CN107191505B - Hydraulic release bearing assembly with stepped double cavities - Google Patents

Abstract

The invention discloses a hydraulic separation bearing assembly with stepped double chambers, which includes a bearing base, and the bearing base is coaxially provided with three layers of cylindrical cylinder walls from the inside to the outside, thereby forming two inner and outer sleeves and The opening faces the step-shaped hydraulic cavity at the end of the separation finger of the diaphragm spring of the automobile clutch. The two hydraulic cavities are connected through an oil spill valve. The two hydraulic cavities are respectively sealed with an inner sliding sleeve and an outer sliding sleeve. One end of the inner sliding sleeve and the outer sliding sleeve facing the end of the release finger of the diaphragm spring of the automobile clutch is respectively equipped with an inner release bearing and an outer release bearing, and the other end is respectively inlaid with a Y-shaped dynamic seal ring that seals and fits the inner wall of the hydraulic chamber. The bottom of the bearing base is plugged with an oil inlet pipe assembly connected to the outermost hydraulic chamber. The invention has small axial size, compact structure, and the step-by-step opening of the inner and outer cavities makes the clutch pedal of the automobile have a suction feeling, is comfortable to operate, and is easy for the driver to feel the coupling point and separation point of the clutch, and is convenient for shifting gears.

Description

A hydraulic release bearing assembly with stepped double chambers

technical field

The invention relates to the field of hydraulic release bearings of automobile clutch control mechanisms, in particular to a hydraulic release bearing assembly with stepped double cavities.

Background technique

Due to the increasingly serious traffic jams and the increasing number of starts and stops during driving, people have higher and higher requirements for the comfort and reliability of the clutch pedal of manual transmission cars. Nowadays, the clutch operating mechanism is developing rapidly in terms of miniaturization, light weight, safety and reliability, and comfortable operation. The clutch release bearing has also developed from the original low-speed unit with no centering performance, the outer ring rotates, and the inner ring and the cylinder liner are integrated into the current high-performance bearing unit that is self-aligning and the inner and outer rings can rotate. Item performance is significantly improved.

However, since a manual transmission car needs to change gears constantly during driving, how to make the driver know exactly that the clutch has been separated or combined, so that it is very important to perform the gear shifting operation. Further, for the requirement of driving comfort, the clutch pedal force-displacement size and matching relationship can be further controlled through the design of the hydraulic release bearing, so as to improve the comfort of the clutch pedal operation. Due to the small axial space between the automotive engine and gearbox, more compact hydraulic release bearing components are required. Therefore, under the premise of considering the driver's driving comfort, handling feeling and installation space, it is very necessary to invent a hydraulic release bearing with a stepped double cavity.

Contents of the invention

The invention provides a hydraulic separation bearing assembly with stepped double chambers. The double-chamber hydraulic release bearing assembly can make the driver feel the separation and connection of the clutch through the change of the pedal force when stepping on the clutch pedal, so as to perform the gear shifting operation. And for driving comfort, the clutch pedal force-displacement size and matching relationship can be controlled through the design of the hydraulic release bearing.

The present invention is realized by the following technical means:

A hydraulic release bearing assembly with stepped double chambers, installed on the end of the release finger of the diaphragm spring of the automobile clutch, used to control the engagement and separation of the clutch, including a double-chamber bearing base, the bearing base is composed of There are three layers of cylindrical cylinder walls arranged coaxially from the inside to the outside, thus forming two stepped hydraulic chambers with inner and outer sleeves and openings facing the end of the separation finger of the diaphragm spring of the automobile clutch. The two hydraulic chambers are connected by an oil spill valve Through, the two hydraulic chambers are respectively sealed with a cylindrical inner sliding sleeve and an outer sliding sleeve that are slidingly fitted with the hydraulic chamber, and the inner sliding sleeve and the outer sliding sleeve face one end of the separation finger end of the diaphragm spring of the automobile clutch The inner release bearing and the outer release bearing are respectively installed, and the other ends are respectively inlaid with a Y-shaped dynamic sealing ring that reciprocates with the sliding sleeve and fits the inner wall of the hydraulic chamber. The bottom of the bearing base is connected to the outermost hydraulic chamber. oil inlet pipe assembly.

When the hydraulic oil enters the base, the outer sliding sleeve is first pushed to move axially in the outermost hydraulic cavity, thereby pushing the outer release bearing to act on the small end of the release finger of the clutch diaphragm spring, so that the clutch enters a semi-separated state; when the hydraulic outer cavity When the Y-shaped dynamic sealing ring moves to the oil spill valve, the oil spill valve opens. At this time, the hydraulic oil enters the innermost hydraulic chamber, and the overall pressure in the chamber decreases. At this time, the inner release bearing will also act on the release finger of the diaphragm spring, and the clutch The pedal force is reduced, and the driver can clearly feel that the clutch is about to enter a fully disengaged state.

Further, the outer peripheral wall of the bearing base is provided with a return spring, one end of the return spring is fixed in the flange groove reserved on the outer peripheral wall of the hydraulic bearing seat, and the other end is snapped into the pre-set inside the outer release bearing. To ensure that when the clutch pedal is released, the outer release bearing will disengage from the small end of the separation finger of the diaphragm spring under the tension of the return spring.

Further, the outer peripheral wall of the bearing base is provided with a telescopic dust cover for protecting the return spring, one end of the dust cover is fixed on the bearing base, and the other end is fixedly connected to the outermost release bearing.

Further, the bearing base has a cylindrical structure as a whole, and the bottom is provided with a base installation hole and an oil inlet for inserting the oil inlet pipe assembly. The three-layer cylindrical cylinder wall includes the outer cylinder wall, The middle cylinder wall and the inner cylinder wall further form two stepped hydraulic chambers, and an oil spill valve is provided at the bottom of the middle cylinder wall to communicate with the two hydraulic chambers.

Further, the bearing base is made of reinforced heat-resistant nylon PA6T/61-GF material.

Further, annular sealing rings are provided on the sliding contact surfaces between the inner sliding sleeve and the outer sliding sleeve and the cylindrical cylinder wall to prevent leakage of hydraulic oil and play the role of secondary sealing.

Further, the inner cylinder wall and the middle cylinder wall are respectively provided with annular limiting grooves at the opening ends, and the limiting snap rings are installed in the limiting grooves, and the inner sides of the upper ends of the inner and outer sliding sleeves are provided with Cooperate with the limit snap ring to act as a limit boss to limit the limit position of the sliding sleeve, so as to prevent the inner sliding sleeve and the outer sliding sleeve from falling off.

Further, the bearing inner ring and the bearing outer ring of the outer release bearing are supported by bearing steel balls and can rotate freely, the bearing inner ring is fixed on the outer sliding sleeve, and the bearing steel balls are installed There is a bearing cage, and a bearing sealing ring and a dustproof ring are also arranged between the bearing inner ring and the bearing outer ring.

Further, the outer peripheral wall of the outer sliding sleeve is provided with an annular installation boss, and a disc spring is arranged between the installation boss and the end of the outer release bearing to automatically align the center when the outer release bearing rotates, which mainly plays the role of The function of automatic centering prevents the eccentricity of the bearing during movement.

Further, the oil inlet pipe assembly includes an oil inlet pipe inserted into the bearing base, an air release valve, and a protective cover, and the plug joint of the oil inlet pipe is provided with an O-ring and a first positioning pin for positioning. circlip; the air release valve is fixedly connected to the oil inlet pipe through the second circlip; the protective cover is fixedly connected to the oil inlet pipe through the second circlip, and the sealing ring is used between the protective cover and the oil inlet pipe. seal. When air enters the hydraulic system, due to the high compressibility of the air, the pedal idle stroke will increase. Therefore, the air present in the system can be bled out by pulling out the bleed valve. The protective cover mainly plays the role of protecting the hydraulic oil circuit and removing excess oil.

Compared with the prior art, the step-type double-chamber hydraulic release bearing provided by the present invention has a small axial dimension and a compact structure, and the step-by-step opening of the inner and outer chambers makes the automobile clutch pedal have a suction feeling, which is easy for the driver to feel the joint point of the clutch , Separation point, easy to shift. The size and matching relationship of the force-displacement curve of the automobile clutch pedal can be better controlled to provide a more comfortable driving experience for automobile driving.

Description of drawings

Fig. 1 is a cross-sectional view of a hydraulic release bearing assembly with stepped double chambers according to an embodiment of the present invention.

Fig. 2 is an isometric view of a base with stepped double cavities according to an embodiment of the present invention.

Fig. 3 is a cross-sectional view of a base with stepped double cavities according to an embodiment of the present invention.

Fig. 4 is a sectional view of an oil inlet pipe assembly according to an embodiment of the present invention.

Fig. 5 is an enlarged sectional view of the installation of the small Y-shaped dynamic sealing ring according to the embodiment of the present invention.

Fig. 6 is an enlarged sectional view of the installation of the outer release bearing according to the embodiment of the present invention.

Fig. 7 Schematic diagram of the pedal force-displacement curves of double-chamber hydraulic release bearings and single-chamber hydraulic release bearings.

Explanation of symbols in the figure: 1 Hydraulic release bearing for vehicle; 2 Bearing base; 201 Oil inlet; 202 Base installation hole; 203 Oil spill valve; 204 Outer cylinder wall; ;3 oil inlet pipe assembly; 301 O-shaped sealing ring; 302 the first circlip; 303 air release valve; 304 the second circlip; 305-sealing ring; 306 protective cover; 402 sealing ring rubber body; 403 sealing ring rubber fixing block; 5 large Y-shaped dynamic sealing rings; 6 outer sliding sleeve; 7 inner sliding sleeve; 8 outer separation bearing; 801 bearing inner ring; 802 bearing sealing ring; 803 bearing steel ball ;804 bearing cage; 805 bearing outer ring; 806 dust ring; 807 disc spring; 9 inner separation bearing; 10 dust cover; 11 return spring; 12 outer wall static seal ring; snap ring.

Detailed ways

In order to enable researchers in the field to further understand the present invention and related technical contents, the present invention will be further described below in conjunction with the accompanying drawings.

As shown in Figure 1, a hydraulic release bearing assembly with a stepped double cavity is installed at the end of the release finger of the diaphragm spring of the automobile clutch to control the engagement and separation of the clutch, including a double cavity bearing base 2 , the bearing base 2 is provided with three layers of cylindrical cylinder walls coaxially from the inside to the outside, thereby forming two stepped hydraulic chambers that are nested inside and outside and open toward the end of the separation finger of the diaphragm spring of the automobile clutch. The cavities are connected through the oil spill valve 203, and the two hydraulic cavities are respectively provided with a cylindrical inner sliding sleeve 7 and an outer sliding sleeve 6 which are slidingly matched with the hydraulic chamber, and the inner sliding sleeve 7 and the outer sliding sleeve 6 One end facing the end of the separation finger of the diaphragm spring of the automobile clutch is respectively equipped with an inner release bearing 9 and an outer release bearing 8, and the other end is respectively inlaid with a large Y-shaped dynamic sealing ring that reciprocates with the sliding sleeve and fits the inner wall of the hydraulic chamber 5 and a small Y-shaped dynamic seal ring 4, the bottom of the bearing base 2 is plugged with an oil inlet pipe assembly 3 communicating with the outermost hydraulic chamber.

When the driver depresses the clutch pedal, the hydraulic oil enters the bearing base 2 from the oil inlet pipe assembly 3, and as the hydraulic oil enters, the outer sliding sleeve 6 moves along the axial direction Ax-Ax under the pressure of the hydraulic oil, and pushes the outer release bearing 8 acts on the small end of the separation finger of the clutch diaphragm spring to make the clutch enter a semi-disengagement state; when the small Y-shaped dynamic sealing ring connected to the outer sliding sleeve 6 moves to the oil spill valve 203, the oil spill valve 203 opens, and the hydraulic oil at this time Entering the innermost hydraulic chamber, the inner sliding sleeve 7 also quickly moves along the axis Ax-Ax under the action of hydraulic oil, and drives the inner release bearing 9 to act on the small end of the release finger of the clutch diaphragm spring. Due to the opening of the innermost hydraulic chamber, the inner release bearing 9 and the outer release bearing 8 act at the same time, so that the oil pressure of the hydraulic system is rapidly reduced, so that the clutch pedal force is also correspondingly reduced. The driver feels that the pedal becomes easy subjectively, and at this moment the clutch is about to disengage, and the driver is ready to perform a gear shift operation. The overall pressure in the cavity decreases, and at this time, the inner release bearing will also act on the release finger of the diaphragm spring, the clutch pedal force decreases, and the driver can clearly feel that the clutch is about to enter a completely disengaged state.

The outer peripheral wall of the bearing base 2 is provided with a return spring 11, one end of the return spring 11 is fixed in the flange groove reserved on the outer peripheral wall of the hydraulic bearing seat 2, and the other end is snapped into the outer release bearing 11 Inside the preset groove, to ensure that when the clutch pedal is released, the outer release bearing will be disengaged from the small end of the diaphragm spring release finger under the action of the tension of the return spring 11. The outer peripheral wall of the bearing base 2 is provided with a telescopic dust cover 10 for protecting the return spring 11. One end of the dust cover 10 is fixed on the bearing base 2, and the other end is fixed to the outermost separating bearing. connect. The dustproof cover 10 can expand and contract with the reciprocating motion of the outer release bearing 8, so as to play a dustproof role.

As shown in Figures 2 and 3, the bearing base 2 has a cylindrical structure as a whole, and is made of reinforced heat-resistant nylon PA6T/61-GF material. There are three base mounting holes 202 at the bottom, and the oil inlet pipe assembly 3 is inserted into it. The oil inlet 201, the three-layer cylindrical cylinder wall sequentially includes the outer cylinder wall 204, the middle cylinder wall 205, and the inner cylinder wall 206 from outside to inside, thereby forming two stepped hydraulic chambers, the middle cylinder An oil spill valve 203 is provided at the bottom end of the wall 205 to communicate with the two hydraulic chambers.

The sliding contact surfaces of the inner sliding sleeve 7 and the outer sliding sleeve 6 and the cylindrical cylinder wall are all provided with annular sealing rings, including an outer wall static sealing ring 12 and an inner wall static sealing ring 13. Made of "EPDM" material, it prevents hydraulic oil from leaking and acts as a secondary seal. During the oil return process of the inner cavity, the outer wall static seal ring 12 and the inner wall static seal ring 13 are also conducive to sealing the hydraulic oil. , so as to smoothly make the hydraulic oil in the inner cavity flow back from the oil overflow hole 203 through the side wall of the small Y-shaped dynamic sealing ring.

The inner cylinder wall 206 and the middle cylinder wall 205 are respectively provided with annular limiting grooves 207 at the opening ends, and the limiting grooves 207 are equipped with a limiting snap ring 14, and the upper ends of the inner sliding sleeve 7 and the outer sliding sleeve 6 The inner side is provided with a limit boss that cooperates with the limit snap ring 14 to limit the limit position of the sliding sleeve. The limit snap ring 14 of the cylinder wall will block the inner sliding sleeve 7 and the outer sliding sleeve 6, so as to play a position-limiting effect and prevent the inner sliding sleeve 7 and the outer sliding sleeve 6 from falling off.

As shown in Figure 4, the oil inlet pipe assembly 3 includes an oil inlet pipe inserted into the bearing base 2, an air release valve 303, and a protective cover 306, and the plug connector of the oil inlet pipe is provided with an O-ring 301 and the first circlip 302 for positioning; the air release valve 303 is fixedly connected to the oil inlet pipe through the second circlip 304; the protective cover 306 is fixedly connected to the oil inlet pipe through the second circlip 304 Above, the sealing ring 305 is used to seal between the protection cover 306 and the oil inlet pipe. When air enters the hydraulic system, due to the high compressibility of the air, the pedal idle stroke will increase. Therefore, the air present in the system can be released by pulling out the purge valve 303 . The protection cover 306 mainly plays the role of protecting the hydraulic oil circuit and removing excess oil.

As shown in accompanying drawing 5, it is an enlarged sectional view of the installation of the small Y-shaped dynamic sealing ring 4 . The small Y-shaped dynamic sealing ring 4 mainly includes a sealing lip film 401, a sealing ring rubber body 402, and a sealing ring rubber fixing block 403, and the large Y-shaped dynamic sealing ring 5 is basically the same in structure. When installing, first press the sealing ring rubber fixing block 403 into the groove of the outer sliding sleeve 6 at low temperature, so as to fix it at the end of the sliding sleeve. When the hydraulic oil enters the hydraulic chamber, the pressure on the Y-shaped sealing ring makes the two blades receive tension to the cylinder walls on both sides, so that it fits more closely with the outer cylinder wall 204 and the middle cylinder wall 205 of the base 2 . In addition, a sealing lip film 401 is attached to the two blades of the sealing ring. The sealing lip film 401 is refined from a flexible and wear-resistant resin material. It expands along the two blades of the Y-shaped sealing ring and sticks to the cylinders on both sides The wall has a good one-way sealing effect under the action of hydraulic pressure. During the oil return process of the hydraulic chamber, since the received hydraulic pressure deviates from the cylinder wall, the oil in the inner chamber can flow back smoothly along the side wall through the oil spill valve 203 .

As shown in Figure 6, the bearing inner ring 801 and the bearing outer ring 805 of the outer release bearing 8 are supported by bearing steel balls 804 and can rotate freely relative to each other, and the bearing inner ring 801 is fixed on the outer sliding sleeve 6, A bearing cage 804 is installed between the bearing steel balls 803, the bearing inner ring 801 has an inner ring mounting portion, the bearing outer ring 805 has an outer ring mounting portion, and the inner ring mounting portion faces The inner mounting boss of the sliding sleeve is extended, the outer ring mounting portion is extended toward the outer mounting boss of the cylinder wall, and the outer mounting portion and the inner ring mounting portion are in contact with the sliding sleeve mounting boss. A bearing sealing ring 802 and a dustproof ring 806 are also arranged between the bearing inner ring 801 and the bearing outer ring 805 . When the hydraulic release bearing presses the release finger of the clutch diaphragm spring, the bearing outer ring 805 and the release finger rotate together at a high speed, while the bearing inner ring 801 plays a supporting role and cannot rotate. The outer peripheral wall of the outer sliding sleeve 6 is provided with an annular installation boss, and a disc spring 807 is arranged between the installation boss and the end of the outer release bearing 8 to automatically center the outer release bearing 8 when it rotates. To the effect of automatic centering, to prevent the eccentricity of the bearing movement.

Figure 7 is a schematic diagram of the pedal force-displacement curves of the stepped double-chamber hydraulic release bearing assembly in this embodiment and the traditional single-chamber hydraulic release bearing. In order to increase the comparison effect, this schematic diagram assumes that the outer cavity of the double-cavity hydraulic release bearing has the same cross-sectional area as the hydraulic cavity of the ordinary single-cavity hydraulic release bearing. It can be seen from the figure that when the inner chamber of the double-chamber hydraulic release bearing has not been opened, the pedal force-displacement curves of the double-chamber hydraulic release bearing and the ordinary single-chamber hydraulic release bearing coincide, and they all increase non-linearly with the increase of the pedal stroke. It is mainly caused by the nonlinear characteristic of clutch diaphragm spring force-displacement. However, when the inner cavity of the hydraulic release bearing with stepped double cavity is opened, it can be seen that the driver will clearly feel that the pedal force is decreasing, the pedal has an obvious "suction feeling", and the operation is comfortable. If this pedal travel point is designed to be close to the clutch separation point and the coupling point, the driver can clearly know when the clutch is separated or combined, so as to perform the gear shifting operation. And the pedal force of the hydraulic release bearing with stepped double cavity is small, which can easily keep the maximum force value of the clutch pedal between 90N-105N, increase the comfort and control feeling of the pedal, reduce traffic congestion and pedal heavy belt coming fatigue.

The above descriptions are only preferred implementations of the present invention, and are not intended to limit the scope of the present invention. Therefore, all equivalent structural transformations made by using the contents of the description and drawings of the present invention are equally included in the scope of the present invention.

Claims (10)

1. A hydraulic release bearing assembly with a stepped double cavity is installed on the end of the release finger of the diaphragm spring of the automobile clutch, and is used to control the engagement and separation of the clutch. It is characterized in that it includes a double cavity bearing base ( 2), the bearing base (2) is provided with three layers of cylindrical cylinder walls coaxially from the inside to the outside, thus forming two inner and outer sleeves with openings facing the end of the separation finger of the diaphragm spring of the automobile clutch. Step-type hydraulic chambers, the two stepped-type hydraulic chambers are connected through the oil spill valve (203) to realize the step-by-step opening of the two hydraulic chambers, and the two hydraulic chambers are respectively sealed with cylinders that are slidingly fitted with the hydraulic chambers Shaped inner sliding sleeve (7) and outer sliding sleeve (6), said inner sliding sleeve (7) and outer sliding sleeve (6) are respectively equipped with an inner release bearing ( 9) and the outer release bearing (8), the other ends are respectively inlaid with a Y-shaped dynamic sealing ring that reciprocates with the sliding sleeve and fits tightly against the inner wall of the hydraulic chamber, and the bottom of the bearing base (2) is connected to the outermost The oil inlet pipe assembly (3) of the hydraulic chamber, when the Y-shaped dynamic sealing ring in the outermost hydraulic chamber moves to the oil spill valve (203), the oil spill valve (203) opens, and the hydraulic oil enters the innermost hydraulic chamber, so The inner sliding sleeve (7) moves under the action of hydraulic oil, and drives the inner release bearing (9) to act on the small end of the release finger of the clutch diaphragm spring, and the inner release bearing (9) and the outer release bearing (8) act simultaneously to Decrease clutch pedal force. 2. The hydraulic release bearing assembly with stepped double chambers according to claim 1, characterized in that: the outer peripheral wall sleeve of the bearing base (2) is provided with a return spring (11), and the One end of the return spring (11) is fixed in a flange groove reserved on the outer peripheral wall of the bearing base (2), and the other end is snapped into a preset groove inside the outer release bearing (8). 3. The hydraulic release bearing assembly with stepped double chambers according to claim 2, characterized in that: the outer peripheral wall of the bearing base (2) is provided with a spring for protecting the return spring (11). A telescopic dust cover (10), one end of the dust cover (10) is fixed on the bearing base (2), and the other end is fixedly connected with the outermost separation bearing. 4. The hydraulic release bearing assembly with stepped double chambers according to claim 1, characterized in that: the bearing base (2) has a cylindrical structure as a whole, and the bottom is provided with base mounting holes (202), Insert the oil inlet (201) of the oil inlet pipe assembly (3), and the three-layer cylindrical cylinder wall includes the outer cylinder wall (204), the middle cylinder wall (205), the inner cylinder wall (206) from the outside to the inside. ), and then form two stepped hydraulic chambers, and the bottom end of the middle cylinder wall (205) is provided with an oil spill valve (203) to communicate with the two hydraulic chambers. 5. The hydraulic release bearing assembly with stepped double chambers according to claim 1, characterized in that: the bearing base (2) is made of reinforced heat-resistant nylon PA6T/61-GF material. 6. The hydraulic release bearing assembly with stepped double cavity according to claim 1, characterized in that: the sliding contact between the inner sliding sleeve (7) and the outer sliding sleeve (6) and the cylindrical cylinder wall The surface is provided with an annular sealing ring. 7. The hydraulic release bearing assembly with stepped double chambers according to claim 4, characterized in that: the inner cylinder wall (206) and the middle cylinder wall (205) are respectively provided with ring-shaped limiters at the opening ends. Position slot (207), the limit slot (207) is equipped with a limit snap ring (14), and the inside of the upper end of the inner sliding sleeve (7) and the outer sliding sleeve (6) are provided with the limit snap ring Ring (14) cooperates and plays the position-limiting boss that limits sliding sleeve limit position. 8. The hydraulic release bearing assembly with stepped double chambers according to claim 1, characterized in that: between the bearing inner ring (801) and the bearing outer ring (805) of the outer release bearing (8) It is supported by bearing steel balls (803) and can rotate freely relative to each other. The bearing inner ring (801) is fixed on the outer sliding sleeve (6), and a bearing cage (804) is installed between the bearing steel balls (803). ), a bearing sealing ring (802) and a dustproof ring (806) are also arranged between the bearing inner ring (801) and the bearing outer ring (805). 9. The hydraulic release bearing assembly with stepped double chambers according to claim 8, characterized in that: the outer peripheral wall of the outer sliding sleeve (6) is provided with an annular installation boss, and the installation boss and the outer Disc springs (807) are arranged between the ends of the release bearings (8) to automatically align the centers when the off-axis release bearings (8) rotate. 10. The hydraulic release bearing assembly with stepped double chambers according to claim 1, characterized in that: the oil inlet pipe assembly (3) includes an oil inlet pipe inserted into the bearing base (2) , air release valve (303), protective cover (306), the plug joint of described oil inlet pipe is provided with O-type sealing ring (301) and the first snap ring (302) that is used for positioning; Described air release valve (303) is fixedly connected on the oil inlet pipe through the second jump ring (304); the described protection cover (306) is fixedly connected on the oil inlet pipe through the second jump ring (304), and the protection cover (306) is connected with the inlet pipe Oil pipes are sealed with sealing rings (305).

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