JP2021148003A - Oil pump manufacturing method - Google Patents

Abstract

To provide an oil pump manufacturing method capable of suppressing deterioration in discharge efficiency of oil and slide resistance.SOLUTION: A manufacturing method for an oil pump 100, which comprises first and second gears 10, 20 meshing with each other, a case 30 rotatably housing the first and second gears 10, 20, and resin films 40, 50 provided on axial end surfaces f1, f2, f4, f5 of the first and second gears 10, 20, comprises plastically deforming the resin films 40, 50 so that gaps S1, S2 between the resin films 40, 50 and wall surfaces f3, f6 facing thereto become zero, when fastening a first case member 31 and a second case member 32 to each other.SELECTED DRAWING: Figure 7

Description

The present disclosure relates to a method for manufacturing an oil pump.

As an oil pump, a gear pump having a first and second gears that mesh with each other and a case that rotatably accommodates the first and second gears is known.

For example, in an inscribed gear pump, an inner rotor as a first gear and an outer rotor as a second gear mesh with each other in a case and rotate to pressurize oil between the tooth surfaces of the rotors. Oil is discharged from the discharge port of the case.

Japanese Unexamined Patent Publication No. 10-299689

By the way, in the above oil pump, in order to suppress a decrease in oil discharge efficiency, the gap between the axial end faces of the first and second gears and the wall surface of the case facing the end faces may be set small. desirable.

However, if this gap is small, the sliding resistance between the facing surfaces may increase.

Therefore, the present disclosure was conceived in view of such circumstances, and an object of the present disclosure is to provide a method for manufacturing an oil pump capable of suppressing a decrease in oil discharge efficiency and sliding resistance.

According to one aspect of the present disclosure, the first and second gears that mesh with each other, the case that rotatably accommodates the first and second gears, and the axial end faces of the first and second gears. A method for manufacturing an oil pump having a resin film provided on at least one of the wall surfaces of the case facing the end face, wherein the cases are axially sandwiched between the first and second gears. It has a first case member and a second case member to be fastened, and the manufacturing method has a resin film and a wall surface facing the resin film when the first case member and the second case member are fastened to each other. Alternatively, there is provided a manufacturing method comprising a plastic deformation step of plastically deforming the resin film between the end face and the wall surface so that the gap between the end face and the end face becomes zero.

Preferably, the method for manufacturing an oil pump further includes a resin film coating step of coating the resin film on at least one of the end face and the wall surface before the plastic deformation step.

Further, the oil pump is provided in a transfer for switching between all-wheel drive and rear-wheel drive or front-wheel drive in a vehicle, and supplies oil to a lubricated portion of the transfer.

According to the present disclosure, it is possible to suppress a decrease in oil discharge efficiency and sliding resistance.

It is a schematic cross-sectional view of the transfer provided with an oil pump. It is an enlarged sectional view of an oil pump. It is an enlarged cross-sectional view of the line III-III shown in FIG. It is a process drawing which shows the manufacturing method of an oil pump. It is an enlarged cross-sectional view which shows the resin film coating process. It is an enlarged cross-sectional view which shows the state before the plastic deformation in the plastic deformation process. It is an enlarged cross-sectional view which shows the state after plastic deformation in a plastic deformation process.

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be noted that the front-back direction shown in the figure is merely defined for convenience of explanation.

First, the structure of the oil pump 100 of the present embodiment will be described with reference to FIGS. 1 to 3. The front-rear direction of this embodiment coincides with the front-rear direction of a vehicle (not shown) provided with the oil pump 100.

As shown in FIG. 1, the oil pump 100 is provided in the transfer 1 of the vehicle. The vehicle is an AWD (All Wheel Drive) vehicle based on an FR vehicle (front engine / rear drive vehicle), and the transfer 1 is configured to switch between all-wheel drive and rear-wheel drive.

The transfer 1 of the present embodiment includes a housing 2, a main shaft 3, a sub-shaft 4, a multi-plate clutch 5 and an actuator 6 housed in the housing 2.

The housing 2 is connected to the rear end of the transmission housing (not shown). The main shaft 3 and the sub-shaft 4 extend in the front-rear direction and are arranged in parallel with each other.

The front end of the spindle 3 is connected to the output shaft 7 of the transmission, and the rear end of the spindle 3 is connected to the front end of the propeller shaft 8. The front end portion of the auxiliary shaft 4 is connected to the rear end portion of the propeller shaft 9 for driving the front wheels.

A first sprocket 3a is rotatably provided on the outer peripheral portion of the spindle 3. On the other hand, a second sprocket 4a is integrally provided on the outer peripheral portion of the sub-shaft 4. A chain C is hung around the first sprocket 3a and the second sprocket 4a.

The multi-plate clutch 5 connects the spindle 3 and the first sprocket 3a in a connectable manner. The actuator 6 is driven by an electromagnet 6a and is configured to adjust the fastening force of the multi-plate clutch 5.

In the present embodiment, the rotational driving force from the engine is transmitted to the propeller shaft 8 via the output shaft 7 of the transmission and the main shaft 3 of the transfer 1. Further, when the multi-plate clutch 5 is in contact, a part of the rotational driving force transmitted from the main shaft 3 to the propeller shaft 8 is distributed to the front wheel drive propeller shaft 9 via the sprockets 3a and 4a and the sub-shaft 4. Will be done.

The oil pump 100 of this embodiment is attached to the spindle 3 of the transfer 1. As shown in FIGS. 2 and 3, an internal gear pump is used for the oil pump 100.

The oil pump 100 includes an inner rotor 10 as a first gear and an outer rotor 20 as a second gear that mesh with each other, and a case 30 that rotatably accommodates the inner rotor 10 and the outer rotor 20.

The inner rotor 10 is a metal external tooth gear, and has a plurality of (9 in the illustrated example) external teeth 11 having a trochoidal curve. The outer rotor 20 is a metal internal tooth gear, and has a plurality of (10 in the illustrated example) internal teeth 21 having a trochoidal curve.

The central axis X1 of the inner rotor 10 and the central axis X2 of the outer rotor 20 extend in the front-rear direction and are arranged eccentrically with each other.

A spline hole 12 is formed in the radial center portion of the inner rotor 10. The spindle 3 is coaxially inserted into the spline hole 12 and spline-fitted. On the other hand, the outer rotor 20 is coaxially and rotatably arranged in the case 30.

As shown in FIG. 2, the inner rotor 10 and the outer rotor 20 have the same thickness D1 in the axial direction.

The case 30 has a pump case 31 as a first case member and a pump cover 32 as a second case member.

The pump case 31 and the pump cover 32 are made of a metal material and are fastened to each other with the inner rotor 10 and the outer rotor 20 sandwiched in the axial direction. However, the pump case 31 and the pump cover 32 may be made of any material, and may be made of, for example, a resin material.

The pump case 31 is formed in a bottomed cylindrical shape having a central axis X2 extending in the front-rear direction. The front end of the pump case 31 is closed by the bottom 31a and the rear end of the pump case 31 is opened.

Further, the pump case 31 has an inner diameter slightly larger than the outer diameter of the outer rotor 20, and rotatably accommodates the inner rotor 10 and the outer rotor 20. Further, the pump case 31 is fixedly supported by the housing 2 (see FIG. 1) of the transfer 1 via a bracket (not shown).

An insertion hole H1 through which the main shaft 3 is inserted is formed in the radial central portion of the bottom portion 31a. Further, a suction port 33 and a discharge port 34 are formed on the rear surface portion of the bottom portion 31a.

The suction port 33 and the discharge port 34 are each formed in a groove shape extending in the circumferential direction, and are arranged so as to be axisymmetric with respect to the insertion hole H1.

The suction port 33 communicates with a suction port 35 formed on the outer peripheral portion of the bottom portion 31a. An oil supply pipe 35a is connected to the suction port 35.

The discharge port 34 communicates with a discharge port 36 (see FIG. 3) formed on the inner peripheral surface of the insertion hole H1. The discharge port 36 is connected to an oil passage 3b formed in the main shaft 3.

A plurality of case-side flanges 37 having bolt insertion holes 37a (four in the present embodiment) are formed on the outer peripheral portion of the pump case 31 at intervals in the circumferential direction.

The pump cover 32 is formed in a disk shape, is coaxially connected to the pump case 31, and covers the rear end of the pump case 31 from the rear side to close the pump case 31. An insertion hole H2 through which the main shaft 3 is inserted is formed in the radial central portion of the pump cover 32.

A plurality of cover-side flanges 38 having bolt insertion holes 38a are formed on the outer peripheral portion of the pump cover 32 (four in the present embodiment) corresponding to the case-side flanges 37. The pump case 31 and the pump cover 32 are flanged to each other using bolts 39a and nuts 39b.

In the oil pump 100 of the present embodiment, the inner rotor 10 is rotationally driven by the spindle 3, and the outer rotor 20 is rotated (differential rotation) accordingly. As a result, the oil stored in the oil storage portion (not shown) of the transfer 1 passes through the oil supply pipe 35a and is sucked into the suction port 33 from the suction port 35. The oil sucked into the suction port 33 is pressurized between the tooth surface 11a of the inner rotor 10 and the tooth surface 21a of the outer rotor 20, and is discharged from the discharge port 34 to the discharge port 36. As shown in FIG. 1, the oil discharged from the discharge port 36 passes through the oil passage 3b formed in the main shaft 3, the first sprocket 3a, which is the lubricated portion of the transfer 1, the multi-plate clutch 5, and the actuator 6. Etc. are supplied.

By the way, in the oil pump 100, the front surface f1 of the inner rotor 10 and the front surface f2 of the outer rotor 20 are arranged so as to face the wall surface (rear wall surface f3) of the bottom portion 31a of the pump case 31. Further, the rear surface f4 of the inner rotor 10 and the rear surface f5 of the outer rotor 20 are arranged so as to face the wall surface (front wall surface f6) of the pump cover 32. These surfaces f1 to f6 are formed in a plane shape perpendicular to the axial direction.

The axial thickness D1 of the inner rotor 10 and the outer rotor 20 is set to be smaller than the distance D2 between the rear wall surface f3 of the pump case 31 and the front wall surface f6 of the pump cover 32 (D1 <D2). ).

Although not shown, in general, in an oil pump, if the gap between the surfaces facing each other in the axial direction is large, the oil pressurized between the tooth surfaces is returned from the discharge port to the suction port through this gap. , The oil discharge efficiency is reduced. Therefore, in the oil pump, it is desirable that the gap between the surfaces facing each other in the axial direction is set small.

However, if this gap is small, the sliding resistance between the facing surfaces may increase. As a result, the rotational resistance of the transfer spindle increases, which may deteriorate the fuel efficiency of the engine. Further, since the oil pump provided in the transfer is always operated by the rotational driving force of the main shaft regardless of all-wheel drive or rear-wheel drive while the vehicle is running, it is particularly required to suppress sliding resistance.

Therefore, the oil pump 100 of the present embodiment is provided on the front resin film 40 as a resin film provided on the front surfaces f1 and f2 of the inner rotor 10 and the outer rotor 20, and on the rear surfaces f4 and f5 of the inner rotor 10 and the outer rotor 20. A rear resin film 50 as a provided resin film is provided.

Hereinafter, a method for manufacturing the oil pump 100 provided with the resin films 40 and 50 will be described with reference to FIGS. 4 to 7.

As shown in FIG. 4, the manufacturing method of the present embodiment includes a resin film coating step S100 and a plastic deformation step S101.

As shown in FIG. 5, in the resin film coating step S100, the front resin films 40 are coated on the front surfaces f1 and f2 of the inner rotor 10 and the outer rotor 20 before the plastic deformation step S101, and the inner rotor 10 and the outer rotor 20 are coated. The rear surface f4 and f5 are coated with the rear resin film 50.

The resin films 40 and 50 are formed of any resin such as a fluororesin or nylon that is easily plastically deformed, preferably nylon (for example, nylon 11).

In the present embodiment, for example, the resin films 40 and 50 are coated by adhering and melting solid powdery nylon to the front surfaces f1, f2 and the rear surfaces f4 and f5 of the heated rotors 10 and 20.

Further, as will be described in detail later, the front resin film 40 is covered with a thickness such that the gap S1 (see FIG. 7) with the rear wall surface f3 of the facing pump case 31 becomes zero after being plastically deformed. .. Further, the rear resin film 50 is covered with a thickness such that the gap S2 (see FIG. 7) with the front wall surface f6 of the facing pump cover 32 becomes zero after being plastically deformed.

That is, in the resin film coating step S100, the total thickness D3 of the resin films 40 and 50 and the rotors 10 and 20 in the axial direction is between the wall surfaces f3 and f6 after the pump case 31 and the pump cover 32 are fastened. The resin films 40 and 50 are coated so as to be larger than the distance D2 (see FIG. 7) (D3> D2).

The rear resin film 50 covers the entire rear surface f4 of the inner rotor 10 and the rear surface f5 of the outer rotor 20.

On the other hand, the front resin film 40 is covered at predetermined positions between the front surface f1 of the inner rotor 10 and the front surface f2 of the outer rotor 20.

As shown in FIGS. 6 and 7, this predetermined position means a position where the front resin film 40 does not enter the suction port 33 and the discharge port 34 during the plastic deformation step S101.

In the plastic deformation step S101, when the pump case 31 and the pump cover 32 are fastened to each other, the rotors 10 and 20 are sandwiched between them, and the resin films 40 and 50 are axially compressed to reduce the thickness. Plastically deformed. That is, the front surface f1 and f2 of the rotors 10 and 20 and the rear wall surface f3 of the pump case 31 plastically deform the front resin film 40, and at the same time, the rear surfaces f4 and f5 of the rotors 10 and 20 and the front wall surface of the pump cover 32. At f6, the rear resin film 50 is plastically deformed.

Further, in the plastic deformation step S101, the gap S1 between the front resin film 40 and the rear wall surface f3 of the pump case 31 and the gap S2 between the rear resin film 50 and the front wall surface f6 of the pump cover 32 become zero. As described above, the resin films 40 and 50 are plastically deformed.

Specifically, as shown in FIG. 6, in the plastic deformation step S101, first, the inner rotor 10 and the outer rotor 20 are arranged in the pump case 31, and the front resin film 40 before the plastic deformation is applied to the pump case. It is brought into contact with the rear wall surface f3 of 31. Further, here, the position and shape of the front resin film 40 are set so as not to enter the suction port 33 and the discharge port 34 when the front resin film 40 is plastically deformed.

Next, the front wall surface f6 of the pump cover 32 is brought into contact with the rear resin film 50, and the bolt insertion holes 37a and 38a of the pump case 31 and the pump cover 32 are arranged coaxially with each other.

Finally, as shown in FIG. 7, the bolt 39a is inserted into the bolt insertion holes 37a and 38a, and the nut 39b is tightened into the male screw portion of the bolt 39a. As a result, the pump case 31 and the pump cover 32 are fastened to each other in the axial direction, and the oil pump 100 is completed.

At this time, the resin films 40 and 50 are axially compressed and plastically deformed by the front surfaces f1 and f2 and the rear surfaces f4 and f5 of the rotors 10 and 20 and the wall surfaces f3 and f6 of the case 31. As a result, the thickness of the resin films 40 and 50 in the axial direction is reduced.

After the resin films 40 and 50 are plastically deformed, the gap S1 between the front resin film 40 and the rear wall surface f3 of the pump case 31 and the gap S2 between the rear resin film 50 and the front wall surface f6 of the pump cover 32 are respectively. It becomes zero. The term "zero" as used herein means a state in which the resin films 40 and 50 and the wall surfaces f3 and f6 are in contact with each other and no compressive stress is generated in the resin films 40 and 50.

According to the manufacturing method of the present embodiment, in the oil pump 100, the gap between the front surfaces f1 and f2 and the rear surfaces f4 and f5 of the rotors 10 and 20 and the wall surfaces f3 and f6 of the case 30 facing the same is formed in the resin film 40. , 50 can be closed to zero.

As a result, it is possible to prevent the oil pressurized between the tooth surfaces 11a and 21a of the rotors 10 and 20 from being returned from the discharge port 34 to the suction port 33. As a result, it is possible to suppress a decrease in oil discharge efficiency.

Further, since the compressive stresses of the resin films 40 and 50 are not generated by the wall surfaces f3 and f6 of the case 30, the sliding resistance between the resin films 40 and 50 and the wall surfaces f3 and f6 can be suppressed.

Therefore, according to the present embodiment, it is possible to suppress a decrease in oil discharge efficiency and a sliding resistance. As a result, the rotational resistance of the spindle 3 of the transfer 1 can be suppressed, and the deterioration of the fuel efficiency of the engine can be suppressed.

Further, according to the present embodiment, by providing the resin films 40 and 50, the machining accuracy of the front surfaces f1 and f2 and the rear surfaces f4 and f5 of the rotors 10 and 20 and the wall surfaces f3 and f6 of the case 30 facing them Can be alleviated.

By the way, as a method for manufacturing an oil pump provided with such a resin film, the following first and second comparative examples can be considered.

Although not shown, in the first comparative example, the resin film is compressed by the front surface and the rear surface of the rotor and the wall surface of the case, and the pump case and the pump cover are fastened to each other in a state where compressive stress is generated in the resin film. Then, the rotor is rotated to polish the resin film by the wall surface of the case until the compressive stress of the resin film disappears.

However, in this first comparative example, since resin wear debris is generated by the polishing process, it is necessary to temporarily release the fastening between the pump case and the pump cover, take out the rotor from the case, and remove the wear debris. Become. Therefore, the working time until the completion of the oil pump increases, and the manufacturing cost of the oil pump may increase. In addition, there is a possibility that the abrasion powder may not be completely removed because it may get stuck in the resin film.

On the other hand, as shown in FIG. 7, in the manufacturing method of the present embodiment, the gaps S1 and S2 between the resin films 40 and 50 and the wall surfaces f3 and f6 of the case 30 become zero as described above. Therefore, since the resin films 40 and 50 are plastically deformed, the polishing treatment as in the first comparative example is unnecessary. Further, even if the rotors 10 and 20 are rotated, the wear debris of the resin films 40 and 50 is substantially not generated, so that the work of removing the wear debris is not necessary and only the pump case 31 and the pump cover 32 are fastened to each other. Then, the oil pump 100 can be completed. As a result, the increase in working time can be suppressed and the manufacturing cost of the oil pump 100 can be suppressed.

On the other hand, in the second comparative example, a resin film having a thickness that does not compress (deform) the resin film between the front and rear surfaces of the rotor and the wall surface of the case and the gap between the resin film and the wall surface becomes zero is formed. Cover.

However, in this second modification, it is necessary to coat the resin film with high accuracy, and it may be difficult to make the gap between the resin film and the wall surface zero.

On the other hand, as shown in FIGS. 5 and 7, in the manufacturing method of the present embodiment, the resin films 40 and 50 are plastically deformed, so that the resin films 40 and 50 and the rotors 10 and 20 are axially oriented. If the resin films 40 and 50 are coated so that the total thickness D3 of the case 30 is thicker than the distance D2 between the wall surfaces f3 and f6 of the case 30, the resin films 40 and 50 and the wall surface f3 of the case 30 are covered. The gaps S1 and S2 with f6 can be easily reduced to zero.

Although the basic embodiments of the present disclosure have been described in detail above, the present disclosure can be a modified example or a combination of the following modified examples. In the following description, the same reference numerals are used for the same or corresponding components as those in the basic embodiment, and detailed description thereof will be omitted.

(Modification example 1)
The resin films 40 and 50 may be provided on the wall surfaces f3 and f6 of the case 30 instead of the front surfaces f1 and f2 and the rear surfaces f4 and f5 of the rotors 10 and 20.

Although not shown, in the resin film coating step of the first modification, the rear wall surface f3 of the pump case 31 is coated with the front resin film, and the front wall surface f6 of the pump cover 32 is coated with the rear resin film.

Further, in the plastic deformation step of the first modification, the gap between the front resin film and the front surfaces f1 and f2 of the rotors 10 and 20 and the gap between the rear resin film and the rear surfaces f4 and f5 of the rotors 10 and 20, respectively, are formed. The resin film is plastically deformed so that it becomes zero.

Also in this case, the same effect as that of the above basic embodiment can be obtained. However, the resin film of the modified example 1 needs to be coated on the wall surfaces f3 and f6 of the case 30 at a position and a thickness that do not penetrate into the gap between the tooth surfaces 11a and 21a of the rotors 10 and 20 during the plastic deformation step. There is.

The resin film may be provided on both the front surfaces f1, f2 and the rear surfaces f4 and f5 of the rotors 10 and 20 and the wall surfaces f3 and f6 of the case 30.

(Modification 2)
Either one of the front resin film 40 and the rear resin film 50 may be omitted.

(Modification example 3)
The oil pump 100 may be an external gear pump, or may be provided in addition to the transfer 1.

The configurations of each of the above embodiments can be combined partially or wholly, unless otherwise inconsistent. The embodiments of the present disclosure are not limited to the above-described embodiments, and all modifications, applications, and equivalents included in the ideas of the present disclosure defined by the claims are included in the present disclosure. Therefore, this disclosure should not be construed in a limited way and may be applied to any other technique that falls within the scope of the ideas of this disclosure.

1 Transfer 10 Inner rotor (1st gear)
20 Outer rotor (second gear)
30 Case 31 Pump case (first case member)
32 Pump cover (second case member)
40 Front resin film (resin film)
50 Rear resin film (resin film)
100 oil pump

Claims (3)

The first and second gears that mesh with each other, the case that rotatably accommodates the first and second gears, the axial end faces of the first and second gears, and the wall surface of the case that faces the end faces. A method for manufacturing an oil pump having a resin film provided on at least one of the above.
The case has a first case member and a second case member that are fastened to each other with the first and second gears sandwiched in the axial direction.
In the manufacturing method, when the first case member and the second case member are fastened to each other, the end face is provided so that the gap between the resin film and the wall surface or the end face facing the resin film becomes zero. A manufacturing method comprising a plastic deformation step of plastically deforming the resin film on the wall surface. The manufacturing method according to claim 1, further comprising a resin film coating step of coating the resin film on at least one of the end face and the wall surface before the plastic deformation step. The manufacturing method according to claim 1 or 2, wherein the oil pump is provided in a transfer for switching between all-wheel drive and rear-wheel drive or front-wheel drive in a vehicle, and supplies oil to a lubricated portion of the transfer.

Images