WO2014199489A1

WO2014199489A1 - Gear wheel pump or motor

Info

Publication number: WO2014199489A1
Application number: PCT/JP2013/066358
Authority: WO
Inventors: 光平松田
Original assignee: 株式会社島津製作所
Priority date: 2013-06-13
Filing date: 2013-06-13
Publication date: 2014-12-18
Also published as: JP6252802B2; JPWO2014199489A1

Abstract

　A gear wheel pump or a motor comprising a pair of meshing gear wheels, a side plate adjacent to the side surfaces of the gear wheels, a casing provided with a gear wheel accommodating chamber for accommodating the gear wheels and bearing holes into which shafts for supporting the gear wheels can be fitted, and a gasket mounted in a gasket-mounting groove provided to the side plate or the casing, wherein a configuration is employed in which a through-hole passing through the side plate in a thickness direction is provided at a location in the side plate that opposes the location where the pair of gear wheels mesh, and a pocket passing through the gasket in the thickness direction and forming a space sectioned off by the side plate, the casing, and the gasket is provided at a location in the gasket that faces the through-hole.

Description

Gear pump or motor

The present invention relates to a gear pump or a motor that is used in industrial vehicles and the like and sends out hydraulic fluid using the tooth spaces of at least a pair of gears that mesh with each other.

Conventionally, in a circumscribed gear pump that feeds hydraulic fluid using the gear grooves of at least a pair of gears that mesh with each other, a movable side plate is provided near the side surface of these gears to reduce the amount of hydraulic fluid leaked to the side. It is known to cause the problem (see, for example, Patent Document 1). The movable side plate in this type of gear pump is driven by the hydraulic pressure of the working fluid confined in the space defined by the teeth of the gears a2 and a3 and the sliding surface a6a of the side plate a6 (hereinafter referred to as the gear sliding portion S). The teeth a2 and a3 receive force in the direction away from the wheel, but the seal part formed between the surface opposite to the sliding surface a6a of the side plate a6, that is, the non-sliding surface, and the inner peripheral surface of the casing (not shown) By introducing high-pressure hydraulic fluid, a force opposite to this force, that is, a force in a direction approaching the gears a2 and a3, is applied to the side plate a6 so as to maintain the pressure balance.

Here, the hydraulic pressure of the hydraulic fluid confined between the teeth changes as follows with the passage of time. First, in the state shown in FIG. 6A and point A in FIG. 5, the hydraulic pressure of the working fluid confined in the gear sliding portion S, that is, the gear sliding portion closing pressure is equal to the suction pressure. On the other hand, since the pressure of the seal portion is equal to the discharge pressure, the side plate is pressed against the gear, and a large loss torque is generated. Next, between the state shown at point B in FIGS. 6B and 5 and the state shown at point C in FIGS. 6C and 5, the pressure of the seal portion is equal to the discharge pressure. On the other hand, the gear sliding portion closing pressure is higher than the discharge pressure because the hydraulic fluid is compressed between the teeth. Therefore, a clearance is generated between the side surfaces of the gears a2 and a3 and the side plate a6, and liquid leakage from the side surfaces of the gears is likely to occur.

Thus, in this type of conventional gear pump, the force pressing the side plate a6 against the gears a2 and a3 from the seal portion side, that is, the non-sliding surface a6b side, separates the side plate a6 from the

gears

2 and 3 from the gear sliding portion S. The area of the portion into which the high-pressure hydraulic fluid in the seal portion is introduced is set so that the sliding surface a6a does not seize while being slightly larger than the pressing force. By setting in this way, it can suppress that a hydraulic fluid leaks from the clearance gap between the gearwheels a2 and a3 and the side plate a6.

However, when set as described in the previous stage, the force pressing the side plate a6 against the gears a2 and a3 from the non-sliding surface a6b side is greater than the force pressing the side plate a6 away from the gears a2 and a3 from the gear sliding portion S. Since it is made slightly larger, the frictional force generated between the gears a2, a3 and the side plate a6 becomes larger, resulting in a problem that the loss torque becomes larger.

JP 2003-83262 A

The present invention pays attention to the above points, and an object thereof is to realize a gear pump or motor having a configuration capable of achieving both suppression of hydraulic fluid leakage from the gap between the gear and the side plate and reduction of loss torque.

In order to solve the above-described problems, the gear pump or motor according to the present invention has a configuration as described below. That is, the gear pump or motor according to the present invention includes at least a pair of meshing gears, side plates adjacent to the side surfaces of the gears, a gear storage chamber for storing the gears, and a bearing into which a shaft for supporting the gears can be fitted. A gear pump or motor comprising a casing having a hole and a gasket mounted in the side plate or a gasket mounting groove provided in the casing, wherein the thickness of the side plate is opposed to a position where the gear meshes with the side plate. A through-hole penetrating in the vertical direction is provided, and a space defined by the side plate, the casing, and the gasket is formed at a location facing the through-hole of the gasket in the thickness direction of the gasket. A pocket is provided.

In such a case, when the hydraulic fluid is compressed between the teeth, the hydraulic fluid is guided to the space inside the pocket of the gasket through the through hole, so that the pressure of the gear sliding portion is reduced and the seal is The leakage of the hydraulic fluid can be suppressed in balance with the force resulting from the pressure from the part side. From this, it is not necessary to press the side plate strongly against the gear side when the hydraulic pressure of the working fluid confined between the teeth, that is, the gear sliding portion closing pressure is equal to the suction pressure, and the loss torque is reduced. Can do.

Further, as a configuration for facilitating the design for balancing the force acting on the side plate due to the hydraulic pressure, the counterbore is connected to the end of the through hole on the gear side. The thing which provides the part is mentioned.

According to the present invention, it is possible to realize a gear pump or motor having a configuration capable of achieving both suppression of hydraulic fluid leakage from the gap between the gear and the side plate and reduction of loss torque.

Schematic which shows the gear pump which concerns on one Embodiment of this invention. The figure which shows the side plate of the gear pump which concerns on the same embodiment. FIG. 3 is a sectional view taken along line AA in FIG. 2. Operation | movement explanatory drawing of the gear pump which concerns on the same embodiment. The figure which shows the time-dependent change of the relationship between the rotation angle of the gear of the embodiment, and the force which acts on a side plate. Operation | movement explanatory drawing of the conventional gear pump.

One embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, the gear pump according to the present embodiment mainly includes a casing 1 having a gear housing chamber 11x therein, and an external gear that is housed and held in the gear housing chamber 11x of the casing 1 and meshes with each other. A pair, that is, a drive gear 2 and a driven gear 3,

movable side plates

6 and 6 that are in contact with both

side surfaces

2 a and 3 a of the

gears

2 and 3, and shafts 4 and 5 that support the

gears

2 and 3. The side plate 6 in a state where it is mounted in the bush 7 disposed between the

bearing holes

12a, 12b, 11a, 11b and the shafts 4, 5 and the

gasket mounting grooves

6x, 6x provided in the

side plates

6, 6. 6 and

gaskets

8, 8 located between the casing 1.

The drive gear 2 and the driven gear 3 are well-known ones provided with a plurality of tooth bodies at predetermined intervals along the outer peripheral surface as shown in FIG. In the present embodiment, the drive shaft 4 is integrally extended from the center of the drive gear 2 in the rotational axis direction, and the driven shaft 5 is integrally extended from the driven gear 3 in the rotational axis direction. However, the drive gear 2 and the drive shaft 4 may be configured separately, and the driven gear 3 and the driven shaft 5 may be configured separately.

As shown in FIG. 1, the casing 1 is composed of a body 11 having the gear housing chamber 11x and a front cover 12 serving as a cover for closing the opening surface of the gear housing chamber 11x. The body 11 is fitted with the substantially spectacle-shaped gear storage chamber 11x that stores the gear pair, that is, the drive gear 2 and the driven gear 3 in mesh, and the drive shaft 4 and the driven shaft 5 that communicate with the gear storage chamber 11x. Possible bearing

holes

11a and 11b are formed. A bush 7 is fitted into the bearing hole 11a near the position where the drive gear 2 is to be inserted, and one end of the drive shaft 4 is fitted into the bush 7 in a rotatable state. On the other hand, a bush 7 is also fitted in the bearing hole 11b near the position where the driven gear 3 is to be inserted, and one end of the driven shaft 5 is fitted in this bush 7 in a rotatable state. Although not shown, the body 11 is provided with a suction port and a discharge port at positions facing the meshing portion of the drive gear 2 and the driven gear 3. The front cover 12 is detachably mounted on the body 11 with bolts or the like, for example, and closes the front opening surface of the gear housing chamber 11x, and a bearing hole into which the drive shaft 4 and the driven shaft 5 can be respectively inserted. 12a and 12b are formed. A bush 7 is fitted into the bearing hole 12a near the position where the drive gear 2 is to be inserted, and one end of the drive shaft 4 is inserted into the bush 7 so as to be rotatably supported. On the other hand, a bush 7 is fitted into the bearing hole 12b near the position where the driven gear 3 is to be inserted, and one end of the driven shaft 5 is inserted into the bush 7 so as to be rotatably supported.

As shown in FIGS. 1 to 3, the movable side plate 6 is disposed at two locations so as to be in contact with both

side surfaces

2 a and 3 a of the drive gear 2 and the driven gear 3, and each side surface of the drive gear 2 and the driven gear 3. It is for sealing 2a and 3a, respectively. Here, high-pressure hydraulic fluid is introduced from the discharge port into the high-pressure side region on the sliding surface 6 a side of the movable side plate 6, and the drive gear 2, the driven gear 3 and the

movable side plates

6, 6 are connected to the casing 1. A sealed portion 6b1 capable of introducing a high-pressure fluid is formed between the non-sliding surface 6b of the movable side plate 6 and the casing 1 in the housed state. Further, the side plate 6 is provided with a shaft hole 6c for allowing the drive shaft 4 or the driven shaft 5 to pass therethrough. Further, in the sliding surface 6a of the side plate 6, the portions facing the suction port and the discharge port are provided with

cuts

6d and 6e with reduced thickness dimensions, respectively. In addition, in order to open a space defined by the central portion of the portion between the

notches

6d and 6e and the pair of

gears

2 and 3 in the sliding surface 6a to the non-sliding surface side in the thickness direction. A penetrating through hole 6 x is provided in the side plate 6. In addition, a counterbore 6y is provided at the end of the through hole 6x on the sliding surface 6a side, that is, on the side of the

gears

2 and 3, and the counterbore 6y communicates with the through hole 6x.

As described above and as shown in FIGS. 1 and 2, the bush 7 is provided between the drive shaft 4 and the bearing holes 11 a and 12 a of the body 11 and the front cover 12, and the driven shaft 5. It is disposed between the body 11 and the bearing

holes

11b, 12b of the front cover 12.

The gasket 8 is made of an elastic material. Further, as described above and as shown in FIGS. 1 to 3, the gasket 8 is mounted in a state of being attached to the gasket mounting protrusion 6g provided on the non-sliding surface 6b of the side plate 6. The seal portion is crimped to the non-sliding surface 6b and the casing 1, and the seal portion is divided into a low pressure side Y, that is, a suction port side, and a high pressure side X, that is, a discharge port side. A pocket for forming a space defined by the side plate 6, the casing 1, and the gasket 8 while penetrating in the thickness direction of the gasket 8 at a location facing the through hole of the side plate 6 of the gasket 8. 8x is provided. Here, the area of the pocket 8x when the gasket 8 is viewed from the direction in which the drive shaft 4 and the driven shaft 5 extend is caused by the pressure of the working fluid introduced into the pocket 8x, as will be described later. The sliding force applied to the side plate 6 and the region defined by the

gears

2, 3 and the sliding surface 6a of the side plate 6 and the counterbore portion 6y (hereinafter, the region and the counterbore portion 6y are combined). The force applied to the side plate 6 due to the pressure of the working fluid confined in the portion S) is set so as to be substantially balanced. And the diameter d2 of the said pocket is set larger than the major axis d1 of the spot facing part 6y provided in the sliding face 6a of the said side plate 6. FIG.

Here, with reference to FIG. 4 and FIG. 5, description will be given below with respect to temporal changes in the pressure at the location facing the location where the gear meshes and the pressure at the seal portion when the gear pump P according to this embodiment is operated.

In the state shown at point b in FIG. 4B and FIG. 5 and the state shown at point c in FIG. 4C and FIG. 5, the hydraulic fluid in the gear sliding portion S is compressed. The hydraulic fluid is discharged from the gear sliding portion S to the pocket 8x. At this time, the pressing force caused by the pressure of the hydraulic fluid in the gear sliding portion S cancels out the pressing force caused by the discharge pressure introduced into the seal portion 6b1 and the pressure of the hydraulic fluid in the pocket 8x. The side plate 6 is kept in light contact with the

gears

2 and 3. On the other hand, in the state shown at (a) in FIG. 4 and point a in FIG. 5, the gear sliding portion S is opened to the suction port side, and the internal pressure is equal to the suction pressure. The pocket 8x is also opened to the suction port side through the through hole 6x. As a result, even in this state, the pressure caused by the discharge pressure introduced into the seal 6b1 portion and the pressure of the working fluid in the pocket 8x The force and the pressing force resulting from the pressure of the hydraulic fluid in the gear sliding portion S cancel each other, and the side plate 6 is maintained in a state where it is in light contact with the

gears

2 and 3.

The gear pump P introduces high-pressure hydraulic fluid from the discharge port, thereby taking out rotational torque from the drive shaft to drive an external load and discharging low-pressure hydraulic fluid from the suction port. It goes without saying that it can also be made to function as a gear motor that performs the motor action.

As described above, in this embodiment, the side plate 6 is provided with the through hole 6x penetrating in the thickness direction so as to open the gear sliding portion S to the non-sliding surface 6b side, and the gasket 8 is provided. Since a pocket 8x is formed at a location facing the through hole 6x in the thickness direction of the gasket 8 and forms a space defined by the side plate 6, the casing 1 and the gasket 8, Even when the hydraulic fluid in the gear sliding portion S is compressed, the hydraulic fluid is guided to the space inside the pocket 8x of the gasket 8 through the through hole 6x. Therefore, the leakage of the hydraulic fluid can be suppressed by maintaining the state in which the side plate 6 is in light contact with the

gears

2 and 3 in balance with the force caused by the hydraulic pressure from the seal portion 6b1 side. Therefore, it is not necessary to strongly press the side plate 6 against the

gears

2 and 3 in a state where the hydraulic pressure in the gear sliding portion S is equal to the suction pressure, and loss torque can be reduced.

Further, since the counterbore 6y is provided in communication with the end of the through hole 6x on the side of the

gears

2, 3, the side plate 6 can be adjusted by adjusting the size of the counterbore 6y and the pocket 8x. It is possible to easily perform a design for balancing the forces caused by the hydraulic fluid pressure acting from the gear sliding portion S side, that is, the sliding surface 6a side, and the seal portion 6b1 side, that is, the non-sliding surface 6b side.

In addition, since the gasket 8 is formed of an elastic material and the pocket 8x is formed by the gasket 8, when the hydraulic pressure of the working fluid confined in the pocket 8x fluctuates, It is possible to obtain a buffering action that elastically deforms and absorbs a change in hydraulic pressure of the working fluid.

In addition, this embodiment is not restricted to embodiment mentioned above.

For example, in the above-described embodiment, the counterbore portion is provided in communication with the end portion on the gear side of the through hole of the side plate. For example, the diameter of the through hole is reduced as the distance from the gear decreases. For example, a space for releasing the working fluid confined in the space between the gear teeth and the sliding surface of the side plate by other means may be formed, and such a space may be omitted.

Further, as in the above-described embodiment, the present invention is not limited to the case where only a pair of gears are provided in the casing, but may be applied to a gear pump or motor in which two or more pairs of gears are provided in the casing.

Other various modifications may be made without departing from the spirit of the present invention.

A pair of meshing gears, side plates adjacent to the side surfaces of these gears, a gear housing chamber for housing the gears, a casing having a bearing hole into which a shaft for supporting the gears can be fitted, and a side plate or a casing. In a gear pump or motor equipped with a gasket mounted in a gasket mounting groove, a gear pump or motor configured to achieve both suppression of hydraulic fluid leakage from the gap between the gear and the side plate and reduction of loss torque is realized. it can.

P: Gear pump 1 ...

Casing

2, 3 ... Gear 6 ... Side plate 6x ... Through hole 8 ... Gasket 8x ... Pocket

Claims

At least a pair of gears that mesh with each other, side plates adjacent to the side surfaces of these gears, a gear housing chamber that houses the gears, a casing that includes a bearing hole into which a shaft that supports the gears can be fitted, and the side plates or the casings. A gear pump or motor comprising a gasket mounted in the provided gasket mounting groove,
A through-hole penetrating in the thickness direction of the side plate is provided at a location facing the location where the gear of the side plate meshes, and the gasket is penetrated in a location facing the through-hole in the gasket in the thickness direction of the gasket. A gear pump or motor comprising a pocket for forming a space defined by the side plate, the casing, and the gasket.
The gear pump or motor according to claim 1, wherein a counterbore portion is provided in communication with an end portion of the through hole on the gear side.