JP2011132894A - Internal gear oil pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal gear oil pump which is not inclined even when a shaft with a rotation transmission member installed is subjected to various external force, in which uneven wear of a bearing part is prevented, and which has parts of long life and satisfactory durability. <P>SOLUTION: The internal gear oil pump includes a cover part 2, the bearing part, a body part 1, a pump housing A having a pump chamber, an intake port 3 and a discharge port 4, the shaft 8 rotatably supported in a cantilever manner, a rotation transmission wheel 6, and a rotary driving part 7. The rotation transmission wheel is arranged at a position closer to a body part 1 side than a cover part side and the bearing part 12 is arranged in the middle of the shaft. The intake port and the discharge port are arranged on the pump housing along the direction of a contact pressure so that, against bending moment generated at the other end of the shaft by the contact pressure, bending moment in the opposite direction is generated at a one end side of the shaft. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention prevents uneven wear that occurs in the bearing portion of the shaft even if various external forces are applied to the shaft on which the rotation transmission member such as the rotor inside the pump, the gear outside the pump, and the belt wheel is mounted. In addition, the present invention relates to an internal gear oil pump having a long service life and good durability.

  Many oil pumps have an internal gear mechanism. A part of the shaft is exposed to the outside from the pump housing, and a rotation transmission wheel such as a gear or a belt wheel is mounted on the shaft end. The rotation is transmitted to the rotation transmission wheel by a gear or a belt mechanism other than the rotation transmission wheel, and the rotation transmission wheel transmits the rotation from the shaft to perform rotation operation. It is. Patent Document 1 is disclosed as such an oil pump.

Japanese Utility Model Sho 63-141885

  Patent Document 1 discloses a cantilever support type internal gear type oil pump. In the description of Patent Document 1, parentheses are attached to the reference numerals in order to distinguish from the description of the present invention. In patent document 1, it is comprised from the pump housing (20) and the cover member (21) fixed to this pump housing (20). A gear chamber (22) is formed between the pump housing (20) and the lid member (21), and an external drive gear (23) (so-called inner rotor) and an internal drive gear (24) (so-called outer rotor). Is stored.

  A support hole (25) is formed in the pump housing (20), a metal member (28) is attached to the support hole (25), and the rotary shaft (26) is rotatably supported. A pulley (27) (hereinafter referred to as a rotary drive member) is attached to one end of the rotary shaft (26), and this rotary drive member is rotationally driven by a power transmission member (timing belt or the like). From the left side of FIG. 1, the rotary drive member, the pump housing (20), the gear chamber (22), and the lid member (21) are arranged.

  A drive gear (23) is attached to the other end of the rotating shaft (26) while being prevented from rotating in the rotating direction of the rotating shaft (26). As shown in FIG. 1, a suction port (30) and a discharge port (31) having the same area and shape are formed in each of the pump housing (20) and the lid member (21). As a result, the same force is applied from both the axial direction of the pump housing (20) side and the lid member (21) side, and the suction pressure and the discharge pressure applied to the side surface of the rotor cancel each other, and the drive gear (23) only in the rotor radial direction. The suction pressure and the discharge pressure in the interdental space, which is the space between the other tooth and the driven gear (24), are applied.

  A belt tension FB is applied to the rotation driving member by winding the belt. The discharge port (31) is formed at a position opposite to the direction in which the belt tension FB of the rotating shaft (26) by the rotation driving member is applied (see FIG. 2). That is, when the belt tension FB applied to the rotating shaft (26) is directed downward, the discharge port (31) is formed on the upper side with respect to the rotating shaft (26). Since the discharge port (31) is formed on the upper side, the suction port (30) is formed on the lower side with respect to the rotating shaft (26).

  When the discharge pressure of the discharge port (31) is applied to the inter-tooth space of the drive gear (23) and the driven gear (24), the inclination direction of the rotary shaft (26) (belt tension FB) is set in the radial direction of the drive gear (23). The pressing force FP is applied in the same direction as (see Fig. 3). Conversely, a pressing force in the direction opposite to the tilt direction FB of the rotating shaft (26) is applied in the radial direction of the driven gear (24). In other words, when a positive pressure is generated at the discharge port (31) in FIG. 3, a downward pressing force FP is applied to the drive gear (23) as shown in FIG. As shown in Fig. 3, upward pressure is applied to 24).

  Since the driven gear (24) tends to move upward with respect to the drive gear (23) that is going to move downward, the forces applied in the radial direction of the rotor cancel each other, and the rotating shaft by the pressing force FP The inclination suppression effect of (26) is actually slight, and it is difficult to maintain the inclination of the rotating shaft (26) in a horizontal state. Therefore, the load concentrates on a part of the metal member (28) attached to the support hole (25), and uneven wear occurs. An object of the present invention (technical problem to be solved) is to prevent the uneven wear of the bearing by suppressing the uneven load on the bearing of the shaft on which the rotor and the rotation transmission wheel are mounted with a very simple configuration, As a result, it is in improving durability.

  Therefore, the inventor has intensively and researched to solve the above problems, and as a result, the invention of claim 1 is composed of a cover portion and a body portion in which a bearing portion is formed, and includes a pump chamber, a suction port, and a discharge portion. A pump housing having a port; a shaft rotatably supported by only the bearing; an inner rotor fixed to one end of the shaft and rotatably disposed in the pump chamber; and an outer periphery of the inner rotor An outer rotor disposed in the pump chamber, a rotation transmission wheel at the other end of the shaft, and a rotation drive unit that transmits contact with the rotation transmission wheel while having contact pressure. In the internal gear oil pump, the rotation transmission wheel is arranged at a position closer to the body part side than the cover part side, and the bearing part is arranged in the middle of the shaft, The suction port and the discharge port follow the direction of the contact pressure so that a bending moment in the opposite direction is generated on one end side of the shaft with respect to a bending moment generated by the contact pressure on the other end side of the shaft. Thus, the above-described problem has been solved by providing an internal gear oil pump disposed in the pump housing.

  According to a second aspect of the present invention, in the first aspect, the discharge port is disposed so as to straddle a line passing through the shaft core in the same direction as the pressure direction of the contact pressure with the shaft core of the bearing portion as a reference center. The suction port is disposed so as to straddle a line that is opposite to the pressure direction of the contact pressure and passes through the shaft core, and the suction port and the discharge port are formed in the cover part, and the cover part The internal gear oil pump in which a suction flow path communicating with the suction port and a discharge flow path communicating with the discharge port are formed to solve the above problem.

  In the invention of claim 1, the rotation transmission wheel receives an appropriate contact pressure from the rotation drive unit, and a bending moment M1 acts by this contact pressure. On the other hand, the suction port and the discharge port are arranged in the pump housing along the direction of the contact pressure so that bending moments in opposite directions are generated on the inner rotor side in the pump housing. . These two bending moments are intended to incline the shafts in opposite directions, and act so as to cancel out the movements in the inclination directions, so that the inclination of the shaft is suppressed. A horizontal state along the axial direction can be maintained in the bearing portion of the pump housing to prevent uneven wear on the bearing portion, and the life of the parts can be extended.

  Thus, since the bearing portion does not wear unevenly, a metal bearing becomes unnecessary, leading to a reduction in the number of parts and assembly man-hours. Furthermore, since the rotation transmission wheel does not move away from the rotation drive unit, proper rotation can be maintained. Further, since the inclination of the rotor is also suppressed, uneven wear of the rotor is prevented, leading to a reduction in rotational load. Furthermore, since the load on the bearing portion of the shaft is reduced, the axial length of the bearing portion can be shortened, and the pump housing can be made compact. Further, since the bearing portion (sliding portion) can be shortened, the rotational sliding loss of the shaft is reduced and the pump efficiency is improved.

  According to the second aspect of the present invention, the load applied in the tilt direction of the shaft is suppressed, and uneven wear on the bearing portion can be prevented. In addition, by forming the suction flow path communicating with the suction port and the discharge flow path communicating with the discharge port on the cover side, the structure on the body side is simplified without forming a flow path on the body side. Therefore, the body part side can be saved in space, and the pump housing can also be reduced in size. In particular, the pump housing can be downsized in the axial direction, and the suction flow path and the discharge flow path are not arranged so as to avoid the rotation transmission wheel, so that no energy loss occurs.

(A) is a longitudinal side view of the present invention, (B) is a view taken along the Ya-Ya arrow of (A), and (C) is a view taken along the Yb-Yb arrow of (A). (A) is a longitudinal side view of the pump housing, inner rotor, and outer rotor, (B) is an enlarged view of (A) part of (A), and (C) is an enlarged view of (A) part of (A). (A) is a schematic diagram showing an action in which a bending moment is generated in a rotation transmission wheel and a shaft in the present invention, (B) is a schematic diagram showing a state in which bending moments in opposite directions cancel each other, and (C) is (B) (D) is an enlarged view of part (c) of (B). (A) is a longitudinal side view of an embodiment in which the rotation transmission wheel and the rotation drive unit of the present invention are used as a belt mechanism, and (B) is a view taken along the arrow Yc-Yc in (A).

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present invention, there are a plurality of embodiments, which will be described from the first embodiment. The pump housing A is composed of a body portion 1 and a cover portion 2 as shown in FIGS. A pump chamber 11 is formed inside the body portion 1, and an inner rotor 51 and an outer rotor 52 are accommodated in the pump chamber 11 (see FIG. 1A). The pump chamber 11 includes a circular bottom surface portion 11a and a cylindrical inner wall surface portion 11b, and the outer rotor 52 is accommodated in the inner wall surface portion 11b so as to be rotatable in the circumferential direction. The cover part 2 has a substantially plate shape and serves to cover the opening of the pump chamber 11 of the body part 1 in a sealed manner.

  Further, the pump housing A is formed with a suction port 3 and a discharge port 4. [Refer FIG. 1 (A) and FIG. 2]. The suction port 3 and the discharge port 4 are formed in the cover portion 2. The suction port 3 is formed with an opening 33 a of a suction flow path 33, and the suction port 3 and the suction flow path 33 are communicated with each other. Similarly, an opening 43a of a discharge channel 43 is formed in the discharge port 4, and the discharge port 4 and the discharge channel 43 communicate with each other.

  The body portion 1 is formed with a bearing portion 12. The bearing portion 12 is formed near the center of the bottom surface portion 11 a of the pump chamber 11. It is formed as a shaft hole that penetrates through. A shaft 8 described later is rotatably supported on the bearing portion 12. The position of the diameter center in the bearing portion 12 is defined as an axis 8k, and this is defined as a reference center K. The reference center K also exists on the cover part 2 side, and the positions of both reference centers K and K of the body part 1 and the cover part 2 coincide with each other when the cover part 2 and the body part 1 are joined. Is.

  In the cover portion 2, the suction port 3 and the discharge port 4 may be formed so as to be substantially symmetrical with respect to a reference center K (see FIG. 1C). The suction port 3 and the discharge port 4 are formed in a substantially arc shape or crescent shape so as to surround the reference center K. The suction port 3 has a start end portion 31 and a terminal end portion 32 in the circumferential direction, and similarly, the discharge port 4 also has a start end portion 41 and a terminal end portion 42 in the circumferential direction (see FIG. 1C). .

  The rotation direction of the inner rotor 51 is clockwise about the reference center K when viewed from the rotation transmission wheel 6 side. Accordingly, the inner rotor 51 has a start end 31 and a terminal end 32 of the suction port 3 and a start end 41 and a terminal end 42 of the discharge port 4 along the clockwise direction. The discharge port 4 is similarly rotated in the order of the start end portion 41 and the end portion 42. In this case, the rotation direction of the outer rotor 52 is also a clockwise direction.

  For the sake of convenience of explanation, an imaginary line indicating a line passing through the reference center K in the same direction as the pressure direction of the contact pressure F applied to the rotation transmission wheel 6 is set in the cover portion 2. This virtual line is referred to as a virtual line L. Further, a boundary line Q that is orthogonal to the virtual line L at the position of the reference center K is set (see FIG. 1C). The cover inner wall surface 21 of the cover part 2 is separated by the boundary line Q into two regions, a proximity region S1 and a separation region S2 (see FIG. 1C and FIG. 2).

  The proximity region S1 is opposed to the cover inner wall surface 21 of the cover portion 2 of the inner rotor 51 when a bending moment M2 that resists the bending moment M1 generated by the contact pressure F acts on the inner rotor 51. The side surface 51b is a region where pressure is applied in a direction approaching the cover inner wall surface 21 (see FIGS. 2A, 2C, 3A, 3B, and 3D). Further, the separation region S2 means that when the bending moment M2 that resists the bending moment M1 generated by the contact pressure F acts on the inner rotor 51, the side surface 51b on the cover portion 2 side of the core inner rotor 51 is This is a region on the side that is pressure-biased in a direction away from the inner wall surface 21 of the cover [see FIGS. 2A, 2B, 3A, 3B, 3C]. The suction port 3 is disposed so as to straddle the virtual line L passing through the reference center K in the direction opposite to the pressure direction of the contact pressure F when viewed from the reference center K.

  Here, “the direction opposite to the pressure direction of the contact pressure F” is a region below the position of the boundary line Q in FIG. 1C, that is, the proximity region S1. Further, the discharge port 4 is disposed so as to straddle the virtual line L passing through the reference center K in the same direction as the pressure direction of the contact pressure F when viewed from the reference center K. The Here, “the same direction as the pressure direction of the contact pressure F” means a region above the position of the boundary line Q in FIG. 1C, that is, the separation region S2.

  Further, the fact that the suction port 3 and the discharge port 4 cross the virtual line L means that the substantially central portion of the suction port 3 and the discharge port 4 in the longitudinal direction intersects the virtual line L. . The suction port 3 and the substantially central portion in the longitudinal direction of the discharge port 4 exclude the ends of the suction port 3 and the discharge port 4 (start end portion 31, end portion 32, start end portion 41, end portion 42). The part is included.

  Specifically, the inner rotor 51 has a trochoidal tooth profile. A plurality of external teeth are formed on the inner rotor 51, and a plurality of internal teeth are formed on the outer rotor 52, and the outer rotor 52 rotates by rotating the inner rotor 51 while meshing the external teeth and the internal teeth. To do. And in the conveyance partition part 61 [refer FIG.1 (C)] between the suction port termination | terminus part 32 and the discharge port start part 41, the space where the external tooth and the internal tooth were closed, ie, the interdental space J is comprised. Then, the oil is conveyed from the suction port 3 to the discharge port 4. In the non-conveyance partition 62 between the discharge port 4 end portion 42 and the suction port 3 start end portion 31, the inner rotor 51 and the outer rotor 52 rotate while the outer teeth and the inner teeth are in meshing contact with each other.

  First, the outer teeth of the inner rotor 51 and the inner teeth of the outer rotor 52 are meshed with each other in an appropriate state, and the inner rotor 51 and the outer rotor 52 are accommodated in the pump chamber 11 in this state. A shaft hole is formed at the center of the inner rotor 51. Further, the shaft 8 is inserted into the bearing portion 12, and its axial end portion is inserted and fixed in the shaft hole of the inner rotor 51. As a means for fixing the shaft hole of the inner rotor 51 and the shaft end portion of the shaft 8, there are fixing by a key and fixing by a press-fitting means, but the most appropriate one may be selected.

  In a state where the inner rotor 51 and the outer rotor 52 are housed in the pump chamber 11 of the body portion 1, the cover portion 2 is joined to the body portion 1 and fixed by a fixing tool such as a bolt and a nut. The shaft 8 protrudes from the position of the bearing portion 12 to the outside of the pump housing A and is exposed. A rotation transmission wheel 6 is mounted on the shaft end portion of the projecting portion outside the shaft 8 (see FIG. 1A). Further, the rotation transmission wheel 6 is rotated by the rotation drive unit 7 and the shaft 8 is rotated to rotate the inner rotor 51 and the outer rotor 52 of the pump chamber 11.

  The shaft 8 and the rotation transmission wheel 6 are fixed by fixing means, and the fixing means is a key or press-fitting means. The rotation transmission wheel 6 and the rotation drive unit 7 are configured by a gear mechanism, the rotation transmission wheel 6 is a driven gear, and the rotation drive unit 7 is a drive gear (see FIG. 1B). The rotary drive unit 7 used as a drive gear receives power from a power source such as an engine or a motor. Further, the rotation transmission wheel 6 and the rotation drive unit 7 may have a belt wheel structure (see FIG. 4). In this case, the rotation transmission wheel 6 is used as a belt wheel such as a pulley. The rotation drive unit 7 is a V belt or the like. Further, the rotation transmission wheel 6 and the rotation driving unit 7 may be chain driven. In this case, the rotation transmission wheel 6 is a so-called sprocket, and the rotation driving unit 7 is a chain.

  Even if the rotation transmission wheel 6 and the rotation driving unit 7 have the above-described various configurations, the rotation transmission wheel 6 receives pressure from the rotation driving unit 7 when contacting. That is, the rotation drive unit 7 serving as a drive gear is configured to transmit rotation in a good meshing state with an appropriate contact pressure F with respect to the rotation transmission wheel 6 serving as a driven gear. In the case of the belt wheel structure, the rotation transmission wheel 6 such as a pulley receives the contact pressure F as an appropriate tension from the rotation driving unit 7 such as a V belt. Even in the case of the chain mechanism, the rotation transmission wheel 6 that is a sprocket substantially similarly receives a contact pressure F as an appropriate tension from the rotation drive unit 7 that is a chain.

  As described above, the rotation transmission wheel 6 always receives an appropriate contact pressure F by the rotation drive unit 7, and the contact pressure F serves as a constituent member composed of the rotation transmission wheel 6 and the shaft 8. On the other hand, a bending moment M1 is generated [see FIG. 3 (A)]. Due to this bending moment M1, a load is applied to incline the rotation transmission wheel 6 and the shaft 8 in the pressure direction of the contact pressure F. Specifically, the shaft 8 is pivotally supported by the bearing portion 12 of the pump housing A, and is intended to tilt with the bearing portion 12 as the center in the bending moment M1.

  Although the positions of the rotation transmission wheel 6 and the shaft 8 are not displaced by the bending moment M1, the shaft 8 is always urged to cause the shaft 8 to be inclined by an external force due to the bending moment M1, An uneven load acts on the bearing portion 12 on which the shaft 8 is pivotally supported (see FIG. 3A). The bending moment M2 for canceling the bending moment M1 that causes an unbalanced load while having an appropriate contact pressure F will be described below.

  As described above, the cover portion 2 is provided with the suction port 3 and the discharge port 4, and is provided with the suction flow path 33 that communicates with the suction port 3 and the discharge flow path 43 that communicates with the discharge port 4. That is, the pressure applied to the side surface of the inner rotor 51 acts on the side surface 51b of the inner rotor 51 on the cover portion 2 side where the suction port 3 and the discharge port 4 are provided.

  In the cover portion 2, a suction port 3 is formed in the proximity region S1, and a discharge port 4 is formed in the separation region S2. In the proximity region S1, the attractive force p1, p1,... Due to the negative pressure fluid in the suction port 3 acts on the side surface 51b on the cover portion 2 side of the inner rotor 51 housed in the pump chamber 11 of the pump housing A. The side surface 51 b on the cover portion 2 side of the inner rotor 51 is biased so as to be attracted in a direction approaching the cover inner wall surface portion 21 of the cover portion 2.

  In the separation region S2, the pressing force p2, p2,... By the positive fluid at the discharge port 4 acts on the side surface 51b on the cover portion 2 side of the inner rotor 51 housed in the pump chamber 11 of the pump housing A. The side surface 51 b on the cover part 2 side of the inner rotor 51 is pressure-biased in a direction away from the cover inner wall surface part 21 of the cover part 2. That is, the pulling caps p1, p1,... Due to the negative pressure of the fluid on the suction port 3 side and the pressing forces p2, p2... Due to the positive pressure of the fluid on the discharge port 4 side make the suction port 3 and the discharge port 4. It acts on both ends of the side surface 51b of the inner rotor 51 on the cover portion 2 side in the diameter direction (see FIGS. 3B, 3C, and 3D).

  The attractive forces p1, p1,... And the pressing forces p2, p2,... Are distributed loads, and the directions of the forces are opposite to each other. The inner rotor 51 is urged to be inclined with respect to the axial direction in the pump chamber 11 by the attracting forces p1, p1,... Due to the negative pressure of the fluid and the pressing forces p2, p2,. . A bending moment M2 is generated in the inner rotor 51 together with the shaft 8.

  Due to the attractive forces p1, p1,... And the pressing forces p2, p2,..., A bending moment M2 that causes the shaft 8 fixed to the inner rotor 51 to tilt with respect to the axial direction is generated. [Refer FIG. 3 (B)]. This bending moment M2 is intended to tilt in the opposite direction to the tilting direction of the bending moment M1 generated by the contact pressure F. That is, the bending moment M1 and the bending moment M2 cancel out the forces that are inclined to each other, that is, the neutral state of the shaft 8 can be maintained by the both bending moments M1 and M2. Therefore, the shaft 8 can be supported by the bearing portion 12 of the pump housing A in a substantially uniform state along the axial direction.

  In the embodiment according to the present invention, the suction port 3 and the discharge port 4 are formed on the cover part 2 side of the pump housing A, so that the suction side applied to the side surface 51b of the inner rotor 51 on the cover part 2 side is reduced. The pulling force p1, p1,... Due to the negative pressure fluid in the port 3 and the pressing force p2, p2,... Due to the positive fluid in the discharge port 4 try to incline the inner rotor 51 with respect to the axial direction. To do. Further, the suction port 3 and the discharge port 4 may be formed on both the body part 1 and the cover part 2.

  In this case, at least one of the suction port 3 and the discharge port 4 is formed on the body part 1 side. In addition, the suction port 3 and the discharge port 4 formed on the body portion 1 side are appropriately smaller in area than the suction port 3 and the discharge port 4 formed on the cover portion 2 side. Thus, by having a difference in the area of the suction port 3 and the discharge port 4 between the body part 1 side and the cover part 2 side, the suction by the negative pressure fluid acting on the side surface 51b of the inner rotor 51 on the cover part 2 side is achieved. The sizes of the attached pressures p1, p1,... And the pressing forces p2, p2,. That is, the magnitude of the bending moment M2 for tilting the inner rotor 51 with respect to the axial direction can be easily adjusted.

  In this way, the rotation transmission wheel 6 has a bending moment M1 caused by the contact pressure F, the pulling force p1, p1,... Of the suction port 3 on the inner rotor 51, and the pressing force p2,. The bending moment M2 generated by p2,... cancels each other, so that the shaft 8 can be always kept horizontal and neutral with respect to the bearing portion 12 of the pump housing A.

A ... Pump housing, 1 ... Body part, 12 ... Bearing part, 2 ... Cover part,
3 ... suction port, 33 ... suction flow path, 4 ... discharge port, 43 ... discharge flow path,
51 ... Inner rotor, 52 ... Outer rotor, 6 ... Rotation transmission wheel,
7 ... Rotation drive part, 8 ... Shaft, 8k ... Axle, F ... Contact pressure,
M1, M2 ... bending moment, K ... reference center, L ... virtual line, Q ... boundary line,
S1 ... proximity area, S2 ... separation area.

Claims (2)

  A pump housing having a cover portion and a body portion on which a bearing portion is formed and having a pump chamber, a suction port, and a discharge port, a shaft that is rotatably supported by the bearing portion, and fixed to one end of the shaft An inner rotor rotatably disposed in the pump chamber, an outer rotor disposed on the outer peripheral side of the inner rotor, disposed in the pump chamber, and a rotation transmission wheel and the rotation transmission at the other end of the shaft. In the internal gear oil pump provided with a rotation drive unit that transmits rotation while having contact pressure with respect to the vehicle, the rotation transmission vehicle is positioned closer to the body unit side than the cover unit side. And the bearing portion is arranged in the middle of the shaft, and the one end of the shaft against the bending moment generated by the contact pressure on the other end side of the shaft. Opposite direction of bending so moment is generated, an internal gear oil pump and the suction port and the discharge port, characterized by comprising disposed on said pump housing along the direction of the contact pressure. 2. The discharge port according to claim 1, wherein the discharge port is disposed so as to straddle a line passing through the shaft core in the same direction as the pressure direction of the contact pressure with the shaft core of the bearing portion as a reference center. The suction port is disposed so as to extend in a direction opposite to the direction and passing through the axis, the suction port and the discharge port are formed in the cover part, and the cover part communicates with the suction port. An internal gear oil pump comprising: a suction flow path that communicates with the discharge port; and a discharge flow path that communicates with the discharge port.

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