JPS60147583A - Position detecting device for variable displacement mechanism - Google Patents

Abstract

PURPOSE:To improve the operability of the mechanism by a method wherein the variable displacement mechanism is moved to a reference position and a detected value of the position is utilized for a value to correct zero point automatically. CONSTITUTION:When it is detected that a start switch 11 is being closed, the variable displacement mechanism 1a of a hydraulic pump 1 having a swash plate, an oblique shaft or the like is moved to a direction, in which the delivery amount of the mechanism is decreased, by operating a regulator 2 by a CPU10c and a digital output circuit 10f. The mechanism 1a is stopped by a stopper 12 at a position whereat the delivery amount is minimum and the position of the mechanism 1a is detected by a position detector 3 while the detected value is inputted into the CPU10c as a signal Y. This signal is memorized in a memory 10e as the correcting value or zero point and the system is constituted so that this operation is carried out whenever the start switch 11 is closed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a position detection device for a variable displacement mechanism that detects the position (tilting amount) of a variable displacement mechanism provided in a hydraulic pump. To achieve this, a device η that electrically controls the discharge amount of a hydraulic pump used in various hydraulic machines and hydraulic devices has been proposed and used. In such a control device, the position of the variable displacement mechanism of the hydraulic pump is automatically detected, and control is performed using the signal. In this case, the position of the displacement displacement mechanism of the hydraulic Honda,
It is necessary to accurately correspond to the signal of the detector that detects it. For this reason, the control device for the hydraulic pump uses a zero point correction circuit that finds the origin (zero point) of the variable displacement mechanism of the hydraulic pump and corrects the signal of the detector.

FIG. 1 is a system diagram of a hydraulic circuit and an electric circuit of a position detection device of a variable displacement mechanism for a hydraulic □ pump equipped with a zero point correction circuit.

In the figure, l is a variable displacement cedar hydraulic pump (hereinafter simply referred to as a hydraulic pump), and la is a displacement variable mechanism of the hydraulic pump l. The variable displacement mechanism 1a has a swash plate, a slant shaft, etc., which are operated by a hydraulic pump 1, and in the following explanation, the swash plate will be used as a representative. 2 is a regulator that drives and operates the swash plate 1a according to an input electric signal; 3 is a swash plate 1a;
It is a position detector that detects the position of , and is composed of a potentiometer temple. The position detector 3 is mechanically coupled to the swash plate 1a and outputs a signal according to the position of the swash plate 1a. 6 is a θ point correction circuit for correcting the 0 point of the position detector 3, and is composed of a variable resistor 6a and an addition circuit 6b. The zero point correction and the zero point correction circuit 6 will be described later. Reference numeral 4 denotes an operating lever for instructing the discharge position of the hydraulic pump 1, and outputs a signal corresponding to its operation. 5
is a control device that outputs a control signal 46 to the regulator 2 based on a signal 4g from the zero point correction circuit 6 and a signal from the operating lever 4, and this control signal causes the position of the swash plate 1a to be adjusted to the position indicated by the operating lever 6. control to match.

7 is a flow meter that measures the discharge amount of the hydraulic pump l.

Here, the 0 point correction and O point correction circuits will be described.

Since the position detector 3 detects the position of the swash plate 1a, the origin of the hydraulic pump, that is, the 0 point of the swash plate 1a, and the corresponding signal output from the position detector 3 at that time, for example, ov, are the same. must be in place. However, the swash plate 1a and the position detector 3 are mechanically coupled, and the swash plate 1a and the position detector 3 are connected mechanically. It is extremely difficult to combine the points and the corresponding signals (OV) so that they perfectly match.

However, if there is a mismatch between the 0 point of the swash plate 1a and the signal of the position detector 3, the signal of the position detector 4 becomes the (J point signal) even though the swash plate 1a is not at the 0 point position, and the control device 7 Control is performed using the position of the swash plate 1a as a point, and as a result, even though the operating lever 4 is at the maximum Mtjt position, that is, the discharge of the oil pump 1 does not reach the set maximum value. Despite the instructions, the actual swash plate 1a.
Saeki' does not reach the maximum flow point, and the maximum flow rate of the hydraulic pump l is insufficient, or excess pressure oil is discharged. In this case, if the maximum flow rate is not enough, the actuator will not be able to achieve the desired performance, and if there is an excess flow rate, a large amount of pressure oil will have to be discarded, resulting in energy loss, or it will be difficult to drive the pump. The motor load becomes larger than the set value, causing a situation such as engine stoppage, which has an undesirable effect on operability, control, etc.

Therefore, in the conventional device, a zero point correction circuit 6 is provided to correct the mismatch between the neutral point of the swash plate 1a and the corresponding signal from the position detector 3. That is, a signal corresponding to the deviation between the signal that should be output when the swash plate 1a is at the 0 point and the signal that is actually output is generated by the variable resistor 6a, and the position is detected by the Ig full adder circuit 6b. Correction is performed by adding power to the output signal of the device 3. Therefore, the %&l 800 points and the 1st number inputted into the control device 7 accordingly match, and the above-mentioned drawbacks are eliminated.

The correct value indicated by the variable resistor 6a of the zero point correction circuit 6 is set as follows. That is, first, the hydraulic pump llr is driven by the IM engine, and the operating lever 4 is set to the O position. In this state, the discharge violet of the Y...pressure pump 1 is set to the IT side using the flowmeter 7, and the variable resistor 6a is adjusted to A so that the current corresponds to the 0 position, that is, so that the swash plate 1a is at the 0 point. . The value of the variable resistor 6a at this time becomes a value corresponding to the above-mentioned provisional safety.

However, it is extremely cumbersome to manually adjust the variable resistor 5a, and as the number of units increases, the trouble increases proportionally. Such adjustments must be made by equipping the hydraulic pump with a flow meter (for example, it would be necessary to intervene in the manufacturing process before shipping, which is obviously undesirable. Even if the swash plate 1a and the position sensor 3 are sold together, discrepancies may occur due to drift of the zero point correction circuit 5 due to subsequent temperature changes or changes in the joint between the swash plate 1a and the position detector 3 over time, so constant monitoring and adjustment is required. , and the effort required for this is enormous.

The present invention has been made in view of the above circumstances, and its purpose is to solve the above-mentioned conventional problems and to constantly and accurately detect the position of the variable displacement displacement structure of a hydraulic pump. The object of the present invention is to provide a position detection device for a displacement variable mechanism that can control the operation rate of a γ output pump.

In order to achieve this object, the present invention moves the variable displacement mechanism of a hydraulic pump to a predetermined reference position, and the position of the variable displacement mechanism when the variable displacement mechanism moves to this reference position. The detected value of the detector that detects the IH is taken out, a correction value is obtained based on this first shift, and the detected value by the detector when the oil outlet pump is unloaded is fixed by the relevant IH positive value. It is characterized by what it did.

Hereinafter, the present invention will be explained based on illustrated embodiments.

FIG. 2 is a schematic diagram of the swash plate position detection device according to the first embodiment (f) of the present invention. In the figure, the same parts as those shown in FIG. 1 are given the same reference numerals. The regulator 2 includes a cylinder 2a1, a piston 2b, a magnet 5P2C12d, and an oil outlet pipe connecting these. The cylinder 2a has W 2 al, 2a2 on both sides of the piston 2b.
The cross-sectional area of the chamber 2a1 is larger than the cross-sectional area of the chamber 2a2. Therefore, the chamber 2a of the piston 2b,
The pressure receiving area on the side is larger than the pressure receiving area on the chamber 2a2 side. A swash plate la is connected to the piston 2b, and when the piston 2b moves in the direction of the arrow, the swash plate ia moves in the direction that maximizes the discharge amount of the hydraulic pump l (Max direction), and the piston 2b moves in the direction of the arrow. When the swash plate 1a moves in the B direction, the swash plate 1a moves in the direction (Man direction) that minimizes the discharge noise of the oil pump l.
The ti valve 2C12d is in the upper position shown in the figure in the OfI''F state, and is switched to the lower position shown in the figure in the OIN state.8
is a hydraulic gallery, and 9 is a tank.

Here, before explaining the configuration of other parts of this embodiment, the operation of the regulator 2 will be explained. Solenoid valve 2C12dtl
- When the state is set to OIII'I11, chamber 2a is replaced by tank 9.
2at is connected to the hydraulic power source 8, the piston 2b is moved in the direction of arrow B, and the swash plate 1a is moved in the Min direction. Next, when the switching valve 2C12d is set to the OIN state, the chamber 2
a1 and 2a2 are connected to the hydraulic power source 8, and due to the difference in their pressure receiving areas, the piston 2b is moved in the direction of the arrow, and the swash plate 1a
moves in the Max direction.

Furthermore, when the solenoid valve 2C is set to the (JFFF state) and the solenoid valve 2d is set to the OIN state, the chamber 2a is shut off, so
The piston 2b moves, and the Asahi plate 1a stops at that position.

We now return to the description of the configuration of this embodiment. IO is controlled by a control device using a microconbeater.

The open side 1!1klU is a multiplexer io a which sequentially switches and inputs the lever from the operating lever (b order value A/LJ converter 10
b) A ROM (read-only memory) that records the control unit III for executing the required control.
10d, RAM that temporarily stores input values, values, etc.
(Random access memory) lOe, mX, digital output ■o r that outputs the obtained 71II11i14I key signal to the dL cicada valves 2c and 2d, and the state of the start switch 11, which will be described later. It consists of 10 g of digital inputs. When the start switch 11 is opened (or opened), the position detector 3
It instructs the control device ii 10 to correct the pump tilt itY detected in . A stopper 12 limits the movement of the swash plate 1a and stops the swash plate 1a at a predetermined reference position. In this embodiment, the swash plate position that minimizes the discharge lid of the hydraulic pump l is selected as the reference position. Therefore, the swash plate 1a is the stopper 1
2 and is in the seventh reference position, the pump 1 rotation amount Y output from the detector 3 should be O.

Next, the operation of this embodiment will be explained in detail with reference to the flowcharts shown in FIGS. 3 and 4. When the operating lever 4 is turned into a lever, the switch Y of the position detector 3 is stored at a predetermined address of the A tvt 10 e via the multiplexer ILI a and the /υ shaker ILI b ( Hand 1 bile a). At the same time, the state of the start switch 11 is read and it is determined whether it is ON or OFF (manual b). If the start switch 11 is set to 'lI' at υ and the controllers It and lO are not instructed to execute the shaft stop, the process goes to jμC and the timer is cleared (set to 0). Here, this timer is used in the information procedure l-f described later, and as a timer) L A
A predetermined address of tV io e is used, and the time is measured by rewriting the value of that address every time a certain period of time elapses. Next, from the input pump tilt amount Y, 0
Tsukuda positive value Y. Determine the corrected and accurate pump resistance value Y' by subtracting (step d). This 0 sleeve positive value Y. is a value calculated and stored by a correction procedure f described later. Next, the process starts with the pump tilt servo routine (step e
).

The procedure of this pump tilt servo routine is shown in FIG. After setting the pump tilt jitY' in step d, take out the lever command value X from RA IVL Kl e, and calculate the deviation ΔY (ΔY==X -Y') (step e-1).

Next, in order to match the pump tilt amount to the lever command value, it is determined whether the deviation ΔY is positive or negative (step e-2). Deviation ΔY
If it is determined that is positive, the digital output O1 outputs a signal that turns the valve 2C12d into the OIN state, and the diagonal & l a t-Max directions move (step e-3). . When it is determined that the deviation ΔY is O, the solenoid valve 2C is turned OFF from the digital output 10 f.
A signal that turns on the solenoid valve 2d is output, and the swash plate 1a
is stopped at the current position (step e-4). Deviation ΔN
is determined to be negative, the digital output 10 f
A signal is output to turn on the solenoid valves 2c and 2d, and the swash plates move in the same direction (step e-5).
).

When any one of steps e-3, e-4, and e-5 ends, the process returns to step a, and the same process is repeated thereafter.

When it is determined that the start switch] 1 is in the closed state, the processing increases by 4 to the correction step f. First, electric (
A signal that sets the valves 2c and 2ct to the (JII'l' state) is output from the digital output 10f, and the plate 1a is moved in the tvlin direction (step f-1) to fit the stopper 12. Next, look at the value of the timer explained in + order C. That is, itA which is added by 1 every fixed time
It is determined whether the value of the predetermined address of MIOe is greater than or equal to a certain set value (f-2).

Here, this set value is selected to be the appropriate time for the swash plate 1a to come into contact with the stopper 12, taking into consideration the moving speed of the swash plate 1a. If the set value has not been reached, the process moves to step f-3, where the value of the predetermined address is set to 1.
is added, the process returns to step a, and the same operation is repeated thereafter. That is, the fixed time period for adding 1 to the value of the predetermined address is the time required to execute the processes of steps a, b1f-1, f-2, and f-3.

At hand +11f-2, the value of the timer, i.e.)1. A.M.
If it is determined that the value of the predetermined address of loe is greater than or equal to the set value, the process moves to step f-4. In this case, the timer value is equal to or greater than the set value, which means that the swash plate 1a contacts the stopper 12, the pump tilting becomes the minimum, and the pump tilting MY output from the position detector 3 becomes O. It means that there is. Therefore, in step f-4, the pump tilting -iY at this time is taken out, this is set as the O correction value Yo, and this value is stored at a predetermined address in the RAM 10e.

If the extracted pump tilt amount Y is 0, the position detector 3 is outputting a signal that accurately corresponds to the position of the swash plate 1a, but if the pump tilt iY is a certain value, If so, the difference will be by that value. Therefore, the pump tilt iY is the correction value Y. , if used in the calculation in ten fil d mentioned earlier, swash plate 1
Even if the connection between a and the position detector 3 is slightly misaligned, the hydraulic pump l can be accurately controlled. Correction value Y. Once stored, the process returns to step a, and the same operation is repeated thereafter.

In the above explanation of the operation, the swash plate 1a is securely moved to the stopper 12.
Although an example has been described in which a timer is used to bring the object into contact with the object, this can be done without using a timer. This operation will be described in detail in the flowchart shown in FIG. Since the steps IIa%b and d%e are exactly the same as the procedure shown with the same reference numerals in FIGS. 3 and 4, their explanation will be omitted. If the start switch 11 is already in the step (JN), the correction step g is executed. In the step g-1, the same as the step f-1 shown in FIG.
A process is performed to move a in the n direction so as to abut the stopper 12 (step g-1). Next, the pump tilting lid that was taken in step a in the previous process (this value is
, and so on. ) is the same as the pump tilt iY taken in step a in the current process (step g-2). If the tilting amounts Y, , Y of both pumps are equal, then the swash plate 1a has moved according to the process of step g-1, and if the tilting amounts Y, , Y of both pumps are equal, the swash plate 1a
It can be determined that a has come into contact with the stopper 12 and is stopped. In addition, the previous pump tilt itY+ was KAM
10e at a predetermined address.

If it is determined in step g-2 that the two pump tilting amounts Y, , Y are not equal, the process moves to the next step, and the current pump tilting amount Y is set as the previous pump tilting amount Y, as described above. to RA
Store in M 10 e (move 1 [h).

The process then returns to step 11a and the same procedure is repeated. If it is determined that both pump tilting amounts Y, Y are equal at hand += g -2, that is, swash plate 1
When a comes into contact with the stopper 12, the process moves to step g-3, where the pump tilting amount Y at that time is stored as a correction value Yo, and the process proceeds to step d, similar to hand 1m f-4 shown in FIG. It is used for calculations and contributes to accurate control of the hydraulic pump l. Once the correction value Yo is stored, the process proceeds to step a.
It was decided that the same action would be repeated.

As described above, in this embodiment, the swash plate position that minimizes the discharge amount of the hydraulic pump is set as the reference position 1, and when the start switch is closed, the swash plate is moved to the reference position, and the swash plate at that time is The pump from the position detector on the board caused the ghost to appear around 1...To be honest, 6 people 1. Since the bong tilting position from the rlBl water ratio pump control temporary position detector was made to be fixed at the corrected value, the value of the temporary position detector was self-restraint corrected,
The swash plate position can be detected accurately at all times, and the hydraulic pump can be moved to the secondary side 1j with good accuracy. Moreover, it is possible to eliminate the need to adjust the connection between the swash plate and the position detector to the correct value when using the product tlL1.

FIG. 6 is a diagram of a swash plate position detection device according to a second embodiment of the present invention. In the figure, parts that are the same as those shown in FIG. 2 are given the same reference numerals, and explanations thereof will be omitted. 13c swash plate 1a
It is a limit switch that produces an output when pressed. The limit switch 13 is the same as the stopper 12 shown in FIG.
The swash plate 1a is installed with a hydraulic pump l.
It is provided at a position that generates an output when the position where the discharge amount of is minimized is reached.

Next, the operation of this embodiment will be explained with reference to the flowchart shown in FIG. Steps a, b, d.

Regarding e, see the 3rd I! ! ! , l and hand) l shown with the same reference numerals in FIG. 4, so the explanation will be omitted.

+11 shell already starts 4 Tsuchi 11 is judged to be (JN), Sensho hand 1k i is laughed out. Masu, 3rd
In the same way as +1lji f -1 shown in the figure, the swash plate 1a should be pushed out to the limit switch 13 (processing to make it move # in the Min direction (procedure 1-1). Next, the limit switch 13 becomes (JN). Swash plate 1a
pushes limit switch 13, and limit switch 1
Determine whether or not output is generated from step 3 (hand 1k i
-2). When no output is generated from the limit switch 13, the process returns to step a. If an output is generated from the limit switch 13 with the hand j-i-2, the output will be output from the n-field 1. That is, when the swash plate 1a is at the reference position and the limit switch 13 is pushed out, the process will be in step 1- Moving on to step 3, similarly to +111tf -4 shown in Fig. 3, the pump Y at that time is stored as the correction value Y0, and one move is 11m.
It is used for calculations in step d and enables accurate control of the hydraulic pump l. Once the correction value Yo is memorized, the process proceeds to step II.
Returning to step a, the same operation is repeated.

As described above, in this embodiment, the swash plate is set to the all reference positions that minimize the discharge value of the hydraulic pump, and when the start switch is closed, the swash plate is moved toward the reference position, and the swash plate is moved to the reference position. The limit switch detects that the position has been reached, and the pump 'IIJi from the position detector of the swash plate at that time is detected.
1. Since the buoy rotation amount from the position detector is memorized as 1 turn lid full sleeve stop hani and the pump buoy rotation amount from the position detector is corrected by the corresponding correction value when controlling the hydraulic pump, the same effect as the previous example '/I: It is something to do.

In addition, in the above explanation of the valley embodiment, the swash plate position that minimizes the discharge amount of the hydraulic pump is set as the reference position, but the reference position is not necessarily limited to such a position, and can be set as the reference position. It is possible to set the swash plate position where the discharge lid is at its maximum, or both positions, or if a limit switch is used, an intermediate position can be set as the reference position. . In these cases, the difference between the determined detection value of the position detector and the actual detection value becomes the correction value. Furthermore, although the lever command value good. Furthermore, the start switch can be configured to be used not only as a manual switch but also as another switch.

? I use this as the engine start switch and MK.
Misuse can be corrected by correcting the engine start point, and erroneous running caused by the contact between the swash plate and the position detector can be overcome by a light sound.

As described above, in the present invention, the swash plate is moved to the reference position of %T, and the swash plate position detector detects 11 at the time of 7.
We determined the correction +m based on the value, and used this correction value to correct the detection 11k detected by the slant & permanent shifter when controlling the hydraulic pump, so the position of the swash plate of the hydraulic pump was It is possible to accurately discharge the engine, and in turn, the hydraulic pump can be controlled 111f. Furthermore, it is important to avoid having to accurately adjust the connection between the swash plate and the detector when shipping the product.

[Brief explanation of the drawing]

FIG. 1 is a diagram of a conventional swash plate position detection device, FIG. 2 is a thread trajectory diagram of a swash plate position detection device according to a first embodiment of the present invention, FIGS. 3, 4, and Figure 5 is the figure shown in Figure 2]
Table 1 is a flowchart to explain the entire operation of the pupil, Section 6 1 is the diagonal mark related to the husband arrangement of the invention 2, and the location of the position detection device, Fig. 7 is shown in Fig. 6 A flowchart is provided to explain the operation of the control device. ■・・・Hydraulic pump, la・・・・・・Additional plate,
2...Reculator, 3...Position sideways (
1) Device, 4... Operating lever, 10...
Control iron tube, 1 (Ja...Multi-breather, 10
b...Al1) Converter, 10C...C
t-'U, lOd... Hill 01VI, lOe...
...KAiJIUf...Digital output,
10 g...Digital input, 11...
・・Start switch, ] 2 ・・・・・・・・・・・・・・Start switch, 1
3...Micro switch.

Claims (1)

[Claims] A hydraulic pump equipped with a variable displacement mechanism and a position detector for detecting the position of the variable displacement mechanism, a moving means for moving the variable displacement mechanism to a predetermined reference position; and a correction means for correcting the detection value of the position detector when controlling the oil pump based on the detection value of the position detector when the displacement volume variable mechanism moves to the reference position. Features: Position detection device for variable displacement mechanism.