JPH09256963A - Oil pump rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a slip component of an external tooth and improve mechanical efficiency of an oil pump, by forming the external tooth of an inner rotor in a specific value range satisfying a relation between an addendum circle diameter of the external tooth and an eccentric amount of an inner/outer rotor. SOLUTION: In a casing 30, an inner rotor 10 having (n) teeth of external teeth and an outer rotor 20 having n+1 teeth of internal teeth, meshed with this inner rotor, are provided. An axial center O1 of the rotor 10 and an axial center O2 of the rotor 20 are eccentrically positioned (e mm). In an external tooth 11 of the rotor 10, when a diameter of an addendum circle P connecting an addendum of each external tooth 11 is assumed as Dmm, in a range satisfying 0.135<=e.n/(π.D)<=0.145, a trochoid curve is generated, a generate circle group positioning the center on the trochoid curve draws an envelope, the external tooth 11 is formed along the envelope, a meshing angle of the external tooth 11 with the internal tooth 21 is set to a suitable range. Consequently, forming of an addendum edge of the external tooth 11 is suppressed, durability is ensured, a rotational component of small slip component can be ensured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil pump rotor which, when an inner rotor and an outer rotor are engaged with each other and rotate, sucks and discharges a fluid by a change in volume of cells formed between tooth surfaces of both rotors. Is.

[0002]

2. Description of the Related Art A conventional oil pump has an inner rotor formed with n (n is a natural number) outer teeth, an outer rotor formed with (n + 1) inner teeth meshing with the outer teeth, and a fluid suction port. And a casing in which a discharge port for discharging the fluid is formed,
By rotating the inner rotor, the outer teeth mesh with the inner teeth to rotate the outer rotor, and the fluid is sucked and discharged by volume changes of a plurality of cells formed between the rotors.

The cells are individually partitioned on the front side and the rear side in the direction of rotation by contact between the outer teeth of the inner rotor and the inner teeth of the outer rotor, and both sides are partitioned by a casing. This constitutes an independent fluid transfer chamber. Then, after the volume of each cell becomes the minimum during the process of meshing between the external teeth and the internal teeth, the volume is expanded when the cells move along the suction port to suck the fluid, and the volume becomes maximum. Then, the volume is reduced as it moves along the discharge port to discharge the fluid.

[0004]

By the way, in the oil pump having the above-described oil pump rotor, the force of the outer teeth of the inner rotor pushing the inner teeth of the outer rotor acts in the tangential direction of the inner rotor. It is decomposed into a rotational component that rotates the outer rotor and a sliding component that acts in the radial direction of the inner rotor to produce slippage between the tooth surfaces, but to reduce the sliding component that causes mechanical loss and increase the rotational component. Was a problem. Further, the inner rotor and the outer rotor are always in sliding contact with the casing and the outer rotor with the casing, and the outer teeth of the inner rotor and the inner teeth of the outer rotor are in contact with each other before and after each cell. Are always in contact with each other. This is an important condition for maintaining the liquid tightness of the cell that conveys the fluid, but on the other hand, if the resistance generated in each sliding contact part is large, the mechanical loss of the oil pump will significantly increase, It has been an issue to reduce the resistance generated in each sliding contact portion.

The present invention has been made in view of the above circumstances, and an object thereof is to improve mechanical efficiency while ensuring durability and reliability as an oil pump.

[0006]

As means for solving the above-mentioned problems, in the oil pump rotor of the present invention, the outer teeth of the inner rotor, the tip circle diameter of the inner rotor are D (mm), the inner When the eccentricity between the rotor and the outer rotor is e (mm), the center is located on the trochoidal curve created within the range that satisfies the following formula 0.135 ≦ e · n / (π · D) ≦ 0.145 It is formed along the envelope drawn by the created circles. The force by which the outer teeth of the inner rotor push the inner teeth of the outer rotor is the rotational component that acts in the tangential direction of the inner rotor to rotate the outer rotor and the force acting between the tooth surfaces of both rotors that acts in the radial direction of the inner rotor. Although it is decomposed into a slip component that causes slippage, in the oil pump rotor of the present invention, the meshing angle between the outer teeth and the inner teeth is set to an appropriate range, so that the inner rotor is provided on both sides of the tips of the outer teeth. A sufficient rotation component is secured while suppressing the formation of the edge portion protruding outward in the rotation direction.

Here, the envelope drawn by the group of generating circles whose center is located on the trochoidal curve created in the range satisfying the following equation e · n / (π · D) <0.135 When formed along the line, the meshing angle between the outer teeth and the inner teeth becomes larger, the rotation component of the force by which the outer teeth push the inner teeth decreases, the half-slip component increases, and the larger force is applied to rotate the outer rotor. Is required.

The outer teeth of the inner rotor are along the envelope drawn by the group of generating circles whose center is located on the trochoidal curve created in the range satisfying the following expression e · n / (π · D)> 0.145. When formed by, the meshing angle between the outer teeth and the inner teeth becomes smaller, the slip component of the force of the outer teeth pushing the inner teeth decreases, and the rotation component increases,
The outer rotor can be rotated with a small force. However, edge portions that protrude outward in the rotation direction of the inner rotor and cause wear of the tooth surface are formed on both sides of the tip of the outer half tooth.

In addition to the above conditions, the outer teeth of the inner rotor are expressed by the following formula: 0.15 ≦ n · R / (π · D) ≦ 0.25 when the radius of the generating circle is R (mm). The shape of the outer rotor is determined according to the shape of the inner rotor while forming along the envelope drawn by the creation circle group whose center is located on the trochoidal curve created in the range that satisfies In the same manner as above, it is formed along the envelope drawn by the group of generating circles whose center is located on the trochoidal curve. As a result, the area of the inner tooth end surface of the outer rotor is reduced to the extent that the inner teeth are not easily damaged, and the sliding area of the outer rotor as a whole is reduced.

Further, in this oil pump rotor, by providing a relief portion which is not in contact with the inner teeth of the outer rotor on the front side in the rotation direction of the outer teeth of the inner rotor, the cell moves along the suction port. The inner rotor and the outer rotor do not come into contact with each other in the process of increasing the volume. Further, by providing an escape portion that does not contact the inner teeth of the outer rotor on the rear side of the outer teeth of the inner rotor in the rotation direction, the process of the cells moving along the suction port and increasing the volume Even in the process of moving along the discharge port and decreasing the volume, the inner rotor and the outer rotor are prevented from coming into contact with each other, and the outer teeth of the inner rotor mesh with the inner teeth of the outer rotor,
The inner rotor and the outer rotor come into contact with each other only in the process in which the cell having the maximum volume moves from the suction port side to the discharge port side.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of an oil pump rotor according to the present invention will be described with reference to the drawings. The oil pump rotor shown in FIG. 1 has an inner rotor 10 having n (n is a natural number, n = 10 in the present embodiment) outer teeth, and n + 1 inner teeth meshing with the outer teeth. The inner rotor 10 and the outer rotor 20 are housed inside a casing 30.

The inner rotor 10 is attached to a rotating shaft (not shown) and is supported rotatably about an axis O ₁ , and the outer rotor 20 has an axis O ₂ on the axis O ₁ of the inner rotor 10. On the other hand, it is eccentrically arranged (amount of eccentricity: e) and is rotatably supported in the casing 30 about the axis O ₂ in the circumferential direction.

The outer teeth 11 of the inner rotor 10 have the following formula: 0.135 ≦ e · n /, where D (mm) is the diameter of a tip circle P connecting the tips of the outer teeth 11 of the inner rotor 10. The outer rotor 20 is formed along the envelope drawn by the generation circle group whose center is located on the trochoidal curve generated in the range satisfying (π · D) ≦ 0.145. The shape of the outer rotor 20 is the inner rotor 10. Is determined by the shape of. (Fig. 1 shows e ・ n
/ (Π ・ D) = 0.143)

Inner rotor 10, outer rotor 20
A plurality of cells C are formed between the tooth flanks along the rotation direction of the rotors 10 and 20. Each cell C has both rotors 1
The inner rotor 10 is provided on the front side and the rear side in the rotation direction of 0 and 20.
The outer teeth 11 and the inner teeth 21 of the outer rotor 20 are individually partitioned by contacting each other, and both side surfaces are partitioned by the casing 30, thereby forming an independent fluid transfer chamber. The cell C is rotationally moved as the rotors 10 and 20 rotate, and the volume is repeatedly increased and decreased with one rotation as one cycle.

The casing 30 includes both rotors 10 and 20.
Among the cells C formed between the tooth flanks, the arc-shaped suction port 31 is formed along the cell C whose volume is increasing, and the arc-shaped suction port 31 is formed along the cell C whose volume is decreasing. Discharge port 32 is formed.

After the volume of the cell C is minimized during the process of meshing between the outer teeth 11 and the inner teeth 21, the cell C expands its volume as it moves along the suction port 31, and sucks fluid. After the volume is maximized, the volume is reduced and the fluid is ejected when moving along the ejection port 32.

By the way, in the oil pump rotor configured as described above, the inner rotor 10 is rotated by the rotation of the rotary shaft to which the inner rotor 10 is fixed.
Is driven, the inner teeth 21 are pushed by the meshing with the outer teeth 11, and the outer rotor 20 is driven. Therefore, the meshing point K between the outer teeth 11 and the inner teeth 21 located at the distance ₁ from the axis O ₁ of the inner rotor 10
Considering ₀ (meshing angle: α ₀ ), the force F by which the outer teeth 11 push the inner teeth 21 acts in a direction perpendicular to the meshing surface I.

[0018] The force F includes a rotary component F ₀₁ for rotating the outer rotor 20 acts in the tangential direction of the inner rotor 10, sliding component F produce a slip between the tooth surfaces acting in the radial direction of the inner rotor 10 It is decomposed into ₀₂ and, and these are expressed as follows. F ₀₁ = F · cos α ₀ F ₀₂ = F · sin α ₀

Based on this fact, along the envelope drawn by the group of generating circles whose center is located on the trochoidal curve created in the range of the following equation e · n / (π · D) <0.135: 2 shows an oil pump rotor in which the outer teeth 11 of the inner rotor 10 are formed.
Shown in In this oil pump rotor, the meshing angle α _{1 at} the meshing point K ₁ between the outer teeth 11 and the inner teeth 21 located at the distance ₁ from the axis O ₁ of the inner rotor 10 is
The force F, which is larger than the meshing angle α _{0 at the} meshing point K _{0 and} causes the outer teeth 11 to push the inner teeth 21, is a rotation component F ₁₁ that rotates the outer rotor 20 and a slip component F ₁₂ that causes slippage between the tooth surfaces. It is decomposed into and and is expressed as follows. F ₁₁ = F · cos α ₁ F ₁₂ = F · sin α ₁ (in FIG. 2, when e · n / (π · D) = 0.1136)

At this time, since α ₁ > α ₀ , the rotation components are compared with each other, F ₁₁ (= F · cos α ₁ ) <F ₀₁ (= F · cos α ₀ ), and the slip components are compared with each other. , F ₁₂ (= F · sin α ₁ )> F ₀₂ (= F · sin α ₀ ). This shows that the rotation component decreases as the meshing angle increases, but the slip component increases. Therefore, the rotation component F ₁₁ becomes smaller than the rotation component F 0 _1, and in order to obtain the rotation component F ₁₁ having the same magnitude as the rotation component F ₀₁ , it is necessary to increase the force with which the outer teeth 11 push the inner teeth 21. is there.

In addition, outside the inner rotor 10 along the envelope drawn by the group of creation circles whose center is located on the trochoidal curve created in the range of the following expression e · n / (π · D)> 0.145 FIG. 3 shows an oil pump rotor having teeth 11 formed thereon.
Shown in In this oil pump rotor, the meshing angle α _{2 at} the meshing point K ₂ between the outer teeth 11 and the inner teeth 21 located at the distance ₁ from the axial center O ₁ of the inner rotor 10 is
The force F, which is smaller than the meshing angle α _{0 at the} meshing point K ₀ and the outer teeth 11 press the inner teeth 21, is a rotation component F ₂₁ that rotates the outer rotor 20 and a slip component F ₂₂ that causes slippage between the tooth surfaces. It is decomposed into and and is expressed as follows. F ₂₁ = F · cos α ₂ F ₂₂ = F · sin α ₂ (in FIG. 3, when e · n / (π · D) = 0.15)

At this time, since α ₂ <α ₀ , the rotation components are compared with each other, F ₂₁ (= F · cos α ₂ )> F ₀₁ (= F · cos α ₀ ), and the slip components are compared with each other. , F ₂₂ (= F · sin α ₂ ) <F ₀₂ (= F · sin α ₀ ). This indicates that the rotational component increases and the slip component decreases as the meshing angle decreases. Therefore, the rotation component F ₂₁ becomes larger than the rotation component F ₀₁ , and the outer rotor 20 can be rotated with a larger force. In other words, the outer teeth 11 are the inner teeth 21.
Even if the pushing force is small, the rotation component F ₂₁ having the same magnitude as the rotation component F ₀₁ can be obtained.

However, paying attention to the shape of the outer teeth 11 of the inner rotor 10, on the other hand, the inner rotor 1 is located on the both sides A of the tip of the outer teeth 11, on the other hand, where the meshing angle α ₂ becomes small.
An edge portion protruding outward in the rotational direction of 0 is formed. Inner rotor 10 with this edge formed
When combined with the outer rotor 20 and rotates, the surface pressure around the protruding edge portion increases, the edge portion becomes more worn, and the durability of the outer teeth 11 decreases.

When the value of e · n / (π · D) is arbitrarily selected, the value is adopted and the mechanical efficiency of the oil pump provided with the inner rotor 10 having the outer teeth 11 is shown in FIG. First, in the range of e · n / (π · D) <0.135, the smaller the value of e · n / (π · D), the lower the mechanical efficiency of the oil pump. It can be seen that in the range of 0.135 ≦ e · n / (π · D) ≦ 0.145, the larger the value of e · n / (π · D), the higher the mechanical efficiency of the oil pump. However, in the range of e · n / (π · D)> 0.145, an edge portion is formed at the tip side A of the external tooth 11 shown in FIG. It becomes severe and the durability of the external teeth 11 deteriorates.

FIG. 5 shows the oil pump rotor used in the oil pump corresponding to each point on the graph of FIG. Oil pump rotors used in the oil pump corresponding to points I and II on the graph are shown in FIGS. 5 (I) and 5 (II), respectively. Note that II on the graph
The oil pump rotors used in the oil pump corresponding to the points I, IV, and V are those shown in FIGS. 1, 2, and 3, respectively.

From these facts, the oil pump rotor shown in FIG. 1 is created in a range where the outer teeth 11 of the inner rotor 10 satisfy the following equation: 0.135 ≦ e · n / (π · D) ≦ 0.145. The outer teeth 11 and the inner teeth 21 are formed along the envelope drawn by the generating circle group whose center is located on the formed trochoidal curve, and the meshing angle between the outer teeth 11 and the inner teeth 21 is set in an appropriate range. Although the formation of the edge portion at the tip is suppressed and the durability of the outer teeth 11 is ensured, the slip component that causes mechanical loss is small and a sufficient rotation component is secured, and the force F for rotating the outer rotor 20 is applied to the outer teeth 11
Can effectively be transmitted to the internal teeth 21.

A second embodiment of the oil pump rotor according to the present invention will be described with reference to the drawings. The components already described are given the same reference numerals and the description thereof will be omitted. In the oil pump rotor shown in FIG. 6, the outer teeth 11 of the inner rotor 10 satisfy the equation 0.135 ≦ e · n / (π · D) ≦ 0.145 shown in the first embodiment, and As shown in FIG. 7, when the radius of the creation circle Q is R (mm), a trochoidal curve created in a range satisfying the following expression 0.15 ≦ n · R / (π · D) ≦ 0.25. The outer rotor 20 is formed along the envelope h drawn by the generation circle group whose center is located on t, and the shape of the outer rotor 20 is determined by the shape of the inner rotor 10.

By the way, in the oil pump rotor constructed as described above, when the rotors 10 and 20 are rotated against the sliding resistance generated between the end surfaces of the rotors 10 and 20 and the casing 30. The friction torque T is expressed by the following formula T, where S is the sliding area, l is the distance from the center of rotation to the sliding portion, and M is the frictional force per unit area acting between the rotors 10 and 20 and the casing 30. = M · S · l From this formula, as a means for reducing the friction torque T, the sliding portion located far from the center of rotation, that is, the casing 30 at the end surface of the outer rotor 20.
It is possible to reduce the sliding area between the and.

Based on this fact, it was created in the range of the following equations 0.135 ≦ e · n / (π · D) ≦ 0.145 and n · R / (π · D)> 0.25. FIG. 8 shows an oil pump rotor including an inner rotor 10 having outer teeth 11 formed along an envelope drawn by a group of generating circles whose center is located on a trochoidal curve. In this oil pump rotor, since the area of the end surface S _o of the inner teeth 21 is larger than the area of the end surface S _i of the outer teeth 11, the sliding area of the outer rotor 20 is also large, and as a result, the friction torque T Will increase. (Fig. 8 shows n ・ R
/ (Π ・ D) = 0.36)

Further, the center is on the trochoidal curve created in the following equations: 0.135 ≦ e · n / (π · D) ≦ 0.145 and n · R / (π · D) <0.15. FIG. 9 shows an oil pump rotor including the inner rotor 10 having the outer teeth 11 formed along the envelope drawn by the positioned generation circle group. In this oil pump rotor, since the area of the end surface S _o of the inner teeth 21 is smaller than the area of the end surface S _i of the outer teeth 11, the sliding area of the outer rotor 20 is also small, and as a result, the friction torque T Decreases. However, since the width W of the inner teeth 21 along the rotation direction of the outer rotor 20 is narrowed, the inner teeth 21 are likely to be chipped due to meshing with the outer teeth 11, and the durability of the inner teeth 21 is reduced.
(In FIG. 9, when n · R / (π · D) = 0.145)

FIG. 10 shows the mechanical efficiency of the oil pump provided with the inner rotor 10 in which the outer teeth 11 are formed by adopting the value of n.R / (. Pi..D) arbitrarily selected. First, it can be seen that in the range of n · R / (π · D)> 0.25, the larger the value of n · R / (π · D), the lower the mechanical efficiency of the oil pump. It can be seen that in the range of 0.15 ≦ n · R / (π · D) ≦ 0.25, the smaller the value of n · R / (π · D), the higher the mechanical efficiency of the oil pump. In the range of n · R / (π · D) <0.15, the mechanical efficiency of the oil pump is not significantly improved, and the smaller the value of n · R / (π · D) is, the more it is as shown in FIG. In addition, the width W of the inner teeth 21 along the rotation direction of the outer rotor 20 is narrowed, and the inner teeth 21 are easily damaged.

FIG. 11 shows the oil pump rotor used in the oil pump corresponding to each point on the graph of FIG. The oil pump rotors used in the oil pump corresponding to the points I, II, and III on the graph are
11 (I), 11 (II), and 11 (III). The oil pump rotors used in the oil pump corresponding to points IV, V, and VI on the graph are those shown in FIGS. 6, 8, and 9, respectively.

From these facts, in the oil pump rotor shown in FIG. 6, the outer teeth 11 of the inner rotor 10 have the following expressions: 0.135 ≦ e · n / (π · D) ≦ 0.145 and 0.15 ≦ It is formed along the envelope drawn by the creation circle group whose center is located on the trochoidal curve created in the range satisfying n · R / (π · D) ≦ 0.25. The shape of the rotor 20 is determined, and the area of the end surface S _o thereof is reduced to such an extent that the inner teeth 21 of the outer rotor 20 are not easily _damaged , the sliding area of the entire outer rotor 20 is reduced, and the drive torque T is reduced. Therefore, in addition to the effect described in the first embodiment, the sliding resistance generated between the outer rotor 20 and the casing 30 is ensured while the durability of the inner teeth 21 is ensured. Reduction of mechanical loss can be reduced. Therefore, it is possible to improve mechanical efficiency while ensuring durability and reliability as an oil pump.

A third embodiment of the oil pump rotor according to the present invention will be described with reference to the drawings. The components already described are given the same reference numerals and the description thereof will be omitted. This oil pump rotor contacts the inner teeth 21 of the outer rotor 20 on the front side and the rear side of the outer teeth 11 of the inner rotor 10 constituting the oil pump rotor shown in the first embodiment in the rotation direction. The escape portion 40 that does not have is formed.

FIG. 12 shows the meshing state of the outer teeth 11 of the inner rotor 10 and the inner teeth 21 of the outer rotor 20. When the tips of the outer teeth 11 of the inner rotor 10 mesh with the tooth spaces of the inner teeth 21 to rotate the outer rotor 20, the line indicating the direction of the force of the outer teeth 11 pushing the inner teeth 21 is called the action line. Indicated by l. The outer teeth 11 and the inner teeth 21 are meshed with each other along the line of action l. The points on the tooth surface of the outer tooth 11 forming the intersection K _{s at} which meshing starts and the intersection K _{e at} which meshing ends are always constant, and these points are referred to as meshing start point k _s and end point k _e of the outer tooth 11. I reckon. Looking at one external tooth 11, the meshing start point k
_s is formed on the rear side in the rotational direction, and the meshing end point k _e is formed on the front side in the rotational direction.

Next, FIG. 13 shows the state of contact between the outer teeth 11 of the inner rotor 10 and the inner teeth 21 of the outer rotor 20 when the volume of the cell C is maximized. The volume of the cell C becomes maximum when the tooth space between the outer teeth 11 and the tooth space between the inner teeth 21 face each other. At this time, the tooth tip of the outer tooth 11 and the tooth tip of the inner tooth 21 located in front of the cell C _max have a contact point P.
_While contacting at _{1, the} tip of the outer tooth 11 located behind the cell C _max contacts at the contact point P2. The points on the tooth surface of the outer tooth 11 forming the contacts P ₁ and P ₂ that maximize the volume of the cell C are always constant, and these points are the front contact point p ₁ and the rear contact point p _{2 of the} outer tooth 11. To consider. Regarding one external tooth 11, the front contact point p ₁ is formed on the rear side in the rotation direction, and the rear contact point p ₂ is formed on the front side in the rotation direction.

The relief portion 40 has a meshing end point k _e and a rear contact point p ₂ located on the front side in the rotational direction with respect to one outer tooth 11.
And the tooth flank between the meshing start point k _s located on the rear side in the rotation direction and the front contact point p ₁ are cut off, and the tooth flank of the external tooth 11 between them is formed. It has no contact with the internal teeth 21.

With respect to the oil pump rotor configured as described above, the increase and decrease in the volume of the cell C in one cycle and the state of contact between the outer teeth 11 of the inner rotor 10 and the inner teeth 21 of the outer rotor 20 are shown below. .

First, in the process of meshing the outer teeth 11 and the inner teeth 21, the outer teeth 11 mesh with the inner teeth 21 to rotate the outer rotor 20, as in the conventional case.

The meshing between the outer teeth 11 and the inner teeth 21 is completed,
When the process of increasing the volume of the cell C along the suction port 31 is performed, the relief portion 40 is provided on the front side in the rotation direction of the outer teeth 11 of the inner rotor 10 that were conventionally in contact with the inner teeth of the outer rotor.
The outer teeth 1 before and after the cell C due to the provision of
1 and the internal teeth 21 are no longer in contact with each other.

When the front of the cell C passes through the suction port 31, first, the tip of the external tooth 11 and the tip of the internal tooth 21 located in front of the cell C come into contact with each other. Then, when the rear side of the cell C passes through the suction port 31, the external teeth 11 located behind the cell C are
The tip of the tooth and the tip of the inner tooth 21 are in contact with each other, and a cell C _max having the maximum volume is formed between the suction port 31 and the discharge port 32. The tooth tips of the external teeth 11 and the internal teeth 21 located behind the cell C
The contact with the tooth tip of is maintained until the contact point reaches the discharge port 31.

In the process of decreasing the volume of the cell C along the discharge port 31, the relief portion 40 is formed on the rear side in the rotation direction of the outer tooth 11 of the inner rotor 10 which was in contact with the inner tooth 21 of the outer rotor 20. Since it is provided, the outer teeth 11 and the inner teeth 21 do not come into contact with each other.

By the way, the volume of the cell C is equal to the suction port 31.
In the process of increasing along with the discharge port 32, and in the process of increasing the volume of the cell C along the discharge port 32, the adjacent cells C are brought into communication by providing the escape portion 40. Cell C is intake port 3
1, or because it is located along the discharge port 32 and is in a communication state from the beginning, this does not cause a reduction in the transfer efficiency of the oil pump.

As a result, the process of meshing the outer teeth 11 and the inner teeth 21 and the volume of the cell C are maximized, so that the suction port 3
The external teeth 11 and the internal teeth 21 contact each other only in the process of moving from the 1st side to the discharge port 32 side, and the process in which the volume of the cell C increases along the suction port 31 and the volume of the cell C changes to the discharge port 32. In the process of decreasing along, the outer teeth 11 and the inner teeth 21 do not come into contact with each other, and the number of sliding contact points between the inner rotor 10 and the outer rotor 20 decreases, so that the sliding resistance generated between the tooth surfaces decreases.

From the above, according to this oil pump rotor, in addition to the effects obtained by the oil pump rotor shown in the first embodiment, the following effects are obtained. That is, the number of sliding contact points between the inner rotor 10 and the outer rotor 20 is reduced, and the sliding resistance generated between the tooth surfaces is reduced. Therefore, the drive torque required to drive the oil pump is reduced, and the machine as an oil pump is reduced. The efficiency can be improved.

Further, by providing the relief portion 40 on the rear side in the rotation direction of the outer teeth 11, the outer teeth 11 of the inner rotor 10 and the outer rotor 20 which are generated by the vibration of the oil pump when the oil pump is actually used. It is possible to prevent interference with the internal teeth 21 and reduce mechanical loss.

In this embodiment, the inner rotor 10 is constructed by providing the relief portions 40 on the front side and the rear side of the outer teeth 11 in the rotation direction, but the relief portions 40 are formed only on the front side in the rotation direction of the outer teeth 11. It may be provided.

A fourth embodiment of the oil pump rotor according to the present invention will be described with reference to the drawings. The components already described are given the same reference numerals and the description thereof will be omitted. The oil pump rotor shown in FIG.
The outer teeth 11 of the formula are 0.15 ≦ n · R / (π · D) ≦ 0.25 and 0.135 ≦ e · n / (π · D) ≦ 0.145 shown in the second embodiment. It is formed along the envelope drawn by the creation circle group whose center is located on the trochoidal curve created in the range that satisfies the above, and further the escape portions 40 are formed on the front side and the rear side in the rotation direction of each external tooth 11. It is a thing.

This oil pump rotor has all the characteristics of the oil pump rotors shown in the first, second and third embodiments, and has the following effects. While ensuring the durability of the inner teeth 21 of the outer rotor 20, mechanical loss due to sliding resistance generated between the end surface of the outer rotor 20 and the casing 30 can be reduced. While ensuring the durability of the outer teeth 11 of the inner rotor 10, it is possible to secure a sufficient rotation component and reduce mechanical loss as a slip component. The outer teeth 11 of the inner rotor 10 and the outer rotor 20
It is possible to reduce mechanical loss due to sliding resistance generated between the tooth surface of the inner tooth 21 and the tooth surface.

[0050]

As described above, in the oil pump rotor of the present invention, the outer teeth of the inner rotor have a tip circle diameter of the inner rotor of D (mm) and the eccentric amount of the inner rotor and the outer rotor is e. (Mm) is defined as the envelope drawn by the creation circle group whose center is located on the trochoid curve created in the range satisfying the following formula: 0.135 ≦ e · n / (π · D) ≦ 0.145. The outer teeth and inner teeth have a meshing angle set within an appropriate range, and the edge of the outer teeth is prevented from forming, which ensures durability of the outer teeth. A slip component that causes a loss is small, a sufficient rotation component is secured, and the force for rotating the outer rotor is effectively transmitted from the outer teeth to the inner teeth. Therefore, it is possible to improve mechanical efficiency while ensuring durability and reliability as an oil pump.

In the range where the outer teeth of the inner rotor satisfy the following formula 0.15 ≦ n · R / (π · D) ≦ 0.25 when the radius of creation circle of the inner rotor is R (mm). It is formed along the envelope drawn by the creation circle group whose center is located on the created trochoidal curve, and the shape of this inner rotor determines the shape of the outer rotor, and the extent that the inner teeth of the outer rotor are not easily damaged The area of the end face is small,
As a result, the sliding area of the entire outer rotor is reduced and the drive torque is reduced, so that mechanical loss due to sliding resistance generated between the outer rotor and the casing is reduced while ensuring the durability of the internal teeth. . Therefore,
Mechanical efficiency can be further improved while ensuring durability and reliability as an oil pump.

Further, in the oil pump rotor according to the present invention, the relief portion is provided on the front side in the rotation direction of the outer teeth of the inner rotor, or in addition to this, on the rear side in the rotation direction,
Only when the outer teeth and the inner teeth mesh with each other and when the cell volume becomes maximum and moves from the suction port side to the discharge port side, the outer teeth and the inner teeth come into contact with each other, and the cell volume becomes the suction port. During the process of increasing along the discharge port and the process of decreasing the cell volume along the discharge port, the outer and inner teeth do not come into contact with each other, and the sliding contact points between the inner rotor and the outer rotor decrease, causing a gap between the tooth surfaces. Since the sliding resistance is reduced, the drive torque required to drive the oil pump can be reduced and the mechanical efficiency of the oil pump can be improved. In addition, by providing a relief portion on the rear side of the external teeth in the rotation direction, interference between the external teeth and internal teeth that occurs when the oil pump vibrates when the oil pump is actually used is reduced, reducing mechanical loss. can do.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of an oil pump rotor according to the present invention, in which the outer teeth of the inner rotor have the following formula: 0.135 ≦ e · n / (π · D) ≦ 0.145 FIG. 6 is a plan view showing an oil pump rotor formed along an envelope drawn by a generation circle group whose center is located on a trochoid curve generated in a range satisfying the above condition.

FIG. 2 is a diagram to be compared with the oil pump rotor shown in FIG. 1, in which the outer teeth of the inner rotor are created in a range satisfying the following formula e · n / (π · D) <0.135. It is a top view which shows the oil pump rotor formed along the envelope which the creation circle group which centered on the trochoid curve draws.

FIG. 3 is a diagram to be compared with the oil pump rotor shown in FIG. 1, in which the outer teeth of the inner rotor are created in a range satisfying the following expression e · n / (π · D)> 0.145. It is a top view which shows the oil pump rotor formed along the envelope which the creation circle group which centered on the trochoid curve draws.

FIG. 4 is a graph showing mechanical efficiency of an oil pump including an inner rotor having external teeth formed by arbitrarily selecting a value of e · n / (π · D).

5 is a plan view showing an oil pump rotor used in the oil pump corresponding to each point shown in FIG. 4. FIG.

FIG. 6 is a view showing a second embodiment of the oil pump rotor according to the present invention, in which the outer teeth of the inner rotor have the following formula: 0.15 ≦ n · R / (π · D) ≦ 0.25 FIG. 6 is a plan view showing an oil pump rotor formed along an envelope drawn by a generation circle group whose center is located on a trochoid curve generated in a range satisfying the above condition.

FIG. 7 is a plan view showing a procedure for creating the inner rotor shown in FIG.

FIG. 8 is a view to be compared with the oil pump rotor shown in FIG. 6, in which the outer teeth of the inner rotor are created in a range satisfying the following expression n · R / (π · D)> 0.25. It is a top view which shows the oil pump rotor formed along the envelope which the creation circle group which centered on the trochoid curve draws.

9 is a view to be compared with the oil pump rotor shown in FIG. 6, in which the outer teeth of the inner rotor are created in a range satisfying the following expression n · R / (π · D) <0.15. It is a top view which shows the oil pump rotor formed along the envelope which the creation circle group which centered on the trochoid curve draws.

FIG. 10 is a graph showing the mechanical efficiency of an oil pump including an inner rotor having outer teeth formed by arbitrarily selecting the value of n · R / (π · D).

11 is a plan view showing an oil pump rotor used in the oil pump corresponding to each point shown in FIG.

FIG. 12 is a view showing a third embodiment of the oil pump rotor according to the present invention, and is a plan view of relevant parts showing a state where the outer teeth of the inner rotor and the inner teeth of the outer rotor are meshed with each other.

FIG. 13 is likewise a plan view of relevant parts showing the state of contact between the outer teeth of the inner rotor and the inner teeth of the outer rotor when the cell volume is maximized.

FIG. 14 is a view showing a fourth embodiment of the oil pump rotor according to the present invention, in which the outer teeth of the inner rotor are
The center is on the trochoidal curve created in the range satisfying the following formulas 0.15 ≦ n · R / (π · D) ≦ 0.25 and 0.135 ≦ e · n / (π · D) ≦ 0.145. FIG. 6 is a plan view showing an oil pump rotor that is formed along an envelope drawn by a group of generating circles that are positioned, and that has escape portions formed on the front side and the rear side in the rotation direction of each external tooth.

[Explanation of symbols]

 10 Inner Rotor 11 Outer Teeth 20 Outer Rotor 21 Inner Teeth 30 Casing 31 Suction Port 32 Discharge Port e Eccentricity P Tip Tip Circle D Tip Tip Circle Diameter

Claims (4)

[Claims] 1. An inner rotor having n (n is a natural number) outer teeth formed, an outer rotor having n + 1 inner teeth formed to mesh with the outer teeth, an intake port for sucking fluid, and a fluid. When the rotors mesh with each other and rotate, the fluid is transferred by sucking and discharging the fluid due to the volume change of the cells formed between the tooth surfaces of the rotors. In an oil pump rotor used for an oil pump, when the outer teeth of the inner rotor have a tip circle diameter of the inner rotor of D (mm) and the eccentricity of the inner rotor and the outer rotor is e (mm). Along the envelope drawn by the creation circle group whose center is located on the trochoidal curve created in the range satisfying the following formula 0.135 ≦ e · n / (π · D) ≦ 0.145 Oil pump rotor, characterized in that it is formed Te. 2. The oil pump rotor according to claim 1, wherein the outer teeth of the inner rotor have a radius of creation circle of R (mm).
Is formed along the envelope drawn by the creation circle group whose center is located on the trochoid curve created in the range satisfying the following formula: 0.15 ≦ n · R / (π · D) ≦ 0.25 The oil pump rotor is characterized by being. 3. The oil pump rotor according to claim 1 or 2, wherein a relief portion that does not contact the inner teeth of the outer rotor is provided on the front side in the rotation direction of the outer teeth of the inner rotor. An oil pump rotor characterized in that 4. The oil pump rotor according to claim 3, wherein the relief portion is provided on the rear side in the rotation direction of the outer teeth of the inner rotor.