GB2578392A

GB2578392A - Screw conveyor and shield tunneling machine

Info

Publication number: GB2578392A
Application number: GB2000529.4A
Authority: GB
Inventors: Oda Makoto; Ito Takao
Original assignee: Kawasaki Heavy Industries Ltd; Kawasaki Jukogyo KK
Current assignee: Kawasaki Heavy Industries Ltd; Kawasaki Motors Ltd
Priority date: 2017-07-14
Filing date: 2018-07-13
Publication date: 2020-05-06
Anticipated expiration: 2038-07-13
Also published as: GB2578392B; JP7033403B2; GB202000529D0; CN110869583B; KR102427744B1; WO2019013328A1; CN110869583A; KR20200022483A; DE112018003616T5; JP2019019518A; DE112018003616T8

Abstract

In an aspect of the present invention, a screw conveyor comprises a helical auger and a central shaft that extends along the center line of the auger and that is formed in the same topological helix as the auger. In another aspect of the present invention, a screw conveyor is a ribbon-type screw conveyor and comprises a helical auger and a plurality of projections that are provided on the inner circumferential surface of the auger and that extend to the center line of the auger.

Description

DESCRIPTION

Title of Invention: SCREW CONVEYOR AND SHIELD MACHINE Technical Field [0001] The present invention relates to a screw conveyor and a shield machine including the screw conveyor.

Background Art

[0002] Screw conveyors include shaft-type screw conveyors having a linear central shaft around which a helical auger is provided and ribbon-type screw conveyors having no central shaft (see Patent Literature 1, for example). Ribbon-type screw conveyors have the advantage of being able to convey larger pieces of material (such as gravel) than shaft-type screw conveyors.

Citation List Patent Literature [0003] Patent Literature 1: Japanese Laid-Open Patent Application Publication No. 2011-

Summary of Invention

Technical Problem [0004] However, a ribbon-type screw conveyor, as viewed in its axial direction, has a through hole formed in the center of its auger. As such, the problem of low water stop performance arises when the material to be conveyed contains a large amount of water.

[0005] It is therefore an object of the present invention to provide a screw conveyor able to convey large pieces of material and having high water stop performance and a shield machine including the screw conveyor.

Solution to Problem [0006] In order to solve the above problem, a screw conveyor according to one aspect of the present invention includes: an auger having a helical shape; and a central shaft extending along a centerline of the auger and formed in a helical shape having the same phase as the helical shape of the auger.

[0007] With the above configuration, the presence of the central shaft ensures that the screw conveyor, as viewed in its axial direction, has no through hole formed in the center of the auger. Thus, improved water stop performance can be achieved. Additionally, since the central shaft is in a helical shape, larger pieces of material can be conveyed than in conventional cases where the central shaft is in a linear shape. Further, since the helical shape of the central shaft has the same phase as the helical shape of the auger, the material to be conveyed can be advanced on a region along the central shaft at the same timing as advanced by the auger.

[0008] An outer peripheral surface of the central shaft may be smoothly continuous with opposite blade surfaces of the auger. With this configuration, for example, if the central shaft and the auger are produced integrally by molding, the need for joining the central shaft and the auger together can be eliminated, and cost reduction can be achieved.

[0009] For example, in a longitudinal cross-section including the centerline of the auger, a minimum distance from the centerline of the auger to an outer peripheral surface of the central shaft may be 1/20 or less of an outer diameter of the auger.

[0010] A screw conveyor according to another aspect of the present invention is a ribbon-type screw conveyor and includes an auger having a helical shape and a plurality of projections disposed on an inner peripheral surface of the auger and extending to a centerline of the auger.

[0011] With the above configuration, the screw conveyor, as viewed in its axial direction, has no through hole formed in the center of the auger. This makes it possible to achieve improved water stop performance while exploiting the ribbon-type screw conveyor's advantage of being able to convey large pieces of material.

[0012] A screw conveyor according to yet another aspect of the present invention is a ribbon-type screw conveyor and includes an auger having a helical shape, wherein a distance from a centerline of the auger to an inner peripheral surface of the auger is substantially zero.

[0013] With the above configuration, the screw conveyor, as viewed in its axial direction, has substantially no through hole formed in the center of the auger. This makes it possible to achieve improved water stop performance while exploiting the ribbon-type screw conveyor's advantage of being able to convey large pieces of material.

[0014] A shield machine of the present invention includes any of the screw conveyors as set forth above.

Advantageous Effects of Invention [0015] The present invention provides a screw conveyor able to convey large pieces of material and having high water stop performance. Brief Description of Drawings [0016] Fig. 1 A is a side view of a screw conveyor according to a first embodiment of the present invention, and Fig. 1B is a cross-sectional view of the screw conveyor.

Fig. 2A is a side view of a screw conveyor according to a second embodiment of the present invention, and Fig. 2B is a cross-sectional view of the screw conveyor.

Fig. 3A is a side view of a screw conveyor according to a third embodiment of the present invention, and Fig. 3B is a cross-sectional view of the screw conveyor.

Fig. 4 is a perspective view of a screw in the third embodiment.

Fig. 5A is a side view of a screw conveyor according to a fourth embodiment of the present invention, and Fig. 5B is a cross-sectional view of the screw conveyor.

Fig. 6A is a side view of a conventional shaft-type screw conveyor, and Fig. 6B is a cross-sectional view of the screw conveyor.

Description of Embodiments

[0017] (First Embodiment) Figs. lA and 1B show a screw conveyor lA according to a first embodiment of the present invention. This screw conveyor IA includes a screw 3A and a tubular casing 2 enclosing the screw 3A. The screw conveyor IA is mounted, for example, in a shield machine.

[0018] The screw 3A includes an auger 5 having a helical shape and a central shaft 4 extending along a centerline L of the auger 5. For example, the central shaft 4 and the auger are joined by welding.

[0019] The central shaft 4 is formed in a helical shape having the same phase as the helical shape of the auger 5. In other words, the central shaft 4, as viewed in a longitudinal cross-section including the centerline L of the auger 5, is corrugated such that the central shaft 4 is convex toward the cross-sectional portion of the auger 5.

[0020] In the longitudinal cross-section of Fig. 1B, which includes the centerline L of the auger 5, a minimum distance D2 from the centerline L of the auger 5 to an outer peripheral surface 41 of the central shaft 4 is desirably 1/20 or less of an outer diameter DI of the auger 5. More desirably, the minimum distance D2 from the centerline L of the auger 5 to the outer peripheral surface 41 of the central shaft 4 is V40 or less of the outer diameter Dl of the auger 5.

[0021] In the present embodiment, the presence of the central shaft 4 ensures that the screw conveyor 1A, as viewed in its axial direction, has no through hole formed in the center of the auger 5. Thus, improved water stop performance can be achieved. Additionally, since the central shaft 4 is in a helical shape, larger pieces of material 10 can be conveyed than by a conventional screw conveyor 100 which, as shown in Figs. 6A and 6B, has a central shaft having a linear shape. Further, since the helical shape of the central shaft 4 has the same phase as the helical shape of the auger 5, the material to be conveyed can be advanced on a region along the central shaft 4 at the same timing as advanced by the auger 5.

[0022] (Second Embodiment) Figs. 2A and 2B show a screw conveyor 1B according to a second embodiment of the present invention. In the present embodiment and third and fourth embodiments described later, elements which are the same as those of the first embodiment are denoted by the same reference signs, and repeated explanation of these elements is omitted.

[0023] The screw conveyor 1B of the present embodiment includes a screw 3B constituted by the central shaft 4 and the auger 5 which visually appear to be formed integrally.

[0024] Specifically, in the present embodiment, the outer peripheral surface 41 of the central shaft 4 is smoothly continuous with opposite blade surfaces 51 and 52 (51: conveyance surface, 52: non-conveyance surface). In the illustrated example, the outer peripheral surface of the central shaft 4 and the opposite blade surfaces 51 and 52 of the auger 5 form a hemispherical curved surface in a longitudinal cross-section including the centerline L of the auger 5.

[0025] With the configuration of the present embodiment, for example, if the central shaft 4 and the auger 5 are produced integrally by molding, the need for joining the central shaft 4 and the auger together can be eliminated, and cost reduction can be achieved.

[0026] (Third Embodiment) Figs. 3A and 3B and Fig. 4 show a screw conveyor IC according to a third embodiment of the present invention.

[0027] The screw conveyor 1C of the present embodiment is a ribbon-type screw conveyor, and includes a screw 3C that does not have the central shaft 4.

[0028] The screw 3C includes the auger 5 having a helical shape and a plurality of projections 6 disposed on an inner peripheral surface of the auger 5. Each projection 6 extends from the inner peripheral surface of the auger 5 to the centerline L of the auger 5. That is, as shown in Fig. 4, the projections 6 are arranged in the form of helical stairs.

[0029] With the configuration of the present embodiment, the screw conveyor IC, as viewed in its axial direction, has no through hole formed in the center of the auger 5. This makes it possible to achieve improved water stop performance while exploiting the ribbon-type screw conveyor's advantage of being able to convey large pieces of material 10.

[0030] (Fourth Embodiment) Figs. 5A and 5B show a screw conveyor 1D according to a fifth embodiment of the present invention.

[0031] The screw conveyor ID of the present embodiment is a ribbon-type screw conveyor, and includes a screw 3D that does not have the central shaft 4.

[0032] The screw 3D includes the auger 5 having a helical shape. In the present embodiment, the distance from the centerline L of the auger 5 to the inner peripheral surface of the auger 5 is substantially zero (e.g., 10 mm or less).

[0033] With the configuration of the present embodiment, the screw conveyor 1D, as viewed in its axial direction, has substantially no through hole formed in the center of the auger 5. This makes it possible to achieve improved water stop performance while exploiting the ribbon-type screw conveyor's advantage of being able to convey large pieces of material 10.

[0034] (Other Embodiments) The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the gist of the present invention. Reference Signs List [0035] lA to 1 D Screw conveyor 4 Central shaft Auger 51, 52 Blade surface 6 Projection

Claims

CLAIMS1. A screw conveyor comprising: an auger having a helical shape; and a central shaft extending along a centerline of the auger and formed in a helical shape having the same phase as the helical shape of the auger.
2. The screw conveyor according to claim 1, wherein an outer peripheral surface of the central shaft is smoothly continuous with opposite blade surfaces of the auger.
3. The screw conveyor according to claim 1 or 2, wherein in a longitudinal cross-section including the centerline of the auger, a minimum distance from the centerline of the auger to an outer peripheral surface of the central shaft is 1/20 or less of an outer diameter of the auger.
4. A ribbon-type screw conveyor comprising: an auger having a helical shape; and a plurality of projections disposed on an inner peripheral surface of the auger and extending to a centerline of the auger.
5. A ribbon-type screw conveyor comprising an auger having a helical shape, wherein a distance from a centerline of the auger to an inner peripheral surface of the auger is substantially zero.A shield machine comprising the screw conveyor according to any one of claims 1 to