WO2013010320A1

WO2013010320A1 - Hydraulic variable pump and displacement control method thereof

Info

Publication number: WO2013010320A1
Application number: PCT/CN2011/077330
Authority: WO
Inventors: 程宇; 王晶; 帕特森查德
Original assignee: 上海萨澳液压传动有限公司
Priority date: 2011-07-19
Filing date: 2011-07-19
Publication date: 2013-01-24
Also published as: CN104136775B; CN104136775A

Abstract

A hydraulic variable pump. The hydraulic variable pump has a swashplate (10) and a servo piston (12) connected to the swashplate. The swashplate adjusts an inclined angle thereof through motion of the servo piston, so as to change the displacement of the hydraulic variable pump. The hydraulic variable pump further comprises an electromagnetic servo valve (20). The electromagnetic servo valve converts an input electric signal into a hydraulic signal and outputs flow to the servo piston; the servo piston then inclines the swashplate. The electromagnetic servo valve is formed of a rotary electromagnetic solenoid (1) and a servo rotary valve (15). Linkage is formed between an output shaft of the rotary electromagnetic solenoid and a spool (2) of the servo rotary valve. When the output shaft of the rotary electromagnetic solenoid rotates, the spool of the servo rotary valve is driven to rotate. Also disclosed is a method using the hydraulic variable pump to perform electrical displacement control and forward/neutral/reverse control.

Description

Hydraulic variable pump and its displacement control method

Technical field

The invention relates to the technical field of hydraulic transmission, in particular to a hydraulic variable pump and a displacement control method thereof. Background technique

The hydraulic pump and the hydraulic motor constitute an energy conversion device in the hydraulic system. The former converts the mechanical energy of the prime mover into the hydraulic energy of the liquid; the latter converts the hydraulic energy into a mechanical energy output to perform the required action. The hydraulic motor is a hydraulic actuator that achieves continuous rotary motion.

Functionally, hydraulic pumps have two types of variable displacement and non-variable displacement. The variable displacement hydraulic pump can output different flows at the same speed as required. This type of pump is called a variable pump. The traditional hydraulic variable pump's electric proportional displacement control (EDC) and / or forward / neutral / reverse three-position control (FNR) use two linear electrical devices or servo valve type devices to drive displacement control.

However, there is a need to further simplify the mechanism for changing the displacement of the EDC and FNR controls described above, and to make it easy to design hardware compatible with mechanical displacement control (MDC). Summary of the invention

It is an object of the present invention to address at least one of the above problems and deficiencies in the prior art.

Accordingly, it is an object of the present invention to provide a hydraulic variable displacement pump that performs displacement control through an integrated rotary electromagnetic servo valve.

In one aspect of the invention, there is provided a hydraulic variable pump having a swash plate and a servo piston coupled to the swash plate, the swash plate adjusting an inclination angle thereof by movement of the servo piston And thereby changing the displacement of the hydraulic variable pump, the hydraulic variable pump further comprising: an electromagnetic servo valve that converts the input electrical signal into a hydraulic signal and outputs a flow rate to the servo piston, and further a servo piston that tilts the swash plate; the electromagnetic servo valve is composed of a rotating electromagnetic solenoid and a servo rotary valve, and an output shaft of the rotary electromagnetic solenoid is linked with a spool of a servo rotary valve, when Rotating the output of the electromagnetic solenoid When the shaft rotates, the spool of the servo rotary valve is excited to rotate.

In one embodiment, the rotating electromagnetic solenoid is a rotating bi-directional proportional electromagnetic solenoid for performing electrical proportional displacement control of the hydraulic variable pump in both forward and reverse directions.

Specifically, the hydraulic variable pump further includes an angle feedback mechanism, the servo rotary valve further includes a valve sleeve, the valve sleeve is rotated relative to a sleeve fixed in a casing of the hydraulic variable pump, and the angle feedback mechanism is connected Valve sleeve and swashplate.

Further, the angle feedback mechanism senses an offset of the swash plate from a preset position, and excites the servo rotary valve according to the offset and controls movement of the servo piston by flow to keep the swash plate at Its predetermined setting position.

In one embodiment, the servo rotary valve is coupled to the swash plate by the angle feedback mechanism when performing electrical proportional displacement control.

Specifically, the servo rotary valve has a return spring, and the return spring performs an automatic returning function and a proportional control function of the spool of the servo rotary valve when the input signal is missing.

In another embodiment, the rotating electromagnetic solenoid is a rotary two-way electromagnetic solenoid for three-position control of forward/neutral/reverse of the hydraulic variable pump.

Alternatively, when the forward/neutral/reverse three-position control is performed, the servo rotary valve and the swash plate are not connected by a feedback mechanism.

Specifically, the servo rotary valve has a return spring, and the return spring performs an automatic returning function of the spool of the servo rotary valve when the input signal is missing.

Additionally, the swash plate is coupled to the servo piston by a slider.

Specifically, the servo rotary valve is a spring-returned 3-position 4-way servo rotary valve.

Preferably, the hydraulic variable pump is an axial piston variable pump.

Preferably, the output shaft of the rotary electromagnetic solenoid and the valve core of the servo rotary valve are directly fixedly connected.

Preferably, the spool and the valve sleeve of the servo rotary valve are sealed by a seal ring and an O-ring.

Another object of the present invention is to provide a technical solution for performing electrical proportional displacement control of a hydraulic variable pump using a rotating bi-directional proportional electromagnetic solenoid.

According to another aspect of the present invention, there is provided a method of performing electrical proportional displacement control using a hydraulic variable pump according to the above, wherein the rotating electromagnetic solenoid is a rotating two-way proportional electric power a magnetic solenoid, the servo rotary valve is a spring-returned servo rotary valve, and the method comprises the following steps:

The output shaft of the rotating bi-directional proportional electromagnetic solenoid generates a positive angle-torque output proportional to the control current signal upon receiving a positive control current signal;

Rotating the output shaft of the rotating bi-directional proportional electromagnetic solenoid and the spool of the servo rotary valve in proportion to the forward angle-torque output, whereby the servo rotary valve outputs and the forward angle - torque output proportional flow to the servo piston, proportionally moving by the servo piston, thereby tilting the swash plate proportionally, thereby achieving positive displacement control of the hydraulic variable pump;

When the control current signal is missing, the spring-returned servo rotary valve resets the swash plate to a neutral position, thereby realizing that the hydraulic variable pump is in a neutral position;

An angle-torque output of an output shaft of the rotating bi-directional proportional electromagnetic solenoid, a rotational angle of the rotating bi-directional proportional electromagnetic solenoid and the spool, and a servo to the servo when a reverse control current signal is input The output flow of the piston will also be reversed, whereby the movement of the servo piston will also be reversed, causing the swash plate to tilt proportionally in the negative direction, thereby achieving negative displacement control of the hydraulic variable pump.

Specifically, the hydraulic variable pump further includes an angle feedback mechanism, wherein the servo rotary valve is connected to the swash plate through the angle feedback mechanism, and the angle feedback mechanism senses an offset of the swash plate from a preset position. Exciting the servo rotary valve according to the offset and controlling the movement of the servo piston by the flow rate to maintain the swash plate at its predetermined set position.

It is still another object of the present invention to provide a three-position control for forward/neutral/reverse three-position control of a hydraulic variable pump using a rotary two-way electromagnetic solenoid.

According to still another aspect of the present invention, there is provided a method of performing forward/neutral/reverse three-position control using a hydraulic variable pump according to the above, wherein the rotary electromagnetic solenoid is a rotary two-way electromagnetic solenoid, the method Includes the following steps:

Upon receiving a positive electrical input signal, the output shaft of the rotating bi-directional electromagnetic solenoid produces a positive maximum angle-torque output;

Rotating an output shaft of the rotating bidirectional electromagnetic solenoid and a spool of the servo rotary valve to a maximum direct angle;

The servo rotary valve outputs a positive maximum flow to the servo piston to make the servo piston position Move to the positive maximum position;

The servo piston tilts the swash plate to a forward maximum position to achieve a positive maximum displacement of the hydraulic variable pump;

Resetting the swashplate to a neutral position by using a servo rotary valve having a return spring or using an electrical input signal such that the hydraulic variable pump is in a neutral position;

An angle-torque output of the output shaft of the rotary bidirectional electromagnetic solenoid, the rotary bidirectional electromagnetic solenoid, and the spool when a reverse electrical input signal is input to the rotary bidirectional electromagnetic solenoid The angle of rotation and the output flow to the servo piston will also be reversed, whereby the servo piston is displaced to a negative maximum position such that the swashplate is tilted to a negative maximum position, thereby achieving a negative maximum of the hydraulic variable pump Displacement.

Specifically, the servo rotary valve and the swash plate are not connected by a feedback mechanism. The present invention creatively proposes a new concept of integrated rotary electromagnetic servo for hydraulic variable displacement pump control. The use of a rotating electromagnetic solenoid and a servo rotary valve for displacement control of the hydraulic variable pump greatly simplifies the operation of the EDC and FNR controls. Further, by adopting the above technical solution, the present invention makes it easier to design hardware compatible with the mechanical displacement control. The device of the present invention is compact in size and achieves the same function while reducing the number and complexity of parts, and is therefore less susceptible to part tolerances. DRAWINGS

These and/or other aspects and advantages of the present invention will become apparent and readily understood from

1 is a perspective view of a hydraulic variable pump in accordance with an embodiment of the present invention;

Figure 2 is a front elevational view of the hydraulic variable pump of Figure 1;

Figure 3A is a cross-sectional view taken along line A-A of Figure 2; and

Fig. 3B is a cross-sectional view taken along line B-B in Fig. 2. detailed description

The technical solution of the present invention will be further specifically described below by way of embodiments and with reference to FIGS. 1-3B. In the specification, the same or similar reference numerals indicate the same or similar parts. The following description of embodiments of the invention with reference to the accompanying drawings is intended to The explanation is not to be construed as a limitation of the present invention.

Referring to Figure 1, a hydraulic variable pump in accordance with an embodiment of the present invention is shown. In the present embodiment, the hydraulic variable pump is an axial piston variable pump. In view of the innovation of the present invention in that a new displacement-reducing mechanism is used for EDC and/or FNR control, the hydraulic variable pump of the present invention may also be a swash plate type axial piston pump or a slant shaft type shaft. Pump to the plunger, etc.

Referring to Figures 2, 3A and 3B, a swash plate type axial piston pump in accordance with an embodiment of the present invention is illustrated. Specifically, the swash plate type axial piston pump has a swash plate 10 and a servo piston 12 connected to the swash plate 10, and the swash plate .10 adjusts the inclination angle thereof by the movement of the servo piston 12, thereby changing the position The displacement of the swash plate type axial piston pump. The swash plate type plunger pump further includes: an electromagnetic servo valve 20 that converts an input electrical signal into a hydraulic signal and outputs a flow rate to the servo piston 12, and the servo piston 12 causes the slant The disk 10 is tilted. Wherein: the electromagnetic servo valve 20 is composed of a rotary electromagnetic solenoid 1 and a servo rotary valve 15, and the servo rotary valve 15 is composed of a spool 2 of a servo rotary valve and a valve sleeve 3 of a servo rotary valve, and the rotary electromagnetic The output shaft of the solenoid 1 is interlocked with the spool 2 of the servo rotary valve, and when the output shaft of the rotary electromagnetic solenoid 1 is rotated, the spool 2 of the servo rotary valve is excited to rotate.

3A and 3B, the output shaft of the rotary electromagnetic solenoid 1 and the valve core 2 of the servo rotary valve are directly fixedly connected, and the spool 2 and the valve sleeve 3 of the servo rotary valve are sealed by the seal ring 6 and the 0-ring 7 . The swash plate type axial piston pump includes a casing 13, a valve sleeve 3 of the servo rotary valve is moved relative to the sleeve 4, and the sleeve 4 is fixed to the outer casing 13. An angle feedback mechanism (such as a feedback link) 5 connects the valve sleeve 3 of the servo rotary valve and the swash plate 10. The swash plate 10 is connected to the servo piston 12 in the servo cylinder 11 via the slider 9. The servo piston 12 is positioned in the servo cylinder 11 by a servo spring 8.

The following describes in detail how the swash plate type axial piston pump of the present invention performs EDC control operations:

When the EDC control is performed, the rotating electromagnetic solenoid 1 is a rotating bidirectional proportional electromagnetic solenoid. When the rotating bi-directional proportional electromagnetic solenoid 1 receives the control current signal, it has an angle-torque output proportional to the control current signal. Since the spool 2 of the servo rotary valve is directly fixedly coupled to the output shaft of the rotary bidirectional proportional electromagnetic solenoid 1, it rotates together with the output shaft of the rotary bidirectional proportional electromagnetic solenoid 1. The rotation of the spool 2 of the servo rotary valve opens the hydraulic port of the valve sleeve 3 of the servo rotary valve. The spool 2 of the servo rotary valve and the valve sleeve 3 of the servo rotary valve are the same. It is a 3-position 4-way servo rotary valve that constitutes a spring return. In the present invention, specifically, the 3-position 4-way servo rotary valve includes a return spring or a return torsion spring (not shown) that interacts with the spool 2. The return spring is used to realize the automatic return function and proportional control function of the spool 2 in the absence of the input control current signal during EDC control. Therefore, the control current signal is converted into a hydraulic pressure signal by the spring-returned 3-position 4-way servo rotary valve 15, and the flow rate is output to the two sides of the servo piston 12 through the 3-position 4-way servo rotary valve 15, and the servo piston is caused by the pressure. 12 linear motion. The servo piston 12 tilts the swash plate 10 by the slider 9, thereby changing the displacement of the hydraulic variable pump from the neutral position to the forward position. When the normal operating force changes, the swash plate 10 is easily offset from a preset position. The offset sensed by the feedback link 5 energizes the 3-position 4-way servo rotary valve 15 and supplies flow to the servo piston 12 to maintain the swash plate 10 in its forward, predetermined position. Specifically, when the swash plate is displaced, since the feedback link 5 is fixedly connected to the swash plate 10, the positional deviation of the swash plate 10 is fed back to the valve sleeve of the 3-position 4-way servo rotary valve through the feedback link 5. 3. When the valve sleeve 3 is rotated by a certain angle, the spool 2 also rotates, and the flow rate outputted to both sides of the servo piston 12 changes until the opening between the spool 2 and the valve sleeve 3 is closed, thereby realizing Balanced state. That is, the servo piston 12 and/or the swash plate 10 are returned to the preset displacement position.

Because the rotary proportional electromagnetic solenoid 1 provides the output flow to the servo piston 12 through the spool 2 of the servo rotary valve, the torque generated by the spring force and the input torque signal can be generated by the action of the three-position four-way servo-turned return spring. Proportional to achieve proportional displacement control. The larger input signal causes a greater spring torque, and in turn corresponds to the larger angle of rotation of the servo spool 2, then increasing the input signal will increase the input flow to the servo piston 12 and change the angle of the swash plate 10, Until the maximum displacement is achieved.

Of course, if the current signal is reversely controlled, the spool 2 of the servo rotary valve will rotate in the reverse direction, and the output of the rotary bidirectional proportional electromagnetic solenoid 1 and the output flow to the servo piston will also be reversed, which causes the swash plate to be changed to Negative position. Similar to the manner of achieving the maximum forward displacement as described above, with the increase of the reverse control signal and the change of the swash plate angle until the maximum negative direction can be achieved, the rotary bidirectional proportional electromagnetic solenoid 1 of the present invention Electrical proportional displacement control of the hydraulic variable pump can be achieved.

In addition, it should be noted that, when performing FNR control, the rotating electromagnetic solenoid 1 It is selected to rotate the two-way electromagnetic solenoid, and the swash plate 10 is not connected to the valve sleeve 3 of the servo rotary valve 15 through the feedback link 5. The other structure of the swash plate type axial piston pump is the same as that of the above-described swash plate type axial piston pump when performing EDC control.

The following describes in detail how the swash plate type axial piston pump of the present invention performs the FNR three-position control operation:

When the rotating bidirectional electromagnetic solenoid 1 receives an electrical input signal, it produces a positive maximum angle - torque output. Since the spool 2 of the servo rotary valve is directly connected to the output shaft of the rotary bidirectional electromagnetic solenoid 1, it rotates to the positive maximum angle together with the output shaft of the rotary bidirectional electromagnetic solenoid 1. Therefore, since the operating electric input signal of the spring-returned 3-position 4-way servo rotary valve 15 is converted into the hydraulic pressure signal, the 3-position 4-way servo rotary valve 15 outputs the maximum hydraulic flow to both sides of the two-way acting servo piston 12 due to The pressure difference across the servo piston 12 is maximized, causing the servo piston 12 to shift to the positive maximum position. The servo piston 12 tilts the swash plate 10 to the forward maximum position by the slider 9, so that the hydraulic variable pump (i.e., the swash plate type axial piston pump) achieves a positive maximum displacement. Similarly, the input signal reversely input to the rotary bidirectional electromagnetic solenoid 1 can achieve the negative maximum displacement of the swash plate type axial piston pump. The input signal is removed. Due to the action of the return spring of the servo rotary valve 15, the pressure on both sides of the servo piston 12 is equal, and the swash plate 10 is reset to the neutral position, which will realize the neutral position of the pump. gP, when the FNR control of the hydraulic variable pump is performed, the return spring of the servo rotary valve 15 can perform the automatic returning function of the spool 2 of the servo rotary valve 15 when the electric input signal is omitted. Therefore, the FNR control of the hydraulic variable pump can be realized by the rotary two-way electromagnetic solenoid 1.

Of course, it can be understood that, when the FNR three-position control is performed, the servo rotary valve 15 may not be provided with a return spring, and in this case, the corresponding input signal can be used to reset the swash plate 10 to the neutral position, thereby The hydraulic variable pump is in the neutral position.

In summary, the EDC or FNR control of the hydraulic variable pump can be easily realized by applying the rotary electromagnetic solenoid 1 and the servo rotary valve 15. Compared with the existing EDC control, the one rotating electromagnetic solenoid of the present invention can replace two linear electrical devices or servo valve type devices in the prior art. Therefore, the EDC, FNR operations are greatly simplified. In addition, by adopting the above technical solution, the present invention makes it easier to design hardware compatible with mechanical displacement control, and the device of the present invention is compact, and achieves the same function while reducing the number and complexity of parts. It is also less affected by part tolerances. While some embodiments of the present general inventive concept have been shown and described, it will be understood by those of ordinary skill in the art that the present invention may be modified without departing from the principles and spirit of the present general inventive concept. The scope is defined by the claims and their equivalents.

Claims

Rights request

A hydraulic variable pump having a swash plate and a servo piston connected to the swash plate, wherein the swash plate adjusts an inclination angle thereof by movement of the servo piston, thereby changing the hydraulic variable pump Displacement, the hydraulic variable pump further includes:

An electromagnetic servo valve that converts an input electrical signal into a hydraulic signal and outputs a flow rate to the servo piston, and the servo piston tilts the swash plate;

The electromagnetic servo valve is composed of a rotary electromagnetic solenoid and a servo rotary valve, and an output shaft of the rotary electromagnetic solenoid is linked with a spool of a servo rotary valve, and an output shaft of the rotary electromagnetic solenoid is rotated. When the spool of the servo rotary valve is excited to rotate.

2. The hydraulic variable displacement pump according to claim 1, wherein:

The rotating electromagnetic solenoid is a rotating bi-directional proportional electromagnetic solenoid for performing electrical proportional displacement control of the hydraulic variable pump in both forward and reverse directions. ·

3. The hydraulic variable displacement pump according to claim 2, wherein:

The hydraulic variable pump further includes an angle feedback mechanism, the servo rotary valve further includes a valve sleeve, the valve sleeve is rotated relative to a sleeve fixed in a casing of the hydraulic variable pump, and the angle feedback mechanism is connected to the valve sleeve And swashplate.

4. The hydraulic variable displacement pump according to claim 3, wherein:

The angle feedback mechanism senses an offset of the swash plate from a preset position, and energizes the servo rotary valve according to the offset and controls movement of the servo piston by flow to maintain the swash plate at its predetermined setting Fixed position.

5. The hydraulic variable displacement pump according to claim 3, wherein:

When the electric proportional displacement control is performed, the servo rotary valve is connected to the swash plate through the angle feedback mechanism.

6. The hydraulic variable displacement pump according to claim 5, wherein:

The servo rotary valve has a return spring that performs an automatic return function and a proportional control function of the spool of the servo rotary valve when the input signal is missing.

7. The hydraulic variable displacement pump according to claim 1, wherein:

The rotating electromagnetic solenoid is a rotating two-way electromagnetic solenoid for performing three-position control of forward/neutral/reverse of the hydraulic variable pump.

The hydraulic variable displacement pump according to claim 7, wherein the servo rotary valve and the swash plate are not connected by a feedback mechanism when the forward/neutral/reverse three-position control is performed.

9. The hydraulic variable displacement pump according to claim 8, wherein:

The servo rotary valve has a return spring that performs an automatic returning function of the wide core of the servo rotary valve when the input signal is missing.

10. The hydraulic variable displacement pump according to claim 1, wherein:

The swash plate is coupled to the servo piston by a slider.

11. The hydraulic variable displacement pump according to claim 1, wherein:

The servo rotary valve is a spring-returned 3-position 4-way servo rotary valve.

12. The hydraulic variable displacement pump according to claim 1, wherein:

The hydraulic variable pump is an axial piston variable pump.

13. The hydraulic variable displacement pump according to claim 1, wherein:

The output shaft of the rotary electromagnetic solenoid and the valve core of the servo rotary valve are directly fixedly connected.

14. The hydraulic variable displacement pump according to claim 13, wherein:

The valve core and the valve sleeve of the servo rotary valve are sealed by a seal ring and an O-ring.

15. A method of performing electrical proportional displacement control using a hydraulic variable displacement pump according to claim 1, wherein said rotary electromagnetic solenoid is a rotary two-way proportional electromagnetic solenoid, said servo rotary valve being spring-returned The servo rotary valve, the method comprises the following steps:

When the reverse control current signal is input, the angle-torque output of the output shaft of the rotating double proportional electromagnetic solenoid, the rotating bidirectional proportional electromagnetic! Ii tube and the rotation of the valve core The angle and the output flow to the servo piston will also be reversed, whereby the movement of the servo piston will also be reversed such that the swash plate is tilted proportionally in the negative direction, thereby achieving a negative of the hydraulic variable pump To the displacement control.

16. The method of claim 15 wherein:

The hydraulic variable pump further includes an angle feedback mechanism, wherein the servo rotary valve is connected to the swash plate through the angle feedback mechanism, and the angle feedback mechanism senses a deviation of the swash plate from a preset position, according to the The offset energizes the servo rotary valve and controls the movement of the servo piston by flow to maintain the swashplate at its predetermined set position.

17. A method of performing forward/neutral/reverse three-position control using a hydraulic variable displacement pump according to claim 1, wherein said rotary electromagnetic solenoid is a rotary two-way electromagnetic solenoid, said method comprising the steps of:

The servo rotary valve outputs a positive maximum flow to the servo piston to move the servo piston to a positive maximum position;

18. The method according to claim 17, wherein - the servo rotary valve and the swash plate are not connected by a feedback mechanism.