JPH07714Y2 - Variable displacement piston pump or motor flow controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a device for controlling a discharge flow rate of a variable displacement piston pump or a motor from a remote position.

[Prior Art] FIG. 2 shows a cross-sectional view of a swash plate type axial piston hydraulic pump and a conventional pump discharge flow rate control device applied thereto. 1 is a swash plate, 2 is a link device, 3 is a piston, 4 is a spring, 5 is a pilot chamber, 6 is a plunger, 7 is a valve, 8 is a piston chamber, 9 is a pump body, 10 is a pump discharge part, and 11 is an orifice. , 12 and 13 are oil passages provided in the pump body, 14 is hydraulic piping, 15 is a pressure gauge provided on the piping, 16 is a pilot relief valve, 17 is a spring for the valve, and 18 is for operating the valve. Is a handle having a threaded portion, 19 is a pilot relief valve main body, and 20 is an oil drain pipe. The X portion is provided on the operation panel located away from the pump body 9. The pump discharge amount is controlled by the following process. First, the handle 18 is operated to adjust the compression amount of the spring 17 to set the oil relief pressure of the pilot relief valve 16. This determines the amount of oil drained from the oil drain pipe 20, and accordingly the pressure in the pilot chamber 5, that is, the pilot pressure, is set via the hydraulic pipe 14. In this conventional example, the pilot pressure is the pressure introduced through the orifice 11 using the pump discharge portion 10 as a pressure source. Therefore, if the separately installed high-pressure hydraulic power source is located near the pump body, there is also one in which these are used. This pilot pressure pushes the plunger 6 and valve 7 in the direction of arrow A. At the same time, the pressure of the pump discharge portion 10 enters the piston chamber 8 through the flow passage 12, the cutout portion of the valve 7 and the flow passage 13, and pushes the piston 3 in the direction of arrow B. At this time, the spring 4 provided at the right end of the valve 7 is compressed. Piston 3 at the position where these forces are balanced
Stops, and the inclination angle of the swash plate 1 connected via the link 2 is determined accordingly, and the discharge amount of the pump is determined according to this inclination angle. In controlling the discharge amount, the relationship between the reading of the pressure gauge 15 linked to the pilot pressure and the discharge amount is verified in advance, and the discharge amount is controlled while observing the pressure gauge 15 on the operation control panel.

Of the above-mentioned parts, the swash plate inclination angle setting device is constituted by the parts denoted by reference numerals 2 to 13, and from the hydraulic part consisting of the reference signs 14 to 16 and 20, and the mechanical part consisting of the reference signs 17 to 19, A pilot chamber pressure setting device for setting the pressure of the pilot chamber from a remote position for pressing the plunger 6, which is a part of the swash plate inclination angle setting device, is configured.

[Problems to be solved by the invention]

Conventionally, the discharge amount of a pump is controlled by operating a handle 18 while observing a pressure gauge 15 on an operation control panel located at a place distant from the pump body. The following problems have arisen in such a remote control system that extends hydraulic piping from such a pilot room.

(1) When the hydraulic pressure piping 14 for setting the pilot chamber pressure is long, a pressure loss between the pilot chamber 5 and the hydraulic pressure gauge 15 is caused because the pilot relief valve 16 constantly supplies 2 to 3 l / h of hydraulic oil. Occurs. Therefore, the pressure gauge 15 displays a pressure lower than the pilot pressure, and since this pressure loss fluctuates as the viscosity changes due to the change in oil temperature, the verification result of the relationship between the pressure gauge reading and the pump discharge rate is displayed. Since it could not be used constantly and the discharge rate changed during operation, the discharge rate could not be controlled accurately. For example, when the length of the hydraulic pipe 14 is 10 m and the pressure in the pilot chamber 5 is 20 kgf / cm ² , the display of the pressure gauge 15 differs depending on the hydraulic oil temperature as illustrated in the table below for a certain oil type. The pressure loss value was low, which caused a control error.

(2) Oil leakage easily occurs due to the long hydraulic piping 14 for setting the pilot chamber pressure, which causes various inconveniences such as an increase in the control error due to a pressure measurement error.

All of the above problems are caused by the long length of the hydraulic piping.

[Means for solving problems]

The present invention solves the above-mentioned problems, in which the hydraulic oil from a high-pressure hydraulic source pushes the plunger, and the swash plate tilts to control the intake and discharge flow rates of the piston pump or motor by the pressing force of the plunger. In a variable displacement piston pump or motor flow path control device equipped with a swash plate inclination angle setting device for setting the angle, a throttle that allows the hydraulic oil from the high-pressure hydraulic source to flow through the pilot chamber installed to drive the plunger. An oil passage that has, a pilot relief valve that is in constant communication with the pilot chamber and that keeps working oil from the pilot chamber at a set pressure according to the inclination angle of the swash plate to constantly flow, and the pilot chamber and the pilot relief valve. Hydraulic means consisting of a short hydraulic transmission passage communicating with each other and a pressing force corresponding to the inclination angle of the swash plate installed on the discharge side of the pilot relief valve are applied. A spring that loads the ilot relief valve, a rod that is installed on the side of the spring opposite to the side in contact with the pilot relief valve and that holds the end of the spring, and one end of the rod that is provided at the remote position. A pilot chamber pressure setting device composed of a wire connected to the other end to operate the position of the rod and mechanical means capable of setting the set pressure of the pilot relief valve from a remote position, and The present invention relates to a flow rate control device for a variable displacement piston pump or a motor, which is provided in a swash plate tilt angle setting device.

[Action]

By installing a pilot relief valve near the pilot chamber and replacing the conventional long hydraulic pipe for remote operation with a short hydraulic transmission passage, the discharge amount control error and oil leakage due to the long hydraulic pipe were eliminated. . The remote operation of the pilot relief valve eliminates the occurrence of the discharge flow rate control error due to the fluctuation of the hydraulic oil temperature by using a mechanical method mainly using a wire instead of using hydraulic pressure.

〔Example〕

 FIG. 1 shows a sectional view of an embodiment of the present invention.

In this figure, the pilot relief valve 16 and spring
The installation location of the pilot relief valve main body 19 having the inside 17 is changed from a conventional remote device to a position adjacent to the pilot chamber. In the figure, 21 is a pilot relief valve
A spring installed at the rear end of the spring 17 that urges the spring 16.
A rod for pushing 17 and a lever 22 for a lever, one end of which is rotatably attached to the pilot relief valve main body 19, a wire 24 which will be described later is attached to the other end, and the rod 21 is rotatably attached in the middle thereof. There is. Reference numeral 23 denotes a spring connecting the lever 22 and the pilot relief valve main body 19 so that the lever 22 is always isolated from the pilot relief valve main body 19 so that a light pulling force is always applied to the wire 24. Reference numeral 24 is a wire connecting one end of the lever 22 and an operation stick 25 described later, and cooperates with the spring 23 to hold the rod 21 at a predetermined position in the pilot relief valve body according to the operation amount of the operation stick 25. ing. 25 is an operation unit of an operation stick type provided on the operation control panel, 26
Is a dial provided adjacent to the operation stick 25. 14 'is the pump body 9 and the pilot relief valve body 19
A short hydraulic transmission passage that is provided inside the valve and connects the pilot chamber 5 and the pilot relief valve 16 to each other; The orifices 20 'are similarly oil drain passages provided inside these bodies. The parts with the numbers other than the above are the same as those in the case of the conventional art, and therefore the description thereof is omitted. In the figure, the portion Y is provided on the operation panel located away from the pump body 9.

In this embodiment, the pilot relief valve main body 19 is provided adjacent to the pump main body 9 as shown in the drawing.
The hydraulic transmission passage 14 'is as short as possible.

Rod 21, lever instead of conventional threaded handle 18
The oil relief pressure of the pilot relief valve 16 that determines the pressure in the pilot chamber 5 is set from a remote position by a mechanical means including a wire 22, a wire 24, and an operation stick 25. The oil relief pressure of the pilot relief valve 16 is
It is decided according to the inclination of 25. Pilot relief valve 16
Is provided adjacent to the pump body 9 in which the pilot chamber 5 is provided, the conventional long hydraulic pipe 14 is unnecessary, and instead, a very short hydraulic transmission passage 14 'is provided in the device. . A throttle 11 is provided on the inlet side of the oil passage communicating with the pilot chamber 5 from the pump discharge unit 10 to the pilot chamber 5, and the throttle 11 prevents pressure fluctuations of the hydraulic oil from the pump discharge unit 10 or the separately placed hydraulic source. Regardless of the fact that a required small flow rate can be made to flow into the pilot chamber 5 and a predetermined depressurizing action is possible, hydraulic oil can be supplied from a hydraulic source of a considerably high pressure that is extremely different from the operating pressure of the pilot chamber 5. Becomes Further, similarly, instead of the conventional oil drain pipe 20, an oil drain passage 20 'is provided in the pump body 9. The principle of changing the tilt angle of the swash plate 1 by the pressure of the pilot chamber 5 held at the pressure set by the pilot relief valve 16 is the same as the conventional one.

Among the above-mentioned parts, hydraulic means including a hydraulic pressure transmission passage 14 ', a pilot relief valve 16 and an oil drain pipe 20', a spring 17, a rod 21, a lever 22, a spring 23, a wire 24, an operation stick 25, and a scale. A swash plate tilt angle setting device is provided with a pilot chamber pressure remote setting device including mechanical means including a plate 26. The wire 24 is responsible for remote transmission of the operation amount for setting the pressure in the pilot chamber 5 for setting the tilt angle of the swash plate from a remote position.

The difference of this embodiment from the prior art is that when setting the pilot chamber pressure from a remote position, the position of the pilot relief valve is brought close to the pilot chamber and a long hydraulic pipe is abolished.
The point is that the pilot relief valve communicates with the pilot chamber through a short hydraulic transmission passage, and the valve is operated by mechanical means. By changing the principle of remote control in this way, it was possible to eliminate all the problems associated with conventional long hydraulic piping. That is, (1) control error due to pressure loss associated with the flow of hydraulic oil acting on a hydraulic pressure gauge in a remote device and pressure loss variation due to hydraulic oil temperature variation, and (2) oil leakage due to long pipe length. Solved.

In the present embodiment, the relationship between the inclination angle of the operation stick 25 and the discharge amount is preliminarily verified, and the scale 26 made by the verification result is provided at a position adjacent to the operation stick 25 to operate. The discharge amount of the pump can be accurately controlled by the operation stick 25 while looking at the scale plate 26 on the operation panel.

Furthermore, by providing a throttle in the oil passage, it is possible to replenish the pilot chamber with operating oil from the high-pressure hydraulic source only at a required small flow rate, so that the discharge amount and discharge pressure of the high-pressure hydraulic source hardly decrease and the swash plate The tilt angle can be controlled.

[Effect of device]

In the variable displacement piston pump or motor flow controller of the present invention, the pilot chamber installed for driving the plunger has an oil passage having a throttle for allowing the working oil from the high-pressure hydraulic source to flow, and the pilot chamber is in constant communication. A hydraulic pressure consisting of a pilot relief valve that keeps the hydraulic oil from the pilot chamber at a set pressure according to the tilt angle of the swash plate and always circulates it, and a short hydraulic transmission passage that connects the pilot chamber and the pilot relief valve. Means, a spring that is installed on the discharge side of the pilot relief valve and that applies a pressing force corresponding to the inclination angle of the swash plate to the pilot relief valve, and a spring that is opposite to the side of the spring that contacts the pilot relief valve. The rod that holds the end of the spring and one end of the rod are connected to the operation unit provided at a remote position. A pilot chamber pressure setting device consisting of a wire for operating the position of the rod at the end side and a mechanical means capable of setting the setting pressure of the pilot relief valve from a remote position is provided. Since it is provided in the device, it is possible to prevent suction of the variable displacement piston pump or motor, occurrence of an error in the discharge flow rate, and oil leakage.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2 is a sectional view of a prior art. 1 ... Swash plate, 2 ... Link device, 3 ... Piston, 4 ... Spring, 5 ... Pilot chamber, 6 ... Plunger, 7 ... Valve, 8 ... Piston chamber, 9 ... Pump body, 10 ... Bomb discharge part, 11 ... Orifice , 12 and 13 ... Oil passage, 14 ... Hydraulic piping, 15 ... Pressure gauge, 16 ... Pilot relief valve, 17 ... Spring, 18 ... Handle with threaded portion, 19 ... Pilot relief body, 20 ... Oil drain pipe, 21 ... Rod , 22 ... lever,
23 ... Spring, 24 ... Wire, 25 ... Operation stick, 26
... scale, 14 '... hydraulic transmission passage, 20' ... drain passage.

Claims (1)

[Scope of utility model registration request] 1. A swash plate tilt angle setting for pressing a plunger with hydraulic oil from a high-pressure hydraulic source, and setting a tilt angle of the swash plate for controlling the intake and discharge flow rates of a piston pump or a motor by the pressing force of the plunger. In a variable displacement piston pump or motor flow rate control device provided with a device, an oil passage having a throttle for allowing hydraulic oil from a high-pressure hydraulic source to flow in a pilot chamber installed for driving the plunger,
Pilot relief valve that constantly communicates with the pilot chamber and keeps working oil from the pilot chamber at a set pressure according to the inclination angle of the swash plate to constantly flow, and short hydraulic pressure transmission that communicates the pilot chamber with the pilot relief valve. The hydraulic means consisting of a passage, the spring installed on the discharge side of the pilot relief valve and applying a pressing force corresponding to the inclination angle of the swash plate to the pilot relief valve, and the side of the spring in contact with the pilot relief valve are The pilot relief is composed of a rod that is installed on the opposite side and holds the end of the spring, and a wire that has one end connected to an operation part provided at a remote position and the other end that operates the position of the rod. A pilot chamber pressure setting device composed of a mechanical means capable of setting the valve setting pressure from a remote position, and a swash plate. Variable displacement piston pump or motor of the flow control device, characterized in that provided on the swash angle setting device.