JPS5983804A - Pump driving mechanism of hydraulic actuator - Google Patents

Abstract

PURPOSE:To cut energy consumption sharply by dividing a stroke of an actuator to set a speed at each position and adjusting the number of rotations of an electric motor for driving a pump according to a set speed signal. CONSTITUTION:An inverter circit is connected to an electric motor 111 for driving a pump 12, and a position detector 18 for an actuator is connected to the inverter circuit through a position read circuit 22, a position comparison circuit 23, a position setting circuit 28 and a speed setting circuit 33. In this arrangement, a set speed sigal is output corresponding to each position of the actuator, and according to the set speed signal input frequency of the electric motor 11 for driving the pump 12 is changed to adjust the number of rotations of the electric motor, whereby the pump 12 is always driven at a proper number of rotations so as to achieve the reduction of energy consumption sharply.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drive mechanism for a pump that is a drive source for a hydraulic actuator.

Generally, the electric motor that drives the hydraulic pump is of a constant rotation type. Recently, energy saving has been called for, and conventional countermeasures for hydraulic actuators have been to release the generated pressure oil using an IJ/IJ-7 valve, etc. in response to the driving pressure on the load side, or to set the pump discharge side pressure to a specified pressure. Therefore, there have been methods such as installing a comparator valve and swinging the pump swash plate to control the pump discharge amount. In the former method, the loss between the pump and the relief valve is an energy loss, and the energy loss is due to the transmission efficiency between the pump and the electric motor.

The latter method also had problems with response and noise, as well as loss between the pump and electric motor.

The present invention has been made from this point of view, and an object thereof is to provide a pump drive #I mechanism for a hydraulic actuator that makes it possible to save energy by making the rotational speed of the electric motor variable.

The present invention will be explained below with reference to figures showing one embodiment. A pump 12 rotationally driven by an electric motor 1 generates pressure in oil in a tank 13, and the maximum pressure is controlled to open by a relief valve 14 and is supplied to and discharged from an actuator 16 via a discharge valve 15. Actuator 16 is load 17
While moving, the position is detected by the pulse scale 18Vc, which is a position detector, and the nozzle scale 18
The signal is amplified by the preamplifier 19 and then sent to the counter 2J as a signal through the branch circuit group.

The output of the preamplifier 19, the frequency dividing circuit, and the counter 2 are collectively referred to as the position reading circuit η. The set position is sent to each of the four position setting elements 29 to 32 for setting the speed switching position. Note that the element 32 sets the forward limit of the actuator 16. The outputs of elements 24 through 36 of the position comparator circuit are sent to respective elements 34 through 36 of the speed setting circuit. The output of each element 34 to 37 enters an inverter section 43 of an inverter circuit 42 via dry nozzles 41. Note that 44 is a converter section, and 45 is a power supply, and the output of the inverter section 43 is supplied to the electric power supply @iso1].

Next, the operation of the present invention will be explained. Actuator 16
With the piston 16A of the electric motor 1] placed at the left limit position,
The pump 12 is operated by. At this time, if the solenoid valve 15 is excited, the pressure oil of the pump 12 will flow into the left chamber of the actuator 16, and the load 17 will move to the right. As the load 17 moves to the right, its position is sent from the nosorus scale 18 to the counter 2J, and the output of the counter 2J is sent to the valley element 24 of the position comparator circuit.
Sent to Tt-i-n. At the beginning of operation of the pump 12, the set value of the first element 37 of the speed setting circuit is applied to the inverter section 43 of the inverter circuit 42 via the driver 41, so that the power of the power supply frequency that matches the set value of the speed setting element 37 is applied. is 1 from the inverter section 43! [Doiso I].

When the actuator 16 advances to the right and reaches the set position of the first element 2911'i of the position setting circuit, the element of the position comparison circuit reads this and transfers the set value of the element of the speed setting circuit 33 to the dry nozzle 41. through the interface part 4
3, the electric motor @1] is rotated at a speed that matches the speed setting circuit. Subsequently, as the actuator 16 advances, the speed setting element A and that setting 1 shift are changed to the driver 41.
are sequentially sent to the inverter section 43 to convert the rotational speed of the electric motor 1. When the position comparison element 27 reads that the position of the actuator 16 matches the position of the position setting element 32, the electric motor 1 is stopped.

In the above description, the forward movement of the actuator 16 has been described, but the same applies to the backward movement of the actuator 16.

As described above, the pump drive mechanism for a hydraulic actuator according to the present invention includes a position detector that detects the position of the actuator in a pump drive mechanism for a hydraulic actuator that adjusts the rotational speed of an electric motor that drives the pump via an inverter circuit. a position reading circuit that reads the signal of the same position detector; a position setting circuit that sets a plurality of positions of the actuator; A position comparison circuit that reads signals from the position reading circuit, a speed setting circuit that sets the speed at each set position of the position setting circuit, and a set speed signal of each speed setting circuit that is connected to an inverter via the position comparison circuit. The pump was constructed with an inverter circuit that received the pump at the pump and supplied the output to the electric motor that drives the pump.

Therefore, in the present invention, the stroke of the actuator is divided and the speed at each position is set, and based on this set speed signal, the frequency of the electric motor that drives the pump is changed via the inverter circuit to increase the motor rotation speed. Adjusted. Therefore, the pump is always operated at an appropriate rotation speed, making it possible to save a lot of energy.

[Brief explanation of the drawing]

The figure is a mechanical diagram in one embodiment of the present invention. 1]...Electric motor, 12...Pump, 16...Actuator, 18...Position detector, η...Position reading circuit, Ru...Position comparison circuit, Ah...Position setting circuit ,
Oh...speed setting circuit, 4y...inverter circuit. λ Applicant Toshiba Machine Co., Ltd.

Claims (1)

[Claims] In a pump drive mechanism for a hydraulic actuator that adjusts the rotation speed of an electric motor that drives a pump via an inverter circuit, the invention further comprises: a position detector that detects the position of the actuator; a position reading circuit that reads signals from the same position detector; a position setting circuit that sets a plurality of positions of the actuator; a position comparison circuit that reads the signals based on the position comparison circuit; a speed setting circuit that sets the speed at each setting position of the position setting circuit; The output is received by the unit and drives the pump! f from the inverter circuit designed to supply the motor
Hydraulic actuator pump drive mechanism.