WO2020170588A1

WO2020170588A1 - Surface processing method for member having through-hole in bottom wall section of recess part, method of manufacturing oil pump, and oil pump

Info

Publication number: WO2020170588A1
Application number: PCT/JP2019/049854
Authority: WO
Inventors: 豊和鮫島; 晶鈴木; 暢昭寒川; 浩二佐賀
Original assignee: 日立オートモティブシステムズ株式会社
Priority date: 2019-02-20
Filing date: 2019-12-19
Publication date: 2020-08-27
Also published as: JP2022074168A

Abstract

According to the present invention, a housing (6) formed of aluminum alloy has: a bottom wall part (10) that is formed relatively thin; and an annular peripheral wall part (11) that extends upward from the outer edge of the bottom wall part (10). A through-hole (10a) is formed through a center of the bottom wall part (10). A bottom surface (28) and a side surface (11a) of a recess part (6a) formed by the bottom wall part (10) and the peripheral wall part (11) are cut by a first end mill (53). During this cutting, a surrounding part (30) is processed by moving the first end mill (53) such that the surrounding part (30) orbits about the fixed housing (6) in a clockwise direction (feeding direction V), and then a peripheral wall part adjacent part (31) and the side surface (11a) are processed by moving the first end mill (53) such that the feeding direction of the first end mill (53) is reversed, and the surrounding part (30) orbits in a counterclockwise direction (feeding direction W).

Description

Surface processing method for member having through hole in bottom wall of recess, oil pump manufacturing method, and oil pump

The present invention relates to a surface processing method for a member having a through hole in the bottom wall of a recess, an oil pump manufacturing method, and an oil pump.

The oil pump described in Patent Document 1 has a housing in which a recess is formed, and a pump structure having an inner rotor, an outer rotor, etc. is arranged in the recess of this housing. Further, a through hole is provided on the bottom surface of the recess, and a drive shaft for rotationally driving the inner rotor is inserted into the through hole.

The bottom surface of the recess forms a part of the hydraulic oil chamber formed inside the housing, and is therefore a part that affects the sealing performance of the hydraulic oil chamber. Therefore, the bottom surface of the recess is finished by using an end mill in order to obtain the sealing property of the hydraulic oil chamber, whereby high flatness is ensured. This finishing of the bottom surface is performed by relatively rotating the end mill around the through hole. Further, when finishing the bottom surface, the side surface of the recess is also processed. Generally, when processing the side surface, the side surface is cut by so-called down-cutting. This is to extend the tool life of the end mill, and the side surface is cut with the orbiting direction of the end mill being reversed with respect to the rotation direction of the end mill.

JP, 2007-85262, A

When machining the bottom surface with the end mill in a state where the orbiting direction of the end mill is reversed with respect to the rotation direction of the end mill as described above, the blade part of the end mill bites into the bottom surface and scoops the bottom surface, so it is cut. The cutting force acting on the end mill in the direction of the rotation axis of the end mill is upward. In particular, when cutting the bottom surface of the peripheral part of the through hole, the blade part of the end mill always scoops the edge part that is the hole edge of the through hole, so the blade part cuts the bottom surface, so Cutting resistance will act more greatly. As described above, when the blade portion cuts the bottom surface while the cutting resistance upward in the rotation axis direction of the end mill is applied, the bottom surface is cut while being lifted by the blade portion, and the bottom surface is too deeply cut. Further, after the recess is processed, the cutting resistance in the direction of the rotation axis upward acting at the time of processing disappears, so that the bottom wall portion is bent toward the side opposite to the opening of the recess. Therefore, there is a problem that it is difficult to secure the flatness of the bottom surface necessary to obtain the sealing property of the hydraulic oil chamber. This problem becomes more remarkable as the bottom wall of the recess is formed thinner and the diameter of the through hole is larger.

In addition, in order to suppress the above-mentioned cutting resistance acting on the end mill in the direction of the rotation axis upward, it is conceivable that the direction in which the end mill orbits is the same as the direction in which the end mill rotates. However, in this case, the side surface of the recess is to be cut by up-cutting when processing the side surface of the recess, which may shorten the tool life of the end mill.

The present invention has been devised in view of the conventional circumstances, and has a through hole in the bottom wall portion of the recess that can improve the tool life of the end mill while ensuring the flatness of the bottom surface of the recess. It is an object to provide a surface treatment method for members and the like.

As one of the preferred embodiments of the present invention, the peripheral portion of the through hole provided in the recess is so arranged that the rotation direction of the end mill and the direction in which the end mill relatively circulates around the through hole are the same direction. The side surface of the recess is processed so that the rotation direction of the end mill and the direction in which the end mill relatively circulates around the through hole are opposite.

According to a preferred aspect of the present invention, it is possible to improve the tool life of the end mill while ensuring the flatness of the bottom surface of the recess.

It is a side view showing an oil pump attached to an engine block of an internal combustion engine. FIG. 2 is a sectional view showing an oil pump and the like cut along the line AA in FIG. 1 with a front cover attached. It is a sectional view of an oil pump before a cam ring rocks. It is sectional drawing of an oil pump after a cam ring rock|fluctuates. It is a front view of a housing. It is a rear view of a housing. FIG. 6 is a cross-sectional view of the housing taken along the line BB of FIG. 5. (A) is an explanatory view showing the positional relationship between the end mill and the work material stepwise when the upper surface of the work material is cut by up-cut using the end mill, and (b) is the line of (a). It is sectional drawing of the end mill and work material which were cut|disconnected along CC. (A) is an explanatory view showing the positional relationship between the end mill and the work material stepwise when the upper surface of the work material is down-cut by using the end mill, (b) is the line of (a) It is a sectional view of an end mill and a work material cut along DD. FIG. 6 is a perspective view showing a positional relationship between the end mill and the work material when the side surface of the work material is cut by upcut using the end mill. FIG. 6 is a perspective view showing a positional relationship between the end mill and the work material when the side surface of the work material is cut by a down cut using the end mill. FIG. 6 is a process diagram showing a roughing process of the bottom surface, side surfaces, opening end surface, etc. of the housing. It is a flowchart showing a finishing process of a contact surface of a housing. FIG. 6 is a process diagram showing a finish processing process of the bottom surface, side surfaces, opening end surface, and the like of the housing. FIG. 7 is a process diagram showing a finish processing step of a conventional surface processing method for a recess of a housing. It is sectional drawing of a housing etc. which shows the solution of another subject of this embodiment.

An embodiment of the oil pump of the present invention will be described below with reference to the drawings.

[Structure of oil pump]
FIG. 1 is a side view showing an oil pump 1 attached to an engine block 3 of an internal combustion engine. FIG. 2 is a sectional view showing the oil pump 1 and the like cut along the line AA in FIG. 1 attached to the front cover 4.

The oil pump 1 is configured as a variable displacement oil pump, and is rotatably driven by the rotational force transmitted from the crankshaft 2 to allow various sliding parts in an internal combustion engine, various valve timing control devices, and the like. It supplies oil (lubricating oil) to equipment. The oil pump 1 is housed in a pump housing section 5 provided between the engine block 3 and the front cover 4. The oil pump 1 includes a housing 6 in which one end side of the crankshaft 2 in the axial direction is open and the other end side is closed, a pump structure 7 housed in the housing 6, and a housing containing the pump structure 7. And a cover 8 that closes the opening 9 of 6.

The housing 6 is formed in a concave shape by aluminum die casting using a metal material such as an aluminum alloy material. A recess 6a for accommodating the pump component 7 is formed in an opening on an end surface of the housing 6 located on the axially one end 2a side of the crankshaft 2. The recess 6a is formed by finishing the inner surface of the recess 6a by cutting using a first end mill 53 described later. The recess 6 a is formed by a bottom wall portion 10 and an annular peripheral wall portion 11 that rises from the bottom wall portion 10 so as to be orthogonal to the bottom wall portion 10. A circular through hole 10a that rotatably supports the crankshaft 2 is formed through the bottom wall portion 10 along the rotation axis direction of the crankshaft 2.

The pump structure 7 is mainly composed of a crankshaft 2 which is a rotating shaft, a rotor 12 which is rotationally driven by the crankshaft 2, a vane 13 and a cam ring 14 which will be described later. The rotor 12 is housed in the recess 6a with the outer peripheral portion of the crankshaft 2 inserted.

Like the housing 6, the cover 8 is formed of a metal material, for example, an aluminum alloy material, and has a circular insertion hole 7a that rotatably supports the crankshaft 2 at a position corresponding to the through hole 10a of the housing 6. , Is fixed to the housing 6 with eight fixing members, for example, bolts 17. The cover 8 is attached and fixed to the engine block 3 together with the housing 6 with four fixing members, for example, bolts 18.

FIG. 3 is a sectional view of the oil pump 1 before the cam ring 14 swings. FIG. 4 is a sectional view of the oil pump 1 after the cam ring 14 swings.

The pump structure 7 is composed of a crankshaft 2 which is a rotating shaft, a rotor 12 mounted on the outer peripheral portion of the crankshaft 2, a vane 13, a cam ring 14, a coil spring 15 and the like. The pump structure 7 discharges the oil, which is the fluid sucked from the suction portion, from the discharge portion due to the volumes of the plurality of hydraulic oil chambers 21 changing as the rotor 12 rotates integrally with the crankshaft 2. ..

As shown in FIGS. 3 and 4, the rotor 12 is fitted in the outer peripheral portion of the crankshaft 2 rotatably provided in the center of the recess 6a in a state in which the relative rotation is restricted, and is housed in the recess 6a. Has been done. Further, on the outer peripheral side of the rotor 12, nine slits 19 extending radially outward from the inner center side of the rotor 12 are formed at equal intervals in the circumferential direction of the rotor 12, and in each slit 19, A thin plate-shaped vane 13 made of metal is arranged so as to be able to appear and disappear. Further, between the outer peripheral surface of the rotor 12 and the inner peripheral surface of the housing 6, there is provided a cam ring 14 which is a rocking member capable of rocking around the pivot pin 20. That is, the tip surface of the vane 13 is slidably in contact with the inner peripheral surface of the cam ring 14, so that the rotor 12, two vanes 13 facing each other in the circumferential direction of the rotor 12, the cam ring 14, the housing 6, and the cover 8 are provided. The space surrounded by and becomes the hydraulic oil chamber 21.

A biasing member, for example, a coil spring 15 compressed by a predetermined set load Ws is provided at a portion of the housing 6 facing the pivot pin 20 on one side of the arm portion 14 a projectingly formed on the cam ring 14. It is arranged so as to be elastically contactable.

A pair of first and second

control oil chambers

25 and 26 are formed in the outer peripheral area of the cam ring 14 by the pivot pin 20 and the first and

second seal members

23 and 24 provided on the outer peripheral portion of the cam ring 14. It is demarcated.

Hydraulic pressure is introduced into the first control oil chamber 25 from the main oil gallery of the internal combustion engine to which the oil discharged from the discharge port formed in the bottom wall portion 10 is supplied. As a result, the first pressure receiving surface 14 b formed by the outer peripheral surface of the cam ring 14 facing the first control oil chamber 25 receives the hydraulic pressure from the discharge port and resists the urging force of the coil spring 15 to move the cam ring 14. A swinging force (moving force) is applied in a direction (counterclockwise direction in FIGS. 3 and 4) in which the amount of eccentricity is reduced.

On the other hand, also in the second control oil chamber 26, the hydraulic pressure from the main oil gallery is appropriately introduced by the on/off operation of the electromagnetic switching valve 27. The second pressure receiving surface 14c formed by the outer peripheral surface of the cam ring 14 facing the second control oil chamber 26 receives the discharge pressure and increases the eccentric amount of the cam ring 14 (clockwise in FIGS. 3 and 4). A swinging force (moving force) is applied.

The oil pump 1 shown in FIG. 4 changes from the state before the swing of the cam ring 14 shown in FIG. 3 to the state shown in FIG. 4 by turning the exciting current supplied from the control unit for controlling the internal combustion engine to the electromagnetic switching valve 27 from ON to OFF. The cam ring 14 is switched to the state after swinging as shown.

[Construction of housing]
FIG. 5 is a front view of the housing 6.

The recess 6a of the housing 6 is relatively thin and has a substantially circular plate-shaped bottom wall portion 10 and a substantially annular peripheral wall portion that rises from the outer edge of the bottom wall portion 10 and surrounds the bottom wall portion 10. 11 and. The bottom wall portion 10 has a bottom surface 28 that is a surface on the opening 9 side of the concave portion 6a, and a relatively large diameter circle into which the crankshaft 2 is rotatably inserted at a substantially central position of the bottom surface 28. A through hole 10a having a shape is formed so as to penetrate therethrough. The surface area of the bottom surface 28 is larger than the outer diameter of the cam ring 14 in order to secure the above-described area where the cam ring 14 swings. The bottom surface 28 is connected to a side surface 11 a that is an inner peripheral surface of the peripheral wall portion 11 orthogonal to the bottom surface 28. The bottom surface 28 and the side surface 11a are formed by finishing by cutting using a first end mill 53 described later.

Here, for convenience of the following description, it is a portion of the bottom surface 28 around the through hole 10a, and substantially in the center between the edge portion of the through hole 10a and the side surface 11a of the peripheral wall portion 11 in the radial direction of the through hole 10a. When the position is indicated by the broken line circle 29 in FIG. 5, the annular region from the edge of the through hole 10a to the circle 29 is defined as the "peripheral portion 30". Further, an annular region of the bottom surface 28 adjacent to the peripheral wall portion 11 from the circle 29 to the side surface 11a of the peripheral wall portion 11 is defined as a "peripheral wall portion adjacent portion 31". In order to simplify FIG. 5, the circle 29 has a shape when the concave and convex portions of the spring accommodating chamber 22 and the like in the recess 6a are omitted and the inner circumference of the recess 6a is circular. ..

Since the peripheral wall portion adjacent portion 31 is continuous with the peripheral wall portion 11, it has a higher rigidity than the peripheral portion 30 adjacent to the through hole 10a.

The outer peripheral portion of the peripheral wall portion 11 has nine boss portions 33a to 33i that are formed to project radially outward of the through hole 10a. In addition, a flat opening end face 32 that surrounds the opening 9 of the recess 6 a is formed at the tip of the peripheral wall 11. The open end surface 32 serves as a contact surface that contacts the cover 8 when the cover 8 is attached to the housing 6. The open end surface 32 is formed by finishing by cutting using a first face mill 55 described later. At the positions corresponding to the six

boss portions

33a, 33c, 33e, 33f, 33h, 33i of the opening end face 32, six female screw holes 34 into which the bolts 17 are screwed when the cover 8 is attached to the housing 6 are respectively provided. Has been formed. Further, two bolt insertion holes (mounting portions) 35 into which bolts 18 are inserted when the housing 6 is attached to the engine block 3 together with the cover 8 are provided at positions corresponding to the two

boss portions

33b and 33d on the opening end surface 32. Are formed through each. Further, a circular knock pin hole 36 used for positioning with the cover 8 when the cover 8 is attached to the housing 6 is formed at a position corresponding to the boss portion 33g on the open end surface 32.

Further, in a part of the outer peripheral portion of the peripheral wall portion 11, a protruding portion 38 protruding from the outer peripheral portion to the outside in the radial direction of the through hole 10a is formed. The outer peripheral portion of the overhanging portion 38 has three

boss portions

33j, 33k, 33m that are formed to project radially outward of the through hole 10a. The overhanging portion 38 has a flat surface 38 a that is flush with the opening end surface 32 and is continuous with the opening end surface 32. The surface 38a is formed by finishing by cutting using a face mill 55 described later as a series of processing when processing the opening end surface 32. Female screw holes 34 into which the bolts 17 are screwed when the cover 8 is attached to the housing 6 are formed near the area between the

bosses

33j and 33k on the surface 38a and at a position corresponding to the bosses 33m. .. Further, two bolt insertion holes (mounting portions) 35 into which the bolts 18 are inserted when the housing 6 is attached to the engine block 3 together with the cover 8 are provided at positions corresponding to the two

boss portions

33j and 33k on the surface 38a. Each is formed.

At the positions adjacent to the

boss portions

33d, 33h, 33k on the outer peripheral surfaces of the peripheral wall portion 11 and the overhang portion 38, the housing 6 is clamped at the time of processing the bottom surface 28, the side surface 11a and the opening end surface 32 of the recess 6a. Two clamp seats 37 are formed so as to project. Each clamp seat 37 has a substantially triangular plate shape, and is formed at a position offset from the opening end face 32 toward the through hole 10a side in the through direction of the through hole 10a. The clamp seat 37 has a bottom surface 28, a side surface 11a, and a surface 37b, which will be described later, which serves as a reference surface for processing when processing the opening end surface 32.

FIG. 6 is a rear view of the housing 6.

On the side opposite to the opening 9 of the housing 6, more specifically, on the rear side of the bottom surface 28 of the bottom wall portion 10, the first block that comes into contact with the engine block 3 that is a counterpart member when attached to the internal combustion engine. One contact surface 39 is formed. As shown in FIG. 6, the first contact surface 39 is continuous in a semi-circular shape at a position near the boss 33a of the bottom wall 10 along the circumferential direction of the through hole 10a. In addition, the surface 40 of the boss portion 33d provided at a position separated from the first contact surface 39 is on the same plane as the first contact surface 39, and contacts the engine block 3 when attached to the engine block 3. It becomes the first contact surface. The first contact surface 39 and the surface 40 are formed by finishing by cutting using a first face mill 55 described later.

In addition, a portion located at the tip of the overhanging portion 38, that is, a portion of the overhanging portion 38 that is most distant from the first contact surface 39 in the radial direction of the through hole 10a is flush with the first contact surface 39. There is a second contact surface 41 that contacts the engine block 3 when attached to the internal combustion engine. The second contact surface 41 is formed by finishing by cutting using a first face mill 55 described later as a series of processing when processing the first contact surface 39.

In order to reduce the weight of the housing 6, a portion of the overhanging portion 38 between the first contact surface 39 and the second contact surface 41 is located closer to the opening 9 than the first and second contact surfaces 39, 41. Eight recessed meat steal portions 42a to 42h are provided.

In addition, parts of the housing 6 other than the first and second contact surfaces 39 and 41 and the surface 40 which are not processed, for example, the meat steal portions 42a to 42h and the

boss portions

33d and 33h, are adjacent to each other, and the first and second contact surfaces Casting surfaces formed by aluminum die casting are left in the

recesses

43 and 44 that are recessed toward the opening 9 side with respect to the

surfaces

39 and 41. The meat stealing portion 42a adjacent to the boss 33m and the

recesses

43 and 44 are portions to be clamped during the finishing process of the first and second contact surfaces 39 and 41 described later. Other parts having a casting surface other than the meat stealing part 42a and the recessed

parts

43 and 44 can also be clamped at the time of finishing the first and second contact surfaces 39 and 41.

FIG. 7 is a cross-sectional view of the housing 6 taken along the line BB in FIG.

As shown in FIG. 7, a groove portion 45 that avoids interference with the stepped portion 2b (see FIG. 2) provided on the crankshaft 2 is provided at a portion between the through hole 10a and the first contact surface 39. A recess is formed from the first contact surface 39 toward the recess 6a.

[Bottom up cut]
FIG. 8A is an explanatory view showing the positional relationship between the end mill 46 and the work material 47 stepwise when the upper surface 47a of the work material 47 is cut by the up-cut using the end mill 46, and FIG. FIG. 8B is a sectional view of the end mill 46 and the work material 47 taken along the line CC of FIG. 8A. In FIG. 8B, cross-sectional hatching of the spiral portion of the end mill 46 is omitted.

Below, as an example for explaining the upcut when processing the bottom surface 28 of the above-mentioned bottom wall portion 10 using the end mill 46, it is the upper surface of the work material 47 formed in a rectangular plate shape. A case of processing the upper surface 47a will be described.

The vertical axis 48 shown in FIG. 8A indicates a machining locus drawn by the rotation axis O of the end mill 46 when the end mill 46 cuts the workpiece 47. The rotation direction P of the end mill 46 is the clockwise direction in FIG. 8A, and the feed direction Q of the end mill 46 is the direction from the lower side to the upper side in FIG. 8A. As shown in FIG. 8A, the end mill 46 is arranged on the vertical axis 48, while the work material 47 is on the right side of the vertical axis 48 when viewed from the feed direction Q of the end mill 46. That is, it is arranged on the right side of the rotation axis O of the end mill 46.

The end mill 46 has a plurality of (four in the present embodiment) blade portions 46a due to the spiral shape formed at the tip thereof. The four blades 46a are provided at equal intervals in the rotation direction P of the end mill 46.

The work material 47 is formed in a rectangular plate shape, and has an edge portion 47b facing the end mill 46 in the direction of the vertical axis 48.

In the first step from the bottom of FIG. 8A, the tip surface 46b of the end mill 46 shown in FIG. 8B is located between the upper surface 47a and the lower surface 47c of the work material 47, and the blade portion 46a is the work material. The state before cutting the upper surface 47a of 47 is shown. When the end mill 46 is fed in the feed direction Q from the state of the first stage, as shown in the second stage from the bottom of FIG. 8A, one blade portion 46 a has a work material 47 facing the vertical axis 48. From the cutting start point 49 on the vertical side portion 47d, the edge portion 47b of the workpiece 47 is scooped into the edge portion 47b. After the blade portion 46a cuts the edge portion 47b, a new edge portion 47b is formed at a position adjacent to the cut edge portion 47b and the end mill 46 in the feed direction Q. Then, as shown in the third row from the bottom in FIG. 8A, the upper surface 47a is cut while sequentially scooping the edge portion 47b. At this time, the edge portion 47b scooped by the blade portion 46a is discharged as cutting chips (shown by a broken line in FIG. 8B) while being lifted obliquely upward as shown by an arrow R in FIG. 8B. .. Therefore, a cutting resistance (arrow S in FIG. 8B) that acts upward in the rotation axis direction of the end mill 46 acts on the end mill 46 along with the force generated when lifting the edge portion 47b.

As described above, when the end mill 46 rotates in the clockwise direction and the work material 47 is on the right side of the rotation axis O of the end mill 46 with respect to the feeding direction Q of the end mill 46, the end mill 46 moves upward. The cutting process in which the blade portion 46a sequentially scoops the edge portion 47b of the work material 47 while receiving the cutting resistance is defined as "upcut" of the upper surface (bottom surface) 47a. When the upper surface 47a is cut by the up-cut, the tool life of the end mill 46 becomes shorter than when the end mill 46 cuts the upper surface 47a by the down-cut described later.

[Down cut on the bottom]
FIG. 9A is an explanatory view showing the positional relationship between the end mill 46 and the work material 47 in stages when the upper surface 47a of the work material 47 is cut by the down mill using the end mill 46, and FIG. 9B is a cross-sectional view of the end mill 46 and the work material 47 taken along the line DD of FIG. 9A. In FIG. 9B as well, cross-sectional hatching of the spiral portion of the end mill 46 is omitted.

Below, as an example for explaining the down-cut when processing the bottom surface 28 of the bottom wall portion 10 using the end mill 46, the upper surface 47a, which is the upper surface of the work material 47 formed in a rectangular plate shape. A case of processing will be described.

In FIG. 9A, the end mill 46 is arranged on the vertical axis 48, while the work material 47 is on the left side of the vertical axis 48 when viewed from the feed direction Q of the end mill 46, that is, the end mill 46. Is arranged on the left side of the rotation axis O. The rotation direction P of the end mill 46 is the clockwise direction in FIG.

In the first step from the bottom of FIG. 9A, the tip surface 46b of the end mill 46 shown in FIG. 9B is located between the upper surface 47a and the lower surface 47c of the work material 47, and the blade portion 46a is the work material. The state before cutting the upper surface 47a of 47 is shown. When the end mill 46 is fed in the feeding direction Q from the state of the first stage, as shown in the second stage from the bottom of FIG. 9A, one blade portion 46 a has a work material 47 orthogonal to the vertical axis 48. The cutting start point 50 on the lower lateral side portion 47e cuts into the edge portion 47b of the work material 47 to cut the edge portion 47b. That is, the one blade portion 46a cuts into the edge portion 47b of the work material 47 from the cutting start point 50 on the horizontal side portion 47e located at the position where the radius of the end mill 46 is separated from the vertical axis 48, and the edge portion 47b is formed. To cut. After that, the end mill 46 is further fed in the feed direction Q, and the next blade portion 46a is offset in the feed direction Q of the end mill 46 from the cutting start point 50, as shown in the third stage from the bottom of FIG. 9(a). The work material 47 is cut at the position. Then, when this cutting is sequentially repeated, as shown in the fourth step from the bottom of FIG. 9A, the blade portion 46a is separated from the vertical axis 48 to the radius separation of the end mill 46 and parallel to the vertical axis 48. The flat surface 51 is cut. The blade portion 46a that cuts the flat surface 51 cuts the arc portion 52 shown by the arc-shaped broken line in FIG. 9A between the flat surface 51 and the vertical side portion 47f, and goes out to the vertical side portion 47f. At this time, the circular arc portion 52 cut by the blade portion 46a is discharged as chips (shown by a broken line in FIG. 9B) while being pushed down as shown by an arrow T in FIG. 9B. For this reason, a cutting resistance (arrow U in FIG. 9B) is applied to the end mill 46 in a downward direction of the rotation axis of the end mill 46 along with the force of pushing down the arc portion 52.

As described above, when the end mill 46 rotates in the clockwise direction and the work material 47 is on the left side of the rotation axis O of the end mill 46 with respect to the feed direction Q of the end mill 46, the end mill 46 faces downward. The cutting process in which the blade portion 46a sequentially pushes down the circular arc portion 52 of the work material 47 under the cutting resistance is defined as "down-cut" of the upper surface (bottom surface) 47a. In the cutting of the upper surface 47a by the down-cut, since the smooth arc portion 52 is cut after cutting the flat surface 51, compared with the up-cut cutting in which the edge portion 47b where the blade portion 46a easily bites is always scooped, the end mill 46 Tool life is extended.

[Side cut]
FIG. 10 is a perspective view showing the positional relationship between the end mill 46 and the work material 47 when the side surface 47g of the work material 47 is cut by the up mill using the end mill 46.

A case of processing the side surface 47g of the block-shaped work material 47 will be described below as an example for explaining the upcut when processing the side surface 11a of the peripheral wall portion 11 using the end mill 46.

In FIG. 10, the rotation direction P of the end mill 46 is the clockwise direction of FIG. 10, and the feed direction Q of the end mill 46 is the direction from the lower side of FIG. 10 to the diagonally upper right side. As shown in FIG. 10, the work material 47 is arranged on the left side of the rotation axis O of the end mill 46 when viewed in the feeding direction Q of the end mill 46. When the side surface 47g of the work material 47 thus arranged is cut by the end mill 46, the side surface 47g is cut so that the cutting edge portion 46c of the end mill 46 is always pressed against the side surface 47g.

As described above, when the end mill 46 rotates in the clockwise direction and the work material 47 is on the left side of the rotation axis O of the end mill 46 with respect to the feed direction Q of the end mill 46, the cutting edge portion of the end mill 46. The cutting process in which 46c is constantly pressed against the side surface 47g and bites is defined as "upcut" of the side surface 47g. When the side surface 47g is cut by up-cutting, the side surface 47g is cut while the cutting edge portion 46c is constantly pressed against the side surface 47g, so the cutting edge portion 46c of the end mill 46 is easily worn, and the tool of the end mill 46 for down cutting described later is used. Shorter than life.

[Side cut]
FIG. 11 is a perspective view showing a positional relationship between the end mill 46 and the work material 47 when the side surface 47g of the work material 47 is cut by the down mill using the end mill 46.

In FIG. 11, the rotation direction P of the end mill 46 is the clockwise direction of FIG. 11, and the feed direction Q of the end mill 46 is the direction from the lower side of FIG. 11 to the diagonally upper left side. As shown in FIG. 11, the work material 47 is arranged on the right side of the rotation axis O of the end mill 46 when viewed from the feed direction Q of the end mill 46. When the side surface 47g of the work material 47 arranged in this way is cut by the end mill 46, the cutting edge portion 46c of the end mill 46 cuts the side surface 47g so as to always escape from the side surface 47g.

As described above, when the end mill 46 rotates in the clockwise direction and the work material 47 is on the right side of the rotation axis O of the end mill 46 with respect to the feed direction Q of the end mill 46, the cutting edge portion of the end mill 46. The cutting process performed by 46c while always escaping from the side surface 47g is defined as "downcut" of the side surface 47g. In the cutting of the side surface 47g by the down cut, the contact of the blade tip portion 46c with the side surface 47g is weaker than in the cutting by the up cut, so that the blade tip portion 46c is less likely to be worn. Therefore, the tool life of the end mill 46 in the down cut becomes longer than the tool life of the end mill 46 in the up cut.

[Oil pump manufacturing method]
FIG. 12 is a process diagram showing one of the various processes of the method for manufacturing the oil pump 1, which is a roughing process of the bottom surface 28, the side surface 11 a, the opening end surface 32, etc. of the housing 6. FIG. 13 is a process diagram showing one of various processes of the method for manufacturing the oil pump 1 and showing a finishing process of the first and second contact surfaces 39, 41 of the housing 6. FIG. 14 is a process diagram showing one of various processes of the method for manufacturing the oil pump 1, which is a finishing process for the bottom face 28, the side face 11 a, the opening end face 32, etc. of the housing 6. The lower side of FIGS. 12 and 14 shows a plan view of the housing 6 as viewed from the opening 9 side, while the lower side of FIG. 13 shows a rear view of the housing 6. 12 to 14 are schematic sectional views of the housing 6 taken along the radial direction of the through hole 10a. Further, in FIGS. 12 to 14, the rotation direction P of the first end mill 53, the second face mill 54, and the first face mill 55, which are indicated by imaginary lines, is the clockwise direction.

First, the housing 6 in a material state formed by aluminum die casting is prepared, and a through hole 10a having a relatively large diameter is formed at the center of the bottom wall portion 10 by using a drilling tool such as a drill. deep. Further, a first positioning hole 57 into which the first positioning pin 56 for positioning is inserted is formed at a predetermined position of the opening end surface 32 of the housing 6 so as to penetrate therethrough. Further, a second positioning hole 59 into which the second positioning pin 58 for positioning is inserted is formed at a predetermined position of the overhanging portion 38 so as to penetrate therethrough. The first and second positioning pins 56, 58 are formed as rod-shaped positioning pins having a truncated cone-shaped positioning portion 60 at their tips. After the through hole 10a and the first and second positioning holes 57 and 59 are formed in the housing 6, the surface of the housing 6 other than the inner peripheral surface of the through hole 10a and the like becomes a casting surface formed by aluminum die casting. ing.

Next, in a roughing process of the bottom surface 28 of the housing 6 shown in FIG. 12, the housing 6 which is a member having the through hole 10a in the bottom wall portion 10 is not shown in a posture in which the opening 9 faces upward. Install inside. When the housing 6 is installed, the housing 6 is positioned on the processing equipment via the first and second positioning pins 56 and 58 inserted into the first and second positioning holes 57 and 59. For example, when the first positioning pin 56 is inserted into the first positioning hole 57, the positioning of the first positioning pin 56 is performed as shown in the frame 61 as a sectional view taken along line EE in FIG. The tip portion 60a of the portion 60 is arranged in the first positioning hole 57, and the inclined portion 60b of the positioning portion 60 is in contact with the lower edge of the first positioning hole 57.

After the housing 6 is installed, the clamp seats 37, which are formed at three predetermined locations on the outer peripheral portion of the housing 6 and have a casting surface, are clamped using the clamp device 62. The clamp device 62 is provided so as to be rotatable around the support pin 63, and has a rectangular plate-shaped pressing portion 64 that presses the surface 37 a of the clamp seat 37 on the side of the opening end surface 32, and the pressing portion 64. It has a clamp pin 65 for pressing a surface 37b of the clamp seat 37 opposite to the opening end surface 32. The clamp pin 65 has a shaft portion 65a and a truncated cone-shaped truncated cone-shaped end portion 65b formed integrally with one end portion of the shaft portion 65a. Further, the pressing force of the clamp pin 65 is appropriately adjusted by the air pressure supplied from an air supply source (not shown). The tip of the truncated cone-shaped end portion 65b has a circular contact surface 65c that can contact the surface 37b of the clamp seat 37 and has a smaller outer diameter than the shaft portion 65a. When the clamp device 62 clamps the clamp seat 37, as shown in the frame 70 as a cross-sectional view taken along line FF in FIG. The peripheral wall portion 11 is pressed against 64. In this state, the stress appropriately acts on the housing 6, and the bending of the bottom wall portion 10 is suppressed. In this way, the roughing process of FIG. 12 is performed using the surface 37b, which is the casting surface, as a processing certificate.

After the clamp seats 37 are clamped, the first and second positioning pins 56 and 58 are removed from the first and second positioning holes 57 and 59.

Next, using a drilling tool such as a drill, the knock pin hole 36 and the pivot pin hole (circular recess) 66 are processed into rough holes with relatively large dimensional tolerances. Further, in preparation for the insertion of the third and fourth positioning pins 67 and 68 in a later step described later, the first and second positioning holes 57 and 59 are finished by using a drill.

After the knock pin hole 36 and the like are machined, the first end mill 53 shown in phantom in FIG. 12 is used to roughly machine the peripheral portion 30, which is the bottom surface 28 around the through hole 10a, to a predetermined cutting depth. .. At the time of this roughing, from the inside of the through hole 10a, the rotation direction P of the first end mill 53 and the direction in which the first end mill 53 relatively circulates around the through hole 10a are the same direction. The first end mill 53 is rotated to roughly process the peripheral portion 30. That is, the first part is arranged so as to orbit the peripheral portion 30 in the clockwise direction in FIG. 12 (the feeding direction of the first end mill 53 shown by reference symbol V in FIG. 12) with respect to the housing 6 fixed by the three clamp devices 62. The peripheral part 30 is roughly processed by moving the end mill 53. At this time, the peripheral portion 30 is always on the left side with respect to the rotation axis O1 of the first end mill 53, and the first end mill 53 down-cuts the peripheral portion 30 roughly (FIGS. 9A and 9B). )reference).

After the peripheral portion 30 is rough-processed by the first end mill 53 for almost one round, as a series of rough machining, the peripheral-wall-adjacent portion 31, which is the bottom surface 28 adjacent to the peripheral-wall portion 11, and the peripheral-wall portion 11. The side surface 11a and the side surface 11a are simultaneously rough-machined with a predetermined cutting depth. During this rough machining, the peripheral wall adjoining portion 31 and the peripheral wall adjoining portion 31 are arranged so that the rotation direction P of the first end mill 53 and the direction in which the first end mill 53 relatively circulates around the through hole 10a are opposite. The side surface 11a is roughly processed. That is, the feed direction of the first end mill 53, which has been orbiting in the clockwise direction, is reversed, and the counterclockwise direction is shown with respect to the housing 6 fixed by the three clamp devices 62 (indicated by W in FIG. 12). By moving the first end mill 53 so as to orbit in the feeding direction of the first end mill 53), the peripheral wall adjacent portion 31 and the side surface 11a are roughly processed. At this time, the peripheral wall portion adjacent portion 31 is always on the right side with respect to the rotation axis O1 of the first end mill 53, and the first end mill 53 rough-machines the peripheral wall portion adjacent portion 31 by up-cutting (FIG. 8(a), See FIG. 8B). The side surface 11a is always on the right side with respect to the rotation axis O1 of the first end mill 53, and the first end mill 53 down-cuts the side surface 11a roughly (see FIG. 11).

Next, using the second face mill 54 (shown by an imaginary line in FIG. 12) having an outer diameter larger than that of the first end mill 53, the opening end surface 32 of the housing 6 and the overhanging portion 38 which are mating surfaces with the cover 8. Surface 38a is roughly processed. At the time of this rough processing, the second face mill 54 is moved from the diagonally lower left side of the housing 6 to the projecting portion 38 side as shown in the feeding direction indicated by X in FIG. The opening end surface 32 and the surface 38a are roughly processed so that the feeding direction of 54 is returned and returned to the opening 9 side.

Next, in the finishing process of the first and second contact surfaces 39, 41 of the housing 6 shown in FIG. 13, which is a process subsequent to the roughing process of the bottom surface 28 of the housing 6, etc., different from the processing equipment of FIG. The housing 6 is installed in the processing equipment with the opening 9 facing downward. When the housing 6 is installed, the housing 6 is positioned on the processing equipment via the cylindrical third and fourth positioning pins 67 and 68 inserted into the first and second positioning holes 57 and 59.

After the housing 6 is installed, instead of the above three clamp seats 37, three clamp portions having a casting surface provided at predetermined positions on the outer peripheral portion of the housing 6, that is, the meat steal portion 42a and the recess portions 43, 44 ( 6) is clamped by using each clamp device 62. In the finishing step of FIG. 13, the casting surface which is on the side opposite to the open end surface 32 of the recessed portion 43a and the recessed

portions

43 and 44 with which the contact surface 65c of the clamping pin 65 abuts serves as a machining certificate.

Next, the first face mill 55 is used to roughly process the first and second contact surfaces 39, 41 with a predetermined cutting depth. At the time of this rough machining, the first face mill 55 is moved from the left side of the first positioning hole 57 to the overhanging portion 38 side as in the feeding direction indicated by symbol Y in FIG. , The second contact surfaces 39, 41 are roughly processed.

After the roughing process of the first and second contact surfaces 39, 41, the knock pin hole 36 and the pivot pin hole 66 are processed into a rough hole having a smaller dimensional tolerance than the roughing process of FIG. 12 using a drill.

After processing the knock pin hole 36 and the pivot pin hole 66, the first face mill 55 is used to finish the first and second contact surfaces 39, 41 with a predetermined cutting depth. In this finishing process, the first face mill 55 is moved in the feed direction Y similar to the roughing process of the first and second contact surfaces 39, 41.

After finishing the first and second contact surfaces 39 and 41, the surface 37b having the casting surface on the first and second contact surfaces 39 and 41 of the clamp seat 37 is flattened by using, for example, the first end mill 53. Finish the surface. As a result, the first and second contact surfaces 39, 41 and the surface 37b are parallel to each other.

Next, in the finishing process of the bottom surface 28 of the housing 6 shown in FIG. 14 which is a post-process of the finishing process of the first and second contact surfaces 39, 41 of the housing 6, the processing equipment shown in FIGS. The housing 6 is installed in a different processing facility with the opening 9 facing upward. When the housing 6 is installed, the housing 6 is positioned on the processing equipment via the third and fourth positioning pins 67 and 68 inserted into the first and second positioning holes 57 and 59.

After the housing 6 is installed, each clamp seat 37 is clamped using each clamp device 62. In the step of FIG. 13, the flat surface 37b formed in the finishing step of the first and second contact surfaces 39, 41 serves as a processing certificate.

After each clamp seat 37 is clamped, a knock is used to finish the knock pin hole 36 and the pivot pin hole 66 into high-precision holes with small dimensional tolerances.

Next, the first end mill 53 is used to finish the peripheral portion 30 of the bottom surface 28 with a predetermined cutting depth. At the time of this finishing process, as in the roughing process of the bottom surface 28 of the housing 6 and the like, the peripheral portion 30 is moved in the clockwise direction (feeding direction) of FIG. The first end mill 53 is moved so as to orbit V). At this time, the first end mill 53 finishes the peripheral portion 30 by down-cutting similarly to the roughing process of the bottom surface 28 of the housing 6 (see FIGS. 9A and 9B).

After the peripheral portion 30 has been finished by the first end mill 53 almost once, the peripheral wall adjacent portion 31 and the side surface 11a are simultaneously finished as a series of finishing operations. At the time of this finishing process, as in the roughing process of the bottom surface 28 of the housing 6 and the like, the feeding direction of the first end mill 53 that has been orbiting in the clockwise direction is reversed and fixed by the three clamp devices 62. The first end mill 53 is moved so as to rotate in the counterclockwise direction (feeding direction W) with respect to the thus-formed housing 6. At this time, the first end mill 53 finishes the peripheral wall adjoining portion 31 by up-cutting similarly to the roughing process of the bottom surface 28 of the housing 6 (see FIGS. 8A and 8B). At the same time, the first end mill 53 finishes the side surface 11a by down-cutting similarly to the roughing process of the bottom surface 28 of the housing 6 (see FIG. 11).

After finishing the peripheral portion 30, the peripheral wall portion adjacent portion 31 and the side surface 11a with a predetermined cutting depth, the peripheral portion 30, the peripheral wall is zero-cut using the first end mill 53 in the same machining trajectory as this finishing processing. The part adjacent part 31 and the side surface 11a are finished again. Here, the "zero cut" is a cutting process performed with a cutting depth of 0 mm, and removes residual stress generated in the peripheral portion 30, the peripheral wall portion adjacent portion 31 and the side surface 11a during the processing in the previous step. However, the flatness of the peripheral portion 30 and the like is stabilized.

After the finishing with the zero cut, the opening face 32 of the housing 6 and the surface 38a of the overhanging portion 38 are finished with a predetermined cutting depth using the first face mill 55. At the time of this finishing process, the first face mill 55 is moved from the diagonally lower left side of the opening 9 to the projecting portion 38 side, as in the feeding direction indicated by symbol Z in FIG.

The roughing and finishing of the housing 6 are performed while appropriately supplying the coolant from a nozzle (not shown) provided in the processing equipment to the cutting edge portion of the peripheral portion 30 and the first end mill 53. Moreover, the coolant may be supplied to the peripheral portion 30 and the like through an oil passage provided inside the first end mill 53 and the like.

After finishing the opening end face 32, the opening end face 32 of the housing 6 and the overhanging portion 38 are provided with a female screw hole 34 (see FIG. 5) for attaching the cover 8 and a bolt insertion hole 35 for attachment to the engine block 3. (See FIG. 5) is formed using a drill.

Then, the pump component 7 including the rotor 12 and the like is housed in the recess 6a of the housing 6, and the cover 8 is covered to close the opening 9 of the recess 6a. When the cover 8 is put on, the cover 8 is positioned with respect to the housing 6 via the knock pin press-fitted into the knock pin hole 36 formed in the opening end surface 32 of the housing 6 and the pivot pin 20 inserted into the pivot pin hole 66. .. After the opening 9 is closed, the cover 8 is attached and fixed to the housing 6 by screwing the bolts 17 into the female screw holes 34 of the housing 6 through the bolt through holes formed in the cover 8.

[Effect of this embodiment]
FIG. 15 is a process diagram showing a finish processing step of a conventional surface processing method for the recess 6 a of the housing 6.

In the finishing process of the prior art, in consideration of extending the tool life of the end mill 46 by cutting the side face 11a by down-cutting when processing the side face 11a of the peripheral wall portion 11, in the rotation direction P of the end mill 46. On the other hand, the bottom surface 28 and the side surface 11a were processed so that the orbiting direction of the end mill 46 was reversed. That is, the end mill 46, which rotates in the rotation direction P, is made to make almost one revolution in the counterclockwise direction in FIG. 15 from the inside of the through hole 10a, as in the feeding direction indicated by reference character G in FIG. The peripheral wall adjoining portion 31 and the side surface 11a were processed by rotating the peripheral wall portion approximately once in the counterclockwise direction.

However, in the processing in the counterclockwise direction as described above, the side surface 11a can be cut by the down cut, but the peripheral portion 30 and the peripheral wall portion adjacent portion 31 are cut by the up cut. More specifically, the peripheral portion 30 and the peripheral wall portion adjacent portion 31 are always on the right side with respect to the rotation axis O of the end mill 46, and the end mill 46 cuts the peripheral portion 30 and the peripheral wall portion adjacent portion 31 by up-cutting (FIG. 8(a) and FIG. 8(b)). At the time of cutting with the up-cut, the blade portion of the end mill 46 bites into the edge portion so as to scoop the edge portion of the peripheral portion 30 and the peripheral wall portion adjoining portion 31, so that the edge portion scooped by the blade portion is slanted. Can be lifted up. Along with this, the end mill 46 receives cutting resistance upward in the rotation axis direction of the end mill 46, and therefore, the peripheral portion 30 and the peripheral wall portion adjacent portion 31 are lifted and cut. Then, when the end mill 46 is removed from the housing 6 after cutting the peripheral portion 30 and the peripheral wall adjacent portion 31, the bottom wall portion 10 made of an aluminum alloy material is returned and deformed by the reaction force of the cutting resistance upward in the rotation axis direction. , Will bend toward the side opposite to the opening 9. As a result, the flatness of the bottom surface 28 of the recess 6a cannot be ensured, and the sealing performance of the hydraulic oil chamber formed inside the housing 6 may deteriorate.

Further, when the end mill 46 cuts the peripheral portion 30 by up-cutting, it cuts by cutting into the edge portion which is the hole edge of the peripheral portion 30, so that the wear amount of the blade portion of the end mill 46 increases and the tool life of the end mill 46 increases. There was a problem of getting worse.

In contrast to the above-described conventional technique, in the present embodiment, when processing the peripheral portion 30, the rotation direction P of the first end mill 53 and the direction in which the first end mill 53 relatively circulates around the through hole 10a are the same. The peripheral portion 30 is processed so as to be oriented. That is, when the peripheral portion 30 is processed, the peripheral portion 30 is processed by causing the first end mill 53, which rotates in the clockwise direction, to rotate in the clockwise direction around the through hole 10a. As a result, the peripheral portion 30 is always on the left side with respect to the rotation axis O1 of the first end mill 53, and the first end mill 53 processes the peripheral portion 30 by down-cutting. At this time, the first end mill 53 cuts the peripheral portion 30 while receiving the downward cutting resistance in the rotation axis direction, but the downward cutting resistance in the rotation axis direction is smaller than the upward cutting resistance in the rotation axis direction in the upcut. Therefore, it is difficult to deform the bottom wall portion 10. Therefore, the bending of the bottom wall portion 10 when the first end mill 53 is detached from the housing 6 is minimized, and the appropriate flatness of the bottom surface 28 can be secured. Therefore, the sealing performance of the hydraulic oil chamber 21 formed inside the housing 6 can be improved.

Further, when the peripheral portion 30 is cut by down-cutting, the blade portion of the first end mill 53 cuts the smooth arc portion 52 (see FIG. 9A), so the amount of wear of the blade portion is suppressed. Therefore, the tool life of the first end mill 53 can be extended as compared with the up-cutting in which the edge portion where the blade portion easily bites is sequentially cut.

Furthermore, in the present embodiment, the side surface 11a of the peripheral wall portion 11 is arranged so that the rotation direction P of the first end mill 53 and the direction in which the first end mill 53 relatively circulates around the through hole 10a are opposite. To process. That is, when processing the side surface 11a, the side surface 11a is processed by orbiting the first end mill 53 rotating in the clockwise direction around the through hole 10a in the counterclockwise direction. As a result, the first end mill 53 processes the side surface 11a by down-cutting in a state where the side surface 11a is always on the right side with respect to the rotation axis O1 of the first end mill 53. Therefore, the tool life of the first end mill 53 can be extended as compared with the case where the side surface 11a is machined by upcut.

Further, in the present embodiment, at the same time when the side surface 11a of the peripheral wall portion 11 is cut, the peripheral wall adjacent portion 31, which is a part of the bottom surface 28, is cut by up-cutting. However, since the peripheral wall portion adjacent portion 31 is continuous with the peripheral wall portion 11, the peripheral wall portion adjacent portion 31 has a higher rigidity than the peripheral portion 30, and the lifting by the blade portion 46a of the first end mill 53 is suppressed. Therefore, the return deformation of the bottom wall portion 10 when the first end mill 53 is detached is suppressed, and the appropriate flatness of the bottom surface 28 can be secured. Further, in the processing of the peripheral wall adjacent portion 31, since the edge portion of the hole edge of the through hole 10a does not enter from the inside of the through hole 10a like the peripheral portion 30 and is not cut from the beginning of the processing, Compared with the processing, the first end mill 53 does not apply an excessive load. Also from this point, the return deformation of the bottom wall portion 10 is suppressed, and the appropriate flatness of the bottom surface 28 can be secured.

Further, in the present embodiment, since the plurality of clamp seats 37 on the outer peripheral portion of the housing 6 are clamped, an appropriate stress is applied to the bottom wall portion 10 via the peripheral wall portion 11 by the clamp, and the bottom wall portion 10 is not bent. The bottom surface 28 of the bottom wall portion 10 can be cut in the suppressed state. Therefore, the deformation of the bottom wall portion 10 is suppressed, and the flatness of the bottom surface 28 is improved. Thereby, the sealing property of the hydraulic oil chamber 21 can be improved.

Further, in the present embodiment, the bottom surface 28 of the bottom wall portion 10 of the housing 6 is roughly machined before the first contact surface 39 on the rear surface side of the housing 6 is machined. When cutting the first contact surface 39, residual stress is generated in the thin bottom wall portion 10, and the bottom wall portion 10 is easily deformed. In order to suppress the deformation of the bottom wall portion 10, it is necessary to minimize the finishing allowance when cutting the first contact surface 39 and reduce the residual stress generated in the bottom wall portion 10 during the cutting process. Therefore, by roughing the bottom surface 28 of the bottom wall portion 10 before cutting the first contact surface 39, the finishing allowance when cutting the first contact surface 39 is minimized and the residual stress is reduced. You can

Further, in the present embodiment, after the first contact surface 39 is cut by the first face mill 55, the bottom surface 28 is finished. That is, after the first contact surface 39 is cut with a small residual stress, the bottom surface 28, which is the final step, is finished. Therefore, even in the finishing process of the bottom surface 28, the cutting can be performed with a small residual stress, and the deformation of the bottom wall portion 10 can be suppressed.

Further, in the present embodiment, the opening end surface 32 of the housing 6, which is the contact surface with the cover 8, is cut after the bottom surface 28 of the bottom wall portion 10 is processed. The bottom surface 28 of the bottom wall portion 10 is formed to have a relatively large area in consideration of the swing of the cam ring 14, while the opening end surface 32 has a smaller area than the bottom surface 28. When the bottom surface 28 having a large area is processed, the housing 6 is more likely to be deformed than when the opening end surface 32 having a small area is processed. If the bottom surface 28 is cut after cutting the opening end surface 32 that is the contact surface with the cover 8, the opening end surface 32 tilts due to the deformation of the housing 6 due to the processing of the bottom wall portion 10, and the bottom surface 28 is cut. There is a possibility that proper contact cannot be maintained. Therefore, by cutting the bottom surface 28 of the bottom wall portion 10 that is likely to be deformed and then cutting the opening end surface 32, it is possible to ensure high contact accuracy with the cover 8.

The opening end surface 32 is continuous with the surface 38a of the protruding portion 38 protruding from the peripheral wall portion 11, and the surface 38a is processed as a series of processing for processing the opening end surface 32. Since it is relatively difficult to machine the flatness of the surface 38a of the projecting portion 38 in addition to the flatness of the opening end surface 32 with high accuracy, it is easy to deform the bottom surface 28 of the bottom wall portion 28. By processing the opening end surface 32 and the surface 38a by a series of processing after the processing of, it is possible to secure high flatness of the surface 38a.

[Other problems of this embodiment]
FIG. 16 is a cross-sectional view of the housing 6 and the like showing a solution to another problem of the present embodiment.

As described above, the peripheral portion 30 of the bottom surface 28 is cut by the down cutting while the first end mill 53 receives the downward cutting resistance in the rotation axis direction. The bottom wall portion 10 may be slightly bent toward the side opposite to the opening portion 9 as shown on the upper side of FIG. At this time, with the bending of the bottom wall portion 10, the first contact surface 39 of the bottom wall portion 10 also slightly bends toward the side opposite to the opening 9.

Therefore, in order to suppress the bending of the bottom wall portion 10, as shown in the lower side of FIG. 16, the bent first contact surface 39 of the housing 6 in the state where the pump structure 7 is housed in the recess 6a. Is pressed against the flat mounting surface 3a of the engine block 3, and the housing 6 is mounted and fixed to the engine block 3 via the bolts 18. Thereby, the first contact surface 39 is pressed by the fastening force of the bolt 18 so as to follow the flat mounting surface 3 a, and the bottom wall portion 10 is corrected by the engine block 3. As a result, an appropriate flatness of the bottom surface 28 can be ensured, and the sealing performance of the hydraulic oil chamber 21 formed inside the housing 6 can be improved.

In the above embodiment, an example in which the surface processing of the housing 6 is performed by moving the first end mill 53 and the like with respect to the housing 6 fixed by the clamp seat 37 is disclosed. However, the first end mill 53 in the fixed state is disclosed. The surface processing of the housing 6 may be performed by moving the housing 6 with respect to the above.

As a surface processing method for a member having a through hole in a recess based on the embodiment described above, for example, the following modes are conceivable.

The surface processing method of processing the inner surface of the recess of the member having a through hole in the bottom wall of the recess using an end mill, as one aspect thereof, the rotation direction of the end mill, and the end mill around the through hole. The peripheral portion of the through hole is processed so that the direction of relative rotation is the same, and the rotation direction of the end mill and the direction of relative rotation of the end mill around the through hole are opposite. The side surface of the recess is processed so as to be oriented.

In a preferred aspect of the surface processing method, the end mill cuts the peripheral portion while moving around the peripheral portion of the through hole.

In another preferred aspect, in any one of the aspects of the surface processing method, the end mill makes one revolution around the peripheral portion of the through hole, and then reverses the traveling direction in the opposite direction to the side surface side of the recess. Orbit around.

Further, as a method for manufacturing an oil pump based on the above-described embodiment, for example, the following modes are possible.

In one aspect of the method for manufacturing an oil pump, a housing having a recess having a through hole at the bottom is formed of a metal material, and a rotation direction of an end mill that processes the inner surface of the recess and the circumference of the through hole are provided. The peripheral portion of the through hole is processed so that the direction in which the end mill relatively circulates is the same direction, the rotation direction of the end mill, and the direction in which the end mill relatively circulates around the through hole. The side surface of the concave portion is processed so that the direction of the concave portion is opposite to that of the concave portion.

In a preferred aspect of the method for manufacturing the oil pump, when processing the inner surface of the recess, a plurality of locations on the outer peripheral portion of the housing are clamped for processing.

In another preferable aspect, in any one of the aspects of the method of manufacturing the oil pump, the mating member is attached to a mating member on a surface of the housing opposite to the opening of the recess. A contact surface is provided for contacting with, the contact surface is cut by a face mill, and the bottom surface of the recess is cut by the end mill.

In another preferable aspect, in any one of the aspects of the method of manufacturing the oil pump, the bottom surface of the recess of the housing is cut before the contact surface is cut.

In another preferable aspect, in any one of the aspects of the method for manufacturing the oil pump, the contact surface of the housing with the cover is cut after the bottom surface of the recess is cut.

Further, as the oil pump based on the embodiment described above, for example, the following modes are possible.

As one aspect thereof, the oil pump is provided with a recess having a through hole into which a drive shaft is inserted in the bottom wall and a surface opposite to the opening of the recess, and when mounted on a mating member. The mating member is provided with a contact surface that comes into contact with the mating member, and a plurality of mounting portions that are provided on an outer peripheral portion of the mating member and that are mounted to the mating member via a fixing member. A housing made of an aluminum alloy that is bent toward the member side, and a drive shaft that is disposed in the recess and inserted into the through hole, are rotationally driven to discharge the fluid sucked from the suction portion. And a cover provided with an insertion hole into which the drive shaft is inserted and closing the opening of the recess.

In a preferred aspect of the oil pump, the fixing member is a bolt, and the mounting portion is a bolt insertion hole into which the bolt is inserted.

In another preferred aspect, in any one of the aspects of the oil pump, the pump structure is configured such that a rotor fixed to the drive shaft rotates to change volumes of a plurality of hydraulic oil chambers and thereby the suction portion. The fluid sucked in from is discharged from the discharge portion, and the bottom surface of the recess forms a part of the hydraulic oil chamber.

In another preferred aspect, in any one of the aspects of the oil pump, the pump structure has a swing member capable of swinging in the recess, and the swing amount of the swing member causes the discharge amount to change. Is variable.

Claims

A surface processing method for processing the inner surface of the recess of a member having a through hole in the bottom wall of the recess using an end mill,
The peripheral direction of the through hole is processed so that the rotation direction of the end mill and the direction in which the end mill relatively circulates around the through hole are the same direction,
A member having a through hole in the recess, characterized in that the side surface of the recess is processed so that the rotation direction of the end mill and the direction in which the end mill relatively circulates around the through hole are opposite directions. Surface treatment method.
The surface processing method for a member having a through hole in a recess according to claim 1, wherein the end mill cuts the peripheral portion while moving around the peripheral portion of the through hole.
The said end mill circulates the said peripheral part of the said through-hole once, and after reversing the advancing direction, it circulates the said side surface side of the said recessed part, It penetrates the recessed part of Claim 2 characterized by the above-mentioned. A surface processing method for a member having holes.
A housing provided with a recess having a through hole in the bottom wall is molded of a metal material,
The rotation direction of the end mill that processes the inner surface of the recess is such that the direction in which the end mill relatively circulates around the through hole is the same direction, and the peripheral portion of the through hole is processed.
The side surface of the recess is processed so that the rotation direction of the end mill and the direction in which the end mill relatively circulates around the through hole are opposite directions,
Assembling the pump structure in the recess,
A method for manufacturing an oil pump, characterized in that the opening of the recess is closed by a cover.
The method for manufacturing an oil pump according to claim 4, wherein when the inner surface of the recess is machined, a plurality of locations on the outer periphery of the housing are clamped and machined.
A contact surface that comes into contact with the mating member when attached to the mating member is provided on the surface of the housing opposite to the opening of the recess, and the contact surface is formed by a face mill. Cutting,
The method of manufacturing an oil pump according to claim 4, wherein the bottom surface of the recess is cut by the end mill.
The method for manufacturing an oil pump according to claim 6, wherein the bottom surface of the recess of the housing is cut before the contact surface is cut.
The method of manufacturing an oil pump according to claim 4, wherein the contact surface of the housing with the cover is cut after the bottom surface of the recess is cut.
A recess having a through hole in the bottom wall for inserting the drive shaft, and a contact surface provided on the surface opposite to the opening of the recess and contacting the mating member when attached to the mating member. And a plurality of mounting portions provided on the outer peripheral portion of the contact surface and mounted on the mating member via a fixing member, wherein the bottom wall portion is formed to bend toward the mating member side. Aluminum alloy housing,
A pump structure that is disposed in the recess and is rotationally driven by the drive shaft that is inserted into the through hole, and that discharges the fluid sucked from the suction portion from the discharge portion;
An insertion hole into which the drive shaft is inserted is provided, and a cover that closes the opening of the recess,
An oil pump characterized by having.
The oil pump according to claim 9, wherein the fixing member is a bolt, and the mounting portion is a bolt insertion hole into which the bolt is inserted.
The pump component is configured to discharge the fluid sucked from the suction part from the discharge part by changing the volumes of the plurality of hydraulic oil chambers by the rotation of the rotor fixed to the drive shaft, The oil pump according to claim 10, wherein a bottom surface of the concave portion constitutes a part of the hydraulic oil chamber.
The oil according to claim 11, wherein the pump structure has a swinging member capable of swinging in the recess, and the swinging member swings to change the discharge amount. pump.