Hydraulic system of machine tool

Abstract

The utility model belongs to the technical field of fluid pressure working systems, and relates to a hydraulic system of a machine tool, which comprises an oil tank, a motor, an oil pump, a reversing valve, an energy accumulator and an oil cylinder, an output shaft of the motor is connected with the oil pump, the oil pump is sequentially connected with the energy accumulator and an oil inlet of the reversing valve, a working oil port of the reversing valve is communicated with the oil cylinder, and the oil cylinder is connected with the oil tank. An oil return opening of the reversing valve is communicated with the oil tank, the pressure transmitter is connected with the energy accumulator and used for detecting the output pressure of the energy accumulator, and the frequency converter, the pressure transmitter and the motor are electrically connected. And the frequency converter receives a signal from the pressure transmitter and controls the operation power of the motor. According to the hydraulic system of the machine tool, the motor can stop running when not running, the motor runs at the most reasonable power when running, and therefore electric energy is saved.

Description

Technical Field

[0001] The utility model relates to a hydraulic system for a machine tool, belonging to the technical field of fluid pressure working systems. Background Art

[0002] The working principle of the hydraulic system of a machine tool is to transfer and control energy through the circulation of hydraulic oil in the system. When the machine tool needs to perform a certain action, the oil pump starts to work, extracts hydraulic oil from the oil tank, and delivers it to the corresponding hydraulic components through the pipeline system. The valve assembly adjusts the flow, pressure and direction of the hydraulic oil according to the control signal, thereby controlling the action of the machine tool.

[0003] After the CNC machine tool is turned on, the hydraulic system of the machine tool starts and its motor will continue to run. This is to ensure the stable operation and precise control of the machine tool. The core function of the hydraulic system is to control the working status of the spindle cylinder and the cutter cylinder. The precise control of these two cylinders is crucial to the machining accuracy and efficiency of the machine tool. Take the spindle cylinder as an example to analyze its hydraulic principle: when the chuck is in the clamped state, the cylinder starts to fill with oil. At this time, the motor remains in operation, and the hydraulic oil continues to enter the oil circuit. On the one hand, it is used to maintain the pressure in the cylinder. On the other hand, when the system pressure reaches the maximum value, the excess hydraulic oil will flow back to the hydraulic station through the overflow valve to achieve pressure balance and regulation. When the chuck needs to be released, the reversing valve performs a reversing operation, and the original oil inlet path is converted into an oil return path, thereby smoothly realizing the release of the chuck.

[0004] From the above hydraulic principle, it can be clearly seen that the power output of the motor is actually effective in the three stages of chuck clamping, loosening and pressure holding, while the operation of the motor is ineffective in other time periods. In addition, since hydraulic stations generally use three-phase asynchronous motors, this type of motor will run at the highest power once powered on, but in actual operation, in many cases, the motor does not need to run at full load, which leads to unnecessary waste of energy. Utility Model Content

[0005] The purpose of the utility model is to provide a new technical solution to improve or solve the technical problems existing in the prior art as described above.

[0006] The technical solution provided by the utility model is as follows: a machine tool hydraulic system, including an oil tank, a motor, an oil pump, a reversing valve, an accumulator and an oil cylinder, the output shaft of the motor is connected to the oil pump, the oil pump is connected to the oil inlet of the accumulator and the reversing valve in sequence, the working oil port of the reversing valve is connected to the oil cylinder, the oil return port of the reversing valve is connected to the oil tank, and also includes a frequency converter and a pressure transmitter, the pressure transmitter is connected to the accumulator for detecting the output pressure of the accumulator, the frequency converter, the pressure transmitter and the motor are electrically connected, the frequency converter receives the signal from the pressure transmitter and controls the operating power of the motor.

[0007] On the basis of the above technical solution, the present invention can also be improved as follows.

[0008] Furthermore, it also includes a safety valve, which is installed at the filling port of the accumulator.

[0009] The beneficial effect of adopting the above further scheme is that the main function of the safety valve is to ensure that the system pressure is within a safe range. Installing a safety valve at the filling port of the accumulator can effectively prevent safety accidents caused by excessive filling or excessive system pressure.

[0010] Furthermore, it also includes a throttle valve, which is arranged on a pipeline connecting the accumulator and the reversing valve.

[0011] The beneficial effect of adopting the above further solution is that by adjusting the opening of the throttle valve, the flow rate in the pipeline can be flexibly adjusted, thereby achieving effective control of the system pressure.

[0012] Furthermore, an oil return pipe is provided on the pipeline between the throttle valve and the accumulator, and the oil return pipe is connected to the oil tank.

[0013] The beneficial effect of adopting the above further solution is that the function of the oil return pipe is to allow excess oil to flow back to the oil tank, thereby maintaining the oil balance in the system.

[0014] Furthermore, a relief valve is provided on the oil return pipe.

[0015] The beneficial effect of adopting the above further solution is that the overflow valve on the oil return pipe can effectively prevent the system from over-pressure. When the system pressure exceeds the set value, the overflow valve will automatically open and guide the excess oil back to the tank through the oil return pipe, thereby ensuring that the system pressure remains within a safe range. By adjusting the set pressure of the overflow valve on the oil return pipe, the system pressure can also be accurately controlled to meet the system pressure requirements under different working conditions, thereby improving the operating efficiency and working performance of the system.

[0016] Furthermore, it also includes a filter, which is installed on the pipeline between the oil return pipe and the throttle valve.

[0017] The beneficial effect of adopting the above further scheme is that the main function of the filter is to filter out impurities in the oil, including solid particles, moisture, oxides, etc., so as to ensure the cleanliness of the oil. In the hydraulic system, the cleanliness of the oil has a crucial impact on the performance of the system and the life of the components. If there are impurities in the oil, it may cause problems such as wear, blockage, and jamming of the components, seriously affecting the normal operation of the system. Therefore, installing a filter between the return pipe and the throttle valve can effectively remove impurities in the oil, maintain the cleanliness of the system, and extend the service life of the components.

[0018] Compared with the prior art, the technical solution provided by the utility model has the following beneficial effects: the utility model sets an accumulator in the hydraulic system of the machine tool, and the motor pre-fills the accumulator with hydraulic oil. When the high-pressure setting value is reached, the motor stops running. At this time, the accumulator is full of hydraulic oil, and the action of the oil cylinder is completely provided by the pressure of the accumulator. During the processing, once the pressure in the accumulator drops to the low-pressure setting value, the motor will automatically run and fill the accumulator with oil again, while the motor will remain in a stopped state during other time periods, so that the motor stops running when it should not run, and runs at the most reasonable power when it should run, thereby saving electric energy. In addition, the utility model also adds a frequency converter, which is used to dynamically adjust the motor power according to the pressure of the accumulator detected by the pressure transmitter, provide the system with the most reasonable power output, achieve energy saving effects, and effectively avoid the problem of burning of the motor due to frequent starting. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0020] Figure 1 It is the hydraulic principle diagram of the hydraulic system of the machine tool of the utility model; DETAILED DESCRIPTION

[0021] The principles and features of the present invention are described below in conjunction with examples. The examples are only used to explain the present invention and are not used to limit the scope of the present invention.

[0022] like Figure 1As shown, a machine tool hydraulic system includes an oil tank, a motor, an oil pump, a reversing valve, an accumulator and an oil cylinder, wherein the output shaft of the motor is connected to the oil pump, and the oil pump is connected to the oil inlet of the accumulator and the reversing valve in sequence, the working oil port of the reversing valve is connected to the oil cylinder, and the oil return port of the reversing valve is connected to the oil tank, and also includes a frequency converter and a pressure transmitter, the pressure transmitter is connected to the accumulator for detecting the output pressure of the accumulator, the frequency converter, the pressure transmitter and the motor are electrically connected, and the frequency converter receives the signal from the pressure transmitter and controls the operating power of the motor.

[0023] The machine tool hydraulic system also includes a safety valve, which is installed at the filling port of the accumulator.

[0024] The machine tool hydraulic system further comprises a throttle valve, which is arranged on a pipeline connecting the accumulator and the reversing valve.

[0025] An oil return pipe is also provided between the throttle valve and the accumulator, and the oil return pipe is communicated with the oil tank.

[0026] The oil return pipe is provided with an overflow valve.

[0027] The machine tool hydraulic system further comprises a filter, which is installed on the pipeline between the oil return pipe and the throttle valve.

[0028] The specific working process of the hydraulic system of the machine tool of the utility model is as follows:

[0029] (1) First, an accumulator is set at the rear end of the oil pump. The motor stores oil and pressure in the accumulator in the initial stage. When the pressure in the accumulator reaches the preset high pressure setting value, the motor automatically stops working and enters the standby state.

[0030] (2) When the chuck of the machine tool needs to clamp the workpiece, the accumulator starts to supply oil to the cylinder to drive the piston to move. At this time, all the movements of the cylinder are completely supplied by the accumulator, ensuring the rapid and stable clamping action. Once the workpiece is clamped, the pressure of the hydraulic system reaches the set value, and the excess hydraulic oil will flow back to the oil tank through the overflow valve, ensuring that the pressure in the cylinder is always maintained at the set value to avoid damage caused by excessive pressure.

[0031] (3) During this process, the pressure transmitter continuously monitors the pressure provided by the accumulator to the machine tool hydraulic system. When the pressure in the accumulator gradually decreases due to the continuous pressure supply and reaches the low pressure setting value, the motor will restart and fill the accumulator with oil through the oil pump to restore its pressure. During this process, the inverter receives the signal from the pressure transmitter and dynamically adjusts the operating power of the motor according to the actual load conditions to ensure that the motor always runs at maximum efficiency, thereby achieving significant power saving effects.

[0032] (4) If the chuck needs to be loosened, the reversing valve will perform a reversing operation, and the original oil inlet pipeline will become the oil return pipeline, so the piston will move in the opposite direction, easily realizing the chuck loosening function.

[0033] The following is a comparison of the operating status of the hydraulic system of the oil-powered double-column vertical lathe before and after the improvement: before the improvement, the motor was always running, and after the improvement, the accumulator was depressurized only during the clamping and loosening stages. Each full charge of the accumulator can meet an average of 4 processing cycles, and the motor only needs 5 seconds to fill the accumulator. Calculated based on the cycle time of 50s, the motor running time after the improvement is only 2.5% of the time before the improvement.

[0034]

[0035] The motor of the hydraulic station of the oil-powered vertical lathe is 2.2kw. After the implementation, the original equipment and the modified equipment were tested with meters respectively. The average power saving rate was 94%. It is estimated that each unit can save 3,600 yuan in electricity bills each year. The modification cost of a single unit is about 3,000 yuan, and the investment payback period is 10 months.

[0036] The machine tool hydraulic system of the utility model can stop the motor from running when it should not run, and run it at the most reasonable power when it should run, thereby saving electric energy.

[0037] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A machine tool hydraulic system, characterized in that: It includes an oil tank, a motor, an oil pump, a reversing valve, an accumulator and an oil cylinder, wherein the output shaft of the motor is connected to the oil pump, the oil pump is connected to the accumulator and the oil inlet of the reversing valve in sequence, the working oil port of the reversing valve is connected to the oil cylinder, the oil return port of the reversing valve is connected to the oil tank, and also includes a frequency converter and a pressure transmitter, the pressure transmitter is connected to the accumulator for detecting the output pressure of the accumulator, the frequency converter, the pressure transmitter and the motor are electrically connected, and the frequency converter receives a signal from the pressure transmitter and controls the operating power of the motor; It also includes a safety valve, which is installed at the filling port of the accumulator; It also includes a throttle valve, which is arranged on a pipeline connecting the accumulator and the reversing valve; An oil return pipe is also provided on the pipeline between the throttle valve and the accumulator, and the oil return pipe is connected to the oil tank; The oil return pipe is provided with a relief valve; It also includes a filter, which is installed on the pipeline between the oil return pipe and the throttle valve.

Images