Steel pipe inner circle supporting device

Abstract

The utility model relates to the technical field of steel pipe butt joint, and discloses a steel pipe inner circle supporting device which comprises a plurality of inner circle supporting single bodies. The multiple power telescopic rods are distributed in a radial shape, the fixed ends of the power telescopic rods are fixedly connected with the inner circle supporting single bodies, the movable ends of the power telescopic rods face the outer sides of the inner circle supporting single bodies and are detachably connected with pushing heads, and the ends, away from the power telescopic rods, of the pushing heads are provided with arc surfaces; and the connecting rods are used for connecting the plurality of inner supporting circle single bodies. Compared with a traditional supporting structure, by arranging the pushing head, the contact area between the supporting structure and the steel pipe is increased, the contact pressure between the supporting structure and the steel pipe is reduced, and the possibility of internal deformation of the steel pipe is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to steel pipe butt joint technical field especially relates to a steel pipe inner supporting round device. BACKGROUND

[0002] At present, the traditional steel pipe manufacturing process includes rolling pipe, welding, roundness correction and other processes. In the rolling and welding process, the steel pipe may have ovality error, which affects the roundness and quality of the steel pipe. The existing supporting round device mainly has two types: welded type and screw rod type. The welded type supporting round device is fixed in the steel pipe by welding, but it needs to be cut and polished in the later stage, which increases the workload and cost. The screw rod type supporting round device needs manual adjustment, which is time-consuming and laborious and has poor roundness adjustment effect.

[0003] The patent with publication number CN214731135U discloses a multi-point synchronous expansion pressure steel pipe inner supporting structure, which comprises a center frame, a first supporting structure and a second supporting structure fixed on the center frame; the center frame comprises a center block, the first supporting structure comprises a plurality of supporting rods, the supporting rods are evenly fixed in a peripheral direction of the center block in a launching manner, the ends of the supporting rods are fixed with the second supporting structure, the second supporting structure comprises a plurality of multi-stage bidirectional hydraulic jacks and a hydraulic pump, each multi-stage bidirectional hydraulic jack is connected with one supporting rod, and all the multi-stage bidirectional hydraulic jacks are connected with the hydraulic pump through a hydraulic pipeline. The multi-stage bidirectional hydraulic jack has an ultra-long stroke, can support synchronously, can accurately control the pressure of the hydraulic jack, can accurately adjust, and can improve the manufacturing and installation quality of the pressure steel pipe.

[0004] However, the above-mentioned scheme still has the following defects: ① the movable end of the hydraulic jack is not provided with a push head, the contact area with the steel pipe is small, and local deformation of the steel pipe is easy to occur; ② the stress of the hydraulic jack directly acts on the supporting rod and is transmitted to the center block, which simultaneously increases the material requirements of the supporting rod and the center block, and the manufacturing cost is high; ③ the center block, the supporting rod and the connecting rod are distributed in a net shape, when multiple supporting structures are arranged, it is difficult for the operator to pass through, and the installation and debugging of the supporting structure are inconvenient.

[0005] Therefore, how to change the above-mentioned situation becomes a technical problem that needs to be solved by the technical personnel in the field. UTILITY MODEL CONTENT

[0006] The utility model discloses a steel pipe inner supporting round device to overcome the above-mentioned situation, aims at providing a steel pipe inner supporting round device to increase the contact area with the inner wall of the steel pipe, thereby reducing the deformation amount of the steel pipe, reducing the use amount of the stress material, thereby reducing the manufacturing cost of the device, and setting an entrance and exit that can be passed through by the operator, thereby facilitating the installation and debugging of the supporting device.

[0007] In order to achieve the above-mentioned purpose, the technical scheme of the utility model is: a steel pipe inner supporting round device, comprising:

[0008] a plurality of inner supporting circular monomers;

[0009] a plurality of radial power telescopic rods, fixed ends of the power telescopic rods are fixedly connected with the inner supporting circular monomers, movable ends of the power telescopic rods are directed to outside of the inner supporting circular monomers, and push heads are detachably connected with the movable ends of the power telescopic rods, and the push heads are provided with arc surfaces at one end away from the power telescopic rods; and

[0010] a connecting rod for connecting the plurality of inner supporting circular monomers.

[0011] Further, the inner supporting circular monomer comprises:

[0012] a plurality of inner supporting plates and outer supporting plates arranged in a ring shape and sequentially from inside to outside, the fixed ends of the power telescopic rods are fixedly connected with outer edges of the inner supporting plates, the movable ends of the power telescopic rods are arranged through the outer supporting plates, and the inner supporting plates and / or the outer supporting plates between adjacent inner supporting circular monomers are connected through the connecting rod; and

[0013] a plurality of supporting rods for connecting the inner supporting plates and the outer supporting plates.

[0014] Further, the push head comprises:

[0015] a push head assembly provided with an arc surface at one end face; and

[0016] a supporting column fixedly connected with the other end of the push head assembly, and the movable end of the power telescopic rod is detachably connected with the other end of the supporting column.

[0017] Further, the push head further comprises a guide rod fixedly connected with the other end of the supporting column, the guide rod is arranged in parallel with the supporting column, and the guide rod is slidably connected with the outer supporting plate.

[0018] Further, the push head assembly comprises:

[0019] a push head plate provided with an arc surface at one end face;

[0020] a supporting plate with a trapezoidal cross section, a lower bottom face of the supporting plate is fixedly connected with the other end of the push head plate; and

[0021] a supporting connecting plate fixedly connected with an upper bottom face of the supporting plate at one end, and the other end of the supporting connecting plate is fixedly connected with the guide rod and the supporting column respectively.

[0022] Further, the push head assembly further comprises a rib plate, the rib plate is arranged between the other end of the push head plate and the supporting plate, and between one end of the supporting connecting plate and the supporting plate.

[0023] Further, the plurality of support rods are distributed radially, and the plurality of support rods on each inner support circle monomer and the plurality of power telescopic rods are arranged at intervals.

[0024] Further, the outer edge of the inner support plate is a regular N-polygon, the outer support plate is a regular 2N-polygon, and the N outer edge sides of the inner support plate are arranged opposite to the N sides of the outer support plate one by one.

[0025] The fixed end of the power telescopic rod is fixedly connected with the outer edge side of the inner support plate, and the movable end of the power telescopic rod penetrates through the side of the outer support plate.

[0026] One end of the support rod is fixedly connected with the outer edge corner of the inner support plate, and the other end of the support rod is fixedly connected with the side of the outer support plate, wherein N is a positive integer greater than 2.

[0027] Further, the connecting rod is a fixed pull rod, bolts are threadedly connected at both ends of the fixed pull rod, the inner support plate is provided with connecting holes, the screw rods of the bolts penetrate through the connecting holes and are threadedly connected with the fixed pull rod, and the heads of the bolts and the fixed pull rod are respectively abutted on both sides of the inner support plate.

[0028] Further, the power telescopic rod is a hydraulic jack, the piston cylinder of the hydraulic jack is fixedly connected with the inner support plate, the piston cylinder is divided into an upper cavity and a lower cavity by a piston in the piston cylinder, a side wall of the piston cylinder is provided with a first oil inlet and a second oil inlet connected with the upper cavity and the lower cavity one by one in correspondence, and a piston rod of the hydraulic jack is detachably connected with the other end of the support column.

[0029] First and second annular oil pipes are fixedly connected to front and rear end faces of the inner support plate respectively, and the first and second annular oil pipes are uniformly provided with oil inlets and outlets, the plurality of first oil inlets on each inner support circle monomer are connected with the first annular oil pipe through a plurality of first connecting pipes one by one, and the plurality of second oil inlets are connected with the second annular oil pipe through a plurality of second connecting pipes one by one.

[0030] Compared with the prior art, the utility model has at least the following advantages:

[0031] After the steel pipe group circle is completed, the device is hoisted into the steel pipe, the length of the power telescopic rod is adjusted, the push head is abutted on the inner wall of the steel pipe, and the steel pipe roundness is ensured to meet the specification requirements. Through the adjustment of the length of the power telescopic rod, the steel pipe roundness can be accurately adjusted, and welding operation is not needed. Compared with the traditional support structure, by arranging the push head, the contact area between the push head and the steel pipe is increased, the contact pressure between the push head and the steel pipe is reduced, and the possibility of deformation of the steel pipe is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings described in the following embodiments are only some of the embodiments of the present application, and not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0033] Figure 1 It is a whole structure schematic view of the steel pipe inner supporting round device of the present application.

[0034] Figure 2 It is an assembly schematic view of the inner supporting round monomer, the power telescopic rod and the connecting rod of the present application.

[0035] Figure 3 It is an assembly schematic view of the inner supporting round monomer, the power telescopic rod and the connecting rod of the present application from another perspective.

[0036] Figure 4 It is a three-dimensional structure view of the push head of the present application.

[0037] Figure 5 It is a sectional view of the push head of the present application.

[0038] Figure 6 It is a three-dimensional structure schematic view of the connecting rod of the present application.

[0039] Figure 7 It is a sectional view of the connecting rod of the present application.

[0040] The drawings are as follows: 1, inner supporting round monomer; 2, power telescopic rod; 3, push head; 4, connecting rod; 5, first annular oil pipe; 6, second annular oil pipe; 11, inner supporting plate; 12, outer supporting plate; 13, supporting rod; 21, piston cylinder; 22, piston rod; 23, first oil inlet; 24, first connecting pipe; 25, second oil inlet; 26, second connecting pipe; 31, push head plate; 32, supporting plate; 33, supporting connecting plate; 34, rib plate; 35, supporting column; 36, guide rod; 41, fixed pull rod; 42, bolt. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, and not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0042] In order to make the above-mentioned purposes, characteristics and advantages of the utility model more apparent, specific and easy to understand, the utility model will be explained in further detail below in combination with the drawings and specific embodiments.

[0043] Referring to Figures 1-3 The utility model provides a kind of steel pipe inner support circle device, including inner support circle monomer 1, power telescopic link 2, push head 3 and connecting rod 4. Among them, the quantity of inner support circle monomer 1 is multiple, multiple inner support circle monomers 1 are arranged in row, and multiple connecting rods 4 are connected between adjacent two inner support circle monomers 1. Multiple power telescopic links 2 are provided on each inner support circle monomer 1, and multiple power telescopic links 2 are distributed radially, and the fixed end of power telescopic link 2 is fixedly connected with inner support circle monomer 1, and the movable end of power telescopic link 2 is towards the outside of inner support circle monomer 1, and is detachably connected with push head 3, and the end of push head 3 away from power telescopic link 2 is provided with cambered surface, and cambered surface is matched with the inner wall for supporting steel pipe. By replacing push head 3 of different diameter cambered surface, it can be applicable to the support of steel pipe of different diameter.

[0044] After steel pipe group circle is completed, the device is hoisted into steel pipe, the length of power telescopic link 2 is adjusted, so that push head 3 is abutted on the inner wall of steel pipe, to ensure that the roundness of steel pipe meets the specification requirements. By the length adjustment of power telescopic link 2, the roundness of steel pipe can be accurately adjusted, and welding operation is not needed. Compared with traditional support structure, by being provided with push head 3, the contact area between push head 3 and steel pipe is increased, the contact pressure between push head 3 and steel pipe is reduced, and the possibility of deformation of steel pipe is reduced.

[0045] The device can accurately control the roundness of steel pipe, and provide very favorable conditions for subsequent welding, stiffening ring assembly and other operations. Since push head 3 does not need to be welded with the body of steel pipe, the disassembly and assembly process is facilitated, the auxiliary work amount of steel pipe manufacturing is greatly reduced, the production efficiency is improved, the cost is saved, and the device can be reused.

[0046] Specifically, inner support circle monomer 1 includes inner support plate 11, outer support plate 12 and support rod 13. Inner support plate 11 and outer support plate 12 are annular and are sequentially arranged from inside to outside, the fixed end of power telescopic link 2 is fixedly connected to the outer edge of inner support plate 11, the movable end of power telescopic link 2 is arranged through outer support plate 12, and the two ends of multiple support rods 13 are connected to inner support plate 11 and outer support plate 12 respectively. Inner support plate 11 and / or outer support plate 12 between adjacent inner support circle monomers 1 are connected by connecting rod 4 to realize the effect of series connection of multiple inner support circle monomers 1.

[0047] As known from the above, the stress of power telescopic link 2 of the utility model directly acts on inner support plate 11, and support rod 13 only plays a connecting role, so that the material requirement of support rod 13 can be greatly reduced, the use amount of core stress material is reduced, and the manufacturing cost of the device of the utility model is further reduced.

[0048] Referring to Figures 4-5 , the push head 3 comprises a push head assembly and a supporting column 35. One end face of the push head assembly is provided with a circular arc surface, one end of the supporting column 35 is fixedly connected with the other end of the push head assembly, and the other end of the supporting column 35 is detachably connected with the movable end of the power telescopic rod 2. By the extension and contraction of the power telescopic rod 2, the supporting column 35 is synchronously moved, so as to drive the push head assembly to be attached to or away from the inner wall of the steel pipe.

[0049] In order to ensure that the push head assembly does not deflect during movement, the push head assembly is better attached to the inner wall of the steel pipe. The push head 3 of the utility model further comprises a guide rod 36 fixedly connected with the other end of the supporting column 35, the guide rod 36 is arranged in parallel with the supporting column 35, and the guide rod 36 is slidably connected with the outer supporting plate 12. In one specific embodiment of the utility model, two guide rods 36 are arranged on each push head 3, and the two guide rods 36 are respectively located on the two sides of the supporting column 35.

[0050] The other end of the supporting column 35 is provided with an internal thread structure, the movable end of the power telescopic rod 2 is provided with an external thread structure, the power telescopic rod 2 is extended and protrudes from the outer supporting plate 12, and the other end of the supporting column 35 and the movable end of the power telescopic rod 2 are connected by screwing. The guide rod 36 is aligned with the sliding hole corresponding to the guide rod 36 on the outer supporting plate 12, the power telescopic rod 2 is retracted, and the installation process of the push head 3 is completed. Conversely, the power telescopic rod 2 is extended and protrudes from the outer supporting plate 12, and the connection between the other end of the supporting column 35 and the movable end of the power telescopic rod 2 is released by reverse screwing. At this time, other sizes of push heads 3 can be replaced to adapt to steel pipes of different diameters.

[0051] Preferably, the push head assembly comprises a push head plate 31, a supporting plate 32 and a supporting connecting plate 33. One end face of the push head plate 31 is provided with a circular arc surface, the cross section of the supporting plate 32 is trapezoidal, the lower bottom surface of the supporting plate 32 is fixedly connected with the other end of the push head plate 31, the upper bottom surface of the supporting plate 32 is fixedly connected with one end of the supporting connecting plate 33, and the other end of the supporting connecting plate 33 is fixedly connected with the guide rod 36 and the supporting column 35 respectively.

[0052] Specifically, in order to improve the stability between the push head plate 31 and the supporting plate 32 and between the supporting connecting plate 33 and the supporting plate 32, the push head assembly of the utility model further comprises a rib plate 34, and the rib plate 34 is arranged between the other end of the push head plate 31 and the supporting plate 32 and between one end of the supporting connecting plate 33 and the supporting plate 32.

[0053] In one specific embodiment of the utility model, the supporting rods 13 are arranged in the same way as the power telescopic rods 2. The plurality of supporting rods 13 are also radially distributed, and the plurality of supporting rods 13 and the plurality of power telescopic rods 2 on each inner supporting circular monomer 1 are arranged at intervals.

[0054] Referring again to Figures 2-3 , the outer edge of the inner support plate 11 is a regular N-polygon, the outer support plate 12 is a regular 2N-polygon, and the N outer edge sides of the inner support plate 11 are arranged opposite to the N sides of the outer support plate 12; the fixed end of the power telescopic rod 2 is fixedly connected to the outer edge side of the inner support plate 11, and the movable end of the power telescopic rod 2 is arranged through the side of the outer support plate 12; one end of the support rod 13 is fixedly connected to the outer edge corner of the inner support plate 11, and the other end of the support rod 13 is fixedly connected to the side of the outer support plate 12, wherein N is a positive integer greater than 2. The actual number of N is determined by the specific steel pipe to be supported, and the present application does not make specific limitations here.

[0055] Optionally, the power telescopic rod 2 is a hydraulic jack, the piston cylinder 21 of the hydraulic jack is fixedly connected to the inner support plate 11, the piston cylinder 21 is divided into an upper cavity and a lower cavity by a piston inside the piston cylinder 21, the side wall of the piston cylinder 21 is provided with a first oil inlet 23 and a second oil inlet 25 corresponding to the upper cavity and the lower cavity, respectively, the piston rod 22 of the hydraulic jack is detachably connected to the other end of the support column 35; the front and rear end faces of the inner support plate 11 are fixedly connected with a first annular oil pipe 5 and a second annular oil pipe 6, respectively, and the first annular oil pipe 5 and the second annular oil pipe 6 are uniformly provided with oil inlet and outlet ports; a plurality of first oil inlets 23 on each inner support plate 1 are connected with the first annular oil pipe 5 through a plurality of first connecting pipes 24, respectively, and a plurality of second oil inlets 25 are connected with the second annular oil pipe 6 through a plurality of second connecting pipes 26, respectively. The oil inlet and outlet ports are connected with the oil pump, and high-pressure oil is injected into or extracted from the first annular oil pipe 5 and the second annular oil pipe 6 through the oil inlet and outlet ports, so that the hydraulic jack can be telescoped. Further, the plurality of jacks can be synchronously telescoped, so that the steel pipe and the push head 3 are uniformly stressed.

[0056] In order to realize the threaded connection of the hydraulic jack and the support column 35, the end of the piston rod 22 of the hydraulic jack can be provided with a threaded structure, or a threaded block can be fixedly connected to the end of the piston rod 22 for connection with the support column 35.

[0057] The inner support plate 11 and the outer support plate 12 are annular as a whole, the inside of the inner support plate 11 can be passed through by the operator, the fitting condition of the push head 3 and the inner wall of the steel pipe can be conveniently observed, and the connection between the oil inlet and outlet ports and the oil pump is facilitated, so as to facilitate the installation and debugging of the support device, and the use convenience of the device is improved.

[0058] Referring to Figures 6-7 , the connecting rod 4 is a fixed pull rod 41, the two ends of the fixed pull rod 41 are threadedly connected with bolts 42, the inner support plate 11 is provided with connecting holes, the screw rods of the bolts 42 penetrate through the connecting holes and are threadedly connected with the fixed pull rod 41, and the heads of the bolts 42 and the fixed pull rod 41 are respectively abutted against the two sides of the inner support plate 11.

[0059] In the description of the utility model, need understanding is, the orientation or position relation that the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" indicate is based on the orientation or position relation shown in the drawing, just is for the convenience of describing the utility model, and is not indicate or imply the device or element that is indicated must have a particular orientation, with a particular orientation configuration and operation, therefore can not be understood as the limitation to the utility model.

[0060] The above-described embodiments are only preferred modes of the utility model, and do not limit the scope of the utility model, and various deformations and improvements of the technical scheme of the utility model made by those skilled in the art without departing from the design spirit of the utility model should fall within the protection scope defined by the claims of the utility model.

Claims

1. A steel pipe inside supporting round device, characterized by, The utility model relates to a steel pipe inner supporting circle device, which comprises the following parts: a plurality of inner supporting circle units (1); a plurality of power telescopic rods (2) radially distributed, the fixed end of the power telescopic rod (2) is fixedly connected with the inner supporting circle unit (1), the movable end of the power telescopic rod (2) is directed to the outside of the inner supporting circle unit (1), and a push head (3) is detachably connected with the movable end of the power telescopic rod (2), and the end of the push head (3) away from the power telescopic rod (2) is provided with a circular arc surface; and a connecting rod (4) for connecting a plurality of the inner supporting circle units (1).

2. The steel pipe and arch apparatus of claim 1, wherein, The inner supporting circle unit (1) comprises: a ring-shaped inner supporting plate (11) and an outer supporting plate (12) arranged in sequence from inside to outside, the fixed end of the power telescopic rod (2) is fixedly connected with the outer edge of the inner supporting plate (11), and the movable end of the power telescopic rod (2) is arranged through the outer supporting plate (12), and the inner supporting plates (11) and / or the outer supporting plates (12) between adjacent inner supporting circle units (1) are connected through the connecting rod (4); and a plurality of supporting rods (13) for connecting the inner supporting plate (11) and the outer supporting plate (12).

3. The steel pipe and arch apparatus of claim 2, wherein, The push head (3) comprises: a push head assembly provided with a circular arc surface on one end face; and a supporting column (35) fixedly connected with the other end of the push head assembly, and the other end of the supporting column (35) is detachably connected with the movable end of the power telescopic rod (2).

4. The steel pipe and bucking round apparatus of claim 3, wherein, The push head (3) further comprises a guide rod (36) fixedly connected with the other end of the supporting column (35), the guide rod (36) is arranged in parallel with the supporting column (35), and the guide rod (36) is slidably connected with the outer supporting plate (12).

5. The steel pipe and bucking round apparatus of claim 4, wherein, The push head assembly comprises: a push head plate (31) provided with a circular arc surface on one end face; a bearing plate (32) in the shape of a trapezoid, the lower bottom face of the bearing plate (32) is fixedly connected with the other end of the push head plate (31); and a supporting connecting plate (33) fixedly connected with the upper bottom face of the bearing plate (32) on one end, and the other end of the supporting connecting plate (33) is fixedly connected with the guide rod (36) and the supporting column (35) respectively.

6. The steel pipe and bucking round apparatus of claim 5, wherein, The push head assembly further comprises a rib plate (34), which is arranged between the other end of the push head plate (31) and the bearing plate (32) and between one end of the supporting connecting plate (33) and the bearing plate (32).

7. The steel pipe and bucking round apparatus of claim 2, wherein, A plurality of the supporting rods (13) are radially distributed, and the plurality of the supporting rods (13) and the plurality of the power telescopic rods (2) on each inner supporting circle unit (1) are arranged at intervals.

8. The steel pipe inner supporting circle device according to claim 2, wherein the outer edge of the inner supporting plate (11) is a regular N-polygon, the outer supporting plate (12) is a regular 2N-polygon, and the N outer edge sides of the inner supporting plate (11) are arranged opposite to the N sides of the outer supporting plate (12) one by one; the fixed end of the power telescopic rod (2) is fixedly connected with the outer edge side of the inner supporting plate (11), and the movable end of the power telescopic rod (2) is arranged through the side of the outer supporting plate (12). One end of the support rod (13) is fixedly connected with the outer edge of the inner support plate (11), and the other end of the support rod (13) is fixedly connected with the edge of the outer support plate (12), wherein N is a positive integer greater than 2.

9. The steel pipe and arch apparatus of claim 2, wherein, The connecting rod (4) is a fixed pull rod (41), both ends of the fixed pull rod (41) are threadedly connected with bolts (42), the inner support plate (11) is provided with a connecting hole, the screw rod of the bolt (42) penetrates through the connecting hole and is threadedly connected with the fixed pull rod (41), and the head of the bolt (42) and the fixed pull rod (41) are respectively abutted on both sides of the inner support plate (11).

10. The steel pipe supporting device according to any one of claims 3 to 6, wherein The power telescopic rod (2) is a hydraulic jack, the piston cylinder (21) of the hydraulic jack is fixedly connected with the inner support plate (11), the piston cylinder (21) is divided into an upper cavity and a lower cavity by a piston inside the piston cylinder (21), the side wall of the piston cylinder (21) is provided with a first oil inlet (23) and a second oil inlet (25) corresponding to the upper cavity and the lower cavity, respectively, the piston rod (22) of the hydraulic jack is detachably connected with the other end of the support column (35); The front and rear end faces of the inner support plate (11) are fixedly connected with a first annular oil pipe (5) and a second annular oil pipe (6), respectively, the first annular oil pipe (5) and the second annular oil pipe (6) are uniformly provided with oil inlets and outlets, a plurality of first oil inlets (23) on each inner support plate (1) are connected with the first annular oil pipe (5) through a plurality of first connecting pipes (24), and a plurality of second oil inlets (25) are connected with the second annular oil pipe (6) through a plurality of second connecting pipes (26).

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