JPH07167065A - Drive device for liquid pump - Google Patents

Abstract

PURPOSE:To eliminate a gear device serving simply as a power transmission device and to reduce the size of a liquid pump drive device by a method wherein a gear pump is utilized as a power transmission mechanism to transfer the power of a prime mover to a main pump and constituted to be also utilizable as a hydraulic source. CONSTITUTION:A gear pump 31 comprises a drive gear 41: two driven gears 42 and 43 geared with the drive gear; and a casing 44. When a prime mover 1 is started, after pressure oil sucked from a pressure oil tank 11 to first and second suction chambers 45 and 47 from a pressure oil tank 11 through suction lines 32 and 33 is boosted, the pressure oil is fed with a pressure from first and second delivery chambers 46 and 48. The pressure oil from the delivery chambers 46 and 48 is fed to the suction ports of main pumps 4 and 5 through delivery line 34 and 35 to increase the suction pressures of the main pumps 4 and 5. Namely, self-suction performance at a high capacity delivery period of the main pumps 4 and 5 being a plunger pump is prevented from lowering and the occurrence of cavitation during high rotation drive, lowering of volume efficiency, and the damage of the interior of the pump are prevented from occurring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive device for a liquid pump mounted on a construction machine or an industrial machine.

[0002]

2. Description of the Related Art FIG. 5 shows an example of a conventionally known liquid pump drive device. As you can see from this figure,
The liquid pump drive device of this example includes a prime mover 1, a pump device 2, and a gear device 3 that transmits the power of the prime mover 1 to the pump device 2.

The pump device 2 comprises two main pumps 4, 5 which are plunger pumps, and auxiliary pumps 6, 7 which are impeller pumps or gear pumps for increasing the suction pressure of each of the main pumps 4, 5. Has been. The first main pump 4 and the first auxiliary pump 6 are coaxially connected to the first pump drive shaft 8, and the second main pump 5 and the second auxiliary pump 7 are the second pump drive shaft 9. Is coaxially connected to. The suction ports of the first and second auxiliary pumps 6 and 7 are connected to the pressure oil tank 11 via the suction pipe line 10,
The discharge ports of the first and second auxiliary pumps 6 and 7 are individually connected to the suction ports of the first and second main pumps 4 and 5 via boost pipe lines 12 and 13. The discharge ports of the first and second main pumps 4 and 5 are the control valve 14,
It is connected to predetermined actuators 16 and 17 via 15.

On the other hand, the gear device 3 includes a driving gear 19 mounted on a driving shaft 18, and two driving gears mounted on the first and second pump drive shafts 8 and 9 and meshed with the driving gear 19. It consists of driven gears 20 and 21.
The gear device 3 is housed in a casing, and the casing is filled with lubricating oil.

In the liquid pump drive device having the above-described structure, the power of the prime mover 1 is transmitted to the drive shaft 2 via the prime mover shaft 18 and the prime mover gear 19.
To the two driven gears 20 and 21 to drive the first main pump 4 and the first auxiliary pump 6 via the first pump drive shaft 8 and the second main drive pump 6 via the second pump drive shaft 9. The main pump 5 and the second auxiliary pump 7 are driven. The first and second auxiliary pumps 6 and 7 increase the suction pressures of the first and second main pumps 4 and 5, respectively, so that the main pumps 4 and 5, which are plunger pumps, are self-priming during large-capacity discharge. The performance is prevented from deteriorating, cavitation is generated at the time of high-speed rotation, the volumetric efficiency is lowered, and the inside of the pump is prevented from being damaged.

[0006]

However, the liquid pump drive device having the above-mentioned structure transmits the power of the prime mover 1 to the pump device 2 through the gear device 3, so that it has a drawback of poor power transmission efficiency. That is, as described above, since the gear device 3 is housed in the casing and the casing is filled with the lubricating oil, a large torque cross occurs due to the stirring resistance of the lubricating oil, and the power transmission efficiency deteriorates. Further, the conventional liquid pump drive device includes a prime mover 1,
Since the gear device 3, the main pumps 4, 5, and the auxiliary pumps 6, 7 are indispensable components, there is also a disadvantage that sufficient miniaturization cannot be achieved.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a liquid pump drive device which is small in size and has high power transmission efficiency.

[0008]

In order to achieve the above-mentioned object, the present invention replaces a gear device in a conventional device with a gear pump, omits an auxiliary pump provided coaxially with a main pump, and drives a liquid pump. The apparatus comprises a prime mover, a drive gear connected to the prime mover shaft, a gear pump having a driven gear driven by the drive gear as a pressure source, and a main pump connected to the driven gear.

[0009]

If the gear device is replaced with a gear pump and the gear pump is used as an auxiliary pump, the gear device, which has been an indispensable component in the related art, can be omitted in terms of form, so that the liquid pump drive device can be integrated and downsized. Can be planned. Further, if the power of the driving shaft is transmitted to the main pump by the gear pump, the torque transmission due to the stirring resistance of the lubricating oil does not become a problem, so that the power transmission efficiency can be improved.

[0010]

【Example】

<First Embodiment> FIGS. 1 and 2 show the configuration of a liquid pump drive apparatus according to the first embodiment. FIG. 1 is a configuration diagram of the apparatus of this example, and FIG. 2 is an explanatory diagram of a gear pump. In these figures, 31 is a gear pump, 32 and 33 are suction pipes of the gear pump 31, 34 and 35 are discharge pipes of the gear pump 31, 36 and 37 are discharge pipes of the main pump, and others,
The same symbols are displayed in the portions corresponding to those in FIG. 5 described above.

As shown in FIG. 2, the gear pump 31 includes a driving gear 41 and two driven gears 4 meshed with the driving gear 41.
2, 43 and a casing 44 having a sliding surface on which the tooth tips of each of the gears 41 to 43 slide while maintaining desired airtightness. A first suction chamber 45 and a first discharge chamber 46 are formed on the inner surface of the casing 44 in correspondence with the meshing portion between the driving gear 41 and the first driven gear 42. A second suction chamber 47 and a second discharge chamber 48 are formed so as to correspond to the meshing portion between 41 and the second driven gear 43. The suction line 32 is connected to the first suction chamber 45, and the first discharge chamber 46 is connected to the discharge line 3
4 is connected to the suction port of the main pump 4. On the other hand, the suction pipe line 33 is connected to the second suction chamber 47,
The second discharge chamber 48 is connected to the main pump 5 via the discharge pipe line 35.
Is connected to the suction port of.

The drive gear 41 is fixed to the drive shaft 2 of the drive motor 1, the first driven gear 42 is fixed to the pump drive shaft 8 of the first main pump 4, and the second driven gear 43 is used. Are fixed to the pump drive shaft 9 of the second main pump 5. Therefore, the power of the prime mover 1 is the power of the prime mover shaft 2
Is transmitted to the driving gear 41 via the first driven gear 42 constituting the gear pump 31, and is transmitted to the first pump drive shaft 8 via the first driven gear 42.
The main pump 4 of is driven. At the same time, it is transmitted to the second pump drive shaft 9 via the second driven gear 43 that constitutes the gear pump 31, and drives the second main pump 5.

When the prime mover 1 is started, the gear pump 31
A first suction chamber 45 and a second suction chamber 47 formed in
The pressure oil from the pressure oil tank 11 is sucked through the suction pipe lines 32 and 33, and is pressure-fed from the first discharge chamber 46 and the second discharge chamber 48. The pressure oil from the first discharge chamber 46 is
It is supplied to the suction port of the main pump 4 via the discharge pipe line 34,
Increase the suction pressure of the main pump 4. On the other hand, the second discharge chamber 48
The pressure oil from is supplied to the suction port of the main pump 5 via the discharge pipe line 35 to increase the suction pressure of the main pump 5. This prevents the self-priming performance of the main pumps 4 and 5 which are plunger pumps from being reduced at the time of large-capacity discharge, causes cavitation at the time of high-speed drive, and eventually reduces the volumetric efficiency and damages the inside of the pump. To be prevented.

In the liquid pump drive device of this embodiment, the gear device is replaced with the gear pump 31, and the gear pump 31 is used as an auxiliary pump for applying boost pressure to the main pumps 4 and 5, so that the gear pump is merely a power transmission device. The device can be omitted in terms of form, and the configuration of the liquid pump drive device can be integrated and downsized. Further, by transmitting the power of the driving shaft 1 to the main pumps 4 and 5 by the gear pump 31 as described above, the torque loss due to the stirring resistance of the lubricating oil does not become a problem, so that the power transmission efficiency can be improved. it can.

<Second Embodiment> FIG. 3 shows the structure of a liquid pump drive apparatus according to the second embodiment. In this figure, 5
1 is a confluent conduit, 52 is a pilot valve for hydraulic operation, 5
3, 54 is a pilot line, 55 is a relief valve,
The other parts corresponding to those shown in FIGS. 1 and 5 have the same reference numerals.

As is apparent from FIG. 3, in the liquid pump drive apparatus of this example, the gear pump 31 is used as a pilot pump for the control valve 14 instead of the structure in which the gear pump 31 is used as an auxiliary pump for the main pumps 4 and 5. It is characterized by being used as a hydraulic pressure source. That is, the first discharge port of the gear pump 31 is connected to the lever-operated pilot valve 52 via the confluent conduit 51, and the discharge port of the pilot valve 52 is connected via the pilot conduits 53 and 54. , Control valve 14
Are connected to the pilot ports on the A side and the B side.
Although not shown, the second discharge port of the gear pump 31 is also connected to the lever-operated pilot valve via the confluence pipe line 56 so that another control valve (not shown) can be operated. There is.

A first auxiliary pump 6 is coaxially provided on a first pump drive shaft 8 for driving the first main pump 4.
A second auxiliary pump 7 is coaxially provided on a second pump drive shaft 9 that drives the second main pump 5. The discharge line of the first auxiliary pump 6 is the first main pump 4
Is connected to the suction port of the second main pump 5, and the discharge line of the second auxiliary pump 7 is connected to the suction port of the second main pump 5. The boost pressure is given to the main pump 5 of No. 2.

In the liquid pump drive system of this embodiment, when the operation lever provided on the pilot valve 52 is operated, the pilot pressure corresponding to the lever operation amount is applied to the pilot conduits 53, 54.
Then, the control valve 14 is switched to the A side or the B side. Then, pressure oil according to the lever operation amount is supplied from the first main pump to the first actuator 14, and the first actuator 14 is driven at a speed according to the lever operation amount. When the other pilot valve 52 (not shown) is operated, the other actuator 14 (not shown) is driven in the same manner.

Since the gear pump 31 is used as the hydraulic pressure source for pilot switching of the control valve 14 in the liquid pump drive apparatus of this embodiment, it is not necessary to separately provide a hydraulic pressure source for pilot switching, and the entire hydraulic circuit is constructed accordingly. Can be miniaturized. The boost pressure is applied to the first and second main pumps 4 and 5 by the first and second auxiliary pumps 6 and 7. It is possible to prevent deterioration of suction performance and cavitation during high rotation driving.

<Third Embodiment> FIG. 4 shows the configuration of a liquid pump drive apparatus according to the third embodiment. In this figure, 6
Reference numeral 1 denotes a merging conduit, 62 denotes an actuator provided in the merging conduit 61, 63 denotes a control valve for controlling the flow of pressure oil to the actuator 62, and other parts corresponding to those in FIG. The same reference numerals are displayed.

As is apparent from FIG. 4, in the liquid pump drive system of this embodiment, the gear pump 31 is used as the hydraulic pressure source of the actuator 62 provided in another hydraulic circuit which does not use the main pumps 4 and 5 as hydraulic pressure sources. It is characterized by That is, the discharge pipe line 3 connected to the discharge port of the gear pump 31.
4, 35 are merged into a merged conduit 61, and an actuator 62 is connected to the merged conduit 61 via a control valve 63. The actuator 62 is driven by operating the control valve 63 and supplying pressure oil according to the operation amount. The other parts are the same as those of the liquid pump drive device according to the second embodiment, and therefore the description thereof is omitted.

In the liquid pump drive system of this embodiment, the gear pump 31 is used to drive the power of the prime mover 1 into the first and second main pumps 4, 4.
5 is used as a power transmission mechanism and also used as a hydraulic power source for driving the actuator 62. Therefore, it is not necessary to separately provide a hydraulic power source for driving the actuator 62, and the entire hydraulic circuit is configured accordingly. Can be miniaturized. The point that the first and second main pumps 4 and 5 can be driven without any inconvenience is the same as the liquid pump drive apparatus according to the second embodiment.

In each of the embodiments described above, the case where one main engine 1 drives two main pumps has been described, but the number of main pumps driven by the prime mover 1 is one. However, it may be a plurality of units of three or more.

[0024]

As described above, according to the present invention,
Since the gear pump is used not only as a power transmission mechanism that transmits the power of the prime mover to the main pump but also as a hydraulic power source, a gear device as a simple power transmission device can be omitted from the form, and the configuration of the liquid pump drive device can be omitted. It is possible to consolidate and downsize. Also, the gear pump
Unlike a simple gear device, torque cross due to stirring resistance of lubricating oil does not pose a problem, so that power transmission efficiency can be increased.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a liquid pump drive device according to a first embodiment.

FIG. 2 is an explanatory diagram of a gear pump.

FIG. 3 is a configuration diagram of a liquid pump drive device according to a second embodiment.

FIG. 4 is a configuration diagram of a liquid pump drive device according to a third embodiment.

FIG. 5 is a configuration diagram of a conventionally known liquid pump drive device.

[Explanation of symbols]

 1 prime mover 2 pump device 4,5 main pump 8,9 pump drive shaft 14,15 control valve 16,17 actuator 31 gear pump 32,33 gear pump suction pipe line 34,35 gear pump discharge pipe 41 drive gear 42,43 driven Gear 44 Casing 51 Confluence line 52 Pilot valve 53, 54 Pilot line

Claims (5)

[Claims] 1. A prime mover, a drive gear connected to a prime mover shaft, a gear pump having a driven gear driven by the drive gear as a pressure generation source, and a main pump connected to the driven gear. Liquid pump drive device. 2. The drive device for a liquid pump according to claim 1, wherein the gear pump is provided with a plurality of driven gears, and a plurality of main pumps are connected to the driven gears. 3. The drive device for a liquid pump according to claim 1, wherein a discharge port of the gear pump is connected to a suction port of the main pump. 4. The gear pump according to claim 1,
A drive device for a liquid pump, which is used as a pilot hydraulic power source for a valve provided in a hydraulic circuit having the main pump as a hydraulic power source. 5. The gear pump according to claim 1,
A drive device for a liquid pump, wherein the main pump is used as a hydraulic pressure source of an actuator provided in another hydraulic circuit that does not use a hydraulic pressure source.