1. relief valve is unstable, such as due to improper coining of the coin press and the valve hole, or the contact between the poppet valve seat and the valve seat is contaminated, the orifice is blocked, the spring skews or fails, etc. live or inactive in the valve hole, causing system pressure fluctuations and noise. in this regard, should pay attention to cleaning, clear yin ni hole; check the overflow valve, if found damaged, or due to wear exceeds the provisions, it should be repaired or replaced;
2. the pressure pump or pressure motor is of poor quality and is usually the main part of noise generated in pressure transmission. game coin molding small presses pressure pumps have poor manufacturing quality, accuracy does not meet technical requirements, pressure and flow fluctuations, oil trapped phenomena are not well eliminated, seals are not good, and poor bearing quality is the main cause of noise. the reason. in use, due to the wear of the pressure pump components, the clearance is too large, the flow rate is insufficient, the pressure is fluctuating, and noise can also be caused. faced with the above reasons, one is to select a good quality pressure pump or pressure motor, and the other is to intensify maintenance and maintenance. for example, if the gear's tooth profile accuracy is low, it should be geared to meet the contact surface requirements; if the vane pump has trapped oil phenomenon ,the triangular groove of the oil pan shall be corrected to eliminate trapped oil; if the axial clearance of the pressure pump is too large and the oil volume is insufficient, it shall be repaired so that the axial clearance is within the allowable range; if the pressure pump is not selected correctly, replace;
3. the air intrusion pressure system is the main cause of noise. because the pressure forming system of the coin forming small press invades the air, the volume in the low pressure area is large, and when compressed into the high pressure area, the volume is suddenly reduced, and when it flows into the low pressure area, the volume suddenly increases. an abrupt change in volume produces an "explosion" phenomenon that produces noise, a phenomenon commonly referred to as "cavity." for this reason, an exhaust device is often provided on the pressure cylinder for exhaust. in addition, after driving, it is also a common method to exhaust the actuators several times in rapid full stroke.
4. improper adjustment of the reversing valve will cause the spool of the reversing valve to move too fast, resulting in commutation impact, thus generating noise and vibration. in this case, if the coin forming small press reversing valve is a pressure reversing valve, the throttling element in the control oil passage should be adjusted so that the reversing is smooth and shock-free. in operation, the valve plug of the pressure valve is supported on the spring. when its frequency is close to the pulse frequency of the pressure pump oil delivery rate or other vibration source frequencies, it will cause vibration and generate noise. at this time, by changing the natural frequency of the piping system, changing the position of the control valve or properly adding the accumulator, vibration and noise reduction can be prevented.
the above is an introduction to the analysis of the noise problems in the use of presses. we hope to help everyone.