Balanced shaft driven 2.0t engine full variable oil pump

Abstract

A kind of balanced shaft driven 2.0T engine full variable oil pump, belong to engine lubrication system technical field.Pump body and pump cover are fixed by bolt and form sealed working chamber one, are equipped with rotor assembly etc., rotor and driving shaft are interference fit, blade separates sealed working chamber two between eccentric ring and rotor;Eccentric ring is connected with pump body through swing pin, eccentric spring abuts against eccentric ring, drive gear is fixed to the end of driving shaft, and is engaged with balance shaft driving gear, balance shaft positioning pin positions and fixes balance shaft.The utility model discloses through displacement adjustment, stable power transmission, fast response capability and reliable sealing and protection design, effectively solve the problem of traditional oil pump in oil supply, driving mode and structure layout etc., significantly improve the fuel economy, power performance and reliability of engine, prolong the service life and reduce maintenance cost simultaneously, have important practical value.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of engine lubricating system, concretely is a kind of 2.0T engine full variable oil pump of balanced axle drive. BACKGROUND

[0002] In the lubricating system of 2.0T engine, the performance of oil pump is crucial, and the traditional oil pump cannot accurately control the oil supply under different working conditions of engine. The rotational speed of oil pump is proportional to the rotational speed of engine. When engine is at low speed and high load, the rotational speed of oil pump is low. To ensure sufficient oil supply, the oil pump needs to have large displacement. However, when engine is at high speed and low load, the rotational speed of oil pump is large, and the oil pressure provided is much higher than the demand of engine. This not only causes energy waste, but also increases the internal loss of engine, leading to the increase of fuel consumption.

[0003] Although the existing variable oil pump can adjust the oil supply to some extent, it still has problems such as insufficient adjustment accuracy and slow response speed. In addition, the driving mode of oil pump also has important influence on the overall performance of engine. The direct drive of crankshaft is limited by space, and the rotational diameter is larger than that of external pump, i.e. the linear speed of rotation is large, and it is easy to cause wear and abnormal noise due to the influence of crankshaft vibration. The transmission of chain and belt is generally hung below the engine, and the position is relatively forward, which affects the overall boundary of engine and is not conducive to the layout of compact cabin. Therefore, it is of great significance to develop a 2.0T engine with accurate oil displacement adjustment, reasonable driving mode and compact structure. SUMMARY

[0004] To solve the problems in the background art, the utility model provides a kind of 2.0T engine full variable oil pump of balanced axle drive, including proportional solenoid valve, pump cover bolt, pump cover, driving gear, balanced axle sealing rubber ring, pump body, M18 screw sleeve, driving gear oil tank, rotor assembly and safety valve;

[0005] The pump body and pump cover are fixedly connected by pump cover bolt and pump cover long bolt to form a sealed working chamber one, and the pump body is provided with a pump body positioning pin for positioning with the pump cover. The rotor assembly includes a swing spring, a sliding seal pad, a sliding seal pad support, a drive shaft, a swing pin, an eccentric ring, a rotor, two vane rings and a plurality of vanes.

[0006] The rotor is in interference fit with the drive shaft, and the rotor is circumferentially provided with a plurality of grooves, each of which is slidably provided with a vane, and two vane rings are slidably arranged at two ends of the plurality of vanes respectively, one of the vane rings is fixed to the inner wall of the pump cover, and the other vane ring is fixed to the inner wall of the pump body, the outer wall of the plurality of vanes is slidably attached to the inner wall of the eccentric ring, the plurality of vanes isolate the plurality of sealed working chambers two between the inner wall of the eccentric ring and the outer wall of the rotor, the eccentric ring is movably connected to the pump body through a swing pin, one end of the swing spring abuts against the eccentric ring, and the other end of the swing spring is fixedly connected to the pump body, the sliding sealing gasket is arranged on one side of the abutting surface between the pump body and the eccentric ring, a sliding sealing gasket support is arranged between the eccentric ring and the sliding sealing gasket, the drive gear is fixed to the end of the drive shaft and is engaged with the driving gear on the balance shaft of the engine, the pump body is positioned by the balance shaft positioning pin and the balance shaft, and the balance shaft positioning pin is connected by bolts, the balance shaft sealing rubber ring is sleeved on the matching part of the balance shaft and the pump body, the drive gear oil groove is fixed to the side of the pump body connected with the balance shaft, and wraps the driving gear and the drive gear, and the arc tangent segment at the end of the drive gear oil groove is arranged in the rotation direction of the drive gear, the safety valve comprises a PRV steel ball, a PRV spring and an M18 screw sleeve, one end of the PRV spring abuts against the PRV steel ball, the other end of the PRV spring is fixedly connected to the M18 screw sleeve, the M18 screw sleeve is fixedly connected to the pump body, the PRV steel ball is arranged corresponding to the oil outlet channel of the pump body, the proportional electromagnetic valve is fixed to the outside of the pump body, the output end of the proportional electromagnetic valve is communicated with the feedback oil chamber in the pump body through a feedback oil path, and the feedback oil chamber is formed between the outer wall of the eccentric ring and the inner wall of the pump body.

[0007] The rotor rotates synchronously with the drive shaft, and the eccentric ring keeps the maximum eccentricity from the rotor under the pushing of the swing spring.

[0008] The sliding sealing gasket support supports the sliding sealing gasket to avoid deformation of the sliding sealing gasket under the action of oil pressure.

[0009] The proportional electromagnetic valve receives the control signal of the engine ECU, controls the oil pressure in the feedback oil chamber according to the engine working condition, balances the oil pressure and the elastic force of the swing spring, drives the eccentric ring to rotate around the swing pin, changes the eccentricity from the rotor, and realizes continuous adjustment of the displacement.

[0010] The drive gear oil groove collects lubricating oil flowing from engine camshafts, crankshafts and other parts to lubricate the driving gear and the drive gear, and the arc tangent segment at the end of the drive oil groove is arranged in the rotation direction of the drive gear, so that the centrifugal force generated by the rotation of the gear can throw out the oil in the oil groove, thereby realizing the circulation and updating of the oil in the oil groove.

[0011] The balance shaft positions the pump body and the balance shaft through the balance shaft positioning pin and is installed through bolts, and the balance shaft positioning pin is used to limit the relative position of the pump body and the balance shaft, and ensure the engagement accuracy of the driving gear and the driving gear.

[0012] Compared with the prior art, the utility model has the advantages of:

[0013] 1. improve fuel economy and power performance: the proportional electromagnetic valve can accurately control the feedback oil chamber oil pressure according to the real-time working condition of the engine, dynamically adjust the eccentric distance of the eccentric ring and the rotor, realize the continuous and accurate regulation of the oil pump displacement; this design avoids the problem of excessive oil pressure of the traditional oil pump at high speed and low load, reduces energy waste and internal loss of the engine, and reduces oil consumption; at the same time, sufficient oil supply is ensured at low speed and high load, and the stability of power output is ensured.

[0014] 2. optimize power transmission stability and compact structure: adopt balanced shaft driving mode, the balance shaft and the crankshaft are accurately matched in speed ratio through gear transmission system, the driving gear and the driven gear are engaged to transmit power, the stable running characteristics of the balance shaft are used to reduce vibration and noise, and the risk of wear and abnormal sound is reduced. In addition, the oil pump and the balance shaft are closely integrated, compared with crankshaft direct drive or chain / belt transmission, the engine volume is effectively reduced, the interference with the engine room is reduced, and the compact layout demand of the engine room is met.

[0015] 3. improve the response speed and running reliability: the proportional electromagnetic valve can quickly adjust the opening degree after receiving the ECU signal, balance the feedback oil chamber oil pressure and the deflection spring force, push the eccentric ring to change the eccentric distance in real time, so that the oil pump displacement quickly adapts to the working condition change, and the dynamic response sensitivity of the engine is improved; at the same time, the driven gear oil groove realizes oil renewal by using centrifugal force through circular arc tangent segment, and ensures the lubrication and cleanliness of the gear; the safety valve automatically unloads pressure through the cooperation of PRV steel ball and spring, avoids system overpressure damage, and further guarantees the running reliability.

[0016] 4. prolong the service life of the engine and reduce the maintenance cost: the sliding sealing gasket and the supporting structure ensure the sealing effect of the bonding surface of the pump body, the eccentric ring and the like, the balance shaft sealing rubber ring blocks the leakage channel, and prevents oil leakage and impurity intrusion; accurate oil supply ensures that each part of the engine can be well lubricated and cooled under different working conditions, reducing the wear and fatigue of parts. These designs prolong the service life of the engine and oil pump, reduce the frequency and cost of maintenance and replacement.

[0017] In summary, the balance shaft driven 2.0T engine full variable oil pump solves the problems of traditional oil pump in oil supply, driving mode and structure layout through displacement regulation, stable power transmission, fast response ability and reliable sealing and protection design, significantly improves the fuel economy, power performance and reliability of the engine, prolongs the service life and reduces the maintenance cost, and has important practical value. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a front view of the utility model;

[0019] Figure 2 is a rear view of the utility model;

[0020] Figure 3 is an explosion view of the utility model. DETAILED DESCRIPTION

[0021] The technical solutions in the utility model will be described clearly and completely below in combination with the drawings in the embodiments of the utility model. Apparently, the described embodiments are only a part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all the other embodiments obtained by those skilled in the art without creative work under the premise belong to the protection scope of the utility model.

[0022] The embodiment discloses a balanced shaft driven 2.0T engine full variable oil pump, which comprises a proportional electromagnetic valve 1, a pump cover bolt 2, a pump cover 3, a driving gear 11, a balanced shaft sealing rubber ring 13, a pump body 15, an M18 screw sleeve 20, a driving gear oil groove 22, a rotor assembly and a safety valve.

[0023] The pump body 15 and the pump cover 3 are fixedly connected through the pump cover bolt 2 and a pump cover long bolt 21, so as to form a sealed working chamber one, provide a closed space for assembly of various components of the oil pump and oil circulation, ensure that oil cannot leak to the outside in the conveying process, and provide a stable environment for operation of the rotor assembly and other components, the pump body 15 is provided with a pump body positioning pin 8, which is used for positioning cooperation with the pump cover 3,

[0024] The rotor assembly comprises a swing spring 5, a sliding sealing gasket 6, a sliding sealing gasket support 7, a driving shaft 10, a swing pin 16, an eccentric ring 17, a rotor 19, two vane rings 4 and a plurality of vanes 18.

[0025] The rotor 19 is interference fit with the drive shaft 10, the rotor 19 is circumferentially uniformly distributed with a plurality of slots, each slot is slidingly provided with a vane 18, the two vane rings 4 are slidingly provided with both ends of the plurality of vanes 18 respectively, one of the vane rings 4 is fixed with the inner wall of the pump cover 3, the other vane ring 4 is fixed with the inner wall of the pump body 15, the outer wall of the plurality of vanes 18 is slidingly fitted with the inner wall of the eccentric ring 17, the plurality of vanes 18 isolates the plurality of sealed working chambers two between the inner wall of the eccentric ring 17 and the outer wall of the rotor 19, for realizing the suction and discharge of the oil, when the rotor rotates with the drive shaft 10, the volume of the working chamber two changes with the relative position of the rotor and the eccentric ring, when the volume increases, the negative pressure is generated to suck the oil, when the volume decreases, the oil is compressed and discharged, the eccentric ring 17 is movably connected with the pump body 15 through the swing pin 16, one end of the swing spring 5 abuts against the eccentric ring 17, the other end of the swing spring 5 is fixedly connected with the pump body 15, in the initial state, the eccentric ring 17 keeps the maximum eccentric distance with the rotor 19 under the action of the swing spring 5, the sliding sealing pad 6 is arranged on one side of the abutting surface between the pump body 15 and the eccentric ring 17, for sealing the abutting surface between the pump body 15 and the eccentric ring 17, preventing the oil from leaking from the working chamber one, the sliding sealing pad support 7 is arranged between the eccentric ring 17 and the sliding sealing pad 6, the drive gear 11 is fixed on the end of the drive shaft 10 and is engaged with the driving gear on the engine balance shaft, the balance shaft is connected with the engine crankshaft through the gear transmission system, and the rotation speed ratio of the two is accurately matched, the balance shaft is positioned by the balance shaft positioning pin 9 and is installed by bolts, the balance shaft sealing rubber ring 13 is sleeved on the matching part of the balance shaft and the pump body 15, the balance shaft sealing rubber ring 13 is made of oil-resistant rubber material, the inner side is closely fitted with the outer wall of the balance shaft, and the outer side is interference fit with the inner wall of the pump body 15 installation hole, for blocking the gap leakage channel between the balance shaft and the pump body, preventing the oil from leaking along the balance shaft axis direction, and avoiding the external impurities from entering the inside of the pump body 15, the drive gear oil groove 22 is fixed on the side of the pump body 15 connected with the balance shaft, and wraps the driving gear and the drive gear 11, the end of the drive gear oil groove 22 is provided with a circular arc tangent segment 23 in the rotation direction of the drive gear 11, the safety valve includes a PRV steel ball 14, a PRV spring 12 and an M18 screw sleeve 20, one end of the PRV spring 12 abuts against the PRV steel ball 14, the other end of the PRV spring 12 is fixedly connected with the M18 screw sleeve 20, the M18 screw sleeve 20 is fixedly connected with the pump body 15, the PRV steel ball 14 is arranged corresponding to the oil outlet channel of the pump body 15, the PRV steel ball 14 blocks the oil outlet channel under the elastic force of the PRV spring 12, when the oil outlet pressure is greater than the preset elastic force of the PRV spring 12, the PRV steel ball 14 is pushed away, realizing pressure unloading, the proportional electromagnetic valve 1 is fixed on the outside of the pump body 15, the output end of the proportional electromagnetic valve 1 is communicated with the feedback oil chamber 24 in the pump body 15 through the feedback oil way, the feedback oil chamber 24 is formed between the outer wall of the eccentric ring 17 and the inner wall of the pump body 15, the oil pressure in the feedback oil chamber 24 can act on the outer wall of the eccentric ring 17,The elastic force of the eccentric spring 5 balances to adjust the position of the eccentric ring.

[0026] The rotor 19 rotates synchronously with the drive shaft 10, and the eccentric ring 17 keeps the maximum eccentricity with the rotor 19 under the push of the eccentric spring 5.

[0027] The sliding seal pad support 7 supports the sliding seal pad 6 to avoid the deformation of the sliding seal pad 6 under the action of the oil pressure.

[0028] The proportional electromagnetic valve 1 receives the control signal of the engine ECU, controls the oil pressure in the feedback oil chamber 24 according to the engine working condition, pushes the eccentric ring 17 to rotate around the swing pin 16 through the balance of the oil pressure and the elastic force of the eccentric spring 5, changes the eccentricity with the rotor 19, and realizes the continuous adjustment of the displacement.

[0029] The drive gear oil groove 22 collects the lubricating oil flowing from the engine camshaft, crankshaft and other parts to lubricate the driving gear 11, and the circular arc tangent segment 23 at the end of the drive gear oil groove 22 is arranged along the rotation direction of the driving gear 11. The centrifugal force generated by the rotation of the gear throws out the oil in the oil groove, thereby realizing the circulation and updating of the oil in the oil groove.

[0030] The balance shaft is positioned and installed with the pump body 15 through the balance shaft positioning pin 9, the balance shaft positioning pin 9 is used to limit the relative position of the balance shaft and the pump body 15, and ensure the meshing accuracy of the driving gear and the driving gear.

[0031] The working principle of the full-variable oil pump of the balance shaft driven 2.0T engine is as follows: after the engine starts, the balance shaft is driven to rotate synchronously by a specific gear transmission system, and the speed ratio of the balance shaft and the crankshaft is accurately matched. The driving gear on the balance shaft rotates synchronously with the driving gear 11 at the end of the driving shaft 10, and the power is transmitted to the driving shaft 10, thereby driving the rotor assembly to rotate synchronously. The rotor 19 rotates with the driving shaft 10 in an interference fit, and the eccentric ring 17 is pushed to be eccentrically arranged with the rotor 19 under the action of the eccentric spring 5. The plurality of blades 18 uniformly distributed along the circumference of the rotor 19 are always in sliding fit with the inner wall of the eccentric ring 17 under the action of centrifugal force and oil pressure, and the two blade rings 4 are arranged at the two ends of the blade 18 respectively, thereby isolating the space between the inner wall of the eccentric ring 17 and the outer wall of the rotor 19 into a plurality of sealed working chambers. When the rotor 19 rotates, the volume of the working chamber changes periodically with the relative position of the rotor 19 and the eccentric ring 17. When the volume increases, negative pressure is formed, and oil is sucked into the working chamber from the oil inlet; when the volume decreases, the oil is compressed and discharged through the oil outlet, thereby completing the oil delivery process. During the oil delivery process, the proportional electromagnetic valve 1 receives the control signal of the ECU according to the real-time working condition of the engine such as the speed and the load, adjusts the opening degree of the proportional electromagnetic valve 1, controls the amount of oil entering the feedback oil chamber 24, and changes the oil pressure in the feedback oil chamber 24. The oil pressure and the elastic force of the eccentric spring 5 are balanced, the eccentric ring 17 is driven to rotate around the swing pin 16, and the eccentric distance between the eccentric ring 17 and the rotor 19 is changed. When the engine is in a high-speed low-load working condition, the opening degree of the proportional electromagnetic valve 1 is increased, the oil pressure in the feedback oil chamber 24 is increased, the eccentric distance is reduced, the volume change range of the working chamber is reduced, and the oil pump displacement is reduced; when the engine is in a low-speed high-load working condition, the opening degree of the proportional electromagnetic valve 1 is reduced, the oil pressure in the feedback oil chamber 24 is reduced, the eccentric ring 17 is reset by the eccentric spring 5, the eccentric distance is increased, the volume change range of the working chamber is increased, and the oil pump displacement is increased, thereby realizing continuous and accurate adjustment of the oil displacement. Meanwhile, the driving gear oil groove 22 wraps the driving gear 11 on the balance shaft and the driving gear 11 of the oil pump, and the lubricating oil dripping from the camshaft, the crankshaft and other components will naturally flow into the oil groove to lubricate the meshing part of the gear. The circular arc tangent segment 23 at the tail end of the oil groove in the rotation direction of the driving gear 11 can use the centrifugal force generated when the driving gear 11 rotates to throw out the old oil in the oil groove, so that fresh oil is continuously supplemented, and the lubrication effect of the gear and the cleanliness of the oil in the oil groove are ensured.In addition, the PRV steel ball 14 in the safety valve blocks the oil outlet channel of the pump body 15 under the elastic force of the PRV spring 12, when the oil outlet pressure exceeds the preset elastic force of the PRV spring 12, the PRV steel ball 14 is pushed away, the oil flows back through the pressure relief channel, avoiding damage to the system due to overpressure; when the oil outlet pressure returns to normal, the PRV steel ball 14 resets under the action of the PRV spring 12, reseals the oil outlet channel, and ensures the safe operation of the oil pump and the engine lubricating system. In addition, the pump body 15 and the pump cover 3 are fixedly connected to form a sealed working chamber I by the pump cover bolt 2 and the pump cover long bolt 21, which provides a closed space for the assembly of the oil pump components and the flow of oil. The pump body positioning pin 8 ensures accurate positioning of the two; the sliding sealing gasket 6 is supported by the sliding sealing gasket support 7 to realize the sealing of the working chamber I, preventing oil leakage; the balance shaft positioning pin 9 is used for positioning the balance shaft and the pump body 15 and is installed by bolts. These structures collectively ensure the stable operation of the oil pump as a whole.

[0032] It is obvious for those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent conditions of the claims are intended to be included in the present application. Any reference signs in the claims should not be regarded as limiting the claims involved.

Claims

1. A balance shaft driven fully variable oil pump for a 2.0T engine, characterized in that: Includes a proportional solenoid valve (1), pump cover bolts (2), pump cover (3), drive gear (11), balance shaft sealing ring (13), pump body (15), M18 threaded sleeve (20), pump cover long bolts (21), drive gear oil groove (22), rotor assembly and safety valve; The pump body (15) and the pump cover (3) are fixedly connected by the pump cover bolts (2) and the pump cover long bolts (21) to form a sealed working chamber. The pump body (15) is provided with a pump body positioning pin (8) for positioning and cooperating with the pump cover (3). The rotor assembly includes a swing spring (5), a sliding sealing gasket (6), a sliding sealing gasket support (7), a drive shaft (10), a swing pin (16), an eccentric ring (17), a rotor (19), two blade rings (4) and multiple blades (18). The rotor (19) is interference-fitted with the drive shaft (10). The rotor (19) has multiple slots evenly distributed along its circumference, and each slot has a sliding blade (18). The two blade rings (4) are slidably arranged corresponding to the two ends of the multiple blades (18). One blade ring (4) is fixed to the inner wall of the pump cover (3), and the other blade ring (4) is fixed to the inner wall of the pump body (15). The outer walls of the multiple blades (18) are all slidably attached to the inner wall of the eccentric ring (17). The multiple blades (18) separate the inner wall of the eccentric ring (17) from the outer wall of the rotor (19). Multiple sealed working chambers are separated. The eccentric ring (17) is movably connected to the pump body (15) through a swing pin (16). One end of the swing spring (5) abuts against the eccentric ring (17), and the other end of the swing spring (5) is fixedly connected to the pump body (15). The sliding sealing gasket (6) is set on the contact surface between the pump body (15) and the eccentric ring (17). A sliding sealing gasket support (7) is provided between the eccentric ring (17) and the sliding sealing gasket (6). The drive gear (11) is fixed to the end of the drive shaft (10) and is connected to the main shaft on the engine balance shaft. The driving gear meshes, and the pump body (15) is positioned with the balance shaft by the balance shaft positioning pin (9) and connected by bolts. The balance shaft sealing ring (13) is fitted at the mating point between the balance shaft and the pump body (15). The drive gear oil groove (22) is fixed on the side where the pump body (15) connects to the balance shaft and wraps around the driving gear and the drive gear (11). The end of the drive gear oil groove (22) is provided with an arc tangent segment (23) along the rotation direction of the drive gear (11). The safety valve includes a PRV steel ball (14), a PRV spring (12), and an M18 threaded sleeve (20). One end of the PRV spring (12) rests against the PRV steel ball (14), and the other end of the PRV spring (12) is fixedly connected to the M18 screw sleeve (20). The M18 screw sleeve (20) is fixedly connected to the pump body (15). The PRV steel ball (14) is set to correspond to the oil outlet channel of the pump body (15). The proportional solenoid valve (1) is fixed to the outside of the pump body (15). The output end of the proportional solenoid valve (1) is connected to the feedback oil chamber (24) inside the pump body (15) through the feedback oil circuit. The feedback oil chamber (24) is formed between the outer wall of the eccentric ring (17) and the inner wall of the pump body (15).

2. The balance shaft driven fully variable oil pump for a 2.0T engine according to claim 1, characterized in that: The rotor (19) rotates synchronously with the drive shaft (10), and the eccentric ring (17) maintains the maximum eccentricity with the rotor (19) under the push of the eccentric spring (5).

3. The balance shaft driven fully variable oil pump for a 2.0T engine according to claim 1, characterized in that: The sliding gasket support (7) provides support for the sliding gasket (6) to prevent the sliding gasket (6) from deforming under the pressure of the oil.

4. The balance shaft driven fully variable oil pump for a 2.0T engine according to claim 1, characterized in that: The proportional solenoid valve (1) receives the control signal from the engine ECU and controls the oil pressure in the feedback oil chamber (24) according to the engine operating conditions. Through the balance between the oil pressure and the elastic force of the eccentric spring (5), it pushes the eccentric ring (17) to rotate around the swing pin (16), changes the eccentricity with the rotor (19), and realizes continuous displacement adjustment.

5. The balance shaft driven fully variable oil pump for a 2.0T engine according to claim 1, characterized in that: The drive gear oil groove (22) collects the lubricating oil flowing from the engine camshaft and crankshaft parts to lubricate the drive gear and drive gear (11). The arc tangent segment (23) at the end of the drive gear oil groove (22) is set along the rotation direction of the drive gear (11). The centrifugal force generated by the rotation of the gear throws the oil in the oil groove out, thereby realizing the circulation and renewal of the oil in the oil groove.

6. The balance shaft driven fully variable oil pump for a 2.0T engine according to claim 1, characterized in that: The balance shaft positions the pump body and the balance shaft by means of the balance shaft positioning pin (9) and is installed by bolts. The balance shaft positioning pin (9) is used to limit the relative position of the pump body and the balance shaft to ensure the meshing accuracy of the drive gear and the driving gear.

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