JP5622033B2 - Fluid pump - Google Patents

Description

  The present invention provides a rotor provided on one side of a rotary shaft, a pump rotor provided on the other side of the rotary shaft and capable of rotating synchronously with the rotor, the rotary shaft, the rotor, and the pump The present invention relates to a fluid pump that includes a rotor, a stator that drives the rotor, and a housing that is provided with a shaft support portion that supports the rotation shaft.

  In such a fluid pump, a rotor is driven by a stator, and a pump rotor connected to the rotor via a rotating shaft rotates synchronously to pump fluid.

  These rotors, rotating shafts, and pump rotors need to be compactly configured for mounting inside the fluid pump. Further, from the viewpoint of economy, it is preferable to configure with a small number of parts. Therefore, in a conventional pump, for example, a rotor and a pump rotor are configured to be press-fitted into a rotating shaft. (For example, refer to Patent Document 1).

JP 2003-269345 A

  When a rotor or a pump rotor is press-fitted into the rotation shaft, for example, a press-fitting hole formed in the pump rotor is expanded by the rotation shaft. At this time, the base material around the hole is subjected to plastic deformation. Therefore, when the press-fitting operation of the rotating shaft is not appropriate, there arises a disadvantage that the rotating shaft is attached with an inclination with respect to the rotating surface of the pump rotor.

As a result, the rotation of the pump rotor is not smooth when the fluid pump is driven, and the performance of the fluid pump cannot be fully exhibited.
In addition, even when the rotation function can be maintained, the pump rotor may interfere with any part of the housing to generate abnormal noise, and the long-term use may cause inconveniences such as wear of the specific part.
Furthermore, in press-fitting work, both the pump rotor and the rotary shaft must be fitted while accurately positioned, and the press-fitting work itself is complicated.
Thus, in order to improve the performance of the fluid pump and improve the production efficiency, there are still points to be improved regarding the structure of the pump rotor, the rotating shaft, and the like.

  An object of the present invention is to provide a fluid pump that has a simple structure, is excellent in assembly workability, and can exhibit stable performance.

A first characteristic configuration of the present invention includes a rotor provided on one side of a rotary shaft, a pump rotor provided on the other side of the rotary shaft and capable of rotating synchronously with the rotor, the rotary shaft, and the rotation And a housing including the pump rotor and a stator that drives the rotor, and a housing provided with a shaft support portion that pivotally supports the rotating shaft. An engagement hole and an engagement shaft portion that can change the extending direction or the extending direction of the rotating shaft with respect to the rotor are separately formed in the pump rotor and the rotating shaft, and the pump rotor in the rotating shaft is formed. The first hole portion is located between the front and back surfaces of the pump rotor, and the engagement hole has a flat portion along the axial direction on one end side and is engageable with the engagement shaft portion. And a part of the housing is inserted on the other end side. In that it has a circular cross section of the second hole portion to be.

  According to this configuration, the pump rotor and the rotating shaft are connected by engaging the engagement hole provided in the pump rotor and the engaging shaft portion provided in the rotating shaft. For this reason, when the rotating shaft rotates, the extending direction or extending direction of the rotating shaft with respect to the pump rotor can be changed within a predetermined range. Usually, the pump rotor rotates in a state in which the variation of the rotation surface is restricted by the members constituting the pump rotor housing. Therefore, with the rotation shaft mounting structure of this configuration, even if the arrangement direction of the rotation shaft is slightly inclined with respect to the rotation plane of the pump rotor, the rotation drive from the rotation shaft is smoothly performed to the pump rotor. Can be communicated to. If the rotating operation is smooth, the discharge capacity of the fluid pump is sufficiently secured, and the occurrence of abnormal noise or the like is suppressed.

Further, with this configuration that does not employ a press-fitting configuration, the assembly work of the pump rotor is greatly simplified. Furthermore, there is no possibility of slipping in the press-fitted portion due to long-term use, and the durability is excellent.
In the fluid pump of the present invention, since the driving force of the rotating shaft is transmitted to the pump rotor by the engagement structure, it is not necessary that the rotating shaft and the pump rotor are firmly fixed as in the conventional structure. . Therefore, as in this configuration, even if the end surface of the rotating shaft is configured to be within the thickness of the pump rotor, the rotation transmission function is secured. If the length of the rotating shaft is shortened as in this configuration, the overall weight is reduced, the moment of inertia of the rotating portion is reduced, and an improvement in rotational performance can be expected.
In addition, since the contact area between the pump rotor and the rotating shaft is reduced, the sliding resistance is reduced even when the rotating shaft slightly swings with respect to the rotating surface of the pump rotor, resulting in smoothness. Rotational characteristics can be obtained.
Furthermore, even if the rotary shaft slides in the axial direction with respect to the pump rotor during rotational driving, it is reliably prevented that the rotary shaft interferes with the wall of the housing, etc., and vibration and noise are generated. It can also be prevented.

  The second characteristic configuration of the present invention is that the housing is provided with one spherical regulating portion that comes into contact with a central portion of an end surface of the rotating shaft on the rotor side.

  According to this configuration, the restricting portion can restrict the rotation shaft from moving from the contact position of the rotation shaft to the housing side while allowing the rotation shaft to rotate. Therefore, for example, it is possible to prevent the performance of the fluid pump from deteriorating due to the axial displacement of the rotor relative to the stator, and to prevent the fluid pump from generating abnormal noise or impact due to the rotation shaft contacting the housing. Can do.

  Since the restricting portion of this configuration is formed in a spherical shape, the restricting portion makes point contact with the center portion of the end surface of the rotating shaft on the rotor side. Therefore, it is possible to reduce the sliding resistance between the restricting portion and the rotating shaft and prevent the fluid pump from generating abnormal noise or impact.

According to a third characteristic configuration of the present invention, the housing includes a pump housing having a pump chamber that houses the pump rotor, and a cover that can close the pump chamber, and the cover is engaged with the pump rotor. It is in the point provided with the convex part inserted in the hole.

  In the fluid pump of the present invention, a situation in which the rotation of the pump rotor is not stable may occur as a result of the engagement flexibility between the pump rotor and the rotating shaft. Therefore, as in the present configuration, by providing the housing cover with a convex portion that is inserted into the engagement hole of the pump rotor, the rotation axis of the pump rotor is reliably prevented from being eccentric. As a result, a fluid pump capable of smooth rotational driving can be obtained.

It is sectional drawing which shows the fluid pump in 1st Embodiment. It is II-II arrow sectional drawing of FIG. It is an exploded sectional view showing the fluid pump in a 1st embodiment. It is a disassembled perspective view which shows the fluid pump in 1st Embodiment. It is sectional drawing which shows the fluid pump in 2nd Embodiment.

[First Embodiment]
Hereinafter, an electric oil pump 1 as an example of a fluid pump according to the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view of an electric oil pump. FIG. 2 is a cross-sectional view taken along the line II-II in FIG. FIG. 3 is an exploded sectional view showing the electric oil pump. FIG. 4 is an exploded perspective view showing the electric oil pump.

  The electric oil pump 1 pumps oil from, for example, an oil pan or an oil tank (not shown) and pumps it to a lubricating part (not shown) of the engine. This electric oil pump 1 is configured by assembling a motor housing 3 (an example of a housing) to a pump housing 2 (an example of a housing).

  The pump housing 2 is made of metal, and includes a main body 4 that opens on one side (the right side in FIG. 1), and a cover 5 that can open and close the opening. Thus, a substantially cylindrical pump chamber 7 for accommodating the pump rotor 6 is formed between the main body 4 and the cover 5.

  The main body portion 4 is formed with a shaft support portion 11 that supports an intermediate portion of the rotation shaft 10. A cylindrical convex portion 12 is formed on the other side surface (left side surface in FIG. 1) of the main body portion 4. Inside the convex portion 12, an oil seal 13 that is adjacent to the shaft support portion 11 and blocks leakage of oil supplied to the shaft support portion 11 is provided.

  The pump rotor 6 is made of metal, and has an inner rotor 21 attached to one end portion (right end portion in FIG. 1) of the rotating shaft 10, and a ring-shaped outer rotor 22 disposed on the outer side of the inner rotor 21. It is equipped with.

  A plurality of external teeth 23 are formed on the outer peripheral portion of the inner rotor 21. A plurality of inner teeth 24 that mesh with a plurality of outer teeth 23 of the inner rotor 21 are formed on the inner peripheral portion of the outer rotor 22. The outer rotor 22 is eccentrically arranged with respect to the rotating shaft 10 of the inner rotor 21. The outer peripheral surface of the outer rotor 22 is configured to be slidable in close contact with the inner peripheral surface of the pump chamber 7. One side surface (the right side surface in FIG. 1) of the outer rotor 22 is in close contact with one side surface of the pump chamber 7, and the other side surface of the outer rotor 22 is configured to be slidable in close contact with the other side surface of the pump chamber 7. .

  The number of teeth of the outer teeth 23 of the inner rotor 21 is one less than the number of teeth of the inner teeth 24 of the outer rotor 22. Thereby, a plurality of working chambers 25 are formed between the outer teeth 23 of the inner rotor 21 and the inner teeth 24 of the outer rotor 22. The volume of each working chamber 25 changes as the inner rotor 21 and the outer rotor 22 rotate.

The cover 5 includes a cover-side suction chamber 26 communicating with an upper working chamber 25a (a working chamber 25a located in a substantially upper half region in FIG. 2) and a lower working chamber 25b (a substantially lower half in FIG. 2). A discharge chamber 27 on the cover side communicating with the working chamber 25b) located in the region is formed.
Although not described in detail, a suction path is connected to the suction chamber 26 on the cover side, and a discharge path is connected to the discharge chamber 27 on the cover side.

  A main body side suction chamber 28 communicating with the upper working chamber 25a and a main body side discharge chamber 29 communicating with the lower working chamber 25b are formed in the main body portion 4, respectively.

  As shown in FIG. 2, when the inner rotor 21 and the outer rotor 22 rotate counterclockwise, the volume of the upper working chamber 25 a increases as the rotors 21 and 22 rotate. As a result, a negative pressure is generated in the upper working chamber 25a, and the oil in the lubricating portion of the engine is sucked into the upper working chamber 25a and the suction chambers 26 and 28 through the suction passage.

  Further, the volume of the lower working chamber 25 b decreases as the rotors 21 and 22 rotate. As a result, a positive pressure is generated in the lower working chamber 25b, and the oil in the lower working chamber 25b and the discharge chambers 27 and 29 is discharged at a predetermined discharge pressure to the lubricating portion of the engine through the discharge passage. The

  The motor housing 3 is made of resin, and includes a motor cover 42 that houses the motor 41 and a driver housing portion 44 that houses a driver 43 that controls the operation of the motor 41.

  A stator 45 of the motor 41 is installed on the inner periphery of the motor cover 42. The motor cover 42 is open on one side, and the opening of the motor cover 42 is extrapolated to the convex portion 12 of the main body 4. The motor cover 42, the main body 4 and the cover 5 are coupled together by bolts. Thus, a substantially cylindrical motor chamber 47 that accommodates the rotor 46 of the motor 41 is formed between the main body 4 and the motor cover 42.

  A rotor 46 is located on the inner peripheral side of the stator 45, and the rotor 46 can be driven by the stator 45. When the rotor 46 is driven, the rotor 46 and the pump rotor 6 rotate synchronously, and oil is pumped.

  The rotor 46 includes a metal back yoke 48 attached to the other end portion (left end portion in FIG. 1) of the rotating shaft 10 and a permanent magnet 49 attached to the outer peripheral portion of the back yoke 48. Yes. The rotating shaft 10 is attached by press-fitting the other end of the rotating shaft 10 into the rotor 46.

  A recess 50 is formed at the center of the bottom of the motor housing 3, and the other steel ball 51 (the other steel ball 51 abutting against the center of the other end surface (left end surface in FIG. 1) of the rotation shaft 46 is formed in the recess 50. An example of a regulation part) is provided.

  Accordingly, the steel ball 51 restricts the movement of the rotating shaft 10 from the contact position of the rotating shaft 10 toward the bottom side of the motor housing 3 while allowing the rotating shaft 10 to rotate. Therefore, the stator 45 and the rotor 46 are displaced in the axial direction to deteriorate the performance of the fluid pump, or the rotating shaft 10 comes into contact with the motor housing 3 to generate a noise or an impact on the fluid pump. This prevents the back yoke 48 from slidingly contacting the resin motor housing 3 and causing the motor housing 3 to wear.

Hereinafter, the structure which attaches a pump rotor to a rotating shaft is demonstrated.
An engagement shaft portion 61 is formed at one end of the rotating shaft 10, and an engagement hole 62 into which the engagement shaft portion 61 is engaged is formed at the center of the inner rotor 21. Further, a convex portion 65 is provided on the other side surface of the cover 5 so as to be inserted into the engagement hole 62 of the inner rotor 21.

  Specifically, the engagement shaft portion 61 is configured such that one end portion of the rotation shaft 10 is cut out in a rectangular shape and the cross-sectional shape is formed in a D shape. The engagement shaft portion 61 includes a first flat surface portion 61a along the axial direction, a second flat surface portion 61b that intersects the axial direction, a first peripheral surface portion 61c, and an end surface portion 61d.

  The engagement hole 62 includes a first hole portion 63 having a D-shaped cross section on the other side, and a cylindrical second hole portion 64 on the one side. The first hole portion 63 includes a third flat surface portion 63a along the axial direction and a second peripheral surface portion 63b. The second hole portion 64 includes a third peripheral surface portion 64a and a bottom surface portion 64b. The convex portion 65 includes a fourth peripheral surface portion 65a and an end surface portion 65b.

  The outer diameter of the engagement shaft portion 61 is set slightly smaller than the inner diameter of the first hole portion 63. Thereby, the extending direction of the rotating shaft 10 with respect to the inner rotor 21 can be changed between the first peripheral surface portion 61c of the engaging shaft portion 61 and the second peripheral surface portion 63b of the first hole portion 63 of the engaging hole 62. Engagement flexibility is formed.

  Thus, since the inner rotor 21 and the rotary shaft 10 are connected by the engagement between the engagement shaft portion 61 and the first hole portion 63 of the engagement hole 62, the rotary shaft is temporarily set with respect to the rotation plane of the inner rotor 21. Even when the arrangement direction of 10 is slightly inclined, the rotational drive from the rotary shaft 10 can be smoothly transmitted to the inner rotor 21. If the rotating operation is smooth, the discharge capacity of the fluid pump is sufficiently secured, and the occurrence of abnormal noise or the like is suppressed.

  In addition, since engagement flexibility is formed between the engagement shaft portion 61 and the first hole portion 63 of the engagement hole 62, when the inner rotor 21 is accommodated in the pump chamber 7 of the pump housing 2, Even when the arrangement direction of the rotation shaft 10 is slightly inclined with respect to the rotation plane of the inner rotor 21, the engagement shaft portion 61 and the first hole portion 63 of the engagement hole 62 can be easily engaged.

  As shown in FIG. 1, one end surface (the right end surface in FIG. 1) of the rotating shaft 10 is configured to be positioned between the front and back surfaces of the inner rotor 21. The other side of the rotating shaft 10 abuts on the steel ball 51 and is prevented from moving leftward in the figure. On the other hand, the movement of the rotary shaft 10 to the other side is prevented by the stepped portion of the rotary shaft 10 coming into contact with the inner rotor 21. In this state, the end of the rotary shaft 10 on the inner rotor 21 side is set so as to remain within the thickness of the inner rotor 21.

In the fluid pump of the present invention, since the driving force of the rotating shaft 10 is transmitted to the inner rotor 21 by the engagement structure, it is not necessary that the rotating shaft 10 and the inner rotor 21 are firmly fixed as in the conventional structure. . Therefore, even if the end surface of the rotating shaft 10 is configured to be within the thickness of the inner rotor 21 as in this configuration, the rotation transmission function is ensured. If the length of the rotating shaft 10 is shortened as in this configuration, the overall weight is reduced, the moment of inertia of the rotating portion is reduced, and an improvement in rotational performance can be expected.
Further, since the contact area between the inner rotor 21 and the rotating shaft 10 is reduced, the sliding resistance is reduced even when the rotating shaft 10 slightly swings with respect to the rotating surface of the inner rotor 21, and as a result. Smooth rotation characteristics can be obtained.
Furthermore, even if the rotary shaft 10 slides in the axial direction with respect to the inner rotor 21 during the rotation drive, the rotary shaft 10 is reliably prevented from interfering with the cover 5 of the housing, and vibration and noise are prevented. Occurrence can also be prevented.

Furthermore, the details of the connecting portion between the rotating shaft 10 and the inner rotor 21 are configured as follows.
As shown in FIG. 4, the second flat surface portion 61 b of the engagement shaft portion 61 abuts on the other side surface of the inner rotor 21, thereby preventing the rotation shaft 10 from moving in the axial direction. On the other hand, a convex portion 65 is formed on the cover 5 side, and a first gap is formed between the end surface portion 65 b and the end surface portion 61 d of the engagement shaft portion 61. This reliably prevents the rotating shaft 10 from coming into contact with the cover 5.

On the other hand, a second gap is formed between the bottom surface portion 64 b of the second hole portion 64 of the engagement hole 62 and the end surface portion 65 b of the convex portion 65. The inner rotor 21 contacts the cover 5 around the convex portion 65, and the position along the axial direction is specified. Therefore, the rotational resistance of the inner rotor 21 can be reduced even slightly by not contacting the convex portion 65 and the inner rotor 21.
In FIG. 1, the end 61 d of the rotating shaft 10 completely penetrates the first hole 63 of the inner rotor 21, and the driving force of the rotating shaft 10 can be reliably transmitted to the inner rotor 21.

[Second Embodiment]
In this embodiment, only a configuration different from the configuration of the first embodiment will be described, and the description of the same configuration will be omitted.

  As shown in FIG. 5, a spline shaft-shaped engagement shaft portion 71 and a columnar insertion portion 72 are formed at one end of the rotary shaft 10, and an engagement shaft portion 71 is formed at the center of the inner rotor 21. An engagement hole 73 to be engaged is formed. The outer diameter of the engagement shaft portion 71 is set slightly smaller than the inner diameter of the engagement hole 73. Thereby, between the engagement shaft part 71 and the engagement hole 73, the engagement accommodation which can change the extension direction of the rotating shaft 10 with respect to the inner rotor 21 is formed.

  An insertion hole 74 for inserting the insertion portion 72 is formed on the other side surface of the cover 5. The outer diameter of the insertion hole 74 is set to be substantially the same as the outer diameter of the insertion portion 72. The insertion hole 74 is provided with one steel ball 75 (an example of one restricting portion) that comes into contact with the central portion of one end surface of the rotary shaft 10. Thereby, the both steel balls 51 and 75 can reliably prevent the rotation shaft 10 from being displaced in the axial direction during driving. For this reason, generation | occurrence | production of the vibration and abnormal noise by the collision with the rotating shaft 10 and the cover 5 is prevented.

  Since the insertion hole 74 has not only a function of accommodating the steel ball 75 but also a function as a radial bearing of the rotating shaft 10, the rotating shaft 10 can be supported at two points together with the shaft support portion 11 provided in the pump housing 2. . For this reason, there is no rotation blur on the rotating shaft 10 as the rotating shaft 10 rotates.

[Another embodiment]
(1) In the first embodiment, an engagement shaft portion 61 having a D-shaped cross section is formed at one end portion of the rotating shaft 10, and an engagement hole 62 into which the engagement shaft portion 61 is engaged is formed in the inner rotor 21. Instead of the configuration to be formed, a spline shaft-shaped engagement shaft portion may be formed at one end portion of the rotary shaft 10, and an engagement hole with which the engagement shaft portion is engaged may be formed in the inner rotor 21.

  In the second embodiment, a spline shaft-shaped engagement shaft portion 71 is formed at one end of the rotary shaft 10, and an engagement hole 73 in which the engagement shaft portion 71 is engaged is formed in the inner rotor 21. Instead, an engagement shaft portion having a D-shaped cross section may be formed at one end portion of the rotating shaft 10, and an engagement hole with which the engagement shaft portion is engaged may be formed in the inner rotor 21.

  In short, the cross-sectional shape of the engagement shaft portion and the engagement hole may be non-circular, and the cross-sectional shape is not particularly limited as long as the rotation of the rotation shaft is transmitted to the inner rotor.

(2) The convex portion 65 may be omitted, and the engagement hole 62 may include only the D-shaped first hole portion 63.

(3) It is not always necessary to attach the rotor 46 to the other end portion of the rotary shaft 10, and any configuration may be used as long as the rotor 46 is attached to the other side of the rotary shaft 10. Moreover, it is not necessary to attach the inner rotor 21 to the one end part of the rotating shaft 10, and what is necessary is just the structure which attaches the inner rotor 21 to the one side of the rotating shaft 10. FIG.

  The present invention can be applied to various pumps that pump liquid in addition to oil pumps.

2, 3 Housing 5 Cover 6 Pump rotor 10 Rotating shaft 11 Shaft support portion 45 Stator 46 Rotor 51, 75 Restricting portion 61, 71 Engaging shaft portion 62, 73 Engaging hole 65 Protruding portion

Claims (3)

A rotor provided on one side of the rotation shaft;
A pump rotor provided on the other side of the rotating shaft and capable of rotating synchronously with the rotor;
A housing including the rotary shaft, the rotor, and the pump rotor, a stator that drives the rotor, and a shaft support portion that supports the rotary shaft;
With
When rotating the rotating shaft,
An engagement hole and an engagement shaft portion that can change the extending direction or the extending direction of the rotating shaft with respect to the pump rotor are formed separately for the pump rotor and the rotating shaft ,
The end surface on the pump rotor side of the rotating shaft is located between the front and back surfaces of the pump rotor,
The engagement hole includes a first hole portion that has a flat portion along the axial direction on one end side and can be engaged with the engagement shaft portion, and a circular cross section in which a part of the housing is inserted on the other end side. the second hole portion and a fluid pump that having a of.   2. The fluid pump according to claim 1, wherein the housing includes a spherical regulating portion that is in contact with a central portion of an end surface of the rotating shaft on the rotor side. The housing includes a pump housing having a pump chamber that houses the pump rotor, and a cover that can close the pump chamber, and the cover is provided with a convex portion that is inserted into the engagement hole of the pump rotor. The fluid pump according to claim 1 or 2 .

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