JPH0625582U - Internal gear pump - Google Patents

Abstract

(57) [Summary] [Purpose] In an internal gear pump, stabilizes volumetric efficiency by suppressing changes in the amount of oil that leaks when flowing through the gap formed on the side surface of the gear. A width dimension H of an external gear 7 out of two gears 6, 7 eccentrically arranged so as to be inscribed in a cylindrical hole 2 of a main body 1 is set to be larger than a width dimension H1 of an internal gear 6. It is provided to be smaller than the depth dimension H2 of the cylindrical hole 2, and both gears 6,
7 have different gaps S and K formed between the side surface of the cover member 9 and the inner surface of the cover member 9, and the cover member 9 is generated by the pump operation.
Both gears 6 and 7 increase with the outward deformation of the central part of
The amount of leaked oil flowing on the side of the is kept within an allowable value.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a small, lightweight internal gear pump that is attached to a vehicle engine or transmission to suck and discharge oil.

[0002]

[Prior art]

 As shown in FIGS. 2 and 3, this type of internal gear pump has an internal gear 23 having internal teeth 23A and an external gear having external teeth 24A in a cylindrical hole 22 formed by recessing from one side surface of a main body 21. The gear 24 and the gear 24 are eccentrically rotatably provided so as to be intermeshed with each other and rotatably provided. One side surface of the main body 21 in which the cylindrical hole 22 is opened is closed and the side surfaces of both gears 23 and 24 are slidably contactable A plate-like lid member 25 is jointly arranged on the inner tooth gear 23 and fixed by a plurality of fastening bolts 26, and the external gear 24 is rotationally driven by the drive shaft 26 bearing the main body 21. The gears are driven to rotate in the same direction by the meshing engagement, and the tooth grooves 27 of both gears 23 and 24 suck and discharge the oil of the suction flow passage 28 to the discharge flow passage 29.

[0003]

[Problems to be solved by the device]

 However, in order to reduce the weight of the pump, the strength of each member in this configuration is close to the allowable limit value. Particularly, since the lid member 25 is formed in a thin plate shape, it is distorted by the discharge pressure of oil. As indicated by the chain line E in FIG. 2, the central portion is easily deformed outward. Due to the deformation of the lid member 25, the gap S formed between the side surface of the external gear 24 and the inner side surface of the lid member 25 is greatly enlarged, and the gap S is located on the discharge flow path 29 side through the enlarged gap S. A large amount of oil having a pressure that fills the tooth spaces 27 and 28 of both gears 23 and 24 leaks to the low pressure side, and as a result, it is difficult to obtain a stable volumetric efficiency of the pump. However, in the worst case, there was a problem in that the amount of oil discharged would cause problems with the installed engine or transmission.

The present invention solves such a problem, and suppresses the amount of leaked oil flowing through the side clearances of both gears, which increases with the deformation of the lid member, within a permissible value, and a stable volumetric efficiency can be obtained. It is an object of the present invention to provide an internal gear pump having such a structure.

[0005]

[Means for Solving the Problems]

 Therefore, according to the present invention, an internal gear having internal teeth and an external gear having external teeth are eccentrically rotatably provided in a cylindrical hole formed in the main body so as to be internally meshed, and the cylindrical hole is opened. The opening is closed on one side surface of the main body, and the side surfaces of both gears are slidably brought into contact with a plate-like lid member that is fixedly attached, and the external gear is driven to rotate on the bottom side of the cylindrical hole. A drive shaft is provided so that it can be engaged with a through hole penetrating the tooth gear, and the width dimension of the external gear is larger than the width dimension of the internal gear so that it is formed between the side surface of both gears and the inner surface of the lid member. It has a different gap.

[0006]

[Action]

 In the structure of the present invention, the width dimension of the external gear is set larger than the width dimension of the internal gear, and the gap formed between the side surface of the external gear and the inner surface of the lid member is provided on the side surface of the internal gear. It is smaller than the gap formed between the lid and the inner surface of the lid member, and is formed between both gears and the lid member when the central part of the lid member is deformed outward due to the rise in the pressure of the discharge oil. Since the side gaps are set to be approximately the same, the amount of leaked oil that flows along the sides of both gears, which increases with the deformation of the lid member, can be suppressed within the allowable value, and the volume efficiency is better than the conventional example. Can be stably obtained.

[0007]

【Example】

 Hereinafter, one embodiment in which the present invention is used in a lubricating oil pump for a vehicle engine will be described. In FIG. 1, reference numeral 1 denotes an engine block which constitutes a main body of a pump, and a cylindrical hole 2 is formed by recessing from one side surface, and a lubricating oil suction passage 3 and a discharge passage 4 are opened in a bottom surface of the cylindrical hole 2. It is formed and has a drive shaft 5 protruding from the bottom surface. Reference numeral 6 denotes an internal gear having internal teeth 6A, which is rotatably fitted in the inner circumference of the cylindrical hole 2. Reference numeral 7 denotes an external gear having external teeth 7A, which is externally engaged with the drive shaft 5 through a through hole 8 penetrating the shaft center and is rotatable integrally with the drive shaft 5. The two gears 6 and 7 are eccentrically arranged so as to be intermeshed with each other and arranged in the cylindrical hole 2 so that the lubricating oil can be sucked and discharged by rotation. The external gear 7 has a width H that is larger than the width H1 of the internal gear 6 and smaller than the depth H2 of the cylindrical hole 2 and has a relationship of H1> H> H2. . Reference numeral 9 denotes a plate-like lid member, which is joined and arranged on one side surface of the engine block 1 so as to close the opening of the cylindrical hole 2 and fixed by a plurality of fastening bolts 10. Reference numeral 11 denotes an O-ring, which is arranged in the vicinity of the opening of the cylindrical hole 2 of the engine block 1 to obtain the sealing action of the joint portion with the lid member 9.

Next, the operation of this configuration will be described. In the state shown in FIG. 1, when the external gear 7 is driven to rotate in one direction by the drive shaft 5, the internal gear 6 is driven to rotate in the same direction by internal meshing, and is sucked by the tooth spaces of both gears 6 and 7. The lubricating oil in the flow path 3 is sucked and discharged into the discharge flow path 4. Then, a part of the lubricating oil having the pressure on the discharge flow path 4 side flows through the gaps S and K formed on the side surfaces of both gears 6 and 7 and leaks to the low pressure side. With this operation, when the lid member 9 is distorted by the pressure increase on the discharge flow path 4 side and the central portion thereof is deformed outward as shown by a chain line E, the side surface of the external gear 7 and the inner side surface of the lid member 9 are The gap K formed between the two increases and the amount of leaked oil increases. At this time, the expanding clearance K formed on the side surface of the external gear 7 is provided because the width dimension H of the external gear 7 is larger than the width dimension H2 of the internal gear 6. The gap S formed between the side surface of the toothed gear 6 and the inner surface of the lid member 9 is substantially the same, and the amount of oil leaking out from the side surfaces of both gears 6 and 7 is suppressed within an allowable value, which is good. Stable volume efficiency can be obtained.

Further, in order to suppress the increase in the amount of leaked oil due to the deformation of the lid member 9 within an allowable value, the width K of the external gear 7 is changed so that the gap K formed on the side surface of the external gear 7 is smaller than that of the conventional example. Since the small size is provided, once the pump is started, the increase of the rotational force of the external gear 7 due to the reduction of the clearance caused by the deformation of the lid member 9 due to the discharge pressure is reduced and the both gears 6 are light. , 7 can be rotated, and the operating efficiency of the pump can be improved in combination with the decrease in the amount of leaked oil. Further, in the pump, since the gap K formed on the side surface of the external gear 7 is enlarged after the pump is started, it is possible to improve durability as compared with simply reducing the gap, and to obtain a desired oil amount over a long period of time. It is possible to discharge and discharge and to operate the engine to be installed satisfactorily.

In one embodiment, the side surfaces of the internal gear 6 and the external gear 7 are provided so as to be in direct slidable contact with the bottom surface of the cylindrical hole 2 and the inner side surface of the lid member 9. It is needless to say that a side plate specially provided so as to be in slidable contact with the side surfaces of both gears 6 and 7 may be arranged in the cylindrical hole 2 without being limited thereto.

[0011]

[Effect of device]

 As described above, according to the present invention, the internal gear and the external gear are eccentric to each other so as to internally mesh with the cylindrical hole formed in the main body and having the opening closed by the plate-like lid member. A rotatably mounted internal gear pump, in which the width dimension of the external gear is larger than the width dimension of the internal gear, and a gap is formed between the side surfaces of both gears and the inner surface of the lid member. Due to the different pressures, the amount of leaked oil flowing on the side surfaces of both gears should be kept within the allowable value when the central part of the lid member is deformed outward due to the pressure on the discharge flow path side that rises due to pump operation. Therefore, good volume efficiency can be stably obtained. Further, since the reduced clearance formed on the side surface of the external gear is enlarged by the operation of the pump, the increase of the rotational force of the external gear is reduced, the external gear can rotate lightly, and its durability can be improved. The pump can discharge a desired amount of oil over a long period of time, and can favorably operate an engine, a transmission, etc. to which the pump is attached.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an internal gear pump showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA in FIG. 3 showing a conventional example.

3 is a cross-sectional view taken along the line BB of FIG.

[Explanation of symbols]

 1 Main Body 2 Cylindrical Hole 5 Drive Shaft 6 Internal Gear 7 External Gear 9 Lid K, S Gap

Claims (1)

[Scope of utility model registration request] 1. An internal gear having internal teeth and an external gear having external teeth are eccentrically rotatably provided so as to be inscribed in a cylindrical hole formed in the main body, and the cylindrical hole is opened. An external gear that closes the opening on one side of the main body and a plate-like lid member is jointly arranged and fixed so that the side faces of both gears are slidably contactable, and the external gear is rotationally driven on the bottom side of the cylindrical hole. A drive shaft is provided so as to be engageable with a through hole penetrating through the gear, and the width dimension of the external gear is larger than the width dimension of the internal gear so that it is formed between the side surfaces of both gears and the inner surface of the lid member. Internal gear pump with different gaps