Pump and bearing mount

Abstract

To provide a pump and a bearing mount having a vibration-proof function with high durability.SOLUTION: A pump 100 comprises: a bearing 20 rotatably supporting a shaft 10; an impeller casing 30 housing an impeller 11; and a motor casing 40 housing a rotary electric motor M, and supporting the bearing 20. The motor casing 40 includes a ram 44 capable of moving in a space S formed between an inner housing 41 and an outer housing 42 while partitioning the space S into a low-pressure chamber S1 to which a first pressure is applied, and a high-pressure chamber S2 to which a second pressure higher than the first pressure is applied. The ram 44 biases a damping member 43 by using a differential pressure ΔP between the first pressure and the second pressure.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a pump and a bearing mount.

Background Art

[0002] Conventionally, there have been pumps and bearing mounts having a vibration damping function.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the conventional friction dampers provided in pumps and bearing mounts, the desired compressed state is achieved by tightening bolts. Therefore, the compressive force acting on the friction damper may be weakened due to wear of the friction damper caused by vibration or creep of the friction damper over time, and the vibration damping function may be impaired.

[0005] An object of the present invention is to provide a pump and a bearing mount having a highly durable vibration damping function.

Means for Solving the Problems

[0006] The present invention has the following aspects. (1) A pump according to one aspect of the present invention comprises a shaft having an impeller that rotates together with the rotor of a rotary motor, a bearing that rotatably supports the shaft, an impeller casing that houses the impeller, and a motor casing that houses the rotary motor and supports the bearing, wherein the motor casing includes an inner housing that supports the bearing, an outer housing disposed outside the inner housing, a damping member disposed between the inner housing and the outer housing, and a ram that is movable within the space formed between the inner housing and the outer housing, with the space divided into a low-pressure chamber for which a first pressure is applied and a high-pressure chamber for which a second pressure higher than the first pressure is applied, wherein the ram biases the damping member by the differential pressure between the first pressure and the second pressure. (2) In (1) above, the high-pressure chamber may be in communication with a high-pressure outlet provided in the impeller casing. (3) In (1) or (2) above, the low-pressure chamber may be in communication with a low-pressure outlet provided in the motor casing. (4) In any of (1) to (3) above, an auxiliary spring for biasing the ram may be provided. (5) In any of (1) to (4) above, the outer housing may be provided with pins that elastically support the inner housing. (6) In any of (1) to (5) above, a packing may be provided between the outer housing and the ram. (7) A bearing mount according to one aspect of the present invention comprises an inner housing that supports a bearing, an outer housing disposed outside the inner housing, a damping member disposed between the inner housing and the outer housing, and a ram that is movable within the space formed between the inner housing and the outer housing, with the space divided into a low-pressure chamber for which a first pressure is applied and a high-pressure chamber for which a second pressure higher than the first pressure is applied, wherein the ram biases the damping member by the differential pressure between the first pressure and the second pressure. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a pump and bearing mount with high durability and vibration damping function. [Brief explanation of the drawing]

[0008] [Figure 1] This is an explanatory diagram of the pump according to the embodiment. [Figure 2] This is an explanatory diagram showing a bearing mount according to an embodiment. [Figure 3] This is a cross-sectional view taken along arrow A in Figure 2. [Modes for carrying out the invention]

[0009] [Embodiment] The pump 100 according to this embodiment will be described below. Figure 1 is an explanatory diagram of the pump 100 according to the embodiment. Figure 2 is an explanatory diagram showing the bearing mount 1 according to the embodiment. Figure 3 is a cross-sectional view taken along arrow A in Figure 2.

[0010] (pump) As shown in Figure 1, the pump 100 according to this embodiment may be a turbo pump that transfers energy to the liquid passing through the impeller casing 30 by centrifugal force generated by the impeller 11. The pump 100 is suitable for applications that are operated for relatively long periods, such as industrial pumps. The pump 100 has, for example, five stages of impeller 11 arranged spaced apart from each other along the longitudinal direction of the shaft 10.

[0011] Pump 100 includes a shaft 10 having an impeller 11 that rotates together with the rotor Mr of a rotary motor M. Pump 100 includes a bearing 20 that rotatably supports the shaft 10. Pump 100 includes an impeller casing 30 that houses the impeller 11. Pump 100 includes a motor casing 40 that houses the rotary motor M and supports the bearing 20. In Figure 1, the direction of liquid flow due to the operation of the pump 100 is indicated by arrows. The liquid in the impeller casing 30 is pressurized by the energy supplied by a suitable number of impellers 11. As a result, the liquid is further drawn in through the suction port V. The liquid in the impeller casing 30 then travels through the flow path in the pump 100 and is discharged from the discharge port E of the motor casing 40.

[0012] (Impeller casing) The impeller casing 30 is a cylindrical body. The impeller casing 30 is connected to the motor casing 40. The impeller casing 30 has a liquid intake port V.

[0013] (Motor casing) The motor casing 40 includes an inner housing 41 that supports the bearing 20, an outer housing 42 positioned outside the inner housing 41, a damping member 43 positioned between the inner housing 41 and the outer housing 42, and a ram 44 that can move within the space S formed between the inner housing 41 and the outer housing 42, with the space S divided into a low-pressure chamber S1 into which a first pressure P1 is applied and a high-pressure chamber S2 into which a second pressure P2 higher than the first pressure P1 is applied. The motor casing 40 has a liquid discharge port E. The discharge port E may also be provided in the impeller casing 30. Figure 1 shows an example in which the discharge port E is provided in the motor casing 40.

[0014] The motor casing 40 includes the bearing mount 1. As shown in Figure 1, the bearing mounts 1 are positioned on both sides of the rotary motor M in the extending direction of the shaft 10. One bearing mount 1 is positioned to support the edge of the shaft 10 (the end on the discharge port E side). The other bearing mount 1 is positioned near the seal portion 50 of the motor casing 40, which seals the rotary motor M from the liquid passing through the impeller casing 30. The structure of one bearing mount 1 and the structure of the other bearing mount 1 may be common.

[0015] (Bearing mount) The bearing mount 1 includes an inner housing 41 that supports the bearing 20, an outer housing 42 disposed outside the inner housing 41, a damping member 43 disposed between the inner housing 41 and the outer housing 42, and a ram 44 that is movable within the space S which is partitioned into a low-pressure chamber S1 to which a first pressure P1 is applied and a high-pressure chamber S2 to which a second pressure P2 higher than the first pressure P1 is applied, in a state where the space S formed between the inner housing 41 and the outer housing 42 is partitioned.

[0016] (Bearing) The bearing 20 is an annular body that rotatably supports the shaft 10. The bearing 20 may include an annular inner ring provided on the outer periphery of the shaft 10, an annular outer ring provided on the inner peripheral surface of the inner housing 41, and balls provided between the inner ring and the outer ring so as to be rollable. The bearing 20 may be a so-called ball bearing.

[0017] (Inner housing) The inner housing 41 is a cylindrical body that passes through the shaft 10 and supports the bearing 20 that supports the shaft 10 on its inner peripheral surface. The inner housing 41 may be elastically supported with respect to the outer housing 42 by pins 70.

[0018] An annular ram 44 is fitted on the outer peripheral surface of the inner housing 41 so as to be movable along the biasing direction D. An annular outer housing 42 is fitted on the outer peripheral surface of the inner housing 41. A part of the outer peripheral surface of the inner housing 41 is exposed to the high-pressure chamber S2.

[0019] The inner housing 41 has an annular flange 41F that protrudes outward. The flange 41F is formed with a number of insertion holes corresponding to the number of pins 70 that penetrate. A damping member 43 is positioned in the biasing direction D of the flange 41F. Preferably, the damping members 43 are positioned on both sides of the flange 41F. The flange 41F is provided so as to protrude outward from the outer circumferential surface where the bearing 20 is located. This allows the bearing mount 1 to effectively dampen vibrations transmitted from the shaft 10 through the bearing 20. Pin 70 passes through flange 41F.

[0020] (Outer housing) The outer housing 42 is a cylindrical body. The outer housing 42 is provided outside the inner housing 41. The outer housing 42 is provided so as to surround the outer circumferential surface of the inner housing 41. The outer housing 42 is located outside the ram 44. A portion of the inner circumferential surface of the outer housing 42 fits onto the outer circumferential surface of the ram 44. The outer housing 42 forms a space S between itself and the inner housing 41. The space S has an annular shape with a rectangular cross-section on one side parallel to the biasing direction D. The outer housing 42 has a portion of its inner circumferential surface exposed to the space S. The outer housing 42 has supply holes 46 that communicate with the space S. The supply holes 46 communicate with a high-pressure outlet 31 provided in the impeller casing 30 via a suitable pipe. As shown in Figure 3, the supply holes 46 may be arranged in a plurality, radially outward from the rotation axis of the shaft 10, and at equal intervals in the circumferential direction.

[0021] (Damping member) The damping member 43 is an annular body. The damping member 43 has holes through which the pins 70 pass, at positions corresponding to the arrangement of the pins 70.

[0022] The damping member 43 is positioned between the inner housing 41 and the outer housing 42. The damping member 43 may also be positioned between the inner housing 41 and the ram 44.

[0023] The damping member 43 may be made of a material that has friction damping properties. The damping member 43 may be made of, for example, wire mesh, laminated plate, brake material (resin molded material, sintered material), etc. Since the damping member 43 dissipates vibration energy through friction, it can dampen the relative vibration between the inner housing 41 and the outer housing 42. The damping member 43 may be made of a material that has hysteresis loss. For example, it may be a high-damping rubber made by adding carbon black to natural rubber.

[0024] During the operation of the pump 100, the damping member 43 is subjected to a compressive force due to the biasing force from the ram 44 caused by the differential pressure ΔP. By changing this compressive force, the spring constant and damping constant can be designed, and a constant compressive force can be applied as long as the differential pressure ΔP does not change, even if the material wears down.

[0025] (Ram) The ram 44 is an annular body. The ram 44 has a shape corresponding to space S. The ram 44 is fitted to the outside of the inner housing 41 so that its inner circumferential surface is slidable against the outer circumferential surface of the inner housing 41. The ram 44 is fitted to the inside of the outer housing 42 so that its outer circumferential surface is slidable against the inner circumferential surface of the outer housing 42. The inner diameter of the ram 44 is slightly larger than the outer diameter of the portion of the inner housing 41 exposed to space S (the inner diameter of space S). The outer diameter of the ram 44 is slightly smaller than the inner diameter of the portion of the outer housing 42 exposed to space S (the outer diameter of space S). The ram 44 is housed in space S so as to be movable along the biasing direction D. The ram 44 includes a low-pressure surface exposed to the low-pressure chamber S1 and a high-pressure surface exposed to the high-pressure chamber S2. The auxiliary spring 60 may be in direct contact with the high-pressure surface. A portion of the ram 44 may be in direct contact with the damping member 43.

[0026] The ram 44 has a pin 70 inserted through an appropriate gap. The ram 44's rotational movement around the axis of rotation of the shaft 10 is restricted by the pin 70, and it is able to move freely in translation using the pin 70 as a guide.

[0027] The ram 44 biases the damping member 43 with the differential pressure ΔP between the first pressure P1 and the second pressure P2. This allows the hydraulic pressure increased by the pump 100 during operation to be supplied to the high-pressure chamber S2 as the second pressure P2 to generate the differential pressure ΔP. Therefore, regardless of the time-dependent decrease in the compressive force acting on the damping member 43, a differential pressure ΔP can always be generated between the low-pressure chamber S1 and the high-pressure chamber S2, which are partitioned by the ram 44, as long as the pump 100 is in operation, pushing the damping member 43 like a piston mechanism. This maintains the biasing force acting on the damping member 43 during the operation of the pump 100. Thus, a pump 100 and bearing mount 1 with high durability and vibration damping function can be provided.

[0028] As shown in Figures 1 and 2, it is preferable that the high-pressure chamber S2 is connected to a high-pressure outlet 31 provided in the impeller casing 30. The high-pressure chamber S2 and the high-pressure outlet 31 are connected by a pipe (not shown). This allows the second pressure P2 to be extracted from the portion of the liquid passing through the inside of the pump 100 that is pressurized to a relatively high pressure, thereby maximizing the differential pressure ΔP. As a result, the biasing force exerted by the ram 44 on the damping member 43 can be maintained at a high level during the operation of the pump 100.

[0029] As shown in Figure 2, it is preferable that the low-pressure chamber S1 is connected to a low-pressure outlet 45 provided in the motor casing 40. The low-pressure chamber S1 and the low-pressure outlet 45 are connected by pipes as appropriate. This allows the first pressure P1 to be extracted from a relatively low-pressure area within the liquid passing through the inside of the pump 100, specifically from the area on the rotary motor M side of the seal portion 50 between the motor casing 40 and the shaft 10, thereby maximizing the differential pressure ΔP. Consequently, the biasing force exerted by the ram 44 on the damping member 43 during the operation of the pump 100 can be maintained at a high level.

[0030] Furthermore, the space enclosed by the seal portion 50 housing the rotary motor M in the motor casing 40 is under relatively low pressure. The low-pressure outlet 45 may communicate with the space where the seal portion 50 is provided. The low-pressure outlet 45 may communicate with the space enclosed by the seal portion 50 housing the rotary motor M. In particular, it is preferable that the high-pressure chamber S2 of the bearing mount 1 on the impeller casing 30 side communicates with the space where the seal portion 50 is provided near the bearing mount 1. In particular, it is preferable that the high-pressure chamber S2 of the bearing mount 1 on the discharge port E side communicates with the space enclosed by the seal portion 50 housing the rotary motor M.

[0031] Furthermore, the location where the low-pressure outlet 45 is provided is not limited to the motor casing 40, as long as a first pressure P1 lower than the second pressure P2 can be obtained. For example, the low-pressure outlet 45 may be provided in the impeller casing 30, on the suction port V side from where the high-pressure outlet 31 is provided. The low-pressure outlet 45 may be provided in piping (not shown) connected to the suction port V or in a tank (not shown) communicating with that piping.

[0032] (Auxiliary spring) As shown in Figures 2 and 3, the bearing mount 1 of the pump 100 may be equipped with an auxiliary spring 60 that biases the ram 44. This allows the biasing force applied to the ram 44 by the differential pressure ΔP to be added to the biasing force applied to the ram 44 by the repulsive force of the auxiliary spring 60. Therefore, by adjusting the balance between the differential pressure ΔP and the repulsive force of the auxiliary spring 60, an appropriate biasing force can be stably applied to the ram 44. Multiple auxiliary springs 60 may be provided at equal intervals in the circumferential direction, centered on the rotation axis of the shaft 10.

[0033] (pin) As shown in Figure 2, it is preferable that the outer housing 42 is provided with pins 70 that elastically support the inner housing 41. The pin 70 is a rod-shaped body extending in a straight line. The pin 70 may be cylindrical with a circular cross-section. The pin 70 may be a bolt without a head. One end of the pin 70 is fixed to the outer housing 42 with a screw. In this way, the pin 70 is fixed to the outer housing 42 and elastically supports the inner housing 41. This allows the inner housing 41 to be elastically supported by the outer housing 42, and the inner housing can be displaced relative to the outer housing 42. Therefore, the effect of damping provided by the damping member 43 can be enhanced.

[0034] The center of pin 70 penetrates the inner housing 41. The center of pin 70 is fitted into the inner housing 41. The other end of pin 70 is inserted through the ram 44. The other end of pin 70 restricts the rotation of the ram 44, thereby guiding the translational movement of the ram 44 along the biasing direction D. The direction of extension of pin 70 is along the biasing direction D of the ram 44. The pin 70 guides the inner housing 41 and the damping member 43 so that they can translate along the biasing direction D of the ram 44. Pin 70 guides the ram 44 so that it can translate along the biasing direction D of the ram 44.

[0035] The pin 70 may have a head. In this case, the pin 70 with a head may apply a compressive force to the damping member 43. Furthermore, a differential pressure ΔP from the ram 44 may be added to the damping member 43, and a biasing force from the auxiliary spring 60 may also be added to the damping member 43.

[0036] (rubber seal) As shown in Figure 2, the bearing mount 1 of the pump 100 may include a packing 80 positioned between the outer housing 42 and the ram 44. The packing 80 seals the space between the low-pressure chamber S1 and the high-pressure chamber S2, thereby suppressing the movement of liquid. The packing 80 may be, for example, an annular, so-called O-ring having a circular cross-section. The packing 80 may be fitted into, for example, an annular groove provided along the outer circumference of the ram, as shown in Figure 2. This allows the space between the low-pressure chamber S1 and the high-pressure chamber S2 to be sealed without hindering the movement of the ram 44 along the inner circumferential surface of the outer housing 42. Furthermore, by changing the rigidity of the packing 80, the dimensions of the packing 80, or the dimensions of the annular groove, the frictional force acting between the packing 80 and the inner circumferential surface of the outer housing 42 can be adjusted, thereby adjusting the biasing force exerted by the ram 44 on the damping member 43.

[0037] A mechanical seal (not shown) may be provided between the inner housing 41 and the ram 44. This seal may be a sheet-like body arranged in an annular shape in the gap between the inner housing 41 and the ram 44. This seal seals the space between the low-pressure chamber S1 and the high-pressure chamber S2, thereby suppressing the movement of liquid.

[0038] Although embodiments have been described above with reference to the drawings, the present invention is not limited to those described above. The features listed as embodiments may be freely combined.

[0039] The pump 100 according to this embodiment includes a shaft 10 having an impeller 11 that rotates together with the rotor Mr of a rotary motor M, a bearing 20 that rotatably supports the shaft 10, an impeller casing 30 that houses the impeller 11, and a motor casing 40 that houses the rotary motor M and supports the bearing 20. The motor casing 40 includes an inner housing 41 that supports the bearing 20, an outer housing 42 disposed outside the inner housing 41, a damping member 43 disposed between the inner housing 41 and the outer housing 42, and a ram 44 that is movable within the space S formed between the inner housing 41 and the outer housing 42, with the space S divided into a low-pressure chamber S1 into which a first pressure P1 is applied and a high-pressure chamber S2 into which a second pressure P2 higher than the first pressure P1 is applied. The ram 44 biases the damping member 43 by the differential pressure ΔP between the first pressure P1 and the second pressure P2. As a result, during the operation of the pump 100, the hydraulic pressure boosted by the pump 100 can be supplied to the high-pressure chamber S2 as a second pressure P2 to generate a differential pressure ΔP. Therefore, regardless of the time-dependent decrease in the compressive force acting on the damping member 43, a differential pressure ΔP can always be generated between the low-pressure chamber S1 and the high-pressure chamber S2, which are partitioned by the ram 44, as long as the pump 100 is in operation, pushing the damping member 43 like a piston mechanism. This allows the biasing force acting on the damping member 43 to be maintained during the operation of the pump 100. Thus, a pump 100 with a highly durable vibration damping function can be provided.

[0040] The bearing mount 1 according to this embodiment includes an inner housing 41 that supports the bearing 20, an outer housing 42 disposed outside the inner housing 41, a damping member 43 disposed between the inner housing 41 and the outer housing 42, and a ram 44 that is movable within the space S formed between the inner housing 41 and the outer housing 42, with the space S divided into a low-pressure chamber S1 into which a first pressure P1 is applied and a high-pressure chamber S2 into which a second pressure P2 higher than the first pressure P1 is applied. The ram 44 biases the damping member 43 by the differential pressure ΔP between the first pressure P1 and the second pressure P2. As a result, during the operation of the pump 100, the hydraulic pressure boosted by the pump 100 can be supplied to the high-pressure chamber S2 as a second pressure P2 to generate a differential pressure ΔP. Therefore, regardless of the time-dependent decrease in the compressive force acting on the damping member 43, a differential pressure ΔP can always be generated between the low-pressure chamber S1 and the high-pressure chamber S2, which are partitioned by the ram 44, as long as the pump 100 is in operation, allowing the damping member 43 to be pushed like a piston mechanism. This maintains the biasing force acting on the damping member 43 during the operation of the pump 100. Thus, a bearing mount 1 with high durability and vibration damping function can be provided. [Explanation of symbols]

[0041] 1. Bearing mount 10 shafts 11 Impeller 20 bearings 30 Impeller Casing 31 High-voltage outlet 40 Motor Casing 41 Inner Housing 41F flange 42 Outer Housing 43 Damping member 44 Lamb 45 Low-pressure outlet 46 Supply hole 50 Seal part 60 Auxiliary spring 70 pins 80 Packing 100 pumps D Force direction E Discharge port M Rotary Electric Motor Mr. Rotor S space S1 Low-pressure chamber S2 High-Pressure Chamber V-shaped suction port

Claims

1. A shaft that rotates together with the rotor of a rotary motor and has an impeller, A bearing that rotatably supports the aforementioned shaft, An impeller casing that houses the impeller, A pump comprising a motor casing that houses the aforementioned rotating electric motor and supports the aforementioned bearing, The motor casing is, An inner housing that supports the bearing, An outer housing positioned outside the inner housing, The damping member is disposed between the inner housing and the outer housing, and the space formed between the inner housing and the outer housing is divided into a low-pressure chamber for applying a first pressure and a high-pressure chamber for applying a second pressure higher than the first pressure, and the ram is movable within the space. The ram biases the damping member by the pressure difference between the first pressure and the second pressure, The biased damping member comes into contact with the inner housing and the outer housing, generating friction that dampens the relative vibration between the inner housing and the outer housing. The high-pressure chamber is in communication with a high-pressure outlet provided in the impeller casing inside the pump. The low-pressure chamber is connected to a low-pressure outlet provided in the motor casing inside the pump.

2. The ram is equipped with an auxiliary spring for biasing it. The pump according to claim 1.

3. The pump according to claim 1, wherein the outer housing comprises pins that elastically support the inner housing.

4. The outer housing is provided with a packing that is positioned between the ram and the outer housing. The pump according to claim 1.

5. An inner housing that supports the bearing, An outer housing positioned outside the inner housing, A damping member disposed between the inner housing and the outer housing, and a ram that is movable within the space formed between the inner housing and the outer housing, with the space divided into a low-pressure chamber for applying a first pressure and a high-pressure chamber for applying a second pressure higher than the first pressure. A bearing mount that includes and supports a shaft driven by a rotary motor, The ram is a bearing mount that biases the damping member by the differential pressure between the first pressure and the second pressure generated by the drive of the rotary motor.

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