machine consists of wheel shovels,
And a steering valve and a priority valve to which pressure oil discharged from the hydraulic pump is supplied.
At the same time installing a flow path for inducing pressure oil to the filling valve through the privacy valve,
Another filter is provided in another flow path that connects the hydraulic pump and the primitive valve, and is provided in the other flow path in parallel with the other filter to allow the flow of oil from the hydraulic pump side to the priority valve side. And a check valve for preventing the flow of oil from the privacy valve side to the hydraulic pump side.

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