CN108869462A - A kind of hydraulic cushion of hydraulic press device with energy recovery function - Google Patents

Abstract

The invention discloses a hydraulic pad device for a hydraulic press with energy recovery function. The controller is connected to the control end of the servo motor, and the output shaft of the servo motor is mechanically connected to the input shaft of the internal gear pump to realize synchronous rotation; the two ends of the rectification device are respectively connected to the servo motor and the energy storage device to realize the The recovery and utilization of the electric energy output by the servo motor; one end of the internal gear pump oil circuit is connected to the hydraulic cylinder through the oil pipe to realize the oil inlet and oil return process; the other end of the internal gear pump oil circuit is connected to the oil tank through the oil pipe for Provide oil during the oil inlet process and recover oil during the oil return process. The invention has a simple mechanical transmission structure; strong low-speed loading performance; less modification to the original hydraulic system, no strict matching requirements, and strong universality; energy recovery and reuse in the production process is realized, the system temperature rises less, and the energy recovery efficiency is higher. .

Description

A hydraulic cushion device for hydraulic press with energy recovery function

technical field

The invention relates to the field of energy recovery, in particular to a hydraulic cushion device for a hydraulic press with the energy recovery function.

Background technique

In the working process of the hydraulic cylinder of the current hydraulic machine, there is a large amount of energy loss phenomenon: the motor drives the hydraulic cylinder to push the hydraulic pad upward, and after the stroke is completed, the hydraulic cylinder moves downward under the action of an external force. One way is to control the hydraulic pressure through the overflow valve, the overflowed oil enters the oil tank, causing overflow loss, the temperature of the oil in the oil tank rises, and the oil in the oil tank is cooled through the cooling system, the system is in the process of overflow loss and cooling There is energy loss in both aspects of the system; another way is to control the hydraulic pressure of the hydraulic cylinder by giving the servo motor torque to the two-way motor. The excess hydraulic pressure drives the two-way motor to rotate, converting the liquid potential energy into the mechanical energy of the rotor. By overcoming the motor torque to do work, the internal resistance of the motor Heat generation, the system still has energy loss in terms of internal resistance heating and driving the servo motor.

The current common hydraulic system energy recovery schemes, such as mechanical compensation energy recovery and hydraulic compensation energy recovery schemes, require major changes to the original hydraulic system, and there are still problems of high cost, complex structure, and installation space when facing actual engineering hydraulic equipment. Therefore, there is a need for an energy recovery device that can achieve the purpose of energy recovery, is low in cost, and requires little modification to the original hydraulic system.

Contents of the invention

The present invention aims to provide a hydraulic cushion device for a hydraulic press with energy recovery function to address the deficiencies in the background technology. The present invention has the following advantages: the mechanical transmission structure of the device is simple; the low-speed loading performance is strong; the transformation of the original hydraulic system is small, there is no strict matching requirement, and the universality is strong; the energy recovery and reuse in the production process is realized, and the temperature rise of the system is small. High energy recovery efficiency.

The technical scheme adopted in the present invention is:

The invention includes a hydraulic cylinder, an internal gear pump, a servo motor, a controller, a rectifier, an energy storage device and an oil tank: the controller is connected to the control end of the servo motor, and the output shaft of the servo motor is connected to the internal gear pump The input shaft of the internal gear pump is mechanically connected to realize synchronous rotation; the two ends of the rectification device are respectively connected with the servo motor and the energy storage device to realize the recovery and utilization of the output electric energy of the servo motor; one end of the internal gear pump oil circuit is connected to the hydraulic cylinder through the oil pipe connected to realize the oil inlet and oil return process; the other end of the internal gear pump oil circuit is connected to the oil tank through the oil pipe, which is used to provide oil during the oil inlet process and recover oil during the oil return process.

A switch is provided between the controller and the servo motor, and the switch is closed during the oil inlet process, and the controller controls the rotation of the servo motor; the switch is turned off during the oil return process, and the servo motor is driven to rotate by the internal gear pump.

During the oil intake process, the servo motor is powered by the external power grid as a motor, and the internal gear pump is driven by the servo motor to rotate as a hydraulic pump, pumping oil into the hydraulic cylinder; during the oil return process, the servo motor outputs current to the outside as a hydraulic pump. The generator and the internal gear pump are driven by the oil between the hydraulic cylinder and the oil tank as a hydraulic motor, which drives the servo motor to generate electricity in reverse.

The energy storage device is selected as a storage battery, and the DC rectified by the rectification device is charged to the storage battery for subsequent power supply.

The servo motor adopts a separately excited DC servo motor.

The servomotor is provided with an armature winding and an excitation winding inside, the armature winding and the excitation winding are not directly connected, the two ends of the excitation winding are connected to an external DC power supply U through an adjustable resistor R, and the excitation current _Ia of the excitation winding is supplied by an external DC The power supply U is provided, and the excitation current can be quickly adjusted through the adjustable resistor R to divide the voltage.

When the servo motor is used as a generator to realize the oil return process, the servo motor changes the excitation current through the improvement of the above circuit structure to control the internal electromagnetic torque, thereby controlling the hydraulic torque of the internal gear pump connected to the mechanical structure of the servo motor, and finally To achieve the purpose of controlling the constant pressure during the oil return process.

The present invention achieves: during the oil feeding process, the servo motor is powered by the power grid as a motor, and the internal meshing gear pump is driven under the action of the controller to realize the liquid feeding, and the electric energy is converted into mechanical energy and then converted into hydraulic energy; during the oil return process, the hydraulic cylinder goes down , the oil is pumped out through the internal gear pump, driving the servo motor to reverse, at this time the controller is disconnected from the servo motor, the servo motor acts as a generator, and the electric energy is rectified and then sent to the energy storage device for storage, so as to realize the return of the hydraulic pad. energy recovery.

The beneficial effects that the present invention has are:

Aiming at the energy loss generated during the working return process of the hydraulic cylinder of the hydraulic machine, including the energy loss in the form of hydraulic energy and internal energy, it can have a good recovery and reuse effect.

Compared with the energy recovery device of the traditional hydraulic system, the present invention uses the internal meshing gear pump as a hydraulic pump when rotating forward, and as a hydraulic motor when rotating reversely; at the same time, the separately excited servo motor is used as a motor when rotating forwardly, and generates electricity when rotating reversely. The characteristics of the machine, while achieving the goal of energy recovery, it also has the advantages of less impact on the modification of the original hydraulic system, lower overall cost, simple mechanical structure, and strong universality.

Description of drawings

Fig. 1 is a schematic diagram of the structure and principle of the device of the present invention, which shows the switch state and energy conversion during the oil feeding process.

Fig. 2 shows the switching state and energy conversion of the present invention during the oil return process.

Figure 3 is a schematic diagram of the inner coil of the separately excited servo motor.

In the figure, 1-hydraulic cylinder; 2-internal gear pump; 3-servo motor; 4-controller; 5-rectifier; 6-battery; 7-oil tank; 8-armature winding; 9-excitation winding.

Detailed ways

The present invention will be described in detail below in conjunction with specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

As shown in Figures 1 and 2, the present invention includes a hydraulic cylinder 1, an internal gear pump 2, a servo motor 3, a controller 4, a rectifier 5, an energy storage device 6 and an oil tank 7: the controller 4 and the servo motor 3 The control terminal is connected to control parameters such as the rotational speed of the servo motor 3 during the liquid inlet process; the output shaft of the servo motor 3 is mechanically connected to the input shaft of the internal gear pump 2 to realize synchronous rotation; the two ends of the rectifier 5 are respectively connected to the servo motor 3, The energy storage device 6 is connected, and the rectifier 5 rectifies the output alternating current to direct current through the rectifier 5 during the oil return process, so as to realize the recovery and utilization of the output electric energy of the servo motor 3; one end of the oil circuit of the internal gear pump 2 is connected with the hydraulic cylinder 1 through the oil pipe , to realize the oil inlet and oil return process; the other end of the oil circuit of the internal gear pump 2 is connected with the oil tank 7 through the oil pipe, which is used to provide oil during the oil inlet process and recover oil during the oil return process.

The input end of the rectification device 5 is connected to the servo motor 3 for rectifying the alternating current output by the servo motor 3 into direct current; the output end of the rectification device 5 is connected to the energy storage device 6 for storing and recycling the electric energy of the direct current to the energy storage device 6 in order to reuse.

In a specific implementation, the energy storage device 6 is selected as a battery, and the DC rectified by the rectifying device 5 is charged to the battery for subsequent power supply.

As shown in Figures 1 and 2, a switch is provided between the controller 4 and the servo motor 3, and the switch is closed during the oil inlet process, and the controller 4 controls the rotation of the servo motor 3; during the oil return process, the switch is disconnected, and the servo The motor 3 is driven to rotate by the internal gear pump 2 .

As shown in Figure 1, during the oil feeding process, the servo motor 3 is powered by an external power grid as a motor, and the internal gear pump 2 is driven by the servo motor 3 to rotate as a hydraulic pump to pump oil into the hydraulic cylinder 1.

As shown in Figure 2, during the oil return process, the servo motor 3 outputs current to the outside as a generator, and the internal gear pump 2 is driven by the oil between the hydraulic cylinder 1 and the oil tank 7 as a hydraulic motor, driving the servo motor 3 to reverse Forward the call.

As shown in FIG. 3 , an armature winding 8 and an excitation winding 9 are arranged inside the servo motor 3 . There is no direct connection between the armature winding 8 and the field winding 9; the armature winding 8 is connected to the external power grid during the oil inlet process, and is directly powered by the external power grid as a motor; the two ends of the armature winding 8 are used as output terminals to connect with the rectifier during the oil return process , the output current is used as a generator, and Vf represents the instantaneous motional electromotive force; the two ends of the excitation winding 9 are connected to the external DC power supply U through the adjustable resistor R, and the excitation current I _a of the excitation winding 9 is provided by the external DC power supply U, through the adjustable resistor R Divide the voltage to quickly adjust the excitation current.

Since it is necessary to ensure that the oil is released at a constant pressure during the oil return process, during the oil return process, the excitation winding in the excitation servo motor 3 is connected with the voltage division method as shown in Figure 3 to achieve control of the excitation current for size purposes. The magnitude of the excitation current determines the magnitude of the magnetic torque provided by the field winding, and since the servo motor is mechanically connected to the output shaft of the internal gear pump, the magnitude of the magnetic torque should be the same as the output torque of the internal gear pump, and The output torque is determined by the pressure of the oil. Therefore, this modification achieves the purpose of controlling the magnetic torque and the output torque of the gear pump by controlling the magnitude of the excitation current, and finally achieves the purpose of controlling the discharge of the oil at a constant pressure.

Working process of the present invention is as follows:

As shown in Figure 1, during the oil feeding process, the servo motor 3 is supplied with electric energy by the external power grid, the switch is closed, and it acts as a motor under the control of the controller 4, which drives the internal gear pump 2 to rotate according to given parameters, and the internal gear pump 2 As a hydraulic pump, the oil is pumped into the hydraulic cylinder 1 from the oil tank 7, and the hydraulic pad rises.

During the above-mentioned oil feeding process, the energy change process is as follows: the electric energy provided by the external power grid is converted into mechanical energy at the servo motor 3 and transmitted to the internal gear pump 2, and the mechanical energy at the internal gear pump is converted into hydraulic energy of the oil and used The hydraulic cushion rises and does work externally.

As shown in Figure 2, during the oil return process, firstly, the switch between the controller 4 and the servo motor 3 is disconnected, the hydraulic pad starts to descend under the action of the external force F, and the oil is discharged through the oil pipe, driving the internal gear pump 2 Reverse rotation. At this time, the internal meshing gear pump 2 is used as a hydraulic motor. Driven by the oil, the servo motor 3 is driven to rotate in the reverse direction through the mechanical structure. Stored in the storage battery 6 after rectification.

During the above oil return process, its energy changes as follows: First, the external force acts on the hydraulic cylinder to discharge the oil, and the hydraulic energy at 2 places of the internal meshing gear pump is converted into mechanical energy, which is transmitted to the servo motor at 3 places. Through the principle of electromagnetic induction, the mechanical energy is converted into The electrical energy is output, and finally converted into chemical energy in the storage battery 6 for next use, realizing the energy recovery effect in the return process of the hydraulic cylinder.

Further, during the oil return process, the pressure of the oil discharge should be constant and adjustable.

According to the condition that the electromagnetic torque on the internal coil of the servo motor 3 is equal to the hydraulic torque provided by the internal gear pump 2 when the servo motor 3 is used as a generator, as well as related theories such as the law of electromagnetic induction, it can be deduced that the pressure Q of the hydraulic cylinder 1 is related to that in the servo motor The relationship between the excitation current I _a is:

Among them, k is a constant, which is related to parameters such as motor speed, radius of energized coil, internal resistance of coil, radius of oil inlet, eccentricity and so on.

Therefore, it is only necessary to control the magnitude of the excitation current to control the pressure of the hydraulic cylinder during the oil discharge process. In order to control the excitation current conveniently, the servo motor 3 is a separately excited servo motor.

As shown in Fig. 3, the armature winding 8 and the excitation winding 9 of the specially improved separately excited servo motor of the present invention are not directly connected, and the excitation current I _a is provided by an additional DC power supply, and can be adjusted conveniently and quickly through the form of a voltage divider circuit Excitation current size.

The present invention transforms the engineering hydraulic equipment represented by the hydraulic cylinder of the hydraulic machine by using the characteristics that the internal meshing gear pump is used as the hydraulic pump and the hydraulic motor in the forward and reverse directions, and the other excitation servo motor is used as the motor and the generator in the forward and reverse directions. , while achieving the effect of energy recovery, it has the advantages of small changes to the original hydraulic equipment, low cost of transformation, strong universality, etc., and has the development prospect of wide popularization and application.

Claims (6)

1. A hydraulic cushion device for a hydraulic press with energy recovery function, characterized in that it includes a hydraulic cylinder (1), an internal gear pump (2), a servo motor (3), a controller (4), and a rectifier (5) , energy storage device (6) and fuel tank (7): the controller (4) is connected to the control end of the servo motor (3), and the output shaft of the servo motor (3) is connected to the internal gear pump (2) The input shaft is mechanically connected to realize synchronous rotation; the two ends of the rectification device (5) are respectively connected with the servo motor (3) and the energy storage device (6), so as to realize the recovery and utilization of the output electric energy of the servo motor (3); One end of the oil circuit of the meshing gear pump (2) is connected with the hydraulic cylinder (1) through the oil pipe to realize the oil inlet and oil return process; the other end of the oil circuit of the internal meshing gear pump (2) is connected with the oil tank (7) through the oil pipe, Provide oil during the oil inlet process and recover oil during the oil return process. 2. A hydraulic cushion device for a hydraulic press with energy recovery function according to claim 1, characterized in that: a switch is provided between the controller (4) and the servo motor (3). When the middle switch is closed, the controller (4) controls the rotation of the servo motor (3); during the oil return process, the switch is turned off, and the servo motor (3) is driven to rotate by the internal gear pump (2). 3. A hydraulic cushion device for a hydraulic press with energy recovery function according to claim 2, characterized in that: during the oil intake process, the servo motor (3) is powered by an external power grid as a motor, and the internal gear pump (2) Driven by the servo motor (3) to rotate as a hydraulic pump, pump oil into the hydraulic cylinder (1); during the oil return process, the servo motor (3) outputs current to the outside as a generator, and the internal meshing gear pump (2) Driven by the oil between the hydraulic cylinder (1) and the oil tank (7) as a hydraulic motor, it drives the servo motor (3) to generate electricity in reverse. 4. The hydraulic pad device of a hydraulic press with energy recovery function according to claim 1, characterized in that: said energy storage device (6) is selected as a storage battery, and the DC rectified by the rectifying device (5) is charged to the storage battery For subsequent power supply use. 5. A hydraulic cushion device for a hydraulic press with energy recovery function according to claim 1, characterized in that: said servo motor (3) is a separately excited DC servo motor. 6. A hydraulic pad device with energy recovery function according to claim 1 or 5, characterized in that: the servo motor (3) is internally provided with an armature winding (8) and an excitation winding (9) , the armature winding (8) and the field winding (9) are not directly connected, the two ends of the field winding (9) are connected to the external DC power supply U through the adjustable resistor R, and the excitation current I _a of the field winding (9) is controlled by the external DC power supply U Provided, the excitation current can be quickly adjusted through the adjustable resistor R voltage divider.