A transmission oil pump

Abstract

The utility model relates to a kind of transmission oil pump, including pump cover, pump body, rotor assembly, the pump cover and pump body sealing cooperation and the pump cavity formed between the two, the rotor assembly includes the inner rotor and outer rotor being set in pump cavity, the pump cavity is equipped with oil suction chamber, oil discharge chamber, transition platform between the oil suction chamber and oil discharge chamber with the rotor assembly cooperation to separate oil suction chamber and oil discharge chamber, when the inner rotor and outer rotor relatively rotate, the inner rotor and the gear gap of outer rotor and the transition platform form high-pressure container chamber, the high-pressure container chamber is located between the oil suction chamber and oil discharge chamber, the transition platform surface is equipped with pressure relief groove, the pressure relief groove is connected with the high-pressure container chamber and oil discharge chamber, so that high-pressure oil flows to oil discharge chamber by the channel of pressure relief groove, reduce pressure peak value, reduce noise, improve stability, play the role similar to safety valve, and the pressure relief groove can maintain the pressure inside pump body in normal range when oil temperature changes.

Description

Technical Field

[0001] This utility model relates to the field of automotive transmission technology, specifically to a transmission oil pump. Background Technology

[0002] The transmission oil pump is the power source of the automatic transmission hydraulic system, responsible for providing stable oil pressure for clutch control, gear lubrication, and cooling systems. With the development of automotive technology, oil pumps need to meet the requirements of higher speed (>6000rpm), lower noise (<70dB), and lower energy consumption. The reliability of its drive structure directly affects the efficiency and lifespan of the transmission.

[0003] Existing transmission rotary oil pumps (internal gear pumps) include a pump housing, a pump cover, and a closed pump chamber. Inner and outer rotors are housed within the pump chamber. When the inner and outer rotors rotate relative to each other, the change in tooth clearance volume creates a low-pressure zone (oil suction) and a high-pressure zone (oil discharge). For detailed information on the structure of the internal gear pump and the principles behind the formation of the high and low pressure zones, please refer to relevant reference books or the background section of the Chinese utility model patent (CN205155526U). This is prior art and will not be elaborated upon here. When a closed high-pressure zone is formed between the adjacent teeth of the inner and outer rotors, the oil pressure rises sharply, generating a pressure peak. Furthermore, when the oil temperature changes (rises), the pressure peak of the high-pressure zone is even higher. Large fluctuations in oil pressure generate significant impact, vibration, and noise, affecting the pump's operational stability. Therefore, it is necessary to reduce the pressure peak, improve oil fluidity, and develop a transmission oil pump that is adaptable to a wide temperature range and has high stability. Utility Model Content

[0004] The purpose of this invention is to develop a transmission oil pump to solve the problem of pressure peaks in the high-pressure zone of the existing transmission rotor oil pump, thereby improving the stability of the transmission oil pump.

[0005] This utility model is achieved through the following technical solution: A transmission oil pump, which is an internal gear pump, includes a pump cover, a pump body, and a rotor assembly. The pump cover and the pump body are sealed together, forming a pump cavity between them. The rotor assembly includes an inner rotor and an outer rotor disposed in the pump cavity. The pump cavity is provided with an oil suction cavity, an oil discharge cavity, and a transition platform located between the oil suction cavity and the oil discharge cavity, which cooperates with the rotor assembly to separate the oil suction cavity and the oil discharge cavity. When the inner rotor and the outer rotor rotate relative to each other, a high-pressure cavity is formed between the tooth gap of the inner rotor and the outer rotor and the transition platform. The high-pressure cavity is located between the oil suction cavity and the oil discharge cavity. The surface of the transition platform is provided with a pressure-reducing groove, which connects the high-pressure cavity and the oil discharge cavity. The distance between the contact points of the gear teeth of the inner rotor and the outer rotor on both sides of the high-pressure cavity is the length a of the high-pressure cavity. The pressure-reducing groove extends from the oil discharge cavity into the high-pressure cavity, and the extension length b of the pressure-reducing groove is less than the length a of the high-pressure cavity.

[0006] The beneficial effects of the above technical solution are as follows: In the transmission oil pump, the rotation of the inner and outer rotors drives the oil flow, forming a high-pressure zone (discharge) and a low-pressure zone (suction) in the pump chamber. The oil pressure reaches its peak before entering the discharge chamber. The design of the pressure relief groove allows the oil in the high-pressure chamber to flow to the discharge chamber through the channel of the pressure relief groove, reducing the pressure peak, reducing noise, improving stability, and playing a role similar to the pressure relief of a safety valve. Furthermore, the existence of the pressure relief groove enables the transmission oil pump to balance the pressure peak caused by temperature changes inside the pump body, making it suitable for a wider range of oil temperatures.

[0007] In one possible implementation, the pressure-reducing groove is a triangular groove with a triangular cross-section (cross-section in the width direction), which has a better flow guiding effect.

[0008] The pressure reducing groove extends from the oil discharge chamber into the high-pressure chamber, and the depth of the pressure reducing groove gradually decreases in the direction of extension. That is, the closer to the oil discharge chamber, the deeper the pressure reducing groove becomes. The oil in the high-pressure chamber flows from the shallower part of the groove to the deeper part, so that the pressure is gradually released and the pressure in the high-pressure chamber is avoided from dropping sharply.

[0009] Specifically, the inner wall of the pump cover is provided with an upper oil inlet groove and an upper oil outlet groove, as well as an upper transition platform separating the upper oil inlet groove and the upper oil outlet groove; the inner wall of the pump body is provided with a lower oil inlet groove and a lower oil outlet groove, as well as a lower transition platform separating the lower oil inlet groove and the lower oil outlet groove; the upper oil inlet groove and the lower oil inlet groove correspond to each other to form an oil suction chamber, and the upper oil outlet groove and the lower oil outlet groove correspond to each other to form an oil discharge chamber; the upper transition platform and the lower transition platform correspond to each other, and the inner rotor and the outer rotor form a high-pressure cavity between the upper transition platform and the lower transition platform during rotation; the surface of the upper transition platform is provided with an upper pressure reducing groove connecting the high-pressure cavity and the upper oil outlet groove, and / or, the surface of the lower transition platform is provided with a lower pressure reducing groove connecting the high-pressure cavity and the lower oil outlet groove.

[0010] Furthermore, the pump body is provided with an oil inlet communicating with the oil suction chamber and an oil outlet communicating with the oil discharge chamber.

[0011] In one feasible embodiment, the rotor assembly includes a drive shaft for driving connection with a drive mechanism external to the transmission oil pump. The inner rotor is driven to the drive shaft via a cylindrical key. The outer peripheral wall of the drive shaft is provided with a first positioning groove for accommodating the key, and the inner peripheral wall of the inner rotor is provided with a second positioning groove for accommodating the key. Compared with splines / flat keys, the key can significantly solve the problems of machining cost, anti-wear, or space limitation. Furthermore, the key can radially adaptively fine-tune the clearance, compensate for shaft misalignment, and reduce the risk of wear.

[0012] Furthermore, the drive shaft is hollow and has splines on its inner peripheral wall, which are used for drive connection with the drive shaft of the drive mechanism that extends into the drive shaft. Attached Figure Description

[0013] Figure 1 A schematic diagram of the overall structure of the transmission oil pump provided by this utility model; Figure 2 for Figure 1 Exploded view of the transmission oil pump; Figure 3 for Figure 1 Schematic diagram of the internal structure of the transmission oil pump (with pump body hidden); Figure 4 for Figure 3 Top view of the transmission oil pump; Figure 5 for Figure 1 Schematic diagram of the internal structure of the pump cover of the intermediate transmission oil pump; Figure 6 for Figure 1 A schematic diagram of the internal structure of the transmission oil pump. Figure 7 for Figure 1 A schematic diagram showing the location of the high-pressure cavity formed by the inner and outer rotors of the intermediate transmission oil pump; Figure 8 for Figure 1 Cross-sectional view of the transmission oil pump; Figure 9 for Figure 7 Enlarged view of point A in the middle; Figure 10 for Figure 1 A cross-sectional view of the transmission oil pump from another angle; Figure 11 for Figure 9 Enlarged view at point B in the middle; Figure 12 This is a schematic diagram of the rotor assembly structure.

[0014] In the diagram, 1. Pump cover; 101. Upper oil inlet groove; 102. Upper oil outlet groove; 103. Upper pressure reducing groove; 11. Upper transition platform; 2. Rotor assembly; 21. Drive shaft; 211. First positioning groove; 212. Circular key; 213. Spline; 22. Inner rotor; 23. Outer rotor; 201. High-pressure cavity; 3. Pump body; 301. Lower oil inlet groove; 302. Lower oil outlet groove; 303. Lower pressure reducing groove; 31. Oil inlet; 32. Oil outlet; 33. Lower transition platform. Detailed Implementation

[0015] First, those skilled in the art should understand that the following embodiments are merely used to explain the technical principles of the embodiments of this application and are not intended to limit the scope of protection of the embodiments of this application. Those skilled in the art can make adjustments as needed to adapt to specific application scenarios.

[0016] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0017] In the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0018] To make the objectives, features and advantages of this utility model more apparent and understandable, the specific embodiments are described in detail below with reference to the accompanying drawings.

[0019] like Figures 1 to 11 As shown, this embodiment provides a transmission oil pump, which is an internal gear pump, including a pump cover 1, a pump body 3, and a rotor assembly 2. The pump cover 1 and the pump body 3 are sealed together, forming a pump chamber between them. The rotor assembly 2 includes an inner rotor 22 and an outer rotor 23 disposed in the pump chamber. The pump chamber is provided with an oil suction chamber, an oil discharge chamber, and a transition platform located between the oil suction chamber and the oil discharge chamber, which cooperates with the rotor assembly 2 to separate the oil suction chamber and the oil discharge chamber. When the inner rotor 22 and the outer rotor 23 rotate relative to each other, the inner rotor 22 and the outer rotor 23... A high-pressure cavity 201 is formed between the tooth gap of the inner rotor 22 and the transition platform. The high-pressure cavity 201 is located between the oil suction chamber and the oil discharge chamber. A pressure-reducing groove is provided on the surface of the transition platform. The pressure-reducing groove connects the high-pressure cavity 201 and the oil discharge chamber. The distance between the contact points of the teeth of the inner rotor 22 and the outer rotor 23 on both sides of the high-pressure cavity 201 is the length a of the high-pressure cavity 201. The pressure-reducing groove extends from the oil discharge chamber into the high-pressure cavity 201, and the extension length b of the pressure-reducing groove is less than the length a of the high-pressure cavity 201.

[0020] The beneficial effects of the above technical solution are as follows: In the transmission oil pump, the rotation of the inner and outer rotors pressurizes the oil, creating a high-pressure zone and a low-pressure zone within the pump chamber. The oil pressure reaches its peak value before entering the discharge chamber. The pressure-reducing groove allows the high-pressure oil in the high-pressure chamber to flow to the discharge chamber through the groove, reducing the pressure peak value and acting as a safety valve. The presence of this pressure-reducing groove enables the transmission oil pump to adapt to oil temperature changes from -40℃ to 140℃, maintaining the internal pressure of the pump body within a normal range, improving stability, and reducing noise. The extension length b of the pressure-reducing groove is less than the length a of the high-pressure chamber 201 to avoid the pressure-reducing groove being too long, causing direct connection between the suction chamber and the discharge chamber, which would affect the suction or discharge effect.

[0021] Furthermore, such as Figure 10 As shown, the pressure reducing groove extends from the oil discharge chamber into the high pressure chamber 201, and the depth of the pressure reducing groove gradually decreases in the direction of extension of the pressure reducing groove, that is, the closer to the oil discharge chamber, the deeper the pressure reducing groove is; the oil in the high pressure chamber 201 flows from the shallower part of the groove to the deeper part of the groove, so that the pressure is gradually released and the pressure in the high pressure chamber 201 is avoided from dropping sharply.

[0022] Furthermore, such as Figure 11 As shown, the pressure-reducing groove is a triangular groove with a triangular cross-section in its width direction. In this embodiment, the ratio of its groove width to groove depth is 2:1, which has a better flow guiding effect.

[0023] Specifically, such as Figures 3 to 6 As shown, in this embodiment, the inner wall of the pump cover 1 is provided with an upper oil inlet groove 101 and an upper oil outlet groove 102, as well as an upper transition platform 11 separating the upper oil inlet groove 101 and the upper oil outlet groove 102; the inner wall of the pump body 3 is provided with a lower oil inlet groove 301 and a lower oil outlet groove 302, as well as a lower transition platform 33 separating the lower oil inlet groove 301 and the lower oil outlet groove 302; the upper oil inlet groove 101 and the lower oil inlet groove 301 correspond to each other to form an oil suction chamber between them, and the upper oil outlet groove 102 and the lower oil outlet groove 302... 02 corresponds to form an oil discharge chamber between the two; the upper transition platform 11 and the lower transition platform 33 correspond to each other, and the inner rotor 22 and the outer rotor 23 form a high-pressure cavity 201 between the upper transition platform 11 and the lower transition platform 33 during rotation; the surface of the upper transition platform 11 is provided with an upper pressure reducing groove 103 that connects the high-pressure cavity 201 and the upper oil outlet groove 102, and the surface of the lower transition platform 33 is provided with a lower pressure reducing groove 303 that connects the high-pressure cavity 201 and the lower oil outlet groove 302.

[0024] Furthermore, the pump body 3 is provided with an oil inlet 31 communicating with the oil suction chamber and an oil outlet 32 ​​communicating with the oil discharge chamber.

[0025] In one embodiment, the rotor assembly 2 includes a drive shaft 21 for transmission connection to a drive mechanism external to the transmission oil pump. The inner rotor 22 is connected to the drive shaft 21 via a cylindrical key 212. The outer peripheral wall of the drive shaft 21 has a first positioning groove 211 for accommodating the key 212, and the inner peripheral wall of the inner rotor 22 has a second positioning groove for accommodating the key 212. Compared to a key, a flat key connection results in significant stress concentration, which can easily lead to keyway cracking during high-speed rotation. Furthermore, the rotor's thermal expansion is limited, making it prone to jamming due to insufficient clearance during low-temperature startup and causing impact noise due to excessive clearance at high temperatures. While a direct-drive rotor assembly simplifies the transmission chain, it requires a custom motor shaft, sacrificing modular component replacement capability. Therefore, this solution uses a key connection. Compared to splines, key connections significantly solve problems related to processing costs, anti-wear, and space limitations. Moreover, the radial adaptive fine-tuning clearance of the key (0.03-0.08mm) compensates for shaft misalignment and reduces the risk of uneven wear.

[0026] Furthermore, the transmission shaft 21 is hollow and has a spline 213 on its inner peripheral wall. The spline 213 is used for transmission connection with the drive shaft of the drive mechanism that extends into the transmission shaft 21.

[0027] In the description of the embodiments of this application, it should be noted that the terms "inner" and "outer" and other terms indicating direction or positional relationship are based on the direction or positional relationship shown in the drawings. This is only for the convenience of description and does not indicate or imply that the device or component must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this application.

[0028] In the description of this application, the reference to terms such as "this embodiment," "an embodiment," etc., means that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0029] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A transmission oil pump, which is an internal gear pump, includes a pump cover (1), a pump body (3), and a rotor assembly (2), wherein the pump cover (1) and the pump body (3) are sealed together and form a pump cavity between them, the rotor assembly (2) includes an inner rotor (22) and an outer rotor (23) disposed in the pump cavity, the pump cavity is provided with an oil suction chamber, an oil discharge chamber, and a transition platform located between the oil suction chamber and the oil discharge chamber, which cooperates with the rotor assembly (2) to separate the oil suction chamber and the oil discharge chamber, and when the inner rotor (22) and the outer rotor (23) rotate relative to each other, a high-pressure cavity (201) is formed between the tooth gap of the inner rotor (22) and the outer rotor (23) and the transition platform, the high-pressure cavity (201) being located between the oil suction chamber and the oil discharge chamber, characterized in that: The transition platform surface is provided with a pressure relief groove, which connects the high pressure cavity (201) and the oil discharge cavity. The distance between the contact points of the gear teeth of the inner rotor (22) and the outer rotor (23) on both sides of the high pressure cavity (201) is the length a of the high pressure cavity (201). The pressure relief groove extends from the oil discharge cavity into the high pressure cavity (201), and the extension length b of the pressure relief groove is less than the length a of the high pressure cavity (201).

2. The transmission oil pump according to claim 1, characterized in that: The cross-section of the pressure-reducing groove is triangular.

3. The transmission oil pump according to claim 1, characterized in that: The pressure reducing groove extends from the oil discharge chamber into the high pressure chamber (201), and the depth of the pressure reducing groove gradually decreases in the direction of extension of the pressure reducing groove.

4. The transmission oil pump according to any one of claims 1-3, characterized in that: The pump cover (1) has an upper oil inlet groove (101) and an upper oil outlet groove (102) on its inner wall, as well as an upper transition platform (11) separating the upper oil inlet groove (101) and the upper oil outlet groove (102). The pump body (3) has a lower oil inlet groove (301) and a lower oil outlet groove (302) on its inner wall, as well as a lower transition platform (33) separating the lower oil inlet groove (301) and the lower oil outlet groove (302). The upper oil inlet groove (101) and the lower oil inlet groove (301) correspond to each other to form an oil suction chamber, and the upper oil outlet groove (102) and the lower oil outlet groove (302) correspond to each other to form an oil discharge chamber; the upper transition platform (11) and the lower transition platform (33) correspond to each other, and the inner rotor (22) and the outer rotor (23) form a high-pressure cavity (201) between the upper transition platform (11) and the lower transition platform (33) during rotation. The surface of the upper transition platform (11) is provided with an upper pressure reducing groove (103) that connects the high pressure cavity (201) and the upper oil outlet groove (102), and / or the surface of the lower transition platform (33) is provided with a lower pressure reducing groove (303) that connects the high pressure cavity (201) and the lower oil outlet groove (302).

5. The transmission oil pump according to claim 4, characterized in that: The pump body (3) is provided with an oil inlet (31) communicating with the oil suction chamber and an oil outlet (32) communicating with the oil discharge chamber.

6. The transmission oil pump according to any one of claims 1-3, characterized in that: The rotor assembly (2) includes a drive shaft (21) for transmission connection with a drive mechanism outside the transmission oil pump. The inner rotor (22) is connected to the drive shaft (21) via a cylindrical key (212). The outer peripheral wall of the drive shaft (21) is provided with a first positioning groove (211) for accommodating the key (212), and the inner peripheral wall of the inner rotor (22) is provided with a second positioning groove for accommodating the key (212).

7. The transmission oil pump according to claim 6, characterized in that: The drive shaft (21) is hollow and has a spline (213) on its inner peripheral wall. The spline (213) is used to drive the drive shaft of the drive mechanism that extends into the drive shaft (21).

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