Integrated servo motor pump based on internal gear pump

Abstract

The invention discloses an integrated servo motor pump based on an internal gear pump, and relates to the field of integrated servo motor pumps, the integrated servo motor pump comprises a shell, an end cover, a servo motor, a bidirectional internal gear pump and a rotating speed sensor, the servo motor and the bidirectional internal gear pump are both arranged in the shell, one end of a motor shaft of the servo motor is connected with a pump shaft of the bidirectional internal gear pump through a spline, so that the motor shaft can drive the pump shaft to rotate together; the end cover is connected to one end of the shell, the rotating speed sensor is connected to the end cover, and a sensor shaft of the rotating speed sensor penetrates through the end cover to be in interference connection with the other end of the motor shaft. And the targets of low noise, high power density and large-range dynamic regulation of the rotating speed are achieved.

Description

Technical Field

[0001] The invention relates to an integrated servo motor pump, in particular to a product of an integrated design of a servo motor and an internal gear pump, belonging to the field of electrostatic hydraulic servo. Background Art

[0002] The integrated servo motor pump is an important part of the electro-hydraulic actuator system (EHA). It adopts the integrated design of servo motor, quantitative pump and speed sensor, and realizes real-time adjustment of output flow by controlling the motor speed. The servo motor pump replaces the traditional valve control link and has obvious advantages in eliminating throttling loss, reducing system energy consumption, enhancing anti-pollution ability and improving system reliability.

[0003] Most of the existing integrated servo motor pumps are based on quantitative plunger pumps, involving patent [A highly integrated oil-liquid internal circulation servo motor pump, ZL202110679550.0, authorized], which proposes a servo motor pump product based on a permanent magnet synchronous motor and a bidirectional quantitative plunger pump core, which has the characteristics of high pressure, high speed, and high dynamic response, and is mainly used in the aerospace field. However, due to the large pressure pulsation and high operating noise of the plunger pump, the application scenarios of the above products are subject to certain restrictions.

[0004] The internal gear pump has the characteristics of low pressure pulsation, low noise and long life, and has obvious advantages in application scenarios that require silent and smooth operation. In engineering, discrete internal gear pumps and motors are often used, connected by couplings, as hydraulic energy sources. At present, there are few products that integrate the motor and the internal gear pump. The patent involved [Internal gear pump, integrated motor pump and vehicle, application number CN202311864861.X] proposes an internal gear motor pump structure. By setting a buffer chamber in the crescent plate, the fluid pressure fluctuation is transmitted to the crescent plate, which can improve the working efficiency of the product. However, the motor pump adopts a split structure, and the motor and gear pump housing are designed separately, and the integration is not high; the pump shaft is supported by two sliding bearings and can only work at medium speed; it does not have a speed sensor, does not belong to a servo motor pump, does not have a servo working condition with a large range of dynamic speed adjustment, and cannot be used as a control element. Summary of the invention

[0005] The technical problem solved by the present application is: to overcome the deficiencies of the prior art and to provide an integrated servo motor pump based on an internal gear pump, so as to achieve the goals of low noise, high power density and wide range of dynamic speed adjustment.

[0006] The technical solutions provided by this application are as follows:

[0007] An integrated servo motor pump based on an internal gear pump comprises a housing, an end cover, a servo motor, a bidirectional internal gear pump and a speed sensor. The servo motor and the bidirectional internal gear pump are both arranged in the housing. One end of the motor shaft of the servo motor is connected to the pump shaft of the bidirectional internal gear pump through a spline so that the motor shaft can drive the pump shaft to rotate together; the end cover is connected to one end of the housing, the speed sensor is connected to the end cover, and the sensor shaft of the speed sensor passes through the end cover and is interference-connected with the other end of the motor shaft.

[0008] The bidirectional internal meshing gear pump comprises a pump shaft, a pump body, a spacing sleeve, an oil separator, an external gear, an internal gear ring, a flat key and a screw. The screw passes through the pump body, the spacing sleeve and the oil separator in sequence and connects the pump body, the spacing sleeve and the oil separator. The spacing sleeve is provided with an inner hole along its own axial direction. The internal gear ring is rotatably connected in the inner hole and is coaxial with the inner hole. The external gear is provided inside the internal gear ring. The inner ring of the internal gear ring is provided with a plurality of teeth. The outer ring of the external gear is provided with teeth. The inner diameter of the internal gear ring is larger than the outer diameter of the external gear. The teeth on the outside of the external gear are partially meshed with the teeth on the inside of the internal gear ring. A through hole is provided at the axial position of the external gear. The pump shaft is located in the through hole. The external gear passes through The flat key is connected to the pump shaft so that the pump shaft drives the external gear to rotate together; the axis of the inner gear ring does not coincide with the axis of the pump shaft; a crescent plate is connected to the side of the oil separator facing the isolation sleeve, the crescent plate is located between the non-meshing parts of the external gear and the inner gear ring, and the crescent plate is in contact with both the external gear and the inner gear ring to form two cavities on both sides of the crescent plate; two grooves are provided on the side of the oil separator facing the isolation sleeve, the two grooves are connected to the two cavities respectively, and an oil hole parallel to the axis of the pump shaft is provided at the bottom of each groove of the oil separator, one oil hole is connected to the hydraulic oil inlet pipe, and the other oil hole is connected to the space requiring high-pressure hydraulic oil.

[0009] The surface of the inner hole is bimetallicly cast with a copper layer.

[0010] The oil separation plate is located at a side of the pump body away from the servo motor.

[0011] A ball bearing is arranged between the pump shaft and the pump body.

[0012] Two ball bearings are provided.

[0013] A needle bearing is arranged between the pump shaft and the oil separation plate.

[0014] A convex ring is provided on the inner wall of the shell, and the convex ring is located between the servo motor and the bidirectional internal meshing gear pump. An internal spline is provided on the end of the motor shaft, and the pump shaft is connected to the motor shaft through an external spline. A first bearing is provided between the motor shaft and the convex ring; a mounting hole is provided on the end cover, and a speed sensor is connected to the mounting hole. A second bearing is provided between the end of the motor shaft and the inner wall of the mounting hole.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects:

[0016] (1) The present invention realizes the integrated design of the servo motor, the bidirectional internal gear pump and the speed sensor, and can adjust the output flow in real time by controlling the motor speed, providing a new form of flow control element, and has the characteristics of low pressure pulsation and low noise;

[0017] (2) The present invention adopts a separate design of the isolation sleeve and the oil separator, which reduces the difficulty of processing compared with the integrated design in the prior art, is conducive to ensuring the shape and position tolerances, controlling the axial and radial clearances, and improving the volumetric efficiency of the motor pump. At the same time, the inner hole of the isolation sleeve is cast in bimetallic casting, and the copper layer is cast on the steel matrix, which improves the friction characteristics between the inner hole of the isolation sleeve and the outer circle of the inner gear ring;

[0018] (3) The present invention adopts ball bearings and needle bearings to replace the sliding bearings in the prior art, thereby solving the problem of bearing scratching caused by poor lubrication at low speeds, solving the problem of bearing failure caused by frictional heat generation at high speeds, and solving the problem of large starting resistance and poor following characteristics near zero speed, thereby meeting the requirements of large-range dynamic speed regulation of the servo motor pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a cross-sectional view of the servo motor pump;

[0020] Figure 2 It is a cross-sectional view of a bidirectional internal gear pump;

[0021] Figure 3 This is the left side view of the bidirectional internal gear pump;

[0022] Figure 4 This is the structural diagram of the oil distribution plate. DETAILED DESCRIPTION

[0023] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments disclosed in the present invention will be further described in detail below with reference to the accompanying drawings.

[0024] The present application embodiment discloses an integrated servo motor pump based on an internal gear pump, such as Figure 1 As shown, it includes a servo motor 1, a bidirectional internal gear pump 2 and a speed sensor 3. The servo motor 1 and the internal gear pump 2 share a housing 4, the speed sensor 3 is installed through an end cover 5, the motor shaft 1-1 and the pump shaft 2-1 are connected by a spline, so that the motor shaft 1-1 can drive the pump shaft 2-1 to rotate together, and the motor shaft 1-1 and the sensor shaft 3-1 are interference connected, so that the speed sensor 3 can measure the speed of the motor shaft 1-1.

[0025] like Figure 2 , 3As shown in Figures 4, the bidirectional internal gear pump 2 includes a pump shaft 2-1, a pump body 2-2, an isolation sleeve 2-3, an oil separator 2-4, an external gear 2-5, an internal gear ring 2-6, a ball bearing 2-7, a needle bearing 2-8, a flat key 2-9 and a screw 2-10.

[0026] The pump body 2-2, the isolation sleeve 2-3, and the oil separator 2-4 are axially connected by screws 2-10. The isolation sleeve 2-3 is provided with an inner hole along its own axial direction, and a copper layer is cast on the surface of the inner hole by bimetallic casting. The inner gear ring 2-6 is rotatably connected in the inner hole. The inner gear ring 2-6 is coaxial with the inner hole and the outer circle of the inner gear ring 2-6 is in contact with the copper layer. The cooperation between the copper layer and the inner gear ring 2-6 improves the friction performance. The inner ring of the inner gear ring 2-6 is provided with multiple teeth; the outer ring of the outer gear 2-5 is provided with teeth, and the outer gear 2-5 is arranged inside the inner gear ring 2-6. The teeth on the outside of the outer gear 2-5 are partially meshed with the teeth inside the inner gear ring 2-6. A through hole is provided at the axial position of the outer gear 2-5, and the pump shaft 2-1 is located in the through hole. The outer gear 2-5 is connected to the pump shaft 2-1 through a flat key 2-9, so that the pump shaft 2-1 drives the outer gear 2-5 to rotate together. A crescent plate is provided on the side of the oil separator 2-4 facing the isolation sleeve 2-3; the crescent plate is located between the non-meshing parts of the outer gear 2-5 and the inner gear ring 2-6, and the outer circle of the outer gear 2-5 contacts and fits with the inner wall of the crescent plate on the oil separator 2-4; the crescent plate forms a seal between the non-meshing parts of the outer gear 2-5 and the inner gear ring 2-6, and seals the meshing parts of the outer gear 2-5 and the inner gear ring 2-6, thereby forming two cavities on both sides of the meshing position of the crescent plate and the outer gear 2-5 and the inner gear ring 2-6, namely, an oil inlet cavity and an oil outlet cavity. The inner gear ring 2-6 is installed in the isolation sleeve 2-3, and the inner hole of the inner gear ring 2-6 is in contact with the outer cylindrical surface of the crescent plate on the oil separator 2-4. The inner gear ring 2-6 has a certain eccentricity relative to the pump shaft 2-1, that is, the axis of the inner gear ring 2-6 does not coincide with the axis of the pump shaft 2-1. The oil separator 2-4 has two grooves on the side facing the isolation sleeve 2-3, and the two grooves are connected to the two cavities respectively; the oil separator 2-4 has oil holes at the bottom of each groove, and the two oil holes are respectively: an oil inlet hole and an oil outlet hole, the oil inlet hole is connected to the hydraulic oil inlet pipeline, and the oil outlet hole is connected to the space where high-pressure hydraulic oil is required.

[0027] Through the rotation of the pump shaft 2-1, the pump shaft 2-1 drives the outer gear 2-5 and the inner gear ring 2-6 to rotate. At this time, the closed volume of the oil inlet chamber becomes larger to form oil suction, and the closed volume of the oil outlet chamber becomes smaller to produce oil discharge.

[0028] The separation sleeve 2-3 and the oil separator 2-4 adopt a split structure, which is conducive to ensuring the shape and position tolerances of the two end faces and the inner hole of the separation sleeve 2-3, and the shape and position tolerances of the crescent plate of the oil separator, which has a positive effect on controlling the axial and radial clearances of the gear pair and can effectively improve the volumetric efficiency of the gear pump. At the same time, the separation sleeve 2-3 adopts a split structure to facilitate the implementation of friction pair strengthening measures in the inner hole (i.e., a bimetallic copper layer is cast on the surface of the inner hole), solving the problems of inner hole wear, bonding, failure, etc. that often occur in engineering practice.

[0029] Traditional sliding bearings are not easy to form oil film at low speeds, and there may be problems such as scratching or even locking between the shaft and the bearing, which is not suitable for the servo motor pump that often works near zero speed; the friction of sliding bearings at high speeds generates a lot of heat, which will cause the bearing temperature to rise rapidly and cause bearing failure, which is not suitable for the high-speed operation of the servo motor pump; in addition, sliding bearings have large starting resistance and are not suitable for the frequent reversing of the servo motor pump. The use of ball bearings 2-7 and needle bearings 2-8 can solve the above problems and meet the requirements of the servo motor pump to adjust the speed over a wide range. At the same time, the use of two ball bearings 2-7 in pairs can improve the axis stiffness and reduce vibration noise. Specifically, the two ball bearings 2-7 are arranged between the pump shaft 2-1 and the pump body 2-2, and the needle bearing 2-8 is arranged between the pump shaft 2-1 and the oil separator 2-4.

[0030] The main innovative features of the present invention are as follows:

[0031] (1) The present invention proposes a servo motor and a bidirectional internal gear pump co-shell design structure to improve integration and reduce size and weight;

[0032] (2) The bidirectional internal gear pump assembly of the present invention adopts a three-section structure of a pump body, a spacer sleeve, and an oil separator, which is easy to process and can accurately control the axial and radial clearances of the gear pair. The inner hole of the spacer sleeve is cast in bimetallic casting, which improves the friction characteristics between the inner hole of the spacer sleeve and the outer circle of the inner gear ring.

[0033] (3) The present invention adopts ball bearings and needle bearings, which solve the problems of severe heat generation at high speed and poor lubrication at low speed compared to commonly used sliding bearings, and can adapt to a wider speed range;

[0034] (4) The present invention installs a speed sensor on the motor pump shaft, so that the servo motor pump has a feedback function and can be used in a servo working condition for dynamically adjusting the speed.

[0035] The contents not described in detail in this application specification belong to the common knowledge of those skilled in the art.

[0036] The present application is described in detail above in conjunction with specific implementation methods and exemplary examples, but these descriptions cannot be understood as limiting the present application. Those skilled in the art understand that, without departing from the spirit and scope of the present application, a variety of equivalent replacements, modifications or improvements can be made to the technical solution of the present application and its implementation methods, all of which fall within the scope of the present application. The scope of protection of the present application shall be subject to the attached claims.

Claims

1. An integrated servo motor pump based on an internal gear pump, characterized in that: The invention comprises a housing (4), an end cover (5), a servo motor (1), a bidirectional internal gear pump (2) and a rotation speed sensor (3); the servo motor (1) and the bidirectional internal gear pump (2) are both arranged in the housing (4); one end of a motor shaft (1-1) of the servo motor (1) is connected to a pump shaft (2-1) of the bidirectional internal gear pump (2) via a spline, so that the motor shaft (1-1) can drive the pump shaft (2-1) to rotate together; the end cover (5) is connected to one end of the housing (4); the rotation speed sensor (3) is connected to the end cover (5); and a sensor shaft (3-1) of the rotation speed sensor (3) passes through the end cover (5) and is interference-connected to the other end of the motor shaft (1-1).

2. The integrated servo motor pump based on an internal gear pump according to claim 1, characterized in that: The bidirectional internal gear pump (2) comprises a pump shaft (2-1), a pump body (2-2), a spacing sleeve (2-3), an oil separator (2-4), an external gear (2-5), an internal gear ring (2-6), a flat key (2-9) and a screw (2-10). The screw (2-10) passes through the pump body (2-2), the spacing sleeve (2-3) and the oil separator (2-4) in sequence and connects the pump body (2-2), the spacing sleeve (2-3) and the oil separator (2-4). The spacing sleeve (2-3) -3) is provided with an inner hole along its own axial direction, the inner gear ring (2-6) is rotatably connected to the inner hole and is coaxial with the inner hole, the outer gear (2-5) is provided inside the inner gear ring (2-6), the inner ring of the inner gear ring (2-6) is provided with a plurality of teeth, the outer ring of the outer gear (2-5) is provided with teeth, the inner diameter of the inner gear ring (2-6) is larger than the outer diameter of the outer gear (2-5), and the teeth on the outside of the outer gear (2-5) are partially meshed with the teeth on the inside of the inner gear ring (2-6) to form the outer gear (2-5) A through hole is provided at the axis position of the pump shaft (2-1), the pump shaft (2-1) is located in the through hole, and the external gear (2-5) is connected to the pump shaft (2-1) via a flat key (2-9), so that the pump shaft (2-1) drives the external gear (2-5) to rotate together; the axis of the inner gear ring (2-6) does not coincide with the axis of the pump shaft (2-1); a crescent plate is provided on the side of the oil separation plate (2-4) facing the isolation sleeve (2-3), and the crescent plate is located at the non-meshing portion of the external gear (2-5) and the inner gear ring (2-6). The crescent plate is in contact with the outer gear (2-5) and the inner gear ring (2-6) to form two cavities on both sides of the crescent plate; the oil separator (2-4) is provided with two grooves on one side facing the isolation sleeve (2-3), and the two grooves are respectively connected to the two cavities; the bottom of each groove of the oil separator (2-4) is provided with an oil hole parallel to the axis of the pump shaft (2-1), one oil hole is connected to the hydraulic oil inlet pipeline, and the other oil hole is connected to the space requiring high-pressure hydraulic oil.

3. The integrated servo motor pump based on an internal gear pump according to claim 2, characterized in that: The surface of the inner hole is bimetallicly cast with a copper layer.

4. The integrated servo motor pump based on an internal gear pump according to claim 2, characterized in that: The oil separation plate (2-4) is located on a side of the pump body (2-2) away from the servo motor (1).

5. The integrated servo motor pump based on an internal gear pump according to claim 2, characterized in that: A ball bearing (2-7) is arranged between the pump shaft (2-1) and the pump body (2-2).

6. The integrated servo motor pump based on an internal gear pump according to claim 5, characterized in that: Two ball bearings (2-7) are provided.

7. The integrated servo motor pump based on an internal gear pump according to claim 2, characterized in that: A needle roller bearing (2-8) is arranged between the pump shaft (2-1) and the oil separation plate (2-4).

8. The integrated servo motor pump based on an internal gear pump according to claim 1, characterized in that: The inner wall of the housing (4) is provided with a convex ring, which is located between the servo motor (1) and the bidirectional internal gear pump (2); the end of the motor shaft (1-1) is provided with an internal spline, the pump shaft (2-1) is connected to the motor shaft (1-1) via an external spline, and a first bearing is provided between the motor shaft (1-1) and the convex ring; the end cover (5) is provided with a mounting hole, the speed sensor (3) is connected to the mounting hole, and a second bearing is provided between the end of the motor shaft (1-1) and the inner wall of the mounting hole.

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