JP2018105341A - Shaft sleeve, rotary machine and method for manufacturing shaft sleeve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shaft sleeve that can prevent detachment of coating from a substrate.SOLUTION: A shaft sleeve 35 includes: a cylindrical substrate 41 formed with an annular recess 51 at an outer peripheral surface; and a coating 43 formed in the annular recess 51 by high-speed flame spraying. The annular recess is constituted of at least: a bottom surface in parallel with a shaft center of the substrate; and two inclined planes extending to an outer peripheral surface of the substrate from both ends of the bottom surface. The angle of the inclined planes relative to the bottom surface is within a range of 10 to 30 degrees.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a shaft sleeve attached to a rotating shaft, and more particularly to a shaft sleeve incorporated in a pump for transferring a liquid such as seawater. The present invention also relates to a rotary machine such as a pump or a compressor incorporating such a shaft sleeve. Furthermore, the present invention relates to a method for manufacturing a shaft sleeve.

  Submersible bearings used in drainage pumps are advantageous in terms of simplifying equipment and facilitating maintenance because they do not require lubricating oil, but the sliding parts of submersible bearings are materials with excellent wear resistance. Must be used. Therefore, ceramic bearings in which a cemented carbide shaft sleeve and a SiC bearing are combined have been developed.

FIG. 8 is a cross-sectional view schematically showing a conventional structure of a shaft sleeve. As shown in FIG. 8, the shaft sleeve 100 includes a cylindrical base material 101 fixed to a rotating shaft (not shown), and a coating 102 formed on the outer peripheral surface of the base material 101 by thermal spraying. For the base material 101, stainless steel having excellent corrosion resistance against liquid is used. The film 102 is formed in a recess formed on the outer peripheral surface of the base material 101. As a thermal spray material for forming the coating 102, at least one of WC (tungsten carbide) and Cr ₃ C ₂ (trichrome dicarbide) is a main component, and the remainder is Ni, Cr, Mo, Co, Fe. What contains the binder which consists of at least 1 and an unavoidable impurity is mentioned.

  When the shaft sleeve 100 rotates, the coating 102 comes into sliding contact with a bearing made of a hard member such as ceramic, and the rotating shaft and the shaft sleeve 100 are rotatably supported by the bearing. The coating 102 made of cemented carbide has excellent wear resistance and corrosion resistance, and can protect the base material 101 made of stainless steel.

JP 2001-82479 A

  In manufacturing the shaft sleeve 100, the coating 102 is formed by high-speed flame spraying. That is, as shown in FIG. 9, the thermal spray material is sprayed at a high speed on the depression 105 formed on the outer peripheral surface of the base material 101. As indicated by the arrows, the thermal spray material is sprayed from a direction perpendicular to the entire depression 105. The high-speed spray material collides with the depression 105 with a strong impact force and bites into the surface of the depression 105. Furthermore, the sprayed material once sprayed is compressed by the subsequent sprayed material. In this way, the thermal spray material adheres strongly to the surface of the recess 105. Such a phenomenon is called an anchor effect.

  Inclined surfaces 105 b are formed at both ends of the recess 105 so that the anchor effect can be obtained at both ends of the recess 105. The angle of the inclined surface 105b with respect to the bottom surface 105a of the recess 105 parallel to the axis C of the substrate 101 is 45 °. Since the inclined surface 105b can receive the spray of the thermal spray material, the anchor effect is obtained in the whole of the recess 51.

  However, the direction of the force of the thermal spray material that collides with the inclined surface 105b is not perpendicular to the inclined surface 105b. As a result, the anchor effect at the inclined surface 105b is weaker than the anchor effect at the bottom surface 105a. For this reason, the coating film 102 formed on the inclined surface 105b may be peeled off.

  Then, an object of this invention is to provide the axial sleeve which can prevent peeling of the film | membrane from a base material. Another object of the present invention is to provide a rotating machine including such a shaft sleeve. Furthermore, this invention aims at providing the manufacturing method of a shaft sleeve.

  In order to achieve the above-described object, according to one aspect of the present invention, a shaft sleeve fixed to the outer peripheral surface of the rotating shaft, and a cylindrical base material having an annular recess formed in the outer peripheral surface; A coating formed in the annular recess by high-speed flame spraying, and the annular recess includes at least a bottom surface parallel to the axis of the substrate, and both ends of the bottom surface to the outer peripheral surface of the substrate. An axial sleeve is provided, characterized in that it is constituted by two inclined surfaces extending, and the angle of the inclined surface with respect to the bottom surface is in the range of 10 to 30 degrees.

  According to one aspect of the present invention, the rotating shaft, the sliding bearing that rotatably supports the rotating shaft, and the shaft sleeve that is fixed to the outer peripheral surface of the rotating shaft and that is in sliding contact with the sliding bearing are provided. A rotating machine is provided.

  According to one aspect of the present invention, a cylindrical base material is prepared, and at least from a bottom surface parallel to the axis of the base material and two inclined surfaces extending from both ends of the bottom surface to the outer peripheral surface of the base material. An annular recess formed is formed on the outer peripheral surface of the substrate, and an angle of the inclined surface with respect to the bottom surface is within a range of 10 degrees to 30 degrees, and a thermal spray material is sprayed on the annular recess by high-speed flame spraying. There is provided a method for manufacturing a shaft sleeve, characterized in that a film is formed by spraying on the annular recess.

  When the spray material collides perpendicularly to the target surface, the anchor effect of the spray material is maximized. According to the present invention, since the inclined surface is inclined at an angle of 10 to 30 degrees with respect to the bottom surface perpendicular to the traveling direction of the thermal spray material, an anchor effect close to the anchor effect on the bottom surface can be obtained even on the inclined surface. Therefore, the coating is difficult to peel off from the inclined surface, and a highly reliable shaft sleeve can be obtained.

It is a mimetic diagram showing a vertical shaft pump in which a shaft sleeve concerning one embodiment of the present invention was built. FIG. 2 is an enlarged view showing a shaft sleeve and an underwater bearing shown in FIG. 1. FIG. 3 is an enlarged view of the shaft sleeve shown in FIG. 2. It is a figure explaining 1 process of the manufacturing method of a shaft sleeve. It is a figure explaining 1 process of the manufacturing method of a shaft sleeve. It is a figure explaining 1 process of the manufacturing method of a shaft sleeve. It is a figure explaining 1 process of the manufacturing method of a shaft sleeve. It is sectional drawing which shows the conventional structure of a shaft sleeve typically. It is a figure which shows a mode that a thermal spray material is sprayed on the base material shown in FIG. 8 by high-speed flame spraying.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic view showing a vertical shaft pump incorporating a shaft sleeve according to an embodiment of the present invention. The vertical shaft pump is a pump for pumping liquids such as seawater and river water from the suction water tank 5 to the discharge water tank 21. The vertical shaft pump shown in FIG. 1 is an example of a pump in which a shaft sleeve according to an embodiment of the present invention is incorporated, and the shaft sleeve can also be applied to pumps of other configurations. Furthermore, the present invention is applicable not only to pumps but also to other types of rotating machines such as compressors and fans.

  As shown in FIG. 1, the vertical shaft pump is connected to an impeller casing 1 having a suction bell mouth 1 a and a discharge bowl 1 b, a pumping pipe 3 for suspending the impeller casing 1 in a suction water tank 5, and an upper end of the pumping pipe 3. The discharge elbow pipe 4, the impeller 10 accommodated in the impeller casing 1, and the rotating shaft 6 to which the impeller 10 is fixed are provided.

  The pump installation floor 22 is connected to the upper part of the suction water tank 5. The pumping pipe 3 extends downward through an insertion port 24 formed in the pump installation floor 22 and is fixed to the pump installation floor 22 via an installation base 23 provided at the upper end of the pumping pipe 3. The rotary shaft 6 extends in the vertical direction through the discharge elbow pipe 4, the pumping pipe 3, and the impeller casing 1. The pump casing 2 includes an impeller casing 1, a pumping pipe 3, and a discharge elbow pipe 4.

  The suction bell mouth 1a opens downward, and the upper end of the suction bell mouth 1a is connected to the lower end of the discharge bowl 1b. The impeller 10 is fixed to the lower end of the rotating shaft 6, and the impeller 10 and the rotating shaft 6 rotate integrally. A plurality of guide vanes 14 are arranged above the impeller 10 (discharge side). These guide vanes 14 are fixed to the inner peripheral surface of the discharge bowl 1b.

  The rotary shaft 6 extends upward through the discharge elbow pipe 4 and is connected to a drive source 18. The drive source 18 is fixed on a gantry 19 fixed to the pump installation floor 22. During operation of the vertical pump, the impeller 10 is located below the liquid level in the suction water tank 5.

  The rotating shaft 6 is rotatably supported by the outer bearing 11 and the underwater bearings 12 and 15. The outer bearing 11 is a rolling bearing such as a ball bearing or a sliding bearing, and the underwater bearings 12 and 15 are sliding bearings. The outer bearing 11 is disposed in the pump casing 2. More specifically, the outer bearing 11 is disposed above the discharge elbow pipe 4.

  The underwater bearing 12 is accommodated in the discharge bowl 1 b and is disposed above the impeller 10. The support member 7 that supports the underwater bearing 12 is fixed to the inner surface of the bowl bush 13, and the bowl bush 13 is supported by the impeller casing 1 via a guide vane 14. The underwater bearing 15 is disposed in the pumping pipe 3. The underwater bearing 15 is supported by a plurality of support members 32, and these support members 32 are fixed to the inner surface of the water pump pipe 3. A shaft sleeve 35 according to an embodiment of the present invention is fixed to the rotating shaft 6. The shaft sleeve 35 and the rotating shaft 6 rotate integrally.

  The vertical pump transfers the liquid in the suction water tank 5 to the discharge water tank 21. That is, when the impeller 10 is rotated through the rotating shaft 6 by operating the drive source 18, the liquid in the suction water tank 5 is sucked from the suction bell mouth 1a, and the discharge bowl 1b, the pumping pipe 3, and the discharge elbow pipe. 4, and the discharge water tank 21 through the discharge pipe 20.

  The discharge pipe 20 extends from the discharge elbow pipe 4 to the discharge water tank 21. The liquid level of the discharge water tank 21 is located above the discharge elbow pipe 4. A gate valve 25 is arranged in the middle of the discharge pipe 20, and the gate valve 25 is opened during normal operation of the vertical shaft pump. When the vertical shaft is stopped, the gate valve 25 is closed to prevent the liquid from flowing back from the discharge water tank 21 to the suction water tank 5 through the discharge pipe 20. Instead of the gate valve 25, a check valve may be provided. Further, a flap valve may be arranged at the discharge end of the discharge pipe 20.

  FIG. 2 is an enlarged view showing the shaft sleeve 35 and the underwater bearing 15 shown in FIG. The shaft sleeve 35 has a cylindrical shape and is fixed to the outer peripheral surface of the rotating shaft 6. The underwater bearing 15 is disposed at the same height as the shaft sleeve 35 and supports the rotary shaft 6 via the shaft sleeve 35. More specifically, when the rotary shaft 6 and the shaft sleeve 35 rotate, the outer peripheral surface of the shaft sleeve 35 comes into sliding contact with the inner peripheral surface of the underwater bearing 15. A minute gap is formed between the outer peripheral surface of the shaft sleeve 35 and the inner peripheral surface of the underwater bearing 15. The liquid existing in the pumping pipe 3 (see FIG. 1) passes through this gap to lubricate the shaft sleeve 35 and the underwater bearing 15.

  The shaft sleeve 35 includes a cylindrical base material 41 and a coating 43 formed on the outer peripheral surface of the base material 41. In this embodiment, the shaft sleeve 35 is arranged vertically, and the coating 43 is located at the same height as the underwater bearing 15. During operation of the vertical shaft pump, only the coating 43 contacts the underwater bearing 15, and the base material 41 does not contact the underwater bearing 15.

FIG. 3 is an enlarged view of the shaft sleeve 35 shown in FIG. The base material 41 is made of a metal such as stainless steel. In the present embodiment, stainless steel having corrosion resistance against liquid is used. The film 43 is formed over the entire circumference of the outer peripheral surface of the base material 41. More specifically, an annular recess 51 extending over the entire circumference is formed on the outer peripheral surface of the substrate 41, and the coating 43 is formed in the recess 51 by thermal spraying. As the thermal spray material for forming the coating 43, WC (tungsten carbide), W ₂ C, Cr ₃ C ₂ (trichrome dicarbide), Cr ₇ C ₃ , Cr ₂₃ C ₆ , NbC (niobium carbide) which are carbide ceramics. , And TiC (titanium carbide) containing at least one binder as a main component, and the remainder containing at least one of Ni, Cr, Mo, Co, and Fe and inevitable impurities. WC and / or Cr ₃ C ₂ are preferably used from the viewpoint of having high wear resistance. High speed flame spraying is used as the spraying method.

  An annular recess 51 formed on the outer peripheral surface of the base material 41 includes a bottom surface 51a parallel to the axis C of the base material 41, and two inclined surfaces 51b extending from both ends of the bottom surface 51a to the outer peripheral surface of the base material 41. At least. The recess 51 has a tapered cross section. The angle θ of each inclined surface 51b with respect to the bottom surface 51a is in the range of 10 degrees to 30 degrees. In order to allow the liquid to pass through the gap between the shaft sleeve 35 and the underwater bearing 15 without stagnation, it is preferable that the outer peripheral surface of the base material 41 and the outer peripheral surface of the coating 43 are in the same plane.

  The shaft sleeve 35 of the present embodiment is manufactured as follows. In step 1, as shown in FIG. 4, a cylindrical base material 41 is prepared. In step 2, as shown in FIG. 5, a cutting tool (not shown) is pressed against the outer peripheral surface of the base material 41 while rotating the base material 41 about its axis C, An annular recess 51 is formed over the entire circumference. More specifically, the outer peripheral surface of the base material 41 is cut so that a bottom surface 51a of the recess 51 and two inclined surfaces 51b extending from the bottom surface 51a to the outer peripheral surface of the base material 41 are formed. The angle θ of the inclined surface 51b with respect to the bottom surface 51a parallel to the axis C of the base material 41 is in the range from 10 degrees to 30 degrees. The inclined surface 51b is formed in order to ensure that the thermal spray material is in close contact with the end of the recess 51 in high-speed flame spraying performed in the next step.

  In step 3, as shown in FIG. 6, a spray material is sprayed on the recess 51 of the base material 41 by high-speed flame spraying to form a coating 43 in the recess 51. In this step 3, the thermal spray material is sprayed until the recess 51 is completely filled with the thermal spray material. The thermal spray material is sprayed from a direction perpendicular to the entire depression 51 (a direction perpendicular to the axis C). Since the entire bottom surface 51a and the inclined surface 51b of the recess 51 can receive a jet of the spray material, the spray material once sprayed on the recess 51 receives the pressure of the subsequent spray material and receives the pressure on the bottom surface 51a and the inclined surface 51b. It can adhere strongly to the whole. That is, the anchor effect is obtained by the entire bottom surface 51a and the inclined surface 51b.

  High-speed flame spraying is a spraying technique in which a high-speed flame is generated by increasing the pressure in the combustion chamber, and a molten or semi-molten spray material is sprayed onto a target surface at a high speed. When the spray material collides perpendicularly to the target surface, the anchor effect of the spray material is maximized. According to the present embodiment, since the inclined surface 51b is inclined at an angle of 10 degrees to 30 degrees with respect to the bottom surface 51a perpendicular to the traveling direction of the sprayed material, the anchor effect close to the anchor effect on the bottom surface 51a is an inclined surface. Even 51b can be obtained. Therefore, the coating 43 is not easily peeled off from the inclined surface 51b, and a highly reliable shaft sleeve 35 is obtained. Furthermore, the effect that the sprayed material is less scattered on the inclined surface 51b is also obtained.

  In step 4, as shown in FIG. 7, surface treatment such as grinding is performed on the film 43 to smooth the outer peripheral surface of the film 43. The shaft sleeve 35 according to this embodiment is manufactured through the above manufacturing steps.

  The embodiment described above is described for the purpose of enabling the person having ordinary knowledge in the technical field to which the present invention belongs to implement the present invention. Various modifications of the above embodiment can be naturally made by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Accordingly, the present invention is not limited to the described embodiments, but is to be construed in the widest scope according to the technical idea defined by the claims.

DESCRIPTION OF SYMBOLS 1a Suction bell mouth 1b Discharge bowl 1 Impeller casing 3 Pumping pipe 4 Discharge elbow pipe 5 Suction water tank 6 Rotating shaft 10 Impeller 11 Outer bearing 12, 15 Underwater bearing 13 Bowl bush 14 Guide vane 18 Drive source 19 Mounting base 20 Discharge piping 21 Discharge Water tank 22 Pump installation floor 23 Installation base 24 Insertion port 25 Gate valve 32 Support member 35 Shaft sleeve 41 Base material 43 Film 51 Annular depression

Claims (3)

A shaft sleeve fixed to the outer peripheral surface of the rotating shaft,
A cylindrical base material having an annular depression formed on the outer peripheral surface;
A coating formed in the annular recess by high-speed flame spraying,
The annular recess is composed of at least a bottom surface parallel to the axis of the substrate and two inclined surfaces extending from both ends of the bottom surface to the outer peripheral surface of the substrate,
The shaft sleeve according to claim 1, wherein an angle of the inclined surface with respect to the bottom surface is in a range of 10 degrees to 30 degrees. A rotation axis;
A sliding bearing that rotatably supports the rotating shaft;
A shaft sleeve fixed to the outer peripheral surface of the rotating shaft and in sliding contact with the sliding bearing;
The rotating machine according to claim 1, wherein the shaft sleeve is a shaft sleeve according to claim 1. Prepare a cylindrical substrate,
Forming an annular recess formed on the outer peripheral surface of the base material at least from a bottom surface parallel to the axis of the base material and two inclined surfaces extending from both ends of the bottom surface to the outer peripheral surface of the base material; The angle of the inclined surface with respect to the bottom surface is in the range of 10 degrees to 30 degrees;
A method of manufacturing a shaft sleeve, comprising spraying a spray material on the annular recess by high-speed flame spraying to form a coating on the annular recess.

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