JP2006170147A - Oil pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oil pump capable of sufficiently reducing generation of an abnormal sound, while minimizing generation of friction. <P>SOLUTION: A driving shaft 6 having a first trochoidal pump 4, a second trochoidal pump 5 and a spacer 3 inside a housing body 1 and driving both trochoidal pumps, is driven by a helical gear 7. A falling-off preventive mechanism 62 is arranged for preventing slipping-out in the pump cover 2 direction of the driving shaft 6. The area of a delivery port 21b arranged in a pump cover 2 contacting with a second inner rotor 5a, is constituted larger than the area of a delivery port 31b of the spacer 3 becoming the opposite side. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention belongs to the technical field of an oil pump driven by an external driving force.

Conventionally, it has been considered to apply a rotational force to a drive shaft by a gear to actuate a pump. Further, this gear is generally constituted by a sprocket that meshes with a spur gear or a chain (see, for example, Patent Document 1).
Japanese Utility Model Publication No. 3-5990

  However, in the above-described prior art, since the gear is constituted by a spur gear or a sprocket, the noise is greatly influenced by the influence of backlash.

  It is also possible to reduce the noise by minimizing the effect of backlash by configuring the gear as a helical gear. However, the helical gear rotates in order to move the drive shaft in the axial direction. There is a problem that the accompanying friction increases.

  The present invention has been made paying attention to the above-mentioned conventional problems, and an object of the present invention is to provide an oil pump that can sufficiently reduce the occurrence of abnormal noise while reducing the occurrence of friction as much as possible. It is to provide.

In order to achieve the above object, in the oil pump of the present invention,
A housing having a pump chamber therein;
A pump structure that is disposed within the housing and sucks and discharges lubricating oil to the outside;
A drive shaft for driving the pump structure;
A helical gear to which a driving force fixed to the driving shaft is transmitted;
A drop-off prevention mechanism that receives axial force on the drive shaft generated by the helical gear on one side of the pump structure, and prevents the drive shaft from coming off;
A suction port and a discharge port respectively provided on both side surfaces of the pump structure;
Have
The area of the discharge port provided on the drop-off prevention mechanism side is configured to be larger than the area of the discharge port provided on the opposite side surface.
It is characterized by that.
Therefore, it is possible to sufficiently reduce the occurrence of abnormal noise while minimizing the occurrence of friction.

  The best mode for carrying out the present invention will be described below based on the first embodiment.

First, the configuration will be described.
1 is a cross-sectional view of the oil pump according to the first embodiment when viewed from above in the direction of gravity. FIG. 2 is a view taken along the arrow V in FIG. 1. In the first embodiment, the oil pump according to the present invention is used for engine lubrication. This is an applied example.

  The oil pump A according to the first embodiment includes a housing body 1, a pump cover 2, a spacer 3, a first trochoid pump 4, a second trochoid pump 5, a drive shaft 6, and a helical gear (power transmission member) 7. It has.

[Housing body]
The housing body 1 is formed in a bottomed cylindrical shape having an opening 1a on the helical gear 7 side and a bottom surface portion 11 on the engine housing 8 side. As shown in FIG. 2, the housing body 1 is formed with a suction port 1c and a discharge port 1d along the axial direction. The suction port 1c communicates with an oil pan (not shown) in which engine oil is stored via an oil passage (not shown) in the engine housing 8. The discharge port 1d communicates with an oil filter (not shown) via an oil passage (not shown) in the engine housing 8. The engine oil filtered by the oil filter is sent to each lubricating part such as a bearing, a camshaft, and a valve.

  Further, as shown in FIG. 2, when the housing body 1 is assembled to the engine housing 8, the suction port 1c is set to be located on the upper side in the gravity direction, and the discharge port 1d is set to be located on the lower side in the gravity direction. ing.

  A through hole 11a for inserting a press-fitting jig 11b (see FIG. 11) that holds the first end 6a of the drive shaft 6 at the time of assembly is formed on the bottom surface 11 of the housing body 1. This penetration part 11a is a circular hole, and the inner periphery of the hole is set to be smaller than the outer diameter of the first end 6a of the drive shaft 6 described later.

  In addition, in the bottom surface portion 11, a suction port 12 a that communicates with the suction port 1 c and a discharge port 12 b that communicates with the discharge port 1 d are formed on the first trochoid pump side surface 12 that contacts the first trochoid pump 4. The suction port 12a is located on the lower side in the gravity direction corresponding to the suction port 1c. The discharge port 12b is located on the upper side in the gravity direction corresponding to the discharge port 1d.

The first trochoid pump side surface 12 will be further described.
The suction port 12 a and the discharge port 12 b are recessed with respect to the surface in contact with the first trochoid pump 4. The plane that can come into contact with the first trochoid pump 4 is a circular portion around the through-hole 11a, and this circular portion is connected to the outer periphery of the suction port 12a and the discharge port 12b so that the suction port 12a and the discharge port are connected. It becomes the part which partitions off 12b, and an outer peripheral part. The circular portion is configured to have a diameter φB as shown in FIG.

[Pump cover]
The pump cover 2 seals the opening 1 a of the housing body 1, and a bearing 2 b that rotatably supports the drive shaft 6 is formed at the center of the pump cover 2. Further, as shown in FIG. 3, in the pump cover 2, the second trochoid pump side surface 21 in contact with the second trochoid pump 5 has a suction port 21a communicating with the suction port 1c and a discharge port 21b communicating with the discharge port 1d. And are formed. Further, the second trochoid pump side surface 21 is formed with a lubrication groove 2c that communicates with the discharge port 21b and lubricates the bearing portion 2b.

The second trochoid pump side surface 21 will be further described.
The suction port 21a and the discharge port 21b are recessed with respect to the surface in contact with the second trochoid pump 5. The plane that can come into contact with the second trochoid pump 5 is a circular portion around the bearing portion 2b, and the circular portion is connected to the outer peripheral side of the suction port 12a and the discharge port 12b so that the suction port 21a and the discharge port are connected. It becomes the part which partitions off 21b, and an outer peripheral part. The circular portion is configured to have a diameter of φA as shown in FIG.

  That is, in the first trochoid pump side surface 12 of the housing body 1, the second trochoid pump side surface 31 and the first trochoid pump side surface 32 of the spacer 3, the diameter of the circular portion is made the same as φB. In contrast, the circular portion of the second trochoid pump side surface 21 of the pump cover 2 has a diameter φA smaller than the diameter φB.

  The housing body 1 and the pump cover 2 are respectively formed with bolt holes 1b and 2a at positions corresponding to the four female screw portions 8a formed in the engine housing 8, and by bolts 9 inserted through these bolt holes 1b and 2a. It is fastened together with the engine housing 8 from the pump cover 2 side.

[Spacer]
4 is a sectional view taken along the line S4-S4 of FIG. 1 showing the second trochoid pump side 31 of the spacer 3, FIG. 5 is a view showing the first trochoid pump side 32 of the spacer 3, and FIG. 6 is a sectional view taken along S6-S6 of FIG. It is.

  The spacer 3 divides the first trochoid pump 4 and the second trochoid pump 5 and supports the drive shaft 6, and a bearing portion 3 a that rotatably supports the drive shaft 6 is formed at the center. Yes.

  In the spacer 3, a suction port 31 a connected to the suction port 1 c and a discharge port 31 b communicating with the discharge port 1 d are formed on the second trochoid pump side surface 31 in contact with the second trochoid pump 5.

The second trochoid pump side surface 31 will be further described.
The suction port 31a and the discharge port 31b are recessed with respect to the surface in contact with the second trochoid pump 5. The plane that can come into contact with the second trochoid pump 5 is a circular portion around the bearing portion 3a, and the circular portion is connected to the outer peripheral side of the suction port 31a and the discharge port 31b. It becomes the part which partitions off 31b, and an outer peripheral part. The circular portion is configured to have a diameter of φB as shown in FIG.
The diameter φB of the circular portion is larger than the pin groove 5d of the second inner rotor 5a with a margin. Thereby, the suction side and the discharge side are not communicated with each other by the pin groove 5d.

  In the spacer 3, a suction port 32 a connected to the suction port 1 c and a discharge port 32 b communicating with the discharge port 1 d are formed on the first trochoid pump side surface 32 that contacts the first trochoid pump 4. Further, the first trochoid pump side surface 32 is formed with a lubrication groove 3b that communicates with the discharge port 32b and lubricates the bearing portion 3a.

  The first trochoid pump side surface 32 will be further described. The shape of the surface of the first trochoid pump side surface 32 in contact with the first trochoid pump 4 is symmetrical to the second trochoid pump side surface 31 except for the lubricating groove 3b as shown in FIG.

[First trochoid pump]
7 is a cross-sectional view of the first trochoid pump 4 taken along the line S7-S7 in FIG.
The first trochoid pump 4 is disposed to face the bottom surface portion 11 in the housing body 1 and includes a first inner rotor 4a that is a drive rotor and a first outer rotor 4b that is a driven rotor. A fitting hole 4c is formed on the inner periphery of the first inner rotor 4a to be fitted to a first end 6a of the drive shaft 6 described later. Here, when the first trochoid pump 4 is assembled to the engine housing 8, the discharge working chamber 4d having a high pressure is positioned above the gravity direction, and the suction working chamber 4e having a negative pressure is positioned below the gravity direction. Is set to

[Second trochoid pump]
8 is a cross-sectional view of the second trochoid pump 5 taken along the line S8-S8 in FIG.
The second trochoid pump 5 is arranged in series with the first trochoid pump 4 on the opening 1a side in the housing body 1, and is composed of a second inner rotor 5a that is a drive rotor and a second outer rotor 5b that is a driven rotor. Yes.

  An insertion hole 5c through which the drive shaft 6 is inserted is formed at the center of the second inner rotor 5a. Further, in the second inner rotor 5a, a pin groove 5d into which a pin 10 inserted into a drive shaft 6 described later is fitted is formed on the spacer side surface 51 in contact with the second trochoid pump side surface 31 of the spacer 3. Similarly to the first trochoid pump 4, when the second trochoid pump 5 is assembled to the engine housing 8, the discharge working chamber 5e having a high pressure is positioned on the upper side in the gravitational direction, and the suction having a negative pressure on the lower side in the gravitational direction. It is set so that the working chamber 5f is located.

FIG. 9 is a view showing the phases of teeth of the first trochoid pump 4 and the second trochoid pump 5. The first trochoid pump 4 and the second trochoid pump 5 are arranged so that the meshing position of the teeth of the inner rotor and the outer rotor is the rotation of the outer rotor. They are offset by 36 ° from each other. Note that the arrows in FIG. 9 indicate the rotation direction of the drive shaft 6.
(The first trochoid pump 4, the spacer 3, and the second trochoid pump 5 correspond to the pump structure)

[Drive shaft]
In the drive shaft 6, the helical gear 7 is press-fitted into the second end 6 b protruding from the pump cover 2 to the outside of the housing body 1, and the rotational force of the helical gear 7 is transmitted to the first trochoid pump 4 and the second trochoid pump 5.

  The drive shaft 6 is composed of a cylindrical member, and has a two-surface width in which only the first end portion 6a corresponding to the first inner rotor 4a is cut out into a two-surface width shape and fitted into the fitting hole 4c of the first inner rotor 4a. A portion 6c is formed.

  In the drive shaft 6, a pin hole 6d penetrates in the radial direction of the drive shaft 6 at a position corresponding to the pin groove 5d, and the pin 10 is inserted into the pin hole 6d. The pin 10 is formed longer than the pin hole 6d, and the pin groove 5d is set so that both ends thereof protrude from both sides of the pin hole 6d. A thrust force acting in the direction from the first end portion 6 a of the drive shaft 6 toward the second end portion 6 b by the pin 10 and the pin groove 5 d formed in the second inner rotor 5 is caused on the side surface of the second inner rotor 5. A drop-off prevention mechanism 62 is configured.

[Helical gear]
The helical gear 7 transmits the rotational force of the crankshaft to the drive shaft 6 through a gear not shown. In the first embodiment, the tooth profile of the helical gear 7 is generated so that a thrust force is generated with respect to the drive shaft 6 in the direction of the arrow in FIG. Is set.

Next, the operation will be described.
[Oil pump drive action]
When the engine is driven, the rotational force of the crankshaft is input to the drive shaft 6 via the helical gear 7. Thereby, the 1st trochoid pump 4 and the 2nd trochoid pump 5 are driven.

  When the first trochoid pump 4 is driven, the suction working chamber 4e in the expansion stroke becomes negative pressure, and the engine oil stored in the oil pan passes through the suction port 12a of the housing body 1 and the suction port 32a of the spacer 3. Then, it flows into the suction working chamber 4e of the first trochoid pump 4.

  The engine oil that has flowed into the working chamber of the first trochoid pump 4 is increased in pressure in the discharge working chamber 4d in the compression process, and is discharged to the discharge port 1d via the discharge port 12b of the housing body 1 and the discharge port 32b of the spacer 3. Discharged.

  Similarly, when the second trochoid pump 5 is driven, the suction working chamber 5f in the expansion stroke becomes negative pressure, and the engine oil passes through the suction port 21a of the pump cover 2 and the suction port 31a of the spacer 3 to the first pressure. 2 It flows into the suction working chamber 5f of the trochoid pump 4.

  The engine oil that has flowed into the working chamber of the second trochoid pump 5 is boosted in the discharge working chamber 5e in the compression process, and is discharged to the discharge port 1d via the discharge port 21b of the pump cover 2 and the discharge port 31b of the spacer 3. Discharged.

[Pulse pressure suppression effect by phase]
The first trochoid pump 4 and the second trochoid pump 5 are arranged so that the meshing positions of the teeth of the inner rotor and the outer rotor are shifted from each other by 36 ° with respect to the outer rotor rotation angle. The pressures are in a phase that cancels each other. Thereby, the synthetic pulse pressure of the engine oil output from the discharge port 1d is suppressed.

[Oil leakage suppression action from penetration part]
In the first embodiment, the bottom portion 11 of the housing main body 1 is formed with a through portion 11a into which the press-fit receiving jig 11b is inserted when the helical gear 7 is assembled. Therefore, when the pump is driven, a slight oil leakage may occur from the through-hole 11a to the outside of the housing body 1.

  In contrast, in the first embodiment, the discharge working chamber 4d of the first trochoid pump 4 is arranged on the upper side in the gravity direction, and the suction working chamber 4e is arranged on the lower side in the gravity direction. As a result, even if a slight oil leak occurs in the penetrating portion 11a, it is immediately absorbed from the suction port 12a to the suction working chamber 4d. Therefore, oil leakage from the bottom surface portion 11 to the outside can be suppressed despite the provision of the penetration portion 11a. Further, it is possible to suppress inhaling air from the outside.

  Further, since the penetrating portion 11a is set to be smaller in diameter than the outer diameter of the first end portion 6a of the drive shaft 6, engine oil leaking from the sliding surface between the bottom surface portion 11 of the housing body 1 and the first trochoid pump 4 is reduced. Then, it passes through the diaphragm formed by the end surface of the first end portion 6a of the drive shaft 6 and the periphery of the through portion 11a of the bottom surface portion 11, and oil leakage can be suppressed.

[Pump assembly method]
Next, a method for assembling the oil pump 4 according to the first embodiment will be described.

(First step)
The first inner rotor 4a, the first outer rotor 4b, and the spacer 3 are assembled to the housing body 1 in this order.

  Subsequently, the pin 10 is inserted into the pin hole 6d of the drive shaft 6, and the drive shaft 6 is inserted from the spacer side surface 51 into the insertion hole 5c of the second inner rotor 5a. Through this step, the drive shaft 6 and the second inner rotor 5a are integrated by the drop-off prevention mechanism 62 (FIG. 11 (a)).

  Next, the opening 1a of the housing body 1 is directed upward, and the first end 6a of the drive shaft 6 is inserted into the bearing 3a of the spacer 3 and the fitting hole 4c of the first inner rotor 4a. At this time, since the second inner rotor 5a is supported on the lower side by the drop-off preventing mechanism 62 due to the engagement between the pin 10 and the pin groove 5d, the second inner rotor 5a falls when the drive shaft 6 is inserted into the first inner rotor 4a. There is nothing to do. Further, since the second inner rotor 5a presses both ends of the pin 10 downward due to gravity, the pin 10 is prevented from falling off from the pin hole 6d.

  Finally, the second outer rotor 5b is assembled in the housing body 1 so as to accommodate the second inner rotor 5a. At this time, the drive shaft 6 is not displaced relative to the housing body 1 because the relative movement in the axial direction is restricted by the drop-off prevention mechanism 62.

(Second step)
The second end 6 b of the drive shaft 6 is inserted into the bearing portion 2 b of the pump cover 2, and the pump cover 2 is put on the opening 1 a of the housing body 1. At this time, the housing body 1 and the pump cover 2 are temporarily fixed with bolts 8 (FIG. 11 (b)).

(Third step)
A press-fitting receiving jig 11b is inserted into the housing body 1 from a through-hole 11a formed in the bottom surface portion 11 of the housing body 1, and the first end 6a of the drive shaft 6 is fixed. In this state, the helical gear 7 is press-fitted into the second end 6b of the drive shaft 6 (FIGS. 11 (c) and 11 (d)). At this time, since the first end portion 6a of the drive shaft 6 is supported by the press-fitting receiving jig 11b, the housing body 1 can be prevented from being deformed along with the press-fitting work of the helical gear 7.

[Reduction of driven thrust force]
In the oil pump A according to the first embodiment, as shown in FIG. 12, the driving gear G, which is a helical gear that rotates by driving the engine, meshes with the helical gear 7 to obtain a driving force. At this time, the helical gear 7 and the drive shaft 6 connected to the helical gear receive a force in the thrust direction due to the twist angle of the tooth trace. The rotation direction of the drive gear G and the helical gear 7 is only a fixed direction.
Therefore, as the oil pump A, the helical gear 7 and the drive shaft 6 receive a force in a direction to come out to the pump cover 2 side. Receiving such an axial force causes a problem of increased friction due to rotation.

  On the other hand, the oil pump of Example 1 has the following configuration. The diameters of the circular portions of the first trochoid pump side surface 12 of the housing body 1, the second trochoid pump side surface 31 and the first trochoid pump side surface 32 of the spacer 3 are φB. Further, the circular portion of the second trochoid pump side surface 21 of the pump cover 2 has a diameter φA smaller than the diameter φB.

Then, on the side surface on the pump cover 2 side of the second inner rotor 5a of the second trochoid pump 5 and the side surface on the spacer 3 side of the second inner rotor 5a, the portions overlapping the recessed discharge port 12b and discharge port 31b, that is, the pressure is increased. The pressure receiving area for oil is different by φA and φB.
Therefore, the force that receives this hydraulic pressure pushes the second inner rotor 5a toward the spacer. When the second inner rotor 5 a is pushed to the spacer side, the helical gear 7 and the drive shaft 6 are pushed through the pin 10 in the direction opposite to the thrust force generated by the spacer side, that is, the helical gear 7. Thereby, the thrust force generated by the helical gear 7 is reduced. The reduction of the thrust force reduces the friction on the side surface of the second inner rotor 5a.

  The suction port 12a and the suction port 21a also have different pressure receiving areas, but oil has no effect because the suction negative pressure is very small compared to the discharge pressure.

[About lubrication groove]
In the oil pump A of the first embodiment, a lubrication groove 2c is provided in a circular portion of φA on the side surface 21 of the second trochoid pump of the pump cover 2. The lubricating groove 2c guides the oil boosted from the discharge port 21b to the bearing portion 2b. As a result, the rotation of the drive shaft 6 is maintained in a smooth state, and malfunctions of the bearing portion 2b caused by insufficient lubrication such as seizure are prevented.
Moreover, since it is provided on the second trochoid pump side surface 21 of the pump cover 2 so as to be connected to the discharge port 21b, the pressure receiving area of the second inner rotor 5a is further increased.

Next, the effect will be described.
In the oil pump A of Example 1, the effects listed below are obtained.

  (1) A housing main body 1 having a pump chamber inside, a first trochoid pump 4, a second trochoid pump 5, a spacer 3 which are arranged in the housing main body 1 and sucks lubricating oil and discharges it to the outside. The driving shaft 6 to be driven, the helical gear 7 to which the driving force fixed to the driving shaft 6 is transmitted, and the axial force on the driving shaft 6 generated by the helical gear 7 are received by one side surface of the second inner rotor 5a, and the driving shaft A pin 10 that penetrates the drive shaft 6 serving as a mechanism for preventing the removal of the pin 6, a second inner rotor 5a having a pin groove 5d that engages with the pin 10, and suction ports 12a provided on both side surfaces of the first trochoid pump 4 32a, discharge ports 12b, 32b, suction ports 21a, 31a and discharge ports 21b, 31b provided on both side surfaces of the second trochoid pump 5, Since the area of the discharge port 21b provided in the pump cover 2 in contact with the rotor 5a is larger than the area of 31b of the spacer 3 on the opposite side, the generation of noise is sufficiently reduced while reducing the generation of friction as much as possible. be able to.

  (2) A housing body 1 having a pump chamber inside, a first inner rotor 4a and a second inner rotor 5a that are rotatably accommodated in the housing body 1 and have a plurality of teeth on the outer periphery, and are rotatable within the housing body 1. The first outer rotor 4b, the second outer rotor 5b, and the first inner rotor 4a, the second outer rotor 5b, and the first inner rotor 4a, the second inner rotor 5b, and the first inner rotor 4b. 4a, a drive shaft 6 for driving the second inner rotor 5a, a helical gear 7 to which a driving force fixed to the driving shaft 6 is transmitted, and an axial force generated by the helical gear 7 to the driving shaft 6 is applied to the second inner rotor 5a. A second inner rotor 5a provided with a pin 10 that passes through the drive shaft 6 and serves as a mechanism for preventing the drive shaft 6 from coming off, and a pin groove 5d that engages with the pin 10 is received on one side. The suction ports 12a and 32a and the discharge ports 12b and 32b provided on both side surfaces of the first trochoid pump 4; the suction ports 21a and 31a and the discharge ports 21b and 31b provided on both side surfaces of the second trochoid pump 5; The area of the discharge port 21b provided in the pump cover 2 in contact with the second inner rotor 5a is larger than the area of 31b of the spacer 3 on the opposite side, so that the generation of friction is reduced as much as possible and Can be sufficiently reduced.

  (3) The drive shaft facing the second inner rotor 5a on the side opposite to the second inner rotor 5a on the side where the pin groove 5d that engages with the pin 10 penetrating the drive shaft 6 is prevented. 6 is provided, and a lubricating groove 2c for guiding lubricating oil from the discharge port 21b to the bearing portion 2b is formed. Therefore, the side where the pin groove 5d is provided for the amount of the lubricating groove 2c formed. The area of the discharge port 21b on the opposite side of the pump cover 2 with respect to this surface is increased, and both effects of lubrication of the bearing portion 2b and reduction of friction can be obtained.

The second embodiment is an example in which the pump structure is composed of a pair of an inner rotor and an outer rotor.
The configuration will be described.
FIG. 13 is a cross-sectional view of the oil pump of Example 2 when viewed from above in the direction of gravity. FIG. 14 is a view of the pump cover 2 as seen from the S11-S11 cross section of FIG. FIG. 15 is a view of the housing body 1 as seen from the S12-S12 cross section of FIG. FIG. 16 is a W view of the housing body 1. FIG. 17 is a cross-sectional view taken along line S13-S13 in FIG.
The oil pump B according to the second embodiment is configured to include a pair of trochoid pumps 40 including an inner rotor 40a and an outer rotor 40b inside the housing body 1. Therefore, the pin 10 attached to the drive shaft 6 is engaged with the pin groove 40c on the bottom surface portion 11 side of the housing main body 1 of the inner rotor 40a.

In this oil pump B, the pump cover 2 is provided with a circular portion of φA and a lubricating groove 2c in the same manner as in the first embodiment.
On the other hand, a circular portion of φB is provided on the bottom surface portion 11 of the housing body 1 in the same manner as in the first embodiment. Further, the bottom surface portion 11 is provided with a lubricating groove 12c that allows the discharge port 12b on the outer peripheral side of the circular portion to communicate with the inner insertion port 11a.

The effect will be described.
[Reduction of driven thrust force]
In the oil pump B of the second embodiment, the circular portion of the pump cover 2 serving as a discharge port on both side surfaces of the inner rotor 40a and the bottom surface portion 11 of the housing body 1 is φA <φB. As a result, the pressure receiving area of the inner rotor 40a at the discharge ports 12b and 21b increases on the pump cover 2 side. Then, since the inner rotor 40a receives a force toward the bottom surface portion 11 side of the housing main body 1, the thrust force caused by the helical gear 7 can be reduced.

Thus, the oil pump may be composed of one trochoid pump.
Other configurations and functions and effects are the same as those of the first embodiment, and thus description thereof is omitted.

Further, the operational effects of the oil pumps of Examples 1 and 2 will be additionally described.
In the oil pumps of the first and second embodiments, the generation of abnormal noise is reduced by providing the helical gear 7, and the generation of friction is suppressed by reducing the axial force generated by the helical gear 7. Even if there is no problem in performance, the generation of abnormal noise is very unfavorable because it is perceived by the driver as an engine malfunction or the driver feels uncomfortable. In particular, since the quietness of the engine has improved in recent years, the generation of such abnormal noise affects the performance and quality of the vehicle.

If the friction increases, it may lead to wear, abnormal noise, and reduced discharge capacity. In the oil pumps of Examples 1 and 2, since the oil fills the inside, good lubrication can be obtained, but an increase in friction is not preferable in the long term.
The environment attached to the engine of the vehicle is a severe vibration environment such as the vibration of the engine itself and the vibration of the vehicle body due to the road surface condition. Therefore, reducing the friction is a very important effect for maintaining good performance in the long term.

  As described above, being able to sufficiently reduce the generation of abnormal noise while reducing the generation of friction as much as possible has a very advantageous effect in an oil pump used in a vehicle.

(Other examples)
The tandem trochoid pump of the present invention has been described based on the first and second embodiments. However, the specific configuration of the present invention is not limited to the configuration shown in each of the embodiments, and the gist of the invention. Any design change within a range that does not deviate from the above is included in the present invention.
For example, a bearing for the drive shaft 6 may be provided in the housing body 1. FIG. 18 is a longitudinal sectional view showing the configuration of the tandem trochoid pump C, and the inner periphery 3 c of the spacer 3 is set so as not to contact the drive shaft 6. A bearing portion 11c is projected on the bottom surface portion 11 of the housing body 1, and a non-bearing portion 6e formed by extending the first end portion 6a of the drive shaft 6 on the inner periphery of the bearing portion 11c is rotatable. It is supported by.

  Further, technical ideas other than the claims that can be grasped from the respective embodiments will be described below together with the effects thereof.

(A) In the oil pump according to claim 1,
The drop-off prevention mechanism includes a pin provided through the drive shaft in the radial direction and an engagement groove formed on one side surface of the inner rotor and engageable with the pin. Oil pump.
Therefore, instead of sliding in a state where a load is applied to a pin having a small area, it is possible to receive the load on the entire surface of the inner rotor on the side opposite to the pin, and local wear can be prevented.

(B) In the oil pump according to claim 1,
In the housing, a second inner rotor, an outer rotor, and a spacer for partitioning the two pumps are provided, and the second inner rotor and the spacer can move relative to the drive shaft in the axial direction. The oil pump according to claim 2, wherein the inner rotor is configured not to move relative to the drive shaft in the rotational direction.
Therefore, since the second inner rotor and the spacer do not receive the axial force from the helical gear, the friction can be reduced.

(C) The housing includes a bottomed cylindrical housing body and a cover that seals the opening of the housing body. The cover includes a bearing portion and an oil groove, and the inner rotor and the outer rotor. An oil pump characterized in that one side surface is slid.
Therefore, since the cover is easy to process with respect to the housing body, the bearing portion, the oil groove, and the sliding surface can be formed easily and with high accuracy.

(D) In the oil pump described in (b) above,
A suction port and a discharge port of both pumps are formed on both side surfaces of the spacer, respectively, and a suction port and a discharge port on the side facing the drop-off prevention mechanism are arranged on the opposite side so as not to face the drop-off prevention mechanism. An oil pump that is smaller than the discharge port.
Therefore, the suction port and the discharge port provided on one side of the spacer do not face the drop-off prevention mechanism, so that the drop-off prevention mechanism does not hinder suction and discharge.

It is sectional drawing when the oil pump A of Example 1 is seen from gravity direction upper direction. It is a V arrow view of FIG. It is S3-S3 sectional drawing of FIG. 1 which shows the 2nd trochoid pump side surface of the pump cover 2. FIG. It is S4-S4 sectional drawing of FIG. 1 which shows the 2nd trochoid pump side surface 31 of the spacer 3. FIG. It is a figure which shows the 1st trochoid pump side surface 32 of the spacer 3. FIG. It is S6-S6 sectional drawing of FIG. It is S7-S7 sectional drawing of FIG. 1 which shows a 1st trochoid pump. It is S8-S8 sectional drawing of FIG. 1 which shows a 2nd trochoid pump. It is a figure which shows the phase of the tooth | gear of the 1st trochoid pump 4 and the 2nd trochoid pump 5. FIG. It is a figure which shows the pulse pressure suppression effect | action of Example 1. FIG. It is a figure which shows the assembly method of the oil pump A of Example 1. FIG. It is explanatory drawing which shows the drive state of the oil pump A of Example 1. FIG. It is sectional drawing when the oil pump B of Example 2 is seen from gravity direction upper direction. It is S11-S11 sectional drawing of FIG. 13 which shows the trochoid pump side side surface 211 of the pump cover 2 in Example 2. FIG. It is S12-S12 sectional drawing of FIG. It is a W arrow view of FIG. It is S13-S13 sectional drawing of FIG. 13 which shows the trochoid pump 40. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Housing main body 1a Opening part 1b Bolt hole 1c Inlet port 1d Outlet port 11 Bottom surface part 11a Through-hole part 11b Press-fit receiving jig 12 First trochoid pump side surface 12a Inlet port 12b Outlet port 2 Pump cover 2a Bolt hole 2b Bearing part 2c Lubrication Groove 21 Second trochoid pump side surface 21a Suction port 21b Discharge port 211 Trochoid pump side surface 3 Spacer 3a Bearing portion 3b Lubrication groove 31 Second trochoid pump side surface 31a Suction port 31b Discharge port 32 First trochoid pump side surface 32a Suction port 32b Discharge port 4 First trochoid pump 4a First inner rotor 4b First outer rotor 4c Fitting hole 4d Discharge working chamber 4e Suction working chamber 5 Second trochoid pump 5a Second inner rotor 5b Second outer rotor 5c Insertion hole 5d Pin groove 5e Discharge working chamber 5f Suction working chamber 51 Spacer side surface 6 Drive shaft 6a First end portion 6b Second end portion 6c Two-sided width portion 6d Pin hole 7 Helical gear 8 Engine housing 8a Female thread portion 9 Bolt 10 Pin 40 Trochoid pump 40a Inner rotor 40b Outer rotor 40c Pin groove 62 Fallout prevention mechanism

Claims (3)

A housing having a pump chamber therein;
A pump structure that is disposed within the housing and sucks and discharges lubricating oil to the outside;
A drive shaft for driving the pump structure;
A helical gear to which a driving force fixed to the driving shaft is transmitted;
A drop-off prevention mechanism that receives axial force on the drive shaft generated by the helical gear on one side of the pump structure, and prevents the drive shaft from coming off;
A suction port and a discharge port respectively provided on both side surfaces of the pump structure;
Have
The area of the discharge port provided on the drop-off prevention mechanism side is configured to be larger than the area of the discharge port provided on the opposite side surface.
An oil pump characterized by that. A housing having a pump chamber therein;
An inner rotor rotatably accommodated in the housing and having a plurality of teeth on the outer periphery;
An outer rotor that is rotatably accommodated in the housing, has inner teeth on the inner periphery that are larger than the number of teeth of the inner rotor, and is configured to mesh with each other;
A drive shaft for driving the inner rotor;
A helical gear to which a driving force fixed to the driving shaft is transmitted;
A drop-off prevention mechanism that receives axial force on the drive shaft generated by the helical gear on one side of the inner rotor and prevents the drive shaft from coming off;
A suction port and a discharge port respectively provided on both side surfaces of the inner rotor and the outer rotor;
Have
The area of the discharge port facing the inner rotor provided on the drop-off prevention mechanism side is configured to be larger than the area of the discharge port facing the inner rotor provided on the opposite side surface.
An oil pump characterized by that. The oil pump according to claim 2,
A bearing portion for bearing the drive shaft facing the inner rotor is provided on a side surface opposite to the side where the drop-off prevention mechanism is provided, and an oil groove for guiding lubricating oil from the discharge port to the bearing portion is formed. ,
An oil pump characterized by that.

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