JP2018044485A - Pump drive structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent breakage of a pump when the rotation of a rotor is locked.SOLUTION: A pump drive structure comprises: a drive shaft 20 in which a male screw part 25 is formed at one end side, gear fixation parts 22A, B to which an inner rotor 11 is fixed are formed at the other end side, and an annular step part 21 is formed between the male screw part 25 and the gear fixing parts 22A, B; a driven gear 30 which is clearance-fit and inserted between the male screw part 25 of the drive shaft 20 and the annular step part 21, and whose one-side face is made to abut on the annular step part 21; a washer member 40 which is fit between the male screw part 25 of the drive shaft 20 and the driven gear 30; and a nut member 50 which is screwed to the male screw part 25, brings the washer member 40 into pressure-contact with the other side face of the driven gear 30, and holds the driven gear 30 by the washer member 40 and the annular step part 21.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a drive structure for a pump.

  Generally, in a transmission, in order to reduce friction generated in a transmission gear, a bearing, and the like, lubricating oil is supplied to a transmission element and a sliding element in the transmission case. For example, trochoid pumps are often used as pumps for supplying such lubricating oil (see, for example, Patent Documents 1 and 2).

  The trochoid pump includes an inner rotor fixed to the pump shaft, an outer rotor arranged eccentrically with respect to the center of rotation of the inner rotor, and a housing that accommodates each of the rotors, and the outer rotor is interlocked with the rotation of the inner rotor. The lubricant oil is pumped by changing the volume of the pump chamber formed between the rotors.

JP, 2006-001037, A JP, 2006-001038, A

  By the way, when the foreign material contained in lubricating oil bites into the rotor of the trochoid pump, the rotation of the rotor may be locked. When torque is continuously transmitted from the pump shaft to the inner rotor in such a state, there is a problem that a large load is applied to each rotor and the rotor, the housing, and the like are damaged.

  The technology of the present disclosure aims to effectively prevent the pump from being damaged when the rotation of the rotor is locked.

  The technology of the present disclosure is a drive structure of a pump including a pair of gears meshing with each other, a male screw portion is formed on one end side, and one gear of the pair of gears is fixed on the other end side. A drive shaft in which an annular step portion is formed between the male screw portion and the gear fixing portion, and a gap between the male screw portion and the annular step portion of the drive shaft. A power transmission element that is inserted and fitted with one side surface thereof in contact with the annular stepped portion to transmit power from a drive source to the drive shaft; and the male screw portion and the power transmission element of the drive shaft; A washer member inserted between the washer member and the male screw portion, and the washer member is brought into pressure contact with the other side surface of the power transmission element so that the power transmission element is connected to the washer member and the annular stepped portion. And a nut member to be sandwiched between It is characterized in.

  The power transmission element may include a drive gear fixed to a shaft to which power is transmitted from the drive source, and a driven gear that meshes with the drive gear and is inserted into the drive shaft with a clearance. .

  Further, the washer member may be fixed to the drive shaft by two-face width fitting.

  The pump is a trochoid pump, wherein one of the pair of gears is an inner rotor having a plurality of external teeth, and the other gear is an outer rotor having a plurality of internal teeth meshing with the external teeth. There may be.

  The pump is a gear pump, wherein one of the pair of gears is a drive gear having a plurality of first gear teeth, and the other gear is a plurality of second gears meshed with the first gear teeth. A driven gear having gear teeth may be used.

  According to the technique of the present disclosure, it is possible to effectively prevent the pump from being damaged when the rotation of the rotor is locked.

It is typical sectional drawing which shows the drive structure of the pump which concerns on one Embodiment of this invention. It is typical sectional drawing which shows a part of pump which concerns on one Embodiment of this invention. It is a typical disassembled perspective view which shows the principal part of the drive structure of the pump which concerns on one Embodiment of this invention. It is typical sectional drawing which shows the pump shaft and washer member which concern on one Embodiment of this invention. It is typical sectional drawing which shows the pump which concerns on other embodiment.

  A pump drive structure according to an embodiment of the present invention will be described below with reference to the accompanying drawings. The same parts are denoted by the same reference numerals, and their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  As shown in FIGS. 1 and 2, the pump 10 of the present embodiment is, for example, a trochoid pump used for supplying lubricating oil for a transmission, and includes an inner rotor 11 having a plurality of external teeth, and external teeth of the inner rotor 11. The outer rotor 12 that has a plurality of meshing internal teeth and is eccentric with respect to the rotation center of the inner rotor 11, the pump housing 13 that houses the rotors 11, 12, and the opening side of the pump housing 13 are not shown. A pump cover 14 (shown only in FIG. 1) fixed with bolts, a suction port and a discharge port (not shown) formed in the pump housing 13, and a pump shaft (drive shaft) for transmitting power (torque) to the inner rotor 11 20.

  In the pump 10, when the inner rotor 11 is rotated by the power transmitted from the pump shaft 20 and the outer rotor 12 is also rotated in conjunction with this, the volume of the pump chamber formed between the rotors 11 and 12 changes. The lubricating oil sucked into the suction port (not shown) is discharged from the discharge port (not shown).

  As shown in FIG. 1, the pump shaft 20 has a substantially cylindrical shape whose distal end side is smaller in diameter than the proximal end side, and between the small diameter portion 20A on the distal end side and the large diameter portion 20B on the proximal end side. An annular step portion 21 is formed.

  Two flat surfaces 22A and 22B (see FIG. 2) facing each other are chamfered on the base end side (large diameter portion 20B) of the pump shaft 20, and the inner rotor 11 can rotate integrally by two-surface width fitting. It is fixed to. In addition, the fixing method of the inner rotor 11 and the pump shaft 20 is not limited to two-sided width fitting, and may be key coupling or spline fitting.

  As shown in FIGS. 1 and 3, a gear insertion portion 23, a washer insertion portion 24, and a male screw portion 25 are formed on the distal end side (small diameter portion 20 </ b> A) of the pump shaft 20 in order from the annular stepped portion 21 side. Yes.

  The gear insertion portion 23 is formed so that its outer diameter is slightly smaller than the inner diameter of the through hole 31 of the driven gear 30. The axial length of the gear insertion portion 23 is preferably slightly shorter than the rotational axis width of the driven gear 30. The driven gear 30 is fitted into the gear insertion portion 23 with a gap fitted in a state where one side surface (the right side surface in the figure) is in contact with the annular step portion 21.

  The driven gear 30 always meshes with a drive gear 34 fixed to the counter shaft 33 of the transmission. That is, the power transmitted from the engine (drive source) (not shown) to each transmission element of the transmission is always transmitted from the counter shaft 33 to the driven gear 30 via the drive gear 34. . The shaft on which the drive gear 34 is provided may be a main shaft of a transmission or the like as long as power from a drive source is transmitted.

  Two flat surfaces 24A and 24B (see FIG. 4) facing each other are chamfered in the washer insertion portion 24, and the washer member 40 is inserted so as to be integrally rotatable by two-surface width fitting. The axial length of the washer fitting portion 24 is preferably formed to be equal to or slightly shorter than the axial length of the washer member 40.

  The washer member 40 has a substantially annular shape, and a pair of fitting flat portions 41A and 41B that come into contact with the flat surfaces 24A and 24B of the washer fitting portion 24 are formed in the through hole 41 thereof. The washer member 40 is fitted into the washer insertion portion 24 with one side surface (right side surface in the figure) in contact with the other side surface (left side surface in the figure). In addition, the fixing method of the washer member 40 and the pump shaft 20 is not limited to the two-surface width fitting, and may be key coupling or spline fitting.

  A nut member 50 is screwed into the male screw portion 25. When the nut member 50 is screwed into the male screw portion 25 and tightened, the washer member 40 is pressed into contact with the driven gear 30, and the driven gear 30 fitted into the pump shaft 20 with a gap is fitted between the washer member 40 and the annular step portion 21. It is pinched by. That is, the power transmitted from the drive source to the drive gear 34 via the counter shaft 33 is transmitted from the driven gear 30 to the pump shaft 20 via the washer member 40 and the annular stepped portion 21, thereby driving the pump 10. It is supposed to let you. The tightening amount of the nut member 50 may be adjusted to an optimal amount as appropriate according to the specifications of the pump 10 and the sizes of the gears 30 and 34.

  According to the present embodiment configured as described above, when the foreign matter is caught in the rotors 11 and 12 of the pump 10 and the rotation of the rotors 11 and 12 is locked, the driven gear 30 is held on the pump shaft 20. When the clamping force of the washer member 40 and the annular step portion 21 is lost to the power (torque) transmitted from the drive gear 34 to the driven gear 30, the driven gear 30 fitted into the pump shaft 20 with a gap is fitted to the pump shaft 20. On the other hand, it rotates relative (idle). That is, when the rotation of the rotors 11 and 12 is locked, the driven gear 30 is idled so that torque transmission from the driven gear 30 to the pump shaft 20 is interrupted. As a result, it is possible to effectively prevent a large load from being applied to the locked rotors 11 and 12, and damage to the rotors 11 and 12 and the pump housing 13 can be reliably prevented.

  In addition, this invention is not limited to the above-mentioned embodiment, In the range which does not deviate from the meaning of this invention, it can change suitably and can implement.

  For example, the pump 10 is not limited to a trochoid pump, and may be a gear pump in which a drive gear 16 and a driven gear 17 are housed in a pump housing 13 as shown in FIG.

  Further, the shape of the washer member 40 is not limited to the flat plate shape in the illustrated example, and may be another shape such as a disc spring shape.

  Further, the power transmission element fitted into the pump shaft 20 with a gap is not limited to the driven gear 30, and other power transmission elements such as a driven sprocket over which an endless chain is extended and a driven pulley over which an endless belt is extended. There may be.

  Further, the pump 10 is not limited to an oil pump for a transmission, and can be widely applied to an oil pump that circulates lubricating oil in an engine, a fuel pump that pumps fuel to an in-cylinder injector, and the like.

DESCRIPTION OF SYMBOLS 10 Pump 11 Inner rotor 12 Outer rotor 13 Pump housing 14 Pump cover 20 Pump shaft 20A Small diameter part 20B Large diameter part 21 Annular level difference part 23 Gear insertion part 24 Washer insertion part 25 Male screw part 30 Drive gear 33 Counter shaft 34 Drive gear 40 Washer member 50 Nut member

Claims (5)

A pump drive structure including a pair of gears meshing with each other,
A male screw portion is formed on one end side, and a gear fixing portion to which one of the pair of gears is fixed is formed on the other end side, and an annular shape is formed between the male screw portion and the gear fixing portion. A drive shaft formed with a stepped portion;
Power that is inserted into the gap between the male screw portion of the drive shaft and the annular step portion, and that transmits power from a drive source to the drive shaft with one side surface being brought into contact with the annular step portion. A transmission element;
A washer member fitted between the male screw portion of the drive shaft and the power transmission element;
A nut member that is screwed into the male screw portion, presses the washer member against the other side surface of the power transmission element, and clamps the power transmission element between the washer member and the annular stepped portion. A pump drive structure characterized by that. The power transmission element includes a drive gear fixed to a shaft to which power is transmitted from the drive source, and a driven gear that meshes with the drive gear and that is inserted into the drive shaft with a gap. The pump drive structure described. The drive structure of the pump according to claim 1, wherein the washer member is fixed to the drive shaft by two-plane width fitting. The pump is a trochoid pump, wherein one gear of the pair of gears is an inner rotor having a plurality of external teeth, and the other gear is an outer rotor having a plurality of internal teeth meshing with the external teeth. Item 4. The pump drive structure according to any one of Items 1 to 3. The pump is a gear pump, and one of the pair of gears is a drive gear having a plurality of first gear teeth, and the other gear is a plurality of second gear teeth meshing with the first gear teeth. The drive structure of the pump according to any one of claims 1 to 3, wherein the drive gear has a drive gear.

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