The tooth profile of a spiral gear has a helical angle with a certain angle. Therefore, when demoulding the spiral gear forging, the ejection mechanism is required to eject according to the demoulding direction. At the same time, the formed tooth cavity or the spiral gear forging itself rotates according to the inclined direction of the tooth shape, so as to achieve the purpose of demoulding.
(1) Centripetal ball bearing is used to make the tooth cavity rotate and demould
The working principle of rotary demoulding of centripetal ball bearing is adopted. During demoulding, the ejector rod is pushed on the spiral gear forging to force the toothed cavity seat integrated with the toothed cavity and fixed to rotate under the action of centripetal ball bearing to complete the demoulding of spiral gear forging. The structure of this kind of demoulding mechanism is not complex, The working principle of rotary demoulding of centripetal ball bearing is adopted. During demoulding, the ejector rod is pushed on the spiral gear forging to force the toothed cavity seat integrated with the toothed cavity and fixed to rotate under the action of centripetal ball bearing to complete the demoulding of spiral gear forging. The structure of this kind of demoulding mechanism is not complex, but due to the large friction between the lower end face of the toothed cavity seat and the support plate in the pushing process, it will affect the rotation of the toothed cavity seat, and the jacking force of the ejector rod is also large.
(2) The steel ball is used to make the tooth cavity rotate and demould
The working principle of using steel balls to rotate and demould the tooth cavity is as follows. The steel ball is installed at the step of the cavity seat. The toothed cavity and the toothed cavity seat are installed in the moving template with a certain gap. There is a certain gap between the steel ball and the moving template. When the ejector rod ejects the spiral gear forging, the lower bottom surface of the toothed cavity seat is pushed a certain distance from the support plate, and then rotate and demould according to the tooth direction. This kind of structure avoids the rotational friction between the toothed cavity base and the support plate, although demoulding can be carried out. However, since the radial ball bearing is not installed in the circumferential direction, the rotation will be affected to some extent.
(3) At the same time, centripetal ball bearing, steel ball and thrust ball bearing are used to rotate and demould the tooth cavity
At the same time, the structure of centripetal ball bearing, steel ball and thrust ball bearing is adopted. After the toothed cavity seat is connected into one, it is installed in the centripetal ball bearing on the moving template. The thrust ball bearing installed in the fixed plate is top at the bottom of the cavity seat, the steel ball is installed on the step of the toothed cavity seat, and there is a large assembly gap between the toothed cavity and the toothed cavity seat and the cavity. In this way, when the ejector rod pushes the spiral gear to demould, the rotation of the tooth cavity is more flexible and reliable.
(4) Demoulding with rotary ejector rod
The working principle of rotary pipe jacking demoulding is as follows. The tooth shaped cavity is fixed in the moving template, a spiral groove is made on the ejector rod along the rotation direction of the spiral gear, and a guide pin is arranged on the core in the center. In the demoulding process, the ejector rod rotates against the spiral gear forging under the action of the guide pin to demould.
In addition, a one-way thrust ball bearing can also be installed at the rear end of the ejector rod. The working principle of the ejector mechanism is that the spiral gear forging rotates with the ejector rod along the tooth rotation direction and demoulds.
The centripetal ball bearing is used to rotate and demould the tooth cavity, and the female die is designed into a centripetal ball shaft multiplication structure. When the ejector rod ejects the spiral gear forging, the tooth cavity rotates under the action of the centripetal ball bearing to complete the demoulding of the spiral gear forging.