57results about How to "Reduce stress difference" patented technology

The invention discloses two control methods for the bridge arm current of a modular multilevel converter, which improve the basic control method, by superimposing opposite additional conduction number instructions or additional voltage instructions in the upper and lower bridge arm control instructions, Realize reducing or even suppressing the bridge arm current asymmetry caused by the bias of the control command issued by the upper controller or the voltage imbalance of the upper and lower bridge arm sub-modules, and reducing the stress difference between the upper and lower bridge arms.

The invention discloses a stamping part side wall curled rebounding control stamping device which comprises an upper die base, a concave die, a blank holder, a convex die and a lower die base from top to bottom, wherein the blank holder is in driving connection with a holder-on rod; the convex die is matched with the concave die; the upper die base is fixedly connected with the concave die and moves synchronously with the concave die; the convex die is fixedly connected with the lower die base; the convex die comprises a first stamping part and a second stamping part from top to bottom; the first stamping part and the second stamping part are in smooth transition by virtue of a transition curve part; a clearance between the outer contour of the side wall of the first stamping part and the side wall of the concave die is 1.2-1.6 times of the thickness of a to-be-stamped plate; a clearance between the outer contour of the side wall of the second stamping part and the side wall of the concave die 2 is 0.8-0.9 times of the thickness of the to-be-stamped plate; the projection length of the transition curve part in the stamping direction is 2-3 times of the thickness of the to-be-stamped plate. According to the stamping part side wall curled rebounding control stamping device, the die clearance is changed during a stamping process, so that the stress difference between inner and outer layers of a material is decreased, side wall curled rebounding of parts is effectively controlled, and the formation precision and quality of the parts are improved.

The invention discloses a support method and support equipment aiming at the ejection of anchor bolt and anchor cable cover plate. According to different surrounding rock conditions, the key parameters of grouting are scientifically selected, and the grouting equipment is used to inject grouting bolts. Internal rapid grouting, the grout diffuses into the cracks of the rock mass through the grouting bolt, and grouts into the surrounding rock body of the roadway, so that the grout diffuses, compacts and condenses in the cracks in the rock mass, and breaks the loose parts within the reach The surrounding rock is cemented into a whole, and the grout under pressure is retained in the surrounding rock body of the roadway to increase the initial support resistance of the surrounding rock, form a slurry cemented reinforced arch, and construct the superficial part of the surrounding rock to have a certain internal stress The ring body of the surrounding rock makes the connection between the multi-layer anchor rod and the multi-layer spray layer more firm, forms multiple protection circles inside the surrounding rock, and at the same time makes the grouting anchor rod and the rock mass quickly cemented together to reduce the depth The stress difference of the surrounding rock, thereby preventing the dangerous situation of ejection of the bolt and the anchor cable.