Internal meshing cycloid gear pump and manufacturing method thereof

Abstract

The present invention discloses an internal meshing cycloidal gear pump and a manufacturing method thereof. The internal meshing cycloidal gear pump comprises a pump body, a rotating shaft, and an inner rotor and an outer rotor meshing with each other. The pump body has a chamber inside, and the inner rotor and the outer rotor are rotatably fixed in the chamber, and one end of the rotating shaft is passed through the chamber through a through hole provided in the pump body and fixedly connected to the inner rotor. The inner rotor and the outer rotor are eccentrically arranged to form an oil supply chamber and an oil pressure chamber. The pump body is provided with an oil inlet hole and an oil outlet hole, which are connected to the oil supply chamber and the oil chamber respectively. A plurality of first tooth blocks are provided on the inner side wall of the outer rotor, and a first tooth groove is formed between each two adjacent first tooth blocks. A plurality of second tooth blocks are provided on the outer side wall of the inner rotor, and a second tooth groove is formed between each two adjacent second tooth blocks. The first tooth groove is adapted to the second tooth block, and the second tooth groove is adapted to the first tooth block. The tooth profile of the first tooth block comprises a first circular arc and a second circular arc symmetrically distributed on both sides of the first circular arc, which increases the volume of the oil chamber and improves the oil pumping efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of volumetric hydraulic pumps, and in particular to an internal meshing cycloid gear pump and a manufacturing method thereof. Background Art

[0002] Internal gear pumps are widely used in many industrial fields due to their compact structure, small flow pulsation, good self-priming performance, long service life, etc. Existing internal gear pumps are divided into involute gear pumps and cycloid gear pumps.

[0003] Figure 1 This is a working diagram of the widely used internal meshing involute gear pump. In the figure, the inner rotor 100 and the outer rotor 200 are eccentrically arranged, and a crescent-shaped wedge 300 is provided between the inner rotor 100 and the outer rotor 200. This type of internal meshing pump usually drives the outer rotor 200 to rotate by the inner rotor 100, and utilizes the change in the tooth groove volume of the inner rotor 100 and the outer rotor 200 to suck oil from the oil supply chamber 600 and then discharge it from the oil pressure chamber 700. The internal meshing involute gear pump needs to be provided with a crescent-shaped wedge 300, and a certain clearance should be left between the wedge 300 and the gear. High-pressure oil is prone to reverse leakage at this clearance. It can be seen specifically that Figure 1 The fit clearance oil chamber shown is located at the 12 o'clock direction (i.e., directly above the figure). When the fit clearance oil chamber rotates from the side to the 12 o'clock direction, its volume first changes from large to small and squeezes the oil, which can easily cause oil trapping; afterwards, when the fit clearance oil chamber rotates from the 12 o'clock direction to the side, its volume changes from small to large, which can easily form a vacuum, causing the oil pump transmission to be unstable and resulting in a decrease in efficiency to a certain extent.

[0004] Figure 2 This is a working schematic diagram of a traditional internal meshing cycloidal gear pump. In the figure, the outer rotor 200 and the inner rotor 100 are arranged eccentrically, and the tooth profile of the outer rotor 200 is usually a convex arc, and the tooth profile of the inner rotor 100 is a concave cycloid that is conjugate with the convex arc. In this way, at any working position, each tooth surface of the inner rotor 100 and the outer rotor 200 is always close and meshed with each other. At the same time, there is a difference in the number of teeth between the inner rotor 100 and the outer rotor 200, so that the tooth grooves of the inner rotor 100 and the outer rotor 200 are divided into multiple independent oil chambers by the meshing tooth surfaces. When the inner rotor 100 drives the outer rotor 200 to rotate, the volume of these oil chambers changes from small to large when passing through the oil supply chamber 600, and the oil is sucked in; when these oil chambers pass through the oil pressure chamber 700, the volume becomes smaller and the oil is discharged. Compared with the involute gear pump, the cycloidal gear pump omits the wedge block 300, has a large meshing overlap coefficient, and works more smoothly.

[0005] However, conventional internal cycloidal gear pumps have a small top fit area (i.e. Figure 2Except for the 12 o'clock direction or directly above as shown in the figure, almost all the matching parts of the inner rotor 100 and the outer rotor 200 are meshed with the arc and the cycloid at the same time. In this way, the pressure angle of each tooth surface meshing point is different during transmission, and is much greater than 20º. Even when the arc of the outer rotor 200 is at the 12 o'clock direction, the pressure angle there is 90º, which is perpendicular to the transmission rotation direction, and the transmission efficiency is extremely low, resulting in the internal meshing cycloid gear pump having a small load bearing capacity, lower transmission efficiency than the internal meshing involute gear pump, low allowable speed, low oil pressure, and usually can only be used under conditions where the oil pump pressure requirements are not high. Moreover, since the arc of the outer rotor 200 and the cycloid of the inner rotor 100 are both arranged vertically symmetrically about the radius, the curvature of the curve is small, the oil cavity is difficult to enlarge, and the displacement is relatively small, which is only suitable for use as a small flow pump.

[0006] In addition, see Figure 2 , located between the two oil chambers in the bottom area of ​​the figure, in order to prevent reverse oil leakage, the inner rotor 100 and the outer rotor 200 should be meshed with each other to reduce the matching clearance and ensure the pump oil pressure. As for the oil chambers on both sides, it is not necessary to mesh the inner rotor 100 and the outer rotor 200 with each other for sealing. However, based on the working principle of the traditional internal meshing cycloidal gear pump, the inner rotor 100 and the outer rotor 200 are still meshed, which will cause certain mechanical losses and affect the performance of the internal meshing cycloidal gear pump.

[0007] Therefore, how to improve the technical defects existing in the prior art has always been a problem that ordinary technicians in this field need to solve urgently. Summary of the invention

[0008] The purpose of the present invention is to provide an internal meshing cycloid gear pump and a manufacturing method thereof, which changes the tooth profile of the traditional outer rotor from one arc segment to three arc segments, and makes the corresponding part of the inner rotor fit the tooth profile of the outer rotor, which can effectively improve the load-bearing capacity of the internal meshing cycloid gear pump, expand the volume of the oil chamber, and increase the oil discharge volume. At the same time, it also reduces the mechanical friction between the inner rotor and the outer rotor, and improves the oil pumping efficiency.

[0009] The technical solution provided by the present invention is as follows:

[0010] An internal meshing cycloid gear pump, comprising:

[0011] Pump body, rotating shaft and inner rotor and outer rotor meshing with each other;

[0012] The pump body has a chamber inside, and the inner rotor and the outer rotor are rotatably fixed in the chamber;

[0013] One end of the rotating shaft is inserted into the chamber through a through hole provided in the pump body and is fixedly connected to the inner rotor;

[0014] The inner rotor and the outer rotor are eccentrically arranged to form an oil supply chamber and an oil pressure chamber, and the pump body is provided with an oil inlet hole and an oil outlet hole, which are respectively connected to the oil supply chamber and the oil pressure chamber;

[0015] The inner side wall of the outer rotor is provided with a plurality of first tooth blocks, and a first tooth groove is formed between each adjacent two of the first tooth blocks; and the outer side wall of the inner rotor is provided with a plurality of second tooth blocks, and a second tooth groove is formed between each adjacent two of the second tooth blocks, the first tooth groove is adapted to the second tooth block, and the second tooth groove is adapted to the first tooth block;

[0016] Wherein, the tooth profile of the first gear block includes a first circular arc and a second circular arc symmetrically distributed on both sides of the first circular arc.

[0017] In some embodiments, the second arc and the outer rotor pitch circle have an intersection, and an angle between a line connecting the intersection and the center of the outer rotor pitch circle and a tangent line of the second arc corresponding to the intersection toward the inside of the outer rotor is 20°.

[0018] In some embodiments, the number of the first tooth blocks is one more than the number of the second tooth blocks, and the diameter of the outer rotor tooth root circle is one more than the diameter of the inner rotor tooth addendum circle by the tooth height of the first tooth block; and

[0019] The second gear block side wall includes a first action surface and second action surfaces symmetrically distributed on both sides of the first action surface, and the first action surface and the second action surface are in an arc transition.

[0020] In some embodiments, the inner rotor is provided with a mounting hole for the rotating shaft to penetrate;

[0021] The side wall of the rotating shaft and the wall of the mounting hole are both provided with a slot, and the two slots form an installation station. A flat key is arranged in the installation station to make the inner rotor and the rotating shaft rotate synchronously.

[0022] In some embodiments, the pump body includes a first shell having an opening and a second shell covering the first shell, and the first shell and the second shell together form the chamber;

[0023] The inner rotor and the outer rotor are rotatably fixed in the first shell opening, and a cover shell is provided at the first shell opening. The cover shell is pressed against the first shell, the inner rotor and the outer rotor under the action of the second shell.

[0024] In some embodiments, at least one mounting groove is provided on a side of the second shell facing the cover shell, an elastic member is provided in the mounting groove, and a steel ball is provided on a side of the elastic member facing the cover shell, and the steel ball abuts against the cover shell.

[0025] In some embodiments, at least one block is provided on a side of the cover shell facing the second shell, and a slot is provided in the second shell corresponding to the block, and the block and the slot cooperate with each other to limit the rotation of the cover shell relative to the second shell.

[0026] In some embodiments, a first bearing is provided at one end of the rotating shaft fixedly connected to the inner rotor and located on a side of the inner rotor away from the second housing, and a first avoidance groove is provided in the chamber corresponding to the first bearing;

[0027] A second bearing is disposed at one end of the rotating shaft away from the inner rotor and in the through hole, and a second avoidance groove is disposed in the second housing corresponding to the second bearing.

[0028] In some embodiments, the first bearing is a needle bearing, and the second bearing is a ball bearing;

[0029] A first retaining ring is disposed on a side of the second bearing away from the second housing, and the first retaining ring is embedded in the second avoidance groove; and

[0030] A second retaining ring is provided on a side of the second bearing facing the second housing, and the second retaining ring is sleeved on the rotating shaft.

[0031] The present invention also provides a method for manufacturing an internal meshing cycloid gear pump, comprising:

[0032] Calculating the displacement per revolution of the internal cycloid gear pump according to the driving speed, required flow rate and volumetric efficiency of the internal cycloid gear pump;

[0033] Determine the number of teeth n, tooth height, thickness and module m of the outer rotor of the internal meshing cycloid gear pump, and the number of teeth, tooth height, thickness and module of the inner rotor, so as to determine the eccentricity and pitch circle of the outer rotor and the inner rotor;

[0034] According to the number of teeth n of the outer rotor, n equally divided lines are divided on the outer rotor, and each equally divided line corresponds to a tooth block of the outer rotor;

[0035] Determine the size of the addendum circle and the root circle of the outer rotor, and select a first arc with a radius of 1.5m to 2.5m as the center on the bisector, wherein the first arc is circumscribed to the addendum circle of the outer rotor and intersects with the root circle of the outer rotor;

[0036] A first ray passing through the center of the outer rotor pitch circle is drawn on both sides of the bisector, and the angle between the first ray and the bisector is (360 / 4n)°. A second ray tangent to the outer rotor pitch circle is drawn toward the bisector at the intersection of the first ray and the outer rotor pitch circle, and a third ray passing through the intersection is drawn on the side of the second ray away from the outer rotor pitch circle, and the angle between the third ray and the second ray is 20°. A second arc with a radius of 3m to 4m is drawn on the third ray, and the second arc intersects with the first arc and the outer rotor tooth root circle. The first arc and the second arc located on both sides of the first arc together form the tooth profile of the outer rotor gear block;

[0037] The tooth profile shape of the inner rotor tooth block is determined according to the tooth profile shape of the outer rotor tooth block, and the tooth blocks of the outer rotor and the inner rotor are modified.

[0038] The technical effects of the present invention are:

[0039] 1. In this patent, the tooth profile of the first gear block is changed from the traditional one consisting of one arc to three arcs, and the second tooth groove and the second gear block of the inner rotor are adapted to the first tooth block and the first tooth groove of the outer rotor, thereby improving the load-bearing capacity, allowable speed and pumping oil pressure of the internal meshing cycloid gear pump provided by the present invention. In addition, this arrangement can also expand the oil supply cavity and the oil pressure cavity formed by the inner rotor and the outer rotor, and reduce the mechanical friction between the inner rotor and the outer rotor, thereby greatly improving the pumping oil displacement and pumping oil efficiency of the internal meshing cycloid gear pump.

[0040] 2. In this patent, by providing a mounting groove on the first housing and an elastic member and a steel ball installed in the mounting groove, the cover can be always pressed against the first housing, the inner rotor and the outer rotor, and no gap will be generated due to vibration, thereby ensuring the sealing of the internal meshing cycloid gear pump. In addition, this patent provides a block and a slot that can be limited and matched on the cover and the second housing, respectively, so that the cover will not be driven by the rotating shaft or rotated by vibration, further improving the sealing of the internal meshing cycloid gear pump.

[0041] 3. In this patent, a first bearing and a second bearing are arranged on the rotating shaft, so that the rotating shaft can rotate more smoothly and stably, and the oil pumping efficiency is high. Among them, the first bearing is a needle bearing, and the second bearing is a ball bearing. In this way, the rotating shaft can be limited to prevent radial shaking or axial movement, and the installation and layout of parts can be facilitated, and the structural setting is optimized. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments:

[0043] Figure 1 It is a working schematic diagram of an internal meshing involute gear pump in the prior art;

[0044] Figure 2 It is a working schematic diagram of an internal meshing cycloid gear pump in the prior art;

[0045] Figure 3 is a schematic structural diagram of the first gear block provided by the present invention;

[0046] Figure 4 This is a view showing the relationship between the inner rotor and the outer rotor provided by the present invention when they are not modified;

[0047] Figure 5 yes Figure 4 A schematic diagram of the part of the second gear block that needs to be reshaped is shown;

[0048] Figure 6 This is a view showing the relationship between the inner rotor and the outer rotor after modification provided by the present invention;

[0049] Figure 7 It is a cross-sectional view of the internal meshing cycloid gear pump provided by the present invention.

[0050] Description of Figure Numbers:

[0051] 100, inner rotor; 110, second tooth block; 111, first action surface; 112, second action surface; 120, second tooth groove; 130, mounting hole

[0052] 200, outer rotor; 210, first tooth block; 211, first circular arc; 212, second circular arc; 220, first tooth groove;

[0053] 300, wedge;

[0054] 400, pump body; 410, chamber; 411, first avoidance groove; 420, first shell; 421, oil inlet hole; 422, oil outlet hole; 430, second shell; 431, mounting groove; 432, elastic member; 433, steel ball; 434, clamping groove; 435, second avoidance groove; 440, cover; 441, clamping block;

[0055] 500, rotating shaft; 510, first bearing; 520, second bearing; 530, first retaining ring; 540, second retaining ring;

[0056] 600, oil supply chamber;

[0057] 700, oil pressure chamber;

[0058] 801, pitch circle; 802, slot; 803, flat key; 804, bisector; 805, first ray; 806, second ray; 807, third ray. DETAILED DESCRIPTION

[0059] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0060] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.

[0061] In order to simplify the drawings, only the parts related to the invention are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically drawn or marked. In this article, "one" not only means "only one", but also means "more than one".

[0062] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0063] In this document, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0064] In the embodiments shown in the drawings, the indications of directions (such as up, down, left, right, front and back) used to explain the structure and movement of the various components of the present invention are not absolute but relative. These descriptions are appropriate when these components are in the positions shown in the drawings. If the descriptions of the positions of these components change, the indications of these directions also change accordingly.

[0065] In addition, in the description of the present application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0066] According to a specific embodiment provided by the present invention, see Figures 3 to 7 , an internal meshing cycloidal gear pump and a manufacturing method thereof. The internal meshing cycloidal gear pump may specifically include a pump body 400, a rotating shaft 500, and an inner rotor 100 and an outer rotor 200 that mesh with each other. Among them, the pump body 400 has a chamber 410 inside, and the inner rotor 100 and the outer rotor 200 are rotatably fixed in the chamber 410. At this time, one end of the rotating shaft 500 is penetrated into the chamber 410 through a through hole provided in the pump body 400, and is fixedly connected to the inner rotor 100. The inner rotor 100 and the outer rotor 200 are eccentrically arranged to form an oil supply chamber 600 and an oil pressure chamber 700, and the pump body 400 is provided with an oil inlet hole 421 and an oil outlet hole 422, which are respectively connected to the oil supply chamber 600 and the oil pressure chamber 700. Specifically, the inner wall of the outer rotor 200 is provided with a plurality of first tooth blocks 210, and a first tooth slot 220 is formed between each two adjacent first tooth blocks 210, and the outer wall of the inner rotor 100 is provided with a plurality of second tooth blocks 110, and a second tooth slot 120 is formed between each two adjacent second tooth blocks 110, wherein the first tooth slot 220 is adapted to the second tooth block 110, and the second tooth slot 120 is adapted to the first tooth block 210. It is worth noting that the tooth profile of the first tooth block 210 includes a first circular arc 211 and second circular arcs 212 symmetrically distributed on both sides of the first circular arc 211.

[0067] In this embodiment, the tooth profile of the first tooth block 210 is changed from the traditional one consisting of one circular arc to three circular arcs, and the second tooth groove 120 and the second tooth block 110 of the inner rotor 100 are adapted to the first tooth block 210 and the first tooth groove 220 of the outer rotor 200, so that the tooth profile of the second tooth block 110 has a cycloid conjugate with the second circular arc 212 on the tooth profile of the first tooth block 210, so that the inner rotor 100 and the outer rotor 200 can maintain a tight conjugate meshing. In this way, when the inner rotor 100 drives the outer rotor 200 to rotate under the drive of the rotating shaft 500, the first tooth block 210 and the second tooth block 110 located between the oil supply chamber 600 and the oil pressure chamber 700 can mesh with each other, and the oil supply chamber 600 and the oil pressure chamber 700 are sealed and pressure-maintained to avoid reverse oil leakage.

[0068] In addition, the tooth profiles of the first tooth block 210 and the second tooth block 110 provided in this embodiment are similar to the tooth profiles of the tooth blocks of the commonly used internal meshing involute gear pumps, which improves the load-bearing capacity, allowable speed and pumping oil pressure of the internal meshing cycloidal gear pump to a certain extent. At the same time, this structure also expands the oil supply chamber 600 and the oil pressure chamber 700 formed by the inner rotor 100 and the outer rotor 200, reduces the mechanical friction between the inner rotor 100 and the outer rotor 200, and greatly improves the pumping oil displacement and pumping oil efficiency of the internal meshing cycloidal gear pump, so that the internal meshing cycloidal gear pump can be competent for the working conditions that the general internal meshing involute gear pump can be used, and has the advantages of both the internal meshing involute gear pump and the internal meshing cycloidal gear pump.

[0069] Specifically, see Figure 1 The second arc 212 and the pitch circle 801 of the outer rotor 200 have an intersection, and the angle between the line connecting the intersection and the center of the pitch circle 801 of the outer rotor 200 and the tangent of the second arc 212 corresponding to the intersection toward the inside of the outer rotor 200 is 20°. In this way, when the inner rotor 100 and the outer rotor 200 rotate driven by the rotating shaft 500, the pressure angle at the meshing point of the first gear block 210 and the second gear block 110 is small, and the transmission efficiency is high, thereby improving the load-bearing capacity, allowable speed and pump oil pressure of the internal meshing cycloid gear pump provided in this embodiment.

[0070] It is worth noting that see Figures 1 to 6 The first arc 211 and the second arc 212 are both convex arcs, which are convenient for the user to determine the conjugate cycloid of the tooth profile of the second gear block 110 of the inner rotor 100 to realize the meshing transmission of the inner rotor 100 and the outer rotor 200, and ensure that the oil supply chamber 600 and the oil pressure chamber 700 are isolated.

[0071] Specifically, see Figure 4 and Figure 6 The number of the first tooth blocks 210 is one more than the number of the second tooth blocks 110 , and the diameter of the tooth root circle of the outer rotor 200 is one more than the diameter of the tooth top circle of the inner rotor 100 by the tooth height of the first tooth block 210 .

[0072] This embodiment utilizes the gear difference between the inner rotor 100 and the outer rotor 200 to form the above-mentioned oil supply chamber 600 and oil pressure chamber 700. At the same time, the diameter of the tooth root circle of the outer rotor 200 is greater than the diameter of the tooth top circle of the inner rotor 100 by the tooth height of the first tooth block 210, so that the first tooth block 210 and the second tooth block 110 located between the oil supply chamber 600 and the oil pressure chamber 700 can mesh as mentioned above, and the oil supply chamber 600 and the oil pressure chamber 700 are sealed and pressure-maintained to avoid reverse oil leakage.

[0073] Of course, generally speaking, the number of first tooth blocks 210 provided on the outer rotor 200 is one more than the number of second tooth blocks 110 provided on the inner rotor 100, but in actual production, the difference in number between the two can be flexibly set according to actual conditions, and is not limited here, and is within the protection scope of the present invention.

[0074] In this embodiment, see Figures 4 to 6 In order to ensure that the inner rotor 100 and the outer rotor 200 do not interfere with each other during the rotation process, the side wall of the second gear block 110 includes a first action surface 111 and a second action surface 112 symmetrically distributed on both sides of the first action surface 111, and the first action surface 111 and the second action surface 112 are in a circular arc transition. Of course, in addition to preventing the inner rotor 100 and the outer rotor 200 from interfering with each other during the rotation process, this setting can also make the first gear block 210 and the second gear block 110 located between the oil supply chamber 600 and the oil pressure chamber 700 meshing, while the remaining first gear block 210 and the second gear block 110 do not mesh, thereby reducing mechanical friction, minimizing mechanical losses, and improving the performance and work efficiency of the internal meshing cycloid gear pump provided in this embodiment.

[0075] It is worth noting that, at this time, the cross-sectional profile of the second action surface 112 distributed on both sides of the first action surface 111 is a cycloid conjugate between the second gear block 110 and the second arc 212 .

[0076] Specifically, see Figure 6 and Figure 7 The inner rotor 100 is provided with a mounting hole 130 for the rotating shaft 500 to penetrate, and the side wall of the rotating shaft 500 and the hole wall of the mounting hole 130 are both provided with a slot 802, and the two slots 802 form an installation station, and a flat key 803 is provided in the installation station to make the inner rotor 100 and the rotating shaft 500 rotate synchronously.

[0077] When the rotating shaft 500 drives the inner rotor 100 and the outer rotor 200 meshing with the inner rotor 100 to rotate, the matching clearance between the inner rotor 100 and the outer rotor 200 corresponding to the oil supply chamber 600 becomes larger, the oil inlet hole 421 absorbs oil, and the matching clearance between the corresponding oil pressure chamber 700 becomes smaller, and the oil outlet hole 422 discharges oil.

[0078] In a specific embodiment, see Figure 7The pump body 400 includes a first shell 420 with an opening and a second shell 430 covering the first shell 420. The first shell 420 and the second shell 430 together form the above-mentioned chamber 410. The inner rotor 100 and the outer rotor 200 are rotatably fixed in the opening of the first shell 420, and a second avoidance groove 440 is covered at the opening of the first shell 420. The second avoidance groove 440 is pressed against the first shell 420, the inner rotor 100 and the outer rotor 200 under the action of the second shell 430. At this time, the oil inlet hole 421 and the oil outlet hole 422 are arranged at the bottom of the opening of the first shell 420 and correspond to the oil supply chamber 600 and the oil pressure chamber 700 respectively.

[0079] In this embodiment, the second avoidance groove 440 is provided, and the second housing 430 is pressed against the first housing 420, the inner rotor 100 and the outer rotor 200, thereby improving the sealing performance of the internal meshing cycloid gear pump, and achieving higher working efficiency and better safety performance. At the same time, the second avoidance groove 440 also plays a certain protective role for the outer rotor 200 and the inner rotor 100, making them less prone to damage and improving their service life. Specifically, the first housing 420 and the second housing 430 are fixedly connected by tightening bolts, and a sealing gasket is provided at the connection between the first housing 420 and the second housing 430.

[0080] Preferably, see Figure 7 , at least one mounting groove 431 is provided on the side of the second housing 430 facing the second avoidance groove 440, and an elastic member 432 is provided in the mounting groove 431, and a steel ball 433 abutting against the second avoidance groove 440 is provided on the side of the elastic member 432 facing the second avoidance groove 440, so that the second avoidance groove 440 can be always pressed against the first housing 420, the inner rotor 100 and the outer rotor 200, and no gap will be generated due to vibration, thereby ensuring the sealing of the internal meshing cycloid gear pump. In this embodiment, the elastic member 432 is preferably a tension spring, and of course, it can also be replaced by a spring or other elastic structure.

[0081] In actual production, the number of the mounting groove 431 and the elastic member 432 and the steel ball 433 disposed in the mounting groove 431 can be flexibly set according to actual needs, which is not limited here and is within the protection scope of the present invention.

[0082] Further, see Figure 7 At least one block 441 is provided on the side of the second avoidance groove 440 facing the second shell 430, and a slot 434 is provided on the second shell 430 corresponding to the block 441. The block 441 and the slot 434 cooperate with each other to limit the rotation of the second avoidance groove 440 relative to the second shell 430, so that the second avoidance groove 440 will not be driven by the rotating shaft 500 or rotated by vibration, thereby further improving the sealing performance of the internal meshing cycloid gear pump.

[0083] Further, see Figure 7 , a first bearing 510 is provided at one end of the rotating shaft 500 fixedly connected to the inner rotor 100 and located on the side of the inner rotor 100 away from the second housing 430, and a first avoidance groove 411 is provided in the chamber 410 corresponding to the first bearing 510. In contrast, a second bearing 520 is provided in the through hole at one end of the rotating shaft 500 away from the inner rotor 100, and a second avoidance groove 435 is provided in the second housing 430 corresponding to the second bearing 520.

[0084] In this embodiment, the first bearing 510 and the second bearing 520 are arranged on the rotating shaft 500, so that the rotating shaft 500 can rotate more smoothly and stably, and the oil pumping efficiency is high. Among them, the first bearing 510 is a needle bearing, the second bearing 520 is a ball bearing, and the side of the second bearing 520 away from the second housing 430 is provided with a first retaining ring 530, and the first retaining ring 530 is embedded in the second avoidance groove 435. Relatively speaking, the side of the second bearing 520 facing the second housing 430 is provided with a second retaining ring 540, and the second retaining ring 540 is sleeved on the rotating shaft 500.

[0085] In this embodiment, the radial shaking of the rotating shaft 500 is limited by setting the first bearing 510, and the radial shaking and axial movement of the rotating shaft 500 are limited by setting the second bearing 520, which can ensure the smooth rotation of the rotating shaft 500 and prevent excessive positioning from causing increased processing difficulty. Moreover, in this embodiment, by arranging the first bearing 510 that only limits the radial shaking of the rotating shaft 500 in the chamber 410, the layout and installation of the overall structure are facilitated, making the internal structure of the internal meshing cycloidal gear pump provided by this embodiment more compact and effective, and optimizing the structural setting. In addition, in this embodiment, the first retaining ring 530 for the hole and the second retaining ring 540 for the shaft are used at both ends of the rotating shaft 500 to limit the axial movement of the second bearing 520, and the limiting effect is better.

[0086] Normally, the internal meshing cycloid gear pump provided in this embodiment is used inside the machine, and no oil seal is provided because there are other gears and shaft parts that need to be lubricated. If the internal meshing cycloid gear pump needs to be used outside the machine, a rotating oil seal can be provided between the rotating shaft 500 and the second housing 430 for sealing.

[0087] See also Figures 2 to 6 The present invention also provides a method for manufacturing an internal meshing cycloid gear pump, which may specifically include the following steps:

[0088] S1. Calculate the displacement per revolution of the internal cycloid gear pump based on the driving speed, required flow rate and volumetric efficiency of the internal cycloid gear pump.

[0089] S2. Determine the number of teeth n, tooth height, thickness and module m of the outer rotor 200 of the internal meshing cycloid gear pump, as well as the number of teeth, tooth height, thickness and module of the inner rotor 100, so as to determine the eccentricity and pitch circle 801 of the outer rotor 200 and the inner rotor 100. Generally speaking, the number of teeth of the inner rotor 100 is n-1. For example, if the number of teeth of the outer rotor 200 required in this embodiment is nine, then the number of teeth of the inner rotor 100 should be 8. Of course, in actual circumstances, the number of teeth of the inner rotor 100 can also be two or three less than the number of teeth n of the outer rotor 200, without limitation. At this time, the eccentricity of the outer rotor 200 and the inner rotor 100 should be m / 2. It is worth mentioning that the tooth height is very important, because in eccentric transmission, in order to maintain sealing, the tooth top circle of the inner rotor 100 needs to be tangent to the tooth root circle of the outer rotor 200, and the tooth top circle diameter of the inner rotor 100 and the tooth top circle diameter of the outer rotor 200 differ by exactly one tooth height of the outer rotor 200.

[0090] S3. According to the number of teeth n of the outer rotor 200, n bisectors 804 are divided on the outer rotor 200, and each bisector 804 corresponds to a tooth block of the outer rotor 200. The size of the tip circle and the root circle of the outer rotor 200 is determined, and the center of the circle is selected on the bisector 804 to form a first arc 211 with a radius of 1.5m to 2.5m. The first arc 211 is circumscribed to the tip circle of the outer rotor 200 and intersects with the root circle of the outer rotor 200. Specifically, if the number of teeth of the outer rotor 200 is nine, then the bisector 804 is divided.

[0091] S4. A first ray 805 passing through the center of the pitch circle 801 of the outer rotor 200 is made on both sides of the bisector 804, and the angle between the first ray 805 and the bisector 804 is (360 / 4n)°. A second ray 806 tangent to the pitch circle 801 of the outer rotor 200 is made toward the bisector 804 at the intersection of the first ray 805 and the pitch circle 801 of the outer rotor 200. A third ray 807 passing through the intersection is made on the side of the second ray 806 away from the pitch circle 801 of the outer rotor 200, and the angle between the third ray 807 and the second ray 806 is 20°. A second arc 212 with a radius of 3m to 4m is made on the third ray 807 with the center selected. The second arc 212 intersects with the first arc 211 and the tooth root circle of the outer rotor 200. The first arc 211 and the second arcs 212 located on both sides of the first arc 211 together form the tooth profile of the tooth block of the outer rotor 200. Specifically, if the number of teeth of the outer rotor 200 is nine, then the angle between the first ray 805 and the bisector 804 is 10°.

[0092] S5. Determine the tooth profile shape of the inner rotor 100 tooth block according to the tooth profile shape of the outer rotor 200 tooth block, and modify the tooth blocks of the outer rotor 200 and the inner rotor 100. Specifically, it can be understood that the edge of the tooth block of the inner rotor 100 is rounded, and the radius of the rounded corner is usually 1.2 to 1.6 m, which can not only avoid interference between the inner rotor 100 and the outer rotor 200 during rotation, but also reduce mechanical friction and minimize mechanical losses, thereby improving the performance and working efficiency of the internal meshing cycloid gear pump.

[0093] The internal meshing cycloid gear pump provided by the present invention has high working efficiency, a rotation speed of up to 4000r / min, a pump oil pressure of up to 20MPa, and a simple structure, small size, no need to set a wedge block, stable transmission, low noise, small pressure fluctuation, and extremely strong performance.

[0094] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0095] It should be noted that the above embodiments can be freely combined as needed. The above are only preferred embodiments of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. An internal meshing cycloid gear pump, characterized in that: include: Pump body, rotating shaft and inner rotor and outer rotor meshing with each other; The pump body comprises a first shell having an opening and a second shell covering the first shell, wherein the first shell and the second shell jointly form a chamber, wherein the inner rotor and the outer rotor are rotatably fixed in the opening of the first shell, and a cover shell is provided at the opening of the first shell, wherein the cover shell is pressed against the first shell, the inner rotor and the outer rotor under the action of the second shell, so as to rotatably fix the inner rotor and the outer rotor in the chamber; One end of the rotating shaft is passed through a through hole provided in the pump body and is arranged in the chamber, and is fixedly connected to the inner rotor; one end of the rotating shaft is fixedly connected to the inner rotor and is provided with a first bearing on a side of the inner rotor away from the second shell, and a first avoidance groove is provided in the chamber corresponding to the first bearing; one end of the rotating shaft is away from the inner rotor and is provided with a second bearing in the through hole, and a second avoidance groove is provided in the second shell corresponding to the second bearing; wherein, the inner rotor is provided with a mounting hole for the rotating shaft to penetrate, and a groove is provided on the side wall of the rotating shaft and the wall of the mounting hole, and the two grooves form an installation station, and a flat key is provided in the installation station to make the inner rotor and the rotating shaft rotate synchronously; The inner rotor and the outer rotor are eccentrically arranged to form an oil supply chamber and an oil pressure chamber, and the pump body is provided with an oil inlet hole and an oil outlet hole, which are respectively connected to the oil supply chamber and the oil pressure chamber; The inner side wall of the outer rotor is provided with a plurality of first tooth blocks, and a first tooth groove is formed between each two adjacent first tooth blocks, and the outer side wall of the inner rotor is provided with a plurality of second tooth blocks, and a second tooth groove is formed between each two adjacent second tooth blocks, the first tooth groove is adapted to the second tooth block, and the second tooth groove is adapted to the first tooth block; the number of the first tooth blocks is one more than the number of the second tooth blocks, and the diameter of the outer rotor tooth root circle is one more than the diameter of the inner rotor tooth top circle by the tooth height of the first tooth block; and the side wall of the second tooth block includes a first action surface and second action surfaces symmetrically distributed on both sides of the first action surface, and the first action surface and the second action surface are in a circular arc transition; Among them, the tooth profile of the first gear block includes a first arc and a second arc symmetrically distributed on both sides of the first arc, the second arc and the outer rotor pitch circle have an intersection, and the angle between the line connecting the intersection and the center of the outer rotor pitch circle and the tangent of the second arc corresponding to the intersection toward the inside of the outer rotor is 20°.

2. The internal meshing cycloid gear pump according to claim 1, characterized in that: The second shell body is provided with at least one mounting groove on a side facing the cover shell, an elastic member is provided in the mounting groove, and a steel ball is provided on a side of the elastic member facing the cover shell, and the steel ball abuts against the cover shell.

3. The internal meshing cycloid gear pump according to claim 1, characterized in that: At least one block is provided on one side of the cover shell facing the second shell, and a slot is provided in the second shell corresponding to the block, and the block and the slot are limitedly matched to limit the cover shell from rotating relative to the second shell.

4. The internal meshing cycloid gear pump according to claim 1, characterized in that: The first bearing is a needle bearing, and the second bearing is a ball bearing; A first retaining ring is disposed on a side of the second bearing away from the second housing, and the first retaining ring is embedded in the second avoidance groove; and A second retaining ring is provided on a side of the second bearing facing the second housing, and the second retaining ring is sleeved on the rotating shaft.

5. A method for manufacturing an internal meshing cycloid gear pump, used for manufacturing the internal meshing cycloid gear pump according to any one of claims 1 to 4, characterized in that: include: Calculating the displacement per revolution of the internal cycloid gear pump according to the driving speed, required flow rate and volumetric efficiency of the internal cycloid gear pump; Determine the number of teeth n, tooth height, thickness and module m of the outer rotor of the internal meshing cycloid gear pump, and the number of teeth, tooth height, thickness and module of the inner rotor, so as to determine the eccentricity and pitch circle of the outer rotor and the inner rotor; According to the number of teeth n of the outer rotor, n equally divided lines are divided on the outer rotor, and each equally divided line corresponds to a tooth block of the outer rotor; Determine the size of the addendum circle and the root circle of the outer rotor, and select a first arc with a radius of 1.5m to 2.5m as the center on the bisector, wherein the first arc is circumscribed to the addendum circle of the outer rotor and intersects with the root circle of the outer rotor; A first ray passing through the center of the outer rotor pitch circle is made on both sides of the bisector, and the angle between the first ray and the bisector is 360 / 4n°. A second ray tangent to the outer rotor pitch circle is made toward the bisector at the intersection of the first ray and the outer rotor pitch circle, and a third ray passing through the intersection is made on the side of the second ray away from the outer rotor pitch circle, and the angle between the third ray and the second ray is 20°. A second arc with a radius of 3m to 4m is selected as the center on the third ray, and the second arc intersects with the first arc and the outer rotor tooth root circle. The first arc and the second arc located on both sides of the first arc together form the tooth profile of the outer rotor gear block; The tooth profile shape of the inner rotor tooth block is determined according to the tooth profile shape of the outer rotor tooth block, and the tooth blocks of the outer rotor and the inner rotor are modified.

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