A connecting rod type rolling mechanism for rolling metal bellows

Abstract

The present invention discloses a connecting-rod type rolling mechanism for metal bellows rolling, which includes a housing, a transmission mechanism and a constraint mechanism. The constraint mechanism is installed on the transmission mechanism to constrain the degrees of freedom of the transmission mechanism, and the transmission mechanism is installed in the housing. Through the combined action of the transmission mechanism and the constraint mechanism, the tool head in the transmission mechanism is driven to displace radially. This mechanism is convenient for installation and disassembly and has strong versatility.

Description

Technical Field

[0001] The present invention relates to an internal rolling forming mechanism for pipe fittings, and particularly to a link-type rolling mechanism for rolling metal bellows. Background Art

[0002] A metal bellows is a pipe-like part with a regular wavy appearance and transverse corrugations. It not only has high bending fatigue strength and elastic stability, but also can generate axial, transverse, and angular displacements under the action of external forces, and is widely used in various industrial fields such as national defense, petrochemical industry, and aerospace. Traditional methods for processing bellows include welding forming, mechanical forming, and hydraulic forming, etc. Various defects such as incomplete penetration and porosity, low roundness, and unfilled waveforms are likely to occur in the key processes of the technological process, making it difficult to ensure the quality of the final formed parts. The incremental forming technology for pipe-like parts introduces the idea of "layered manufacturing". By applying a load through a simple rolling forming mechanism and following a pre-set forming trajectory, the required parts can be obtained layer by layer, and various complex formed parts can be formed. This process does not require pre-manufacturing of molds, has a short manufacturing cycle, and is suitable for multi-variety and small-batch production and low-cost rapid prototyping of new products. Summary of the Invention

[0003] For the internal incremental forming process of metal bellows, the present invention proposes a link-type rolling mechanism for rolling metal bellows with strong versatility, simple operation, high efficiency, and convenient installation and disassembly.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0005] A link-type rolling mechanism for rolling metal bellows, the mechanism includes a housing, a transmission mechanism, and a constraint mechanism. The constraint mechanism is installed on the transmission mechanism to constrain the degrees of freedom of the transmission mechanism, and the housing is used to wrap and fix the transmission mechanism and the constraint mechanism;

[0006] Further, the transmission mechanism includes two first support rods, two second support rods, a first socket head bolt, a second socket head bolt, a lead screw transmission shaft, four third socket head bolts, two double-headed bolts, and two tool heads. One end of the first support rod is processed with a first U-shaped groove, the other end is processed with a second U-shaped groove, a first through hole is processed at the first U-shaped groove end, a second through hole is processed at the second U-shaped groove end, and a first threaded hole is processed at the middle position of the rod;

[0007] One end of the second support rod is processed with a third U-shaped groove, the other end is processed with a fourth U-shaped groove, a third through hole is processed at the third U-shaped groove end, a fourth through hole is processed at the fourth U-shaped groove end, and a second threaded hole is processed at the middle position of the rod;

[0008] The shaft sections of the first round head bolt, the second round head bolt, and the third round head bolt all include a smooth shaft section and a threaded section.

[0009] A first left-handed threaded through hole is provided on the smooth shaft section of the first round head bolt, and a first right-handed threaded through hole is provided on the smooth shaft section of the second round head bolt. The second U-shaped groove end of the first support rod is placed in the third U-shaped groove of the second support rod. The second through hole and the third through hole on it are concentric. Here, the first round head bolt is inserted, and a nut is screwed on the other end of the bolt to connect the first support rod and the second support rod. Similarly, another pair of the first support rod and the second support rod are connected by the second round head bolt.

[0010] The lead screw transmission shaft is designed as a stepped shaft with a thick middle and thin ends. One end is provided with a first left-handed thread, and the other end is provided with a first right-handed thread. A first keyway is provided at the end of the end set with the right-handed thread. The first round head bolt is installed on the first left-handed thread of the lead screw transmission shaft through the first left-handed threaded through hole, and the second round head bolt is installed on the first right-handed thread of the lead screw transmission shaft through the first right-handed threaded through hole.

[0011] A fifth through hole is provided on the shaft section of the third round head bolt. The double-headed bolt is designed as a stepped shaft with a thick middle and thin ends. The four third round head bolts are respectively inserted into the first through holes of the two first support rods and the fourth through holes of the two second support rods, and nuts are respectively screwed on the ends. The tool head is disc-shaped and has a sixth through hole in the center. The tool head is installed on the thicker middle shaft section of the double-headed bolt through the sixth through hole in the center. The two ends of the two double-headed bolts are respectively inserted into the fifth through holes of the four third round head bolts, and nuts are screwed on the ends to fix.

[0012] Further, the constraint mechanism includes four constraint rods, four constraint bolts, and two constraint support shafts. The constraint support shafts are designed as stepped shafts with a thick middle and thin ends. A seventh through hole is provided in the middle position of the thicker middle shaft section, and first circular grooves are respectively provided on the thinner shaft sections at both ends. The constraint rods are respectively provided with eighth through holes at both ends. The two constraint support shafts pass through the lead screw transmission shaft through the seventh through hole in the middle. The constraint rods are respectively installed on both sides of the thicker shaft section of the constraint support shafts through the eighth through holes. The constraint bolts include a smooth shaft section and a threaded section, and a second circular groove is provided at the smooth shaft end of the constraint bolts. The four constraint bolts are respectively screwed into the first threaded holes of the two first support rods and the second threaded holes of the two second support rods. One end of the constraint rod is installed on the constraint bolt through the eighth through hole on it, and the other end is installed on the constraint support shaft. A hole retaining ring is clamped on the second circular groove of the constraint bolt and the first circular groove of the constraint support shaft for positioning.

[0013] Furthermore, the outer shell includes a circular left end cap, two semi-cylindrical outer shells, and a circular right end cap. The circular left end cap and the circular right end cap are fixed at both ends of the two semi-cylindrical outer shells. Two second blind holes are provided on the inner cylindrical surface of the semi-circular outer shell to provide rotatable support for both ends of the two constraint support shafts. A first blind hole is provided at the center of the circular left end cap to support one end of the lead screw transmission shaft with a left-handed thread. A ninth through hole is provided at the center of the circular right end cap for one end of the lead screw transmission shaft with a right-handed thread to extend out.

[0014] The beneficial effects of the present invention are as follows:

[0015] (1) In the link-type rolling mechanism for rolling metal bellows of the present invention, by applying torque to the lead screw transmission shaft with left-handed and right-handed threads at both ends, relative movement is generated between the first cylindrical head bolt and the second cylindrical head bolt thereon. Furthermore, through the first support rod and the second support rod, the tool head generates a radial displacement, causing local extrusion and rolling inside the high-speed rotating thin-walled tube, resulting in continuous plastic deformation.

[0016] (2) In the link-type rolling mechanism for rolling metal bellows of the present invention, through the constraint of the constraint rod on the first support rod and the second support rod, a uniquely determined movement is generated.

[0017] (3) In the link-type rolling mechanism for rolling metal bellows of the present invention, by controlling the rotation speed of the lead screw transmission shaft to control the radial feed speed of the tool head, and by controlling the number of rotations of the lead screw transmission shaft to control the radial feed amount of the tool head, it is convenient to form target workpieces with different qualities and different shapes.

[0018] (4) The link-type rolling mechanism for rolling metal bellows of the present invention is convenient to replace and has strong versatility. Description of the Drawings

[0019] Figure 1 is an exploded schematic view of the link-type rolling mechanism for rolling metal bellows of the present invention;

[0020] Figure 2 is Figure 1 a schematic view of the transmission mechanism and the constraint mechanism in

[0021] Figure 3 is Figure 2 a schematic view of the specific part of the first support rod in

[0022] Figure 4 is Figure 2 a schematic view of the specific part of the second support rod in

[0023] Figure 5 is Figure 2 a schematic view of the specific part of the first cylindrical head bolt in

[0024] Figure 6 is Figure 2 a schematic diagram of the specific parts of the second cylindrical head in

[0025] Figure 7 is Figure 2 a schematic diagram of the specific parts of the lead screw drive shaft in

[0026] Figure 8 is Figure 2 a schematic diagram of the specific parts of the third cylindrical head in

[0027] Figure 9 is Figure 2 a schematic diagram of the specific parts of the restraint support shaft in

[0028] Figure 10 is Figure 2 a schematic diagram of the specific parts of the restraint bolt in

[0029] Figure 11 is Figure 1 a schematic diagram of the specific parts of the circular left end cover in

[0030] Figure 12 is Figure 1 a schematic diagram of the specific parts of the semi-circular housing in

[0031] Figure 13 is Figure 1 a schematic diagram of the specific parts of the circular right end cover in

[0032] In the figure, housing 11, transmission mechanism 12, restraint mechanism 13, circular left end cover 111, first threaded through hole 1111, first blind hole 1112, semi-cylindrical housing 112, third threaded hole 1121, second blind hole 1122, circular right end cover 113, second threaded through hole 1131, ninth through hole 1132, fourth threaded hole 1133, first support rod 121, first U-shaped groove 1211, second U-shaped groove 1212, first through hole 1213, second through hole 1214, first threaded hole 1215, second support rod 122, third U-shaped groove 1221, fourth U-shaped groove 1222, third through hole 1223, fourth through hole 1224, second threaded hole 1225, first cylindrical head bolt 123, first left-handed threaded through hole 1231, second cylindrical head bolt 124, first right-handed threaded through hole 1241, lead screw drive shaft 125, first left-handed thread 1251, first right-handed thread 1252, first keyway 1253, third cylindrical head bolt 126, fifth through hole 1261, stud bolt 127, tool head 128, sixth through hole 1281, restraint rod 131, eighth through hole 1311, restraint bolt 132, second circular groove 1321, restraint support shaft 133, seventh through hole 1331, first circular groove 1332. Detailed implementation mode

[0033] The present invention will be described in detail below according to the accompanying drawings and preferred embodiments. The purpose and effect of the present invention will become more apparent. The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0034] As Figure 1-13 shown, a connecting rod type rolling mechanism for rolling a metal bellows of the present invention includes a housing 11, a transmission mechanism 12, and a constraint mechanism 13. The transmission mechanism 12 includes two first support rods 121, two second support rods 122, a first round head bolt 123, a second round head bolt 124, a lead screw transmission shaft 125, four third round head bolts 126, two double-headed bolts 127, and two tool heads 128. One end of the first support rod 121 is processed with a first U-shaped groove 1211, and the other end is processed with a second U-shaped groove 1212. A first through hole 1213 is processed at the end of the first U-shaped groove 1211, a second through hole 1214 is processed at the end of the second U-shaped groove 1212, and a first threaded hole 1215 is processed at the middle position of the rod; one end of the second support rod 122 is processed with a third U-shaped groove 1221, and the other end is processed with a fourth U-shaped groove 1222. A third through hole 1223 is processed at the end of the third U-shaped groove 1221, a fourth through hole 1224 is processed at the end of the fourth U-shaped groove, and a second threaded hole 1225 is processed at the middle position of the rod;

[0035] The shaft sections of the first round head bolt 123, the second round head bolt 124, and the third round head bolt 126 all include a smooth shaft section and a threaded section;

[0036] The smooth shaft section of the first round head bolt 123 is provided with a first left-handed threaded through hole 1231, and the smooth shaft section of the second round head bolt 124 is provided with a first right-handed threaded through hole 1241. The end of the second U-shaped groove 1212 of the first support rod 121 is placed in the third U-shaped groove 1221 of the second support rod 122. The second through hole 1214 and the third through hole 1223 are concentric here, and the first round head bolt 123 is installed here. A nut is screwed on the other end of the bolt to connect the first support rod 121 and the second support rod 122; similarly, another pair of the first support rod 121 and the second support rod 122 are connected by the second round head bolt 124.

[0037] The described lead screw transmission shaft 125 is designed as a stepped shaft with a thicker middle part and thinner ends. One end is provided with a first left-handed thread 1251, and the other end is provided with a first right-handed thread 1252. A first keyway 1253 is provided at the end of the end set with the right-handed thread; the first round head bolt 123 is installed on the first left-handed thread 1251 of the lead screw transmission shaft 125 through the first left-handed thread through hole 1231, and the second round head bolt 124 is installed on the first right-handed thread 1252 of the lead screw transmission shaft 125 through the first right-handed thread through hole 1241.

[0038] The optical axis section of the described third round head bolt 126 is provided with a fifth through hole 1261, and the stud bolt 127 is designed as a stepped shaft with a thicker middle part and thinner ends; the four third round head bolts 126 are respectively inserted into the first through holes 1213 of the two first support rods 121 and the fourth through holes 1224 of the two second support rods 122, and nuts are screwed on the ends respectively; the tool head 128 is designed as a disc shape, with a sixth through hole 1281 in the center, and the tool head 128 is installed on the thicker middle shaft section of the stud bolt 127 through the sixth through hole 1281 in the center; the two ends of the two stud bolts 127 are respectively inserted into the fifth through holes 1261 of the four third round head bolts 126, and nuts are screwed on the ends to fix.

[0039] The described constraint mechanism 13 includes four constraint rods 131, four constraint bolts 132, and two constraint support shafts 133. The constraint support shafts 133 are stepped shafts with a thicker middle part and thinner ends. A seventh through hole 1331 is provided in the middle position of the thicker middle shaft section, and first circular grooves 1332 are respectively provided on the thinner shaft sections at both ends; the constraint rods 131 are respectively provided with eighth through holes 1311 at both ends, the two constraint support shafts 133 pass through the lead screw transmission shaft 125 through the middle seventh through hole 1331, and the constraint rods 131 are respectively installed on both sides of the thicker shaft section of the constraint support shafts 133 through the eighth through holes 1311; the constraint bolts 132 (as Figure 10 shown) include an optical axis section and a threaded section, and the optical axis section of the constraint bolt 132 is provided with a second circular groove 1321. The four constraint bolts 132 are respectively screwed into the first threaded holes 1215 of the two first support rods 121 and the second threaded holes 1225 of the two second support rods 122; one end of the constraint rod 131 is installed on the constraint bolt 132 through the eighth through hole 1311 on it, and the other end is installed on the constraint support shaft 133, and a retaining ring is clamped on the second circular groove 1321 of the constraint bolt 132 and the first circular groove 1332 of the constraint support shaft 133 for positioning.

[0040] The described housing 11 includes a circular left end cover 111, two semi-cylindrical housings 112, and a circular right end cover 113. The periphery of the end face of the circular left end cover 111 is provided with six uniformly distributed first threaded through holes 1111, and a first blind hole 1112 is provided at the center position of the end face for installing a rolling bearing; each of the two end faces of the semi-cylindrical housing 112 is provided with three third threaded holes 1121, and two second blind holes 1122 are provided on the inner cylindrical surface; the periphery of the end face of the circular right end cover 113 is provided with six uniformly distributed second threaded through holes 1131, and a ninth through hole 1132 with a larger diameter at the front section and a smaller diameter at the rear section is provided at the center position of the end face for installing a rolling bearing, and six uniformly distributed fourth threaded holes 1133 are provided around the through hole. The two semi-cylindrical housings 112 are relatively installed at both ends of the constraint support shaft 133 through the second blind holes 1122 on their inner surfaces, wrapping the transmission mechanism 12 and the constraint mechanism 13; the circular end cover 11 is installed at the left-handed threaded end of the lead screw transmission shaft 125 through the first blind hole 1112 with a bearing at the center of the end face, and the first threaded through holes 1111 thereon are concentric with the third threaded holes 1121 on the end face of the semi-cylindrical housing 112, and screws are screwed in for fixed connection; the circular right end cover 113 passes through the right-handed threaded end of the lead screw transmission shaft 125 through the ninth through hole 1132 with a bearing at the center of the end face, and the second threaded through holes 1131 thereon are concentric with the third threaded holes 1121 on the end face of the semi-cylindrical housing 112, and screws are screwed in for fixed connection.

[0041] During installation, first place the end of the second U-shaped groove 1212 of the first support rod 121 into the third U-shaped groove of the second support rod 122. The second through hole 1214 on it is concentric with the third through hole 1223, and a first socket head cap bolt 123 is installed here. A nut is screwed onto the other end of the bolt to connect the first support rod 121 and the second support rod 122. Similarly, another pair of the first support rod 121 and the second support rod 122 are connected by a second socket head cap bolt 124. Then, pass two constraint support shafts 133 through the seventh through holes 1331 in the middle and place them on both sides of the thicker shaft section at both ends of the lead screw transmission shaft 125. Then, install the first socket head cap bolt 123 through its first left-handed threaded through hole 1231 on the first left-handed thread 1251 of the lead screw transmission shaft 125, and install the second socket head cap bolt 124 through its first right-handed threaded through hole 1241 on the first right-handed thread 1252 of the lead screw transmission shaft 125. Then, insert 4 third socket head cap bolts 126 into the first through holes 1213 of the two first support rods 121 and the fourth through holes 1224 of the two second support rods 122 respectively, and screw nuts onto the ends respectively. Then, install two tool heads 128 through the sixth through holes 1281 in the center on the middle thicker shaft sections of two double-headed bolts 127 respectively. Then, insert both ends of the two double-headed bolts 127 into the fifth through holes 1261 of the four third socket head cap bolts 126 respectively, and screw nuts onto the ends to fix. Then, screw 4 constraint bolts 132 into the first threaded holes 1215 of the two first support rods 121 and the second threaded holes 1225 of the two second support rods 122 respectively. Then, install the four constraint rods 131 through the eighth through holes 1311 on them. One end is installed on the four constraint bolts 132 respectively, and the other end is installed on both ends of the two constraint support shafts 133 respectively. And snap retaining rings into the second circular grooves 1322 of the four constraint bolts 132 and the first circular grooves 1332 of the two constraint support shafts 133 respectively for positioning. Then, install two semi-circular outer shells 112 opposite to each other through the two second blind holes 1122 on their inner surfaces at both ends of the two constraint support shafts 133, and wrap the transmission mechanism 12 and the constraint mechanism 13 therein. Then, press-fit the bearing into the first blind hole 1112 at the center of the end face of the circular end cover 11. Then, install the circular end cover 11 through the first blind hole 1112 with a bearing at the center of the end face on the left-handed threaded end of the lead screw transmission shaft 125. The first threaded through hole 1111 on it is concentric with the third threaded hole 1121 on the end face of the semi-circular outer shell 112, and then screw a screw here to fix the connection. Finally, press-fit the bearing into the ninth through hole 1132 at the center of the end face of the perforated circular end cover 113. Then, install the perforated circular end cover 113 through the ninth through hole 1132 with a bearing at the center of the end face on the right-handed threaded end of the lead screw transmission shaft 125. The second threaded through hole 1131 on it is concentric with the third threaded hole 1121 on the end face of the semi-circular outer shell 112, and then screw a screw here to fix the connection.

[0042] During use, first support the thin-walled tube inside through the iron core and then clamp it on the three-jaw chuck of the lathe. After clamping and fixing the rolling forming mechanism, extend it to the position where the tube needs to be expanded. Then start the lathe to make the thin-walled tube rotate at high speed, and drive the lead screw transmission shaft 125 to rotate, driving the first round head bolt 123 and the second round head bolt 124 on it to move towards each other. Further, through the first support rod 121 and the second support rod 122, the tool head 128 generates a radial displacement, thereby locally extruding and rolling the thin-walled tube, causing it to undergo continuous plastic deformation, and finally cumulatively forming the target part.

[0043] Those of ordinary skill in the art can understand that the above are only preferred examples of the invention and are not used to limit the invention. Although the invention has been described in detail with reference to the foregoing examples, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing examples, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, etc. made within the spirit and principle of the invention shall be included within the protection scope of the invention.

Claims

1. A connecting rod type rolling mechanism for rolling a metal bellows, characterized in that, the mechanism comprises a housing (11), a transmission mechanism (12) and a constraint mechanism (13), the constraint mechanism (13) is installed on the transmission mechanism (12) to constrain the degree of freedom of the transmission mechanism (12), and the housing (11) is used to wrap and fix the transmission mechanism (12) and the constraint mechanism (13); the transmission mechanism (12) includes two first support rods (121), two second support rods (122), a first cylinder head bolt (123), a second cylinder head bolt (124), a lead screw transmission shaft (125), four third cylinder head bolts (126), two double-headed bolts (127) and two tool heads (128). One end of the first support rod (121) is processed with a first U-shaped groove (1211), and the other end is processed with a second U-shaped groove (1212). A first through hole (1213) is processed at the end of the first U-shaped groove (1211), and a second through hole (1214) is processed at the end of the second U-shaped groove (1212). A first threaded hole (1215) is processed at the middle position of the rod; one end of the second support rod (122) is processed with a third U-shaped groove (1221), and the other end is processed with a fourth U-shaped groove (1222). A third through hole (1223) is processed at the end of the third U-shaped groove (1221), and a fourth through hole (1224) is processed at the end of the fourth U-shaped groove. A second threaded hole (1225) is processed at the middle position of the rod; the shaft sections of the first cylinder head bolt (123), the second cylinder head bolt (124) and the third cylinder head bolt (126) all include a smooth shaft section and a threaded section; a first left-handed threaded through hole (1231) is provided on the smooth shaft section of the first cylinder head bolt (123), and a first right-handed threaded through hole (1241) is provided on the smooth shaft section of the second cylinder head bolt (124); the end of the second U-shaped groove (1212) of the first support rod (121) is placed in the third U-shaped groove (1221) of the second support rod (122), and the second through hole (1214) thereon is concentric with the third through hole (1223), and the first cylinder head bolt (123) is installed here, and a nut is screwed on the other end of the bolt to connect the first support rod (121) and the second support rod (122); similarly, another pair of the first support rod (121) and the second support rod (122) are connected by the second cylinder head bolt (124); The described constraint mechanism (13) includes four constraint rods (131), four constraint bolts (132), and two constraint support shafts (133); the constraint support shafts (133) are in the shape of stepped shafts that are thick in the middle and thin at both ends. A seventh through-hole (1331) is provided at the middle position of the thicker shaft section in the middle, and first circular grooves (1332) are respectively provided on the thinner shaft sections at both ends; the constraint rods (131) are respectively provided with eighth through-holes (1311) at both ends. The two constraint support shafts (133) pass through the lead screw transmission shaft (125) through the middle seventh through-hole (1331), and the constraint rods (131) are respectively installed on both sides of the thicker shaft section of the constraint support shafts (133) through the eighth through-holes (1311); the constraint bolts (132) include a smooth shaft section and a threaded section, and a second circular groove (1321) is provided at the smooth shaft end of the constraint bolts (132); the four constraint bolts (132) are respectively screwed into the first threaded holes (1215) of the two first support rods (121) and the second threaded holes (1225) of the two second support rods (122); one end of the constraint rod (131) is installed on the constraint bolt (132) through the eighth through-hole (1311) thereon, and the other end is installed on the constraint support shaft (133), and a hole retaining ring is clamped on the second circular groove (1321) of the constraint bolt (132) and the first circular groove (1332) of the constraint support shaft (133) for positioning.

2. The link-type rolling mechanism for rolling metal bellows according to claim 1, characterized in that, the lead screw transmission shaft (125) is designed in the shape of a stepped shaft that is thick in the middle and thin at both ends. One end is provided with a first left-handed thread (1251), and the other end is provided with a first right-handed thread (1252). A first keyway (1253) is provided at the end of the end provided with the right-handed thread; the first socket head bolt (123) is installed on the first left-handed thread (1251) of the lead screw transmission shaft (125) through the first left-handed thread through-hole (1231), and the second socket head bolt (124) is installed on the first right-handed thread (1252) of the lead screw transmission shaft (125) through the first right-handed thread through-hole (1241); the shaft section of the third socket head bolt (126) is provided with a fifth through-hole (1261), and the double-headed bolt (127) is designed in the shape of a stepped shaft that is thick in the middle and thin at both ends; the four third socket head bolts (126) are respectively inserted into the first through-holes (1213) of the two first support rods (121) and the fourth through-holes (1224) of the two second support rods (122), and nuts are respectively screwed on the ends; the tool head (128) is disc-shaped, and a sixth through-hole (1281) is provided at the center. The tool head (128) is installed on the thicker shaft section in the middle of the double-headed bolt (127) through the sixth through-hole (1281) at the center. The two ends of the two double-headed bolts (127) are respectively inserted into the fifth through-holes (1261) of the four third socket head bolts (126), and nuts are screwed on the ends for fixation.

3. The link-type rolling mechanism for metal bellows rolling according to claim 1, characterized in that, the housing (11) includes a circular left end cover (111), two semi-cylindrical housings (112), and a circular right end cover (113). The circular left end cover (111) and the circular right end cover (113) are fixed at both ends of the two semi-cylindrical housings (112). Two second blind holes (1122) are provided on the inner cylindrical surface of the semi-cylindrical housing (112) to provide support for both ends of the two constraint support shafts. A first blind hole (1112) is provided at the center of the circular left end cover (111) to support one end of the lead screw transmission shaft (125) with a left-handed thread. A ninth through hole (1132) is provided at the center of the circular right end cover (113) for the end of the lead screw transmission shaft (125) with a right-handed thread to extend out.

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