JP3960517B2 - Oil pump structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to the structure of an oil pump.
[0002]
[Prior art]
A configuration in which a relief valve for adjusting hydraulic pressure is provided in an oil pump is known. For example, Japanese Utility Model Publication No. 60-24882 discloses a technique of disposing a relief valve in an oil discharge passage from a pump unit.
[0003]
[Problems to be solved by the invention]
In the case of an oil pump, when the structure of the pump unit includes, for example, a rotary pump mechanism, it is known that a slight period of fluctuation (pulsation) occurs in the oil discharge pressure from the pump unit. . Therefore, when a relief valve is arranged in the discharge passage as in the prior art, the relief valve is directly affected by this pulsation, and there is a problem that the operation of the relief valve tends to become unstable.
[0004]
The present invention was created to solve the above problems, and an object of the present invention is to provide an oil pump structure that can reduce the influence of oil pulsation on a relief valve and thereby stabilize the operation of the relief valve. It is said.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, the present invention includes a hollow knock pin that forms part of the discharge passage of the oil pump, an elastic member is provided on the inner surface of the knock pin, and a downstream side of the discharge passage is formed on the knock pin. Branching into a downstream discharge passage and a branch passage, a relief valve is disposed in the branch passage, and an oil flow direction in the discharge passage upstream of a branch point between the downstream discharge passage and the branch passage The oil pump structure is characterized in that a bent portion directed to the downstream discharge passage is formed, and the elastic member is provided at a position opposite to the oil flow direction changed by the bent portion .
[0009]
The branch passage is bent so that the downstream side thereof is aligned with the upstream side of the discharge passage, and the relief valve has an oil pump structure arranged in the bent downstream branch passage.
[0010]
With this structure, the relief valve can be arranged in a compact manner, and the oil pump can be downsized.
[0011]
Furthermore, an oil pump structure is provided in which an elastic member is provided at a position facing the oil flow direction in the branch passage.
[0012]
With this structure, oil pulsation is effectively attenuated on the front side of the relief valve in the branch passage, and the operation of the relief valve can be further stabilized.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the invention will be described with reference to the drawings. 1 is a longitudinal sectional view of an oil pump according to the present invention, FIG. 2 is a sectional view taken along line AA in FIG. 1, and FIG. 3 is a sectional view taken along line BB in FIG.
[0014]
The oil pump 1 in this embodiment is a rotary oil pump installed in an oil pan of a vehicle engine, and is a two-rotor type having two sets of rotors. In FIG. 1 or FIG. 3, both the first pump unit 10 and the second pump unit 20 have a configuration in which an inner rotor 2 having external teeth and an outer rotor 3 having internal teeth mesh with each other, and are accommodated in a housing 4. Rotating and driving by one gear shaft 5 serves as a pump.
[0015]
In the first pump unit 10 and the second pump unit 20, as shown in FIG. 3, the inner rotor 2 has six external teeth, and a through hole 2 a through which the gear shaft 5 is inserted is formed at the center. Yes. Although not described in detail, the inner rotor 2 is fixed to the gear shaft 5 via a knock pin 2b.
[0016]
The outer rotor 3 has the same thickness as the inner rotor 2 and has a circular outer periphery. Seven inner teeth are formed on the inner periphery of the outer rotor 3, one more than the number of outer teeth of the inner rotor 2. The outer rotor 3 and the inner rotor 2 are positioned so that their centers are eccentric from each other, and FIGS. 1 and 3 show a state in which only the lower teeth mesh with each other. Then, by rotating the inner rotor 2, oil is sent from the suction port 6 to the discharge port 7 (see FIG. 2, indicated by a virtual line in FIG. 3) while changing the space between the inner teeth and the outer teeth. It is like that.
[0017]
The housing 4 is a member that covers one side of the inner rotor 2 and the outer rotor 3 and the outer periphery of the outer rotor 3 and forms the suction port 6. As shown in FIG. 1, the housing 4 is integrally formed with a bearing portion 4 a that supports the gear shaft 5. On one end side of the gear shaft 5, a sprocket portion 5 a for transmitting rotational force to the gear shaft 5 by being connected to a sprocket (not shown) provided on the crankshaft of the internal combustion engine by a chain is formed. Yes.
[0018]
The spacer 8 is a member that constitutes a part of the casing of the oil pump 1 that is provided to take a space between the first pump unit 10 and the second pump unit 20. The housing 4 described above is attached to both side surfaces. An oil discharge passage 9 (FIG. 2) from the first pump unit 10 and the second pump unit 20 is formed in the spacer 8. That is, on the upstream side of the discharge passage 9, a portion facing the space between the outer teeth of the inner rotor 2 and the inner teeth of the outer rotor 3 constitutes the discharge port 7 (the portion surrounded by the oblique lines in FIG. 2).
[0019]
With reference to FIG. 2, in the spacer 8, the discharge passage 9 extends obliquely downward from the discharge port 7, and a bent portion 11 is formed to change the oil flow direction in the middle. In the present embodiment, the discharge passage 9 on the downstream side of the bent portion 11 extends vertically upward, and the downstream end port of the discharge passage 9 communicates with the main gallery (not shown) side. Is configured. Specifically, a knock pin 12a having a hollow shape for positioning with respect to a cylinder block (not shown) is fitted into the spacer 8, and the tip of the knock pin 12a constitutes the oil discharge part 12.
[0020]
In the bent portion 11 or in the vicinity of the bent portion 11, the discharge passage 9 extends in a direction opposite to the oil flow direction in the downstream discharge passage (downstream discharge passage 9 b) in a cross-sectional view. A branch passage 13 is formed. That is, in the relationship between the upstream discharge passage (upstream discharge passage 9a), the downstream discharge passage 9b, and the branch passage 13, the downstream discharge passage 9b and the branch passage are substantially T-shaped when viewed in cross-section so as to be positioned in a straight line. It is set as the structure to be made.
[0021]
The branch passage 13 branched from the discharge passage 9 is extended downward, and then bent and formed in a substantially right angle toward the discharge port 7 side, that is, toward the upstream side of the discharge passage 9 in the cross-sectional view. The And the relief valve 14 is arrange | positioned in the extension site | part of the branched passage 13 after this bending. A well-known structure can be applied as the relief valve 14. Further, a pair of discharge ports 15 communicating with the oil pan side are formed in the peripheral wall portion of the extended portion of the branched passage 13 after bending.
[0022]
According to the above structure, the branch passage 13 is formed by branching the oil discharge pressure fluctuation (pulsation) in the discharge passage 9 (downstream discharge passage 9b) downstream of the bent portion 11 in the opposite direction to the downstream discharge passage 9b. Difficult to get to the side. In FIG. 2, the oil flow direction in the downstream discharge passage 9b is indicated by reference symbol P1, and the oil flow direction in the branch passage 13 is indicated by reference symbol P2. The flow directions of the two are opposite to each other by 180 degrees. It is easy to see that Therefore, since the oil pulsation becomes difficult to be transmitted to the branch passage 13 side, the operation of the relief valve 14 disposed in the branch passage 13 is stabilized, and the supply of oil to the downstream side (main gallery side) is stabilized. The effect is played.
[0023]
Next, in the present embodiment, as shown in FIG. 2, a pulsation suppressing wall 16 having a wall surface substantially orthogonal to the oil flow direction in the discharge passage 9 is formed at a position facing the branch passage 13. . The “oil flow direction in the discharge passage 9” herein refers to the oil flow direction immediately before colliding with the pulsation suppression wall 16.
[0024]
Therefore, in FIG. 2, due to the presence of the bent portion 11, the oil flow direction is indicated by a symbol P <b> 3, and the pulsation suppressing wall 16 is formed so as to be a wall surface orthogonal to the oil flow direction P <b> 3. . As described above, the pulsation suppression wall 16 is formed at a position facing the branch passage 13, and as can be seen from FIG. 2, the wall surface of the pulsation suppression wall 16 extends in the extending direction of the branch passage 13 (that is, the oil flow). It becomes the structure which exhibits an inclined surface with respect to the direction P2).
[0025]
In the case of the embodiment shown in FIG. 2, the downstream discharge passage 9 b is formed on the back side of the drawing in FIG. 2 with respect to the pulsation suppressing wall 16. However, even in this case, the downstream discharge passage 9b and the branch passage 13 are formed to be substantially straight with a predetermined overlap margin without being completely stepped.
[0026]
Thus, if the pulsation suppression wall 16 having a wall surface substantially orthogonal to the oil flow direction in the discharge passage 9 is formed, the pulsation in the discharge passage 9 is effectively attenuated by the pulsation suppression wall 16. Become. Since the pulsation suppression wall 16 is formed at a position facing the branch passage 13, the damped pulsation can be effectively reflected on the branch passage 13 side, and thereby the relief disposed in the branch passage 13. The operation of the valve 14 is stabilized, and the effect that the oil supply to the downstream side (main gallery side) is stabilized is exhibited.
[0027]
Further, as described above, the branch passage 13 extends downward, and is bent and formed at a substantially right angle toward the discharge port 7 in the middle, that is, toward the upstream side of the discharge passage 9. In other words, the branch passage 13 is bent so that the downstream side thereof is aligned with the upstream discharge passage 9 (upstream discharge passage 9a), and the relief valve 14 is arranged in the branch passage 13 after the bending.
[0028]
With this configuration, the relief valve 14 can be arranged in a compact manner, and the oil pump 1 can be downsized.
[0029]
Further, as shown in FIG. 4, if the elastic member 17 is provided in a position facing the oil flow direction P <b> 2 in the branch passage 13, oil pulsation is effective on the front side of the relief valve 14 in the branch passage 13. Therefore, the operation of the relief valve 14 can be further stabilized.
[0030]
The elastic member 17 is made of a rubber material, for example. In the example shown in FIG. 4, the elastic member 17 is disposed so as to be orthogonal to the oil flow direction P <b> 2 in the branch passage 13 at or near the bent portion of the branch passage 13. Specifically, the elastic member 17 is a member having a disk shape, for example, and is disposed in the branch passage 13 so that the disk surface portion is orthogonal to the oil flow direction P2.
[0031]
As a means for attaching the elastic member 17, for example, a slit 18 is formed in each of the spacer 8 and the housing 4, and in a state where the spacer 8 and the housing 4 are joined as shown in FIG. It is set to be fitted and held inside. By setting it as such an attachment aspect, a simple attachment structure is implement | achieved and an assembly | attachment operation | work becomes easy.
[0032]
As described above, with the structure in which the elastic member 17 is provided at a position facing the oil flow direction P <b> 2 in the branch passage 13, the elastic member 17 is elastically deformed along with the oil pulsation, and thus in the branch passage 13. The pulsation will be attenuated. Further, as shown in FIG. 4, if the elastic member 17 is thin and disposed so that the surface portion is orthogonal to the oil flow direction P2, the elastic deformation of the elastic member 17 increases. As a result, the degree of attenuation of the pulsation is increased, and the operation of the relief valve 14 is further stabilized.
[0033]
Further, as shown in FIG. 4, in the discharge passage 9, for example, by providing the elastic member 19 at a position facing the oil flow direction P <b> 3 in the bent portion 11 (for example, the wall surface portion of the downstream discharge passage 9 b), Because of the elastic deformation of the elastic member 19, the pulsation can be damped in advance when the oil flows into the branch passage 13, so that the operation of the relief valve 14 can also be stabilized by this structure. The elastic member 19 is also made of, for example, a rubber material, and is fixed to the wall surface of the discharge passage 9 in a thin shape. If the elastic member 19 is fixed to the inner surface of the hollow positioning knock pin 12a in which the discharge passage 9 (downstream discharge passage 9b) is formed inside by being fitted to the spacer 8, the elastic member 19 is attached. Becomes easy.
[0034]
The preferred embodiments of the present invention have been described above. However, the layout, shape, number, etc. of each component are not limited to those described in the drawings, and the present invention can be appropriately changed in design without departing from the spirit of the present invention. Is possible.
[0035]
【The invention's effect】
According to the present invention, oil pulsation in the discharge passage is hardly transmitted to the branch passage side, can be effectively attenuated, and the operation of the relief valve provided in the branch passage can be stabilized. In addition, the relief valve can be arranged in a compact manner, and the oil pump can be downsized.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of an oil pump according to the present invention.
FIG. 2 is a cross-sectional view taken along the line AA in FIG.
3 is a cross-sectional view taken along line BB in FIG.
4 is a cross-sectional view taken along the line AA in FIG. 1 (partially omitted), and is an explanatory diagram of a mode in which an elastic member is provided.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Oil pump 9 Discharge passage 10, 20 Pump part 11 Bending part 13 Branching passage 14 Relief valve 16 Pulsation suppression wall 17 Elastic member

Claims (3)

A hollow knock pin that forms part of the discharge passage of the oil pump is provided, and an elastic member is provided on the inner surface of the knock pin,
The downstream side of the discharge passage is branched into a downstream discharge passage formed in the knock pin and a branch passage, and a relief valve is disposed in the branch passage,
In the discharge passage upstream of the branch point between the downstream discharge passage and the branch passage, a bent portion that directs the oil flow direction toward the downstream discharge passage is formed,
An oil pump structure characterized in that the elastic member is provided at a position opposite to a flow direction of oil whose flow direction is changed by the bent portion. The branch passage is formed by bending so that its downstream side along with the upstream side of said discharge passage, said relief valve, according to claim 1, characterized in that disposed downstream of the branch path and the bent Oil pump structure. The oil pump structure according to claim 2 , wherein an elastic member is provided at a position facing the oil flow direction in the branch passage.

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