Device for measuring rotating speed of submersible motor for well

Abstract

A rotating speed measuring device for a well submersible motor belongs to the technical field of well submersible motors. The motor comprises a thrust bearing seat connected with the bottom of a motor shell, the upper side of the thrust bearing seat is connected with a first thrust bearing, a rotating part in the middle of the first thrust bearing is connected with a rotor shaft, a rotor permanent magnet is fixed at the bottom end of the rotor shaft, and the bottom of the thrust bearing seat is connected with an encoder fixing base. An encoder is arranged at the bottom in the encoder fixing base, a second thrust bearing is arranged in the middle of the encoder fixing base, a speed measuring permanent magnet is arranged at the top of the second thrust bearing, the speed measuring permanent magnet is connected with the encoder through a coupler, and the speed measuring permanent magnet is matched with the rotor permanent magnet. According to the utility model, the real-time rotating speed of the submersible motor can be accurately measured, and favorable conditions are provided for measuring the operation performance of the motor and realizing variable-frequency driving closed-loop control.

Description

Technical Field

[0001] The utility model belongs to the technical field of well-used submersible motors, and in particular relates to a speed measuring device for well-used submersible motors. Background Art

[0002] Submersible well motors are typically installed in deep wells with submersible well pumps to extract water. Both the motor and pump are submerged in water. Cooling water is filled inside the motor to ensure internal heat dissipation and lubrication of the sliding bearings. Currently, to precisely control the pump, submersible motors are typically driven by a frequency converter (VFD). To improve control accuracy, real-time motor speed monitoring is required to implement variable-frequency closed-loop control. Factory performance testing also requires accurate motor speed readings. Because both the motor and pump are submerged in water, photoelectric tachometers are ineffective. While encoders can accurately measure motor speed, they are generally not waterproof and are unsuitable for use in water with even a modicum of pressure. Utility Model Content

[0003] The present invention aims to solve the above problems, remedy the deficiencies of the prior art, and provide a submersible motor speed measuring device for wells; the present invention can accurately measure the real-time speed of the submersible motor, providing favorable conditions for measuring the motor's operating performance and realizing variable frequency drive closed-loop control.

[0004] In order to achieve the above-mentioned purpose, the present utility model adopts the following technical solutions.

[0005] The utility model provides a speed measuring device for a submersible motor for a well, characterized in that it comprises a thrust bearing seat connected to the bottom of a motor housing, a first thrust bearing being connected to the upper side of the thrust bearing seat, a middle rotating part of the first thrust bearing being connected to the rotor shaft, a rotor permanent magnet being fixed to the bottom end of the rotor shaft, an encoder fixing base being connected to the bottom of the thrust bearing seat, an encoder being provided at the inner bottom of the encoder fixing base, a second thrust bearing being provided in the middle of the encoder fixing base, a speed measuring permanent magnet being provided on the top of the second thrust bearing, the speed measuring permanent magnet being connected to the encoder via a coupling, and the speed measuring permanent magnet being matched with the rotor permanent magnet.

[0006] Furthermore, an opening is provided in the middle of the thrust bearing seat corresponding to the rotor permanent magnet, and the rotor permanent magnet extends from the opening. The thrust bearing seat is provided with a sealing sleeve at the opening for separating the interior of the thrust bearing seat from the interior of the encoder fixed base.

[0007] Furthermore, the first thrust bearing is a thrust sliding bearing, and the second thrust bearing is a thrust ball bearing.

[0008] Furthermore, the speed measuring permanent magnet and the rotor permanent magnet are arranged with opposite poles, and the speed measuring permanent magnet rotates at the same speed as the rotor permanent magnet, and drives the encoder to rotate.

[0009] Furthermore, a washer is provided between the first thrust bearing and the rotor permanent magnet, and the washer is sleeved on the outside of the rotor shaft.

[0010] The beneficial effects of the utility model.

[0011] The utility model can realize accurate measurement of the rotation speed of a submersible motor for a well in a waterless environment by using an encoder, provides favorable conditions for measuring the operating performance of the motor and realizing variable frequency drive closed-loop control, and solves the problem that the rotation speed of existing submersible motors for wells cannot be accurately measured during operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0013] Figure 1 It is a schematic diagram of the cross-sectional structure of the present utility model.

[0014] Markings in the figure: 1 is the motor housing, 2 is the thrust bearing seat, 3 is the first thrust bearing, 4 is the rotor shaft, 5 is the rotor permanent magnet, 6 is the encoder fixing base, 7 is the encoder, 8 is the second thrust bearing, 9 is the speed measuring permanent magnet, 10 is the coupling, 11 is the sealing sleeve, and 12 is the gasket. DETAILED DESCRIPTION

[0015] As shown in the accompanying drawings, this embodiment provides a submersible motor speed measuring device for a well, including a thrust bearing seat 2 connected to the bottom of the motor housing 1, and the thrust bearing seat 2 is fixed to the motor housing 1 by screws and nuts.

[0016] The upper side of the thrust bearing seat 2 is connected to the first thrust bearing 3. Since the first thrust bearing 3 is to be used in water and to withstand a certain axial force, a thrust sliding bearing with better strength is used.

[0017] The middle rotating part of the first thrust bearing 3 is connected to the rotor shaft 4. The rotor permanent magnet 5 is fixed to the bottom end of the rotor shaft 4. A washer 12 is provided between the first thrust bearing 3 and the rotor permanent magnet 5 to play a buffering role. The washer 12 is sleeved on the outside of the rotor shaft 4.

[0018] The bottom of the thrust bearing housing 2 is connected to an encoder mounting base 6. An opening is provided in the center of the thrust bearing housing 2, corresponding to the rotor permanent magnet 5. The rotor permanent magnet 5 extends from this opening. Because submersible motors of varying powers have different rotor shafts 4, the length and thickness of the rotor permanent magnet 5 may vary. Therefore, the opening facilitates processing and adaption to submersible motors of varying powers.

[0019] In order to ensure that no water can enter the encoder fixing base 6, a sealing sleeve 11 is provided at the opening of the thrust bearing seat 2 to separate the interior of the thrust bearing seat 2 from the interior of the encoder fixing base 6, ensuring that water inside the motor does not flow into the area where the encoder 7 is located.

[0020] An encoder 7 is provided at the bottom of the encoder fixed base 6 for measuring the speed of the submersible motor. A second thrust bearing 8 is provided in the middle of the encoder fixed base 6. The second thrust bearing 8 is in an air environment and does not need to bear axial force, so a thrust ball bearing with lower friction loss is used.

[0021] A speed measuring permanent magnet 9 is provided on the top of the second thrust bearing 8. The speed measuring permanent magnet 9 and the rotor permanent magnet 5 are arranged opposite to each other with different poles. The speed measuring permanent magnet 9 is connected to the encoder 7 through a coupling 10. The speed measuring permanent magnet 9 cooperates with the rotor permanent magnet 5.

[0022] The speed measuring permanent magnet 9 rotates at the same speed as the rotor permanent magnet 5 and drives the encoder 7 to rotate, thereby measuring the real-time speed of the motor.

[0023] It can be understood that the above specific description of the present invention is only used to illustrate the present invention and is not limited to the technical solutions described in the implementation methods of the present invention. Ordinary technicians in this field should understand that the present invention can still be modified or replaced by equivalents to achieve the same technical effects; as long as the use requirements are met, they are within the scope of protection of the present invention.

Claims

1. A submersible motor speed measuring device for a well, characterized in that: The invention comprises a thrust bearing seat (2) connected to the bottom of the motor housing (1), a first thrust bearing (3) being connected to the upper side of the thrust bearing seat (2), a middle rotating part of the first thrust bearing (3) being connected to the rotor shaft (4), a rotor permanent magnet (5) being fixed to the bottom end of the rotor shaft (4), an encoder fixed base (6) being connected to the bottom of the thrust bearing seat (2), an encoder (7) being provided at the bottom of the encoder fixed base (6), a second thrust bearing (8) being provided in the middle of the encoder fixed base (6), a speed measuring permanent magnet (9) being provided on the top of the second thrust bearing (8), the speed measuring permanent magnet (9) being connected to the encoder (7) via a coupling (10), and the speed measuring permanent magnet (9) being matched with the rotor permanent magnet (5).

2. A submersible motor speed measuring device for wells according to claim 1, characterized in that: An opening is provided in the middle of the thrust bearing seat (2) corresponding to the rotor permanent magnet (5), and the rotor permanent magnet (5) extends from the opening. The thrust bearing seat (2) is provided with a sealing sleeve (11) at the opening for separating the interior of the thrust bearing seat (2) from the interior of the encoder fixed base (6).

3. A submersible motor speed measuring device for wells according to claim 1, characterized in that: The first thrust bearing (3) adopts a thrust sliding bearing, and the second thrust bearing (8) adopts a thrust ball bearing.

4. A submersible motor speed measuring device for wells according to claim 1, characterized in that: The speed measuring permanent magnet (9) and the rotor permanent magnet (5) are arranged with opposite poles. The speed measuring permanent magnet (9) rotates at the same speed as the rotor permanent magnet (5) and drives the encoder (7) to rotate.

5. A submersible motor speed measuring device for wells according to claim 1, characterized in that: A washer (12) is provided between the first thrust bearing (3) and the rotor permanent magnet (5), and the washer (12) is sleeved on the outside of the rotor shaft (4).

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