JPS5818580A - Pump controller - Google Patents

Abstract

PURPOSE:To aim at minimizing a swash plate tilting angle when a main selector valve is neutral and lowering a motor load in time of neutrality, by controlling a regulator with pilot pressure employed, in case of a control device provided with such a regulator that adjusts the swash plate tilting angle of a main pump. CONSTITUTION:Compressed fluid out of a main pump 2 driven by a motor 1 is led to plural main selector valves 4-7 being connected to each operating unit via a compressed fluid tube 3 and one of the main selector valves 4-7 is switched by control levers 8-11 whereby the operating units concerned are energized. In this case, a pilot pump 15 driven by the motor 1 is installed, receiving pilot pressure from the pump 15 via a feed tube 16, and thereby a tilting angle theta of a swash plate 19 of the main pump 2 is controlled via control cylinders 17 and 18 by a regulator 20. In addition, on the way to the feed tube 16, a pilot pressure selector valve 22 to be controlled via selector bracket 23 by the said levers 8-11 is installed.

Description

[Detailed description of the invention] The present invention relates to a control device for a pump in a hydraulic circuit.

Conventionally, as a device for controlling the operation of a pump in relation to the operation of a control lever, a mechanical connection means such as a cam, a rod, a lever, etc., which is operated in response to the operation of a control lever, is used to control the operation of a pump through a hydraulic servo, etc. A variable displacement pump in which the amount of liquid discharged from the pump is controlled by changing the swash plate angle has been considered.

However, in the conventional method described above, the pump is controlled via a mechanical connection means that is linked to the operation of the operating lever, making it difficult to achieve precision in the cam, rod, lever, etc., and making adjustments very troublesome. At the same time, there is a problem that the installation position is restricted.Furthermore, since the prime mover side vibrates, the mechanical connection means is directly affected by vibration, and it is necessary to provide a hydraulic servo. At the same time, in order to ensure the responsiveness of the hydraulic servo, the pump that drives the hydraulic servo also needs to be enlarged, making the entire device expensive.

The present invention solves the problems of the conventional system described above, and is provided with a pilot pump in an apparatus equipped with a regulator for controlling the tilt angle of the swash plate of the main pump. a switching bracket connected to the regulator by a pilot pressure supply pipe having a pilot pressure switching valve, and moving together with the main switching valve connected to the main pump to switch the pilot switching valve; When the main switching valve is in neutral mode, the pilot pressure is introduced into the regulator and the main pump's swash plate tilt angle is minimized, and when the main switching valve is switched, the introduction of pilot pressure to the regulator is cut off and the main pump's swash plate is tilted. The present invention relates to a pump control device characterized in that it is configured to maximize the angle of rotation.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of a hydraulic circuit to which the present invention is applied, in which pressure fluid from a main pump (2) driven by a prime mover (1) is passed through pressure fluid pipes (3) to each operating section ( 3) O9, the operating lever (Ill (91 (IQI)) is the main switching valve (41 (51 (C11)) configured to actuate the actuating part connected to it by switching one of the forces. ing.

In the figure (121 is the pressure liquid return pipe that returns the return liquid from main switching 4 (41 (51 (61) (7) to tank α3), 0a is between the pressure liquid pipe (3) and the pressure liquid return pipe Oz This is a relief valve installed in the

In the above configuration, the main pump (
2) A pilot pump (
15) is provided, and by receiving the pilot pressure from the pilot pump (151 through the pilot pressure supply pipe (16)), the swash plate a9 of the main pump (2) is connected via the control cylinder (171 (1) to A regulator (20) is provided to control the tilt angle θ.In addition, a regulator (20) for setting the pilot pressure is provided in the pilot pressure supply pipe <161.
J IJ-Fuvalve Cυ is installed. Furthermore, the pilot pressure supply pipe (pilot for supplying and shutting off pilot pressure in the middle of 1ω) and a lot pressure switching valve (2) are provided, and the pilot pressure switching valve (2) is equipped with a switching platen for sudden switching operation. )
(23) by operating the operating levers (8) (4) (91 (IQI Q +))
41 (51 (6) and (7)).The figure shows the pilot pressure return pipe connecting between the Fi pilot pressure switching valve (24) and the pressure liquid return pipe Q2). . Further, the switching platen l-(23) is formed to switch the pilot pressure switching valve (24) via a roller (26) by a cut (25) at a predetermined angle, and the cut (251) is , main switching valve (41 (5)
1 (61) The force and pilot pressure switching valves (22) are formed so as to have valve characteristics such that they are switched with mutually synchronized metering (adjustment amounts) as shown in FIG. The above switching bracket (23 is the main switching valve f4) (5)
(When either of 61 (7) is switched, it is sufficient to switch the pilot pressure switching valve in conjunction with it. Therefore, one or more main switching valves (41 (51 (61), It may be set in

Next, the action will be explained.

Operation lever (81(9)001 (when Ill is in neutral,
Pressure liquid sent from the main pump (2) via the pressure liquid pipe (3) passes through the main switching valve (41 (51 (6) (force) and enters the tank 03 via the pressure liquid return pipe a2). be returned.

At this time, the pilot pressure discharged from the pilot pump Q5), set to a pressure by the relief valve (21), and sent by the pilot pressure supply pipe (16) passes through the pilot pressure switching valve (22) to the regulator (20). ). As a result, the regulator (near 2) operates the control cylinder αη in the direction b and the control cylinder 08) in the direction C, so that the tilting angle θ of the pump swash plate Q9 is minimized. Control is performed so that the amount of discharged liquid is minimized. As a result, the operating lever (8) (91GO)
(11) Main switching valve by K (4) (51 (6) (7
It is possible to save energy by minimizing the load on the pump prime mover (1) when the pump motor (1) is in the neutral state (when the operating portion is not operating).

Next, when any of the operating levers (8) (9) α0) αD is switched, - the main switching valve [(41 (51 (6) (one of force)) switched by the operating lever is connected. Pressure liquid is supplied from the pressure liquid pipe (3) to the actuating part (not shown) to perform the actuation.

At this time, the switching platen (23) also moves in the direction of the arrow at the same time, so the pilot pressure switching valve 122 is switched via the roller (26) by the two notches, and the introduction of pilot pressure to the regulator screen is cut off. The pilot pressure is released into the return pipe (2). As a result, the regulator (20) operates the control cylinder αη in the α direction and the control cylinder 08) in the d direction, respectively, and operates the swash plate (1'l
Control is performed so that the tilt angle θ of the main pump (2) becomes maximum and the amount of liquid discharged from the main pump (2) becomes maximum.

At this time, the main switching valve (41 (51 (6) 23) notch (25+ shape A, B
, A', and B' are metered the same as shown in Figure 2, so the main switching valve (41T
5) fil (The amount of liquid discharged from the main pump (2) can be controlled with good responsiveness by following the opening degree of the force.

5 and 4 show specific examples of the switching section of the pilot pressure switching valve (221), and the main switching valve (41 (51)
(6) (Switching bracket C'7 that operates integrally with 71)
) (28) (29) (30) f: Provided and the roller 01 provided to adapt to each notch (251) of the switching bracket (2η(28) (29GO)) (a) (to) A roller (26) attached to one rotating shaft (to) and a lever provided at the end of the rotating shaft (to)
The pilot pressure switching valve (2-pressure switching is performed through the pilot pressure switching valve).Those with the same reference numerals in the drawings indicate the same ones.

It should be noted that the present invention is not limited to the above-described embodiments, but may be modified in various ways without departing from the gist of the present invention.

According to the pump control device of the present invention described above, the following excellent effects can be achieved.

(+1) The tilting angle of the main pump's swash plate is minimized when the main switching valve is in neutral (when the actuating part is not operating), so the load on the main pump prime mover is minimized and energy is saved when the main switching valve is in neutral. be able to.

(11) Since the pilot pressure from the pilot pump is used to operate the regulator and adjust the main pump's swash plate tilt angle θ, no hydraulic servo is required compared to the conventional method using mechanical connection means. Therefore, the configuration can be simplified and implemented at low cost.

(iH) By forming the cut so that the characteristics of the main switching valve and the pilot pressure switching valve match, it becomes possible to adjust the discharge amount of the main pump with accuracy and good responsiveness.

(ivl The pilot tank only needs to be able to obtain the required pilot pressure, so a small capacity one is sufficient.

(v) There are few mechanical parts that require precision and adjustment, and since they are provided on the operating lever side away from the prime mover side, they are hardly affected by vibrations caused by the prime mover.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing one embodiment of the present invention, Fig. 2 is an explanatory diagram of the switching characteristics provided to the main switching valve and the pilot pressure switching valve, and Fig. 6 is the switching section of the pilot pressure switching valve. FIG. 4 is an explanatory diagram showing a specific example of the above, and FIG. 4 is a view taken along the line IV-IV in FIG. 6. (1) is the prime mover, (2) is the main pump, (41(5) (
6) (7) is the main switching valve, (8) (91QO) IJ
1) is the operating lever, (151 is the pilot pump, 09
Group 0 indicates the control cylinder, 0 (g) indicates the swash plate, (201 indicates the regulator, (22 indicates the pilot pressure switching valve, e3) indicates the switching bracket, (251 indicates the notch, and (26) indicates the roller. Patent applicant Ishikawajima Harima Heavy Industries Co., Ltd. Patent applicant Ishikawajima Construction Machinery Co., Ltd.

Claims (1)

[Claims] 1) In a device equipped with a regulator for adjusting the swash plate tilt angle of the main pump, a pilot pump is provided and a pilot pressure switching valve is installed between the pilot pump and the regulator. A switching bracket is provided that is connected to the main switching valve through a pressure supply pipe and moves together with the main switching valve connected to the main pump to switch the pilot pressure switching valve, so that the pilot pressure in the neutral state of the main switching valve is transferred to the regulator. When the main pump is introduced, the swash plate tilting angle of the main pump reaches a maximum of 7, and when the main switching valve is switched, the introduction of pilot pressure to the regulator is cut off, so that the main pump's M[li tilting angle becomes the maximum. A pump control device characterized by: