Hydraulic retarder

Abstract

This invention relates to the field of retarder technology, and more particularly to a hydraulic retarder. The hydraulic retarder includes a housing, a rotor shaft, a stator, a rotor, and a flow disruptor. The housing has a cavity, and the rotor shaft rotatably passes through the cavity, with a drive gear at one end extending out of the cavity. An external splined gear is located at the end of the rotor shaft within the cavity. The stator is fixedly mounted on the housing and fitted onto the rotor shaft, with the stator blades sealingly extending into the cavity. The rotor is located within the cavity and meshes with the external splined gear for transmission. The rotor is rotatably fitted onto the stator, and the rotor blades are fixedly clearance-fitted with the stator blades to form a working chamber. The flow disruptor is retractably positioned within the fixed gap between the stator and the rotor. The flow disruptor extends into the working chamber after the hydraulic retarder exits operation or exits the working chamber when the hydraulic retarder enters operation. This shortens the response time for entering and exiting operation, and reduces the no-load loss of the hydraulic retarder through the flow disruptor.

Description

Technical Field

[0001] This invention relates to the field of retarder technology, and more particularly to a hydraulic retarder. Background Technology

[0002] A hydraulic retarder mainly consists of a working chamber composed of a rotor and a stator, an oil sump composed of a housing, and a heat exchanger. When the retarder is working, oil needs to enter the working chamber. Under the action of the rotor blades, the oil accelerates and rotates, impacting the stator blades. After being impacted by the stator blades, the oil acts in the opposite direction on the rotor blades, causing the rotor blades to receive a reverse braking force. The braking torque is transmitted to the wheels through the rotor shaft via the internal spline gears of the rotor, thus slowing down the vehicle.

[0003] Currently, hydraulic retarders have a detachable stator and rotor structure, with the rotor connected to the rotor shaft via an involute spline. Existing hydraulic retarders have a large number of parts, are complex to install, and are costly. When the hydraulic retarder engages, the rotor needs to compress the spring between itself and the rotor shaft to approach the stator and form the working chamber. Because the rotor needs to overcome the spring force, it takes time for the rotor to move into position. When the hydraulic retarder disengages, the spring and rotor also need time to reset, resulting in a long response time for the hydraulic retarder to engage and disengage, affecting driving comfort. In addition, when the hydraulic retarder disengages, the rotor blades agitate the airflow and act on the stator blades, generating an unloaded braking torque, increasing the no-load loss of the hydraulic retarder. Summary of the Invention

[0004] The purpose of this invention is to provide a hydraulic retarder to shorten the response time of the hydraulic retarder when entering and exiting operation, reduce the no-load loss of the hydraulic retarder, simplify the structure of the hydraulic retarder, and improve assembly efficiency.

[0005] To achieve this objective, the technical solution adopted by the present invention is as follows:

[0006] A hydraulic retarder, comprising:

[0007] A housing having a cavity inside;

[0008] The rotor shaft rotatably passes through the cavity and has a drive gear at one end extending out of the cavity; the end of the rotor shaft located in the cavity has an external spline gear.

[0009] The stator and rotor are provided. The stator is fixedly mounted on the housing and fitted onto the rotor shaft. The blade ends of the stator are sealed and extend into the cavity. The rotor is located in the cavity and meshes with the external spline gear for transmission. The rotor is rotatably fitted onto the stator. The blade ends of the rotor and the blade ends of the stator are fixedly clearance-fitted and form a working cavity.

[0010] A deflector is retractably disposed within a fixed gap between the stator and the rotor, the deflector being configured to extend into the working chamber after the hydraulic retarder has ceased operation or to retract from the working chamber when the hydraulic retarder has commenced operation.

[0011] As a preferred embodiment, the hydraulic retarder further includes a metal ring, and a first sealing groove is formed around the outer surface of the stator in a circumferential manner. The metal ring is fitted into the first sealing groove and sandwiched between the rotor and the stator.

[0012] As a preferred embodiment, the metal ring has two overlapping open ends, and a pressure relief gap is formed between the two open ends of the metal ring.

[0013] As a preferred embodiment, a first oil reservoir and a second oil reservoir are respectively formed around the rear side of the blade end of the rotor in a circumferential manner. The first oil reservoir and the side wall of the cavity form an oil inlet cavity, and the second oil reservoir and the side wall of the cavity form an oil return cavity. Both the oil inlet cavity and the oil return cavity are connected to the working cavity.

[0014] As a preferred embodiment, a partition is provided around the rear side of the blade end of the rotor in a circumferential manner, and the partition is located between the first oil storage tank and the second oil storage tank.

[0015] The sidewall of the cavity is provided with circumferentially distributed annular grooves, which are located between the oil inlet chamber and the oil return chamber, and the partition is inserted into the annular grooves with a gap.

[0016] As a preferred embodiment, the rotor has a plurality of rotor blades, and the plurality of rotor blades are selectively provided with oil inlets and oil outlets at their roots. The oil inlet chamber is connected to the working chamber through the oil inlet, and the oil return chamber is connected to the working chamber through the oil outlet.

[0017] As a preferred embodiment, the cross-sectional area of ​​the oil inlet is 1.9 to 1.94 times the cross-sectional area of ​​the oil outlet.

[0018] As a preferred embodiment, the stator has a plurality of stator blades, and ventilation holes are selectively provided on the plurality of stator blades. The working chamber is connected to the ventilation holes so that external air can enter the working chamber through the ventilation holes or air in the working chamber can be discharged through the ventilation holes.

[0019] As a preferred embodiment, the outer periphery of the rotor shaft is provided with a first lubrication groove and a second lubrication groove, the first lubrication groove extending along the axial direction of the rotor shaft to the external spline gear, and the second lubrication groove being distributed around the external spline gear in the circumferential direction and communicating with the first lubrication groove.

[0020] As a preferred embodiment, the hydraulic retarder further includes a coupling, wherein the rotor shaft has a mounting groove at the end with the external spline gear, one end of the coupling is fixedly engaged in the mounting groove, and the other end of the coupling can be connected to the drive shaft.

[0021] As a preferred embodiment, the rotor shaft further includes a shaft body and a counting gear, wherein the counting gear, the drive gear, and the external spline gear are integrally formed on the shaft body along its axial direction.

[0022] The beneficial effects of this invention are as follows:

[0023] The hydraulic retarder proposed in this invention includes a housing, a rotor shaft, a stator, a rotor, and a baffle. The blade ends of the rotor and the blade ends of the stator are fixedly fitted with a clearance to form a working chamber. This ensures that the rotor does not need to overcome elastic force to shift when the hydraulic retarder enters operation, and the rotor will not reset under elastic force when the hydraulic retarder exits operation. This not only simplifies the structure of the hydraulic retarder and improves assembly efficiency, but also prevents reciprocating movement of the rotor and shortens the response time for entering and exiting operation. Furthermore, when the hydraulic retarder enters operation, the baffle is forced out of the working chamber by the oil pressure, without affecting the flow of high-pressure oil in the working chamber, allowing the hydraulic retarder to quickly generate braking torque. When the hydraulic retarder exits operation, the baffle enters the working chamber and blocks the flow of air between the rotor and the stator, thus preventing the rotor from agitating the air and generating braking torque, reducing the no-load loss of the hydraulic retarder. Attached Figure Description

[0024] Figure 1 This is a partial cross-sectional view of the hydraulic retarder provided in an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of the stator structure provided in an embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the rotor shaft provided in an embodiment of the present invention;

[0027] Figure 4 This is a cross-sectional view of the rotor provided in an embodiment of the present invention;

[0028] Figure 5 yes Figure 1 A magnified view of a section at point A in the middle;

[0029] Figure 6 This is a schematic diagram of the rotor structure provided in an embodiment of the present invention;

[0030] Figure 7This is a schematic diagram of the structure of the metal ring provided in an embodiment of the present invention;

[0031] Figure 8 This is a partial structural diagram of the assembled metal ring provided in an embodiment of the present invention.

[0032] The component names and labels in the diagram are as follows:

[0033] 10. Working chamber; 20. Oil inlet chamber; 30. Oil return chamber;

[0034] 1. Shell; 11. Cavity; 12. Circumferential groove; 13. Annular groove;

[0035] 2. Rotor shaft; 21. Drive gear; 22. External spline gear; 23. Counting gear; 24. First lubrication groove; 25. Second lubrication groove; 26. Mounting groove;

[0036] 3. Stator; 31. Stator blades; 32. Vent holes; 33. Support;

[0037] 4. Rotor; 41. Rotor blades; 42. Internal spline gear; 43. First oil reservoir; 44. Second oil reservoir; 45. Divider; 46. Oil inlet;

[0038] 5. Spoiler; 6. Metal ring; 61. Groove; 62. Locking arm; 7. Sealing ring; 8. Bearing; 9. Coupling. Detailed Implementation

[0039] To make the technical problems solved by the present invention, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention. Furthermore, it should be noted that, for ease of description, only the parts related to the present invention are shown in the accompanying drawings, not all of them.

[0040] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0041] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0042] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0043] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0044] Currently, hydraulic retarders have a detachable stator and rotor structure, with the rotor connected to the rotor shaft via an involute spline. Existing hydraulic retarders have a large number of parts, are complex to install, and are costly. When the hydraulic retarder engages, the rotor needs to compress the spring between itself and the rotor shaft to approach the stator and form the working chamber. Because the rotor needs to overcome the spring force, it takes time for the rotor to move into position. When the hydraulic retarder disengages, the spring and rotor also need time to reset, resulting in a long response time for the hydraulic retarder to engage and disengage, affecting driving comfort. In addition, when the hydraulic retarder disengages, the rotor blades agitate the airflow and act on the stator blades, generating an unloaded braking torque, increasing the no-load loss of the hydraulic retarder.

[0045] To solve the above problems, such as Figure 1As shown, this embodiment proposes a hydraulic retarder, which includes a housing 1, a rotor shaft 2, a stator 3, a rotor 4, and a flow disruptor 5. The housing 1 has a cavity 11. The rotor shaft 2 rotatably passes through the cavity 11, and one end extending out of the cavity 11 has a drive gear 21. The end of the rotor shaft 2 located in the cavity 11 has an external spline gear 22. The stator 3 is fixedly mounted on the housing 1 and fitted onto the rotor shaft 2. The blade ends of the stator 3 are sealed and extend into the cavity 11. The rotor 4 is located in the cavity 11 and meshes with the external spline gear 22 for transmission. The rotor 4 is rotatably fitted onto the stator 3. The blade ends of the rotor 4 and the blade ends of the stator 3 are fixedly clearance-fitted and form a working cavity 10. The flow disruptor 5 is retractably disposed within the fixed gap between the stator 3 and the rotor 4. The flow disruptor 5 can extend into the working cavity 10 after the hydraulic retarder is out of operation or retract from the working cavity 10 when the hydraulic retarder is in operation.

[0046] In this embodiment, the rotor 4 does not need to overcome the spring force to shift when the hydraulic retarder enters operation, and the rotor 4 will not reset under the action of the spring force when the hydraulic retarder exits operation. This not only simplifies the structure of the hydraulic retarder and improves assembly efficiency, but also prevents the rotor 4 from reciprocating and shortens the response time of the hydraulic retarder entering and exiting operation. In addition, when the hydraulic retarder enters operation, the baffle 5 is removed from the working chamber 10 by the oil pressure in the working chamber 10, without affecting the flow of high-pressure oil in the working chamber 10, so that the hydraulic retarder can quickly generate braking torque. When the hydraulic retarder exits operation, the baffle 5 enters the working chamber 10 and blocks the flow of air in the working chamber 10, thereby preventing the rotor 4 from stirring the air and generating braking torque, and reducing the no-load loss of the hydraulic retarder.

[0047] It should be noted that the spoiler 5 is retractably mounted in the clearance groove 12 within the housing 1 via a spring. When the hydraulic retarder is in operation, the spoiler 5 is compressed by the oil pressure within the working chamber 10, causing it to retract from the working chamber 10. When the hydraulic retarder is out of operation, the spring causes the spoiler 5 to reset and re-enter the working chamber 10, thus separating the working chamber 10 and preventing the rotor 4 from agitating the air and generating braking torque. Since the spoiler 5 is existing technology, its specific structure and working principle will not be described in detail.

[0048] like Figure 1 and Figure 2As shown, the stator 3 has several stator blades 31, and vent holes 32 are selectively formed on the stator blades 31. The working chamber 10 is connected to the vent holes 32, so that external air can enter the working chamber 10 through the vent holes 32 or the air in the working chamber 10 can be discharged through the vent holes 32. In this embodiment, one of the stator blades 31 has a vent hole 32. When the hydraulic retarder is in operation, the gas in the working chamber 10 is discharged through the vent hole 32 after being squeezed by the oil. When the hydraulic retarder is out of operation, the oil is discharged from the working chamber 10, and the external air re-enters the working chamber 10 through the vent hole 32, so as to avoid a vacuum environment in the working chamber 10 and thus avoid affecting the smooth entry and exit of the oil in the working chamber 10.

[0049] Specifically, the stator 3 also includes a bracket 33, and two triangular brackets 33 are symmetrically arranged on the blade ends of the stator 3. The stator 3 is fixedly installed at the front end of the housing 1 and fixedly installed at the rear end of the gearbox in front of the hydraulic retarder through the brackets 33.

[0050] like Figure 1 and Figure 3 As shown, the rotor shaft 2 is a one-piece molded structure, which reduces the installation difficulty and improves the installation efficiency. The rotor shaft 2 also includes a shaft body and a counting gear 23. The shaft body is integrally molded along its axial direction, with the counting gear 23, drive gear 21, and external spline gear 22. The front end of the rotor shaft 2 extends into the gearbox, and the counting gear 23 at its front end directly measures the actual rotational speed of the rotor shaft 2 through a speed sensor within the gearbox. The drive gear 21 can mesh with the input gear of the gearbox to input power to the rotor shaft 2. The rotor shaft 2 passes sequentially through the inner holes of the stator 3 and rotor 4. The stator 3 is mounted on the rotor shaft 2 via bearings 8. The external spline gear 22 at the rear end of the rotor shaft 2 meshes with the rotor 4 to transmit torque to the rotor 4 and drive the rotor 4 to rotate synchronously.

[0051] Furthermore, such as Figure 3 As shown, a first lubrication groove 24 and a second lubrication groove 25 are respectively formed on the outer circumference of the rotor shaft 2. The first lubrication groove 24 extends axially along the rotor shaft 2 to the external spline gear 22, and the second lubrication groove 25 is distributed circumferentially around the external spline gear 22 and communicates with the first lubrication groove 24. The communication between the first lubrication groove 24 and the second lubrication groove 25 facilitates the introduction of lubricating oil from the external spline gear 22 into the bearing 8 near the external spline gear 22, realizing splash lubrication of the bearing 8 and improving the lubrication effect of the bearing 8.

[0052] Furthermore, such as Figure 1 and Figure 3As shown, the hydraulic retarder also includes a coupling 9. The rotor shaft 2 has an external splined gear 22 at one end with a mounting groove 26. One end of the coupling 9 is fixedly engaged in the mounting groove 26, and the other end of the coupling 9 can be connected to the drive shaft. Specifically, the front end of the coupling 9 is clearance-fitted with the mounting groove 26 of the rotor shaft 2 to reduce the rigidity of the connection, giving the coupling 9 a better buffering effect and reducing the impact force caused by sudden changes in speed when the hydraulic retarder exits or enters operation. The front end face of the coupling 9 presses against the rotor 4 and is connected to the internal threaded hole of the rotor shaft 2 via a long bolt passing through the center hole of the coupling 9, allowing the coupling 9 to rotate synchronously with the rotor shaft 2.

[0053] In this embodiment, the inner bore of the rotor 4 has an internal spline gear 42, which can mesh with the external spline gear 22 of the rotor shaft 2. The rotor 4 rotates synchronously with the rotor shaft 2. The rotor 4 has several rotor blades 41, and the rotor blades 41 of the rotor 4 are arranged opposite to the stator blades 31 of the stator 3. When the hydraulic retarder is in operation, the oil enters the working chamber 10 and accelerates under the drive of the rotor 4, impacting the stator blades 31. After impacting the stator blades 31, the oil then acts in the opposite direction on the rotor blades 41, causing the rotor 4 to be subjected to a reverse braking force.

[0054] like Figure 1 and Figure 4 As shown, a first oil storage tank 43 and a second oil storage tank 44 are respectively formed around the rear side of the blade end of the rotor 4. The first oil storage tank 43 and the side wall of the cavity 11 form an oil inlet chamber 20, and the second oil storage tank 44 and the side wall of the cavity 11 form a return oil chamber 30. Both the oil inlet chamber 20 and the return oil chamber 30 are connected to the working chamber 10. The housing 1 has an oil pool for storing oil. The oil enters the working chamber 10 from the oil inlet chamber 20. The oil in the working chamber 10 is heated by rotation and then flows into the return oil chamber 30. Finally, after being cooled by the heat exchanger of the hydraulic retarder, it flows back into the oil pool to realize the recycling of the oil.

[0055] To prevent oil flow from affecting the stability of the braking torque, the return oil chamber 30 needs to be isolated from the inlet oil chamber 20. For example... Figure 4 and Figure 5 As shown, a partition 45 is circumferentially protruding around the rear side of the blade end of the rotor 4, located between the first oil reservoir 43 and the second oil reservoir 44. A corresponding circumferentially distributed annular groove 13 is formed on the sidewall of the cavity 11, located between the oil inlet cavity 20 and the oil return cavity 30. The partition 45 is interposed within the annular groove 13. Specifically, the partition 45 is a rectangular plate surrounding the rotor 4, and the annular groove 13 is a 360° annular groove 61. When the partition 45 is inserted into the annular groove 13, a labyrinthine sealing structure is formed between the oil inlet cavity 20 and the oil return cavity 30, ensuring a reliable isolation seal between them.

[0056] It should be noted that because the partition 45 has a small gap with the annular groove 13, when the rotor 4 rotates synchronously with the rotor shaft 2, the partition 45 can rotate within the annular groove 13 without friction. When the rotor 4 rotates, an oil film is formed between the partition 45 and the annular groove 13, further improving the sealing effect of the labyrinth seal structure.

[0057] like Figure 6 As shown, several rotor blades 41 are selectively provided with oil inlets 46 and oil outlets at their roots. The oil inlet chamber 20 is connected to the working chamber 10 through the oil inlet 46, and the oil return chamber 30 is connected to the working chamber 10 through the oil outlet. In this embodiment, the oil inlets 46 are rectangular, and the oil outlets are circular. The number of oil inlets 46 and oil outlets are the same, and they have the same inclination angle. The location of the oil outlet is in the same annular groove as the rotor blades 41 with oil inlets 46, so that oil can enter the working chamber 10 through the oil inlets 46 and be discharged from the working chamber 10 through the oil outlets.

[0058] Furthermore, the cross-sectional area of ​​the oil inlet 46 is 1.9 to 1.94 times that of the oil outlet, to ensure that sufficient oil enters the working chamber 10 through the oil inlet 46, thereby increasing the filling rate of the working chamber 10. This enables the hydraulic retarder to have a stable braking torque and reduces the temperature rise of the oil in the working chamber 10, ensuring the thermal balance inside the working chamber 10.

[0059] To maintain a good seal in the working chamber 10, such as Figure 1 As shown, the stator 3 and the inner wall of the cavity 11 are sealed together by a sealing ring 7 to ensure good sealing between the stator 3 and the cavity 11. Specifically, a second sealing groove is formed around the outer periphery of the stator 3 that contacts the inner wall of the cavity 11, and the sealing ring 7 is fitted into the second sealing groove. The hydraulic retarder also includes a metal ring 6. A first sealing groove is formed around the outer surface of the stator 3, and the metal ring 6 is fitted into the first sealing groove and sandwiched between the rotor 4 and the stator 3 to achieve a good seal between the stator 3 and the rotor 4. The sealing ring 7 and the metal ring 6 together achieve a good seal in the working cavity 10.

[0060] Furthermore, the metal ring 6 in this embodiment can be a steel ring. The steel ring has good structural strength and rigidity, which can not only ensure that the sealing effect is not affected by erosion during installation, but also resist the high oil pressure in the working chamber 10, and prevent structural deformation or damage under the action of oil pressure.

[0061] like Figure 7 and Figure 8As shown, the metal ring 6 has two overlapping open ends, and a pressure relief gap is formed between the two open ends of the metal ring 6. The two open ends of the metal ring 6 are formed by a cut, which reduces the assembly difficulty of the metal ring 6 and improves the assembly and disassembly efficiency. At the same time, because there is a pressure relief gap between the two open ends of the metal ring 6, the internal pressure of the working chamber 10 can be reduced, preventing damage to internal parts from the hydraulic retarder due to instantaneous high braking torque.

[0062] Specifically, the open end of the metal ring 6 has a recessed groove 61 formed along its axial direction, and the outer wall of the groove 61 forms a locking arm 62, making the open end of the metal ring 6 form a double L-shaped structure. After the metal ring 6 is assembled, the locking arm 62 of the first open end is inserted into the groove 61 of the second open end, and at the same time, the locking arm 62 of the second open end is inserted into the groove 61 of the first open end, so as to realize the overlapping and locking of the two open ends, improving the structural stability and assembly efficiency of the metal ring 6.

[0063] The above embodiments merely illustrate the basic principles and characteristics of the present invention. The present invention is not limited to the above embodiments. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A hydraulic retarder, characterized in that, The hydraulic retarder comprises: a shell (1) having a cavity (11) therein; a rotor shaft (2) rotating through the cavity (11) and having a driving gear (21) at one end thereof extending out of the cavity (11), the rotor shaft (2) having an external spline gear (22) at the end thereof located in the cavity (11); a stator (3) fixedly arranged on the shell (1) and sleeved on the rotor shaft (2), the blade end of the stator (3) sealingly extending into the cavity (11); and a rotor (4) located in the cavity (11) and in meshing transmission with the external spline gear (22), the rotor (4) being rotatably sleeved on the stator (3), the blade end of the rotor (4) being fixedly and gapingly matched with the blade end of the stator (3) and surrounding a working cavity (10); a spoiler (5) being telescopically arranged in the fixed gap between the stator (3) and the rotor (4), the spoiler (5) being configured to be capable of extending into the working cavity (10) after the hydraulic retarder exits work or exiting the working cavity (10) when the hydraulic retarder enters work; the hydraulic retarder further comprises a metal ring (6), a first sealing groove being formed around the circumference of the outer surface of the stator (3), the metal ring (6) being sleeved in the first sealing groove and clamped between the rotor (4) and the stator (3); a first oil storage groove (43) and a second oil storage groove (44) being respectively formed around the circumference of the rear side of the blade end of the rotor (4), the first oil storage groove (43) and the side wall of the cavity (11) surrounding an oil inlet cavity (20), the second oil storage groove (44) and the side wall of the cavity (11) surrounding an oil return cavity (30), the oil inlet cavity (20) and the oil return cavity (30) being in communication with the working cavity (10); a separation part (45) being protruded around the circumference of the rear side of the blade end of the rotor (4), the separation part (45) being located between the first oil storage groove (43) and the second oil storage groove (44); a circumferentially distributed ring groove (13) being formed in the side wall of the cavity (11), the ring groove (13) being located between the oil inlet cavity (20) and the oil return cavity (30), the separation part (45) being gapingly inserted into the ring groove (13).

2. The hydraulic retarder according to claim 1, characterized in that The metal ring (6) has two opening ends which are mutually overlapped and matched, and a pressure relief gap is formed between the two opening ends of the metal ring (6).

3. The hydraulic retarder of claim 1, wherein, The rotor (4) has a plurality of rotor blades (41), the plurality of rotor blades (41) selectively having an oil inlet (46) formed thereon and having an oil outlet formed at the root thereof, the oil inlet cavity (20) being in communication with the working cavity (10) through the oil inlet (46), and the oil return cavity (30) being in communication with the working cavity (10) through the oil outlet.

4. The hydraulic retarder according to claim 3, characterized in that The cross-sectional area of the oil inlet (46) is 1.9-1.94 times the cross-sectional area of the oil outlet.

5. The hydraulic retarder according to any one of claims 1 to 4, characterized in that The stator (3) has a plurality of stator blades (31), and a plurality of air holes (32) are selectively formed in the stator blades (31), the working cavity (10) is communicated with the air holes (32) to make external air enter the working cavity (10) through the air holes (32) or make air in the working cavity (10) discharge through the air holes (32).

6. The hydraulic retarder according to any one of claims 1 to 4, characterized in that The outer periphery of the rotor shaft (2) is respectively provided with a first lubricating groove (24) and a second lubricating groove (25), the first lubricating groove (24) extends to the outer spline gear (22) along the axial direction of the rotor shaft (2), and the second lubricating groove (25) is distributed around the outer periphery of the outer spline gear (22) and is communicated with the first lubricating groove (24).

7. The hydraulic retarder according to any one of claims 1 to 4, characterized in that The hydraulic retarder further comprises a shaft coupling (9), the rotor shaft (2) is provided with a mounting groove (26) at the end of the outer spline gear (22), one end of the shaft coupling (9) is fixedly connected in the mounting groove (26), and the other end of the shaft coupling (9) can be connected with a transmission shaft.

8. The hydraulic retarder according to any one of claims 1 to 4, characterized in that The rotor shaft (2) further comprises a shaft body and a counting gear (23), the counting gear (23), the driving gear (21) and the outer spline gear (22) are integrally formed on the shaft body along the axial direction of the shaft body.

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