JP2002227774A - Gear pump or motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain pressure balance of a side plate in a gear pump or a motor. SOLUTION: This gear pump or this motor is structure so as to carry hydraulic fluid sucked from a suction opening by a pair of gears 12, 14 and discharge it to a discharge opening, and is equipped with side plates 16 disposed on both sides of the pair of gears 12, 14 to be slid by the side face of the gear and cut out the suction opening side, and a 3-shaped gasket 23 to partition the discharge opening side and the suction opening side, on the opposite gear face of the side plate 16. A hydraulic fluid leading-in region is provided on the gear side face of a shaft hole part provided in the side plate 16, wherein oil pressure gets low, by forming a chamfering part in the shaft hole part o the side plate 16. Thereby, the area of the working oil leading-in region changes only by changing the thickness of the side plate 16, a pressure increase to widen a gap between the gear side face and the side plate surface is suppressed, and leakage of the hydraulic fluid caused by the increase of the gaps between the gears 12, 14 and the side plates 16, even if the capacity of the pump is made small by reducing the face width of the gears 12, 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear pump or a motor commonly used in the field of hydraulic equipment.

[0002]

2. Description of the Related Art As shown in FIG. 3, a gear pump (the structure of a gear motor is also the same, and the gear pump will be described below) is driven by a driving gear 102 mounted on a driving shaft 101. Driven gear 1 mounted on shaft 103
04 are disposed in the casing 105 so as to mesh with each other. Further, the drive shaft 101 and the driven shaft 1 of the two gears are used.
Reference numeral 03 is rotatably supported by bearings arranged in combination in the casing 105. In the gear pump of FIG. 3, a side plate 106 (107) having shaft holes 114 and 115 as shown in FIG. Seals the tooth side surface.

[0003] As shown in FIG.
On the side of the gear, high pressure introduction grooves 109 and 110 for introducing pressure oil from the discharge port 116 are formed on the gear surface of the side plate 106. On the other hand, the discharge port 11 is also provided on the opposite gear surface of the side plate.
6, a high-pressure introduction groove 111 for introducing pressure oil is formed, and a three-letter gasket (seal material) 113 is fitted into the high-pressure introduction groove 111 to form a region between the suction port 108 side and the discharge port 116 side. Is clearly specified.

[0004] By the way, the side plate 106 generates an elastic force due to the crushing allowance of the three-shaped gasket 113 together with the operating oil pressure on the gear surface and the operating oil pressure on the opposite gear surface. By doing so, the side plate 1
06 is not depressed more than necessary against the driving gear 102 and the driven gear 104.

[0005]

By the way, by sharing parts, the side plate 106 designed for a gear pump / motor having a predetermined capacity is also used for a gear pump / motor having a small capacity and a small gear width. Had the following problems.

That is, in a gear pump / motor having a small gear width, the capacity between the teeth is small. Therefore, if the pressure propagation speed of the hydraulic oil is constant, the time required for the hydraulic oil between the teeth to reach a predetermined pressure is short. . Therefore, the apparent high pressure area of the gear sliding surface of the side plate slightly increases, and the side plate 1
06 is pressed by the hydraulic oil between the teeth to increase the pressure. Since this force widens the gap between the side surfaces of the gears 102 and 104 and the surface of the side plate 106, the amount of hydraulic oil leakage increases.
Further, the pressure balance in the side plate 106 is lost, which causes vibration.

Accordingly, the present invention maintains the pressure balance of the side plates even in a gear pump or motor having a small capacity,
An object of the present invention is to reduce leakage from a gap between a gear and a side plate and suppress vibration.

[0008]

A gear pump or motor according to the present invention is configured so that hydraulic oil sucked from a suction port is conveyed by a pair of gears and discharged to a discharge port, and is disposed on both side surfaces of the pair of gears. A side plate that slides on the side surface of the gear and has a cut-out side of the suction port, and a three-letter gasket that partitions the discharge port side and the suction port side on the opposite gear surface of the side plate, and is provided on the side plate. If the hydraulic oil introduction region is provided on the gear side surface of the shaft hole, the hydraulic oil introduction region has a low pressure, so that it is possible to prevent the force acting on the side plate from widening the gap with the gear side surface from increasing. Furthermore, based on the pump size,
By changing the size of the basin area of the hydraulic oil introduction region, the pressure for widening the gap between the gear side surface and the side plate surface can be optimized according to the pump capacity.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of a gear pump or a motor according to the present embodiment will be described below. FIG. 1 is a schematic diagram of a gear pump or a motor of the present embodiment, and FIG. 2 is a schematic diagram of a side plate of the gear pump or the motor of the present embodiment.

In this embodiment, as shown in FIG. 1, the basic structure of the gear pump is such that a drive gear 12 mounted on a drive shaft 11 and a driven gear 14 mounted on a driven shaft 13 have a casing. 15 are arranged in mesh with each other. The drive shaft 11 and the driven shaft 13 of the two gears are rotatably supported by bearings arranged in combination in the casing 15. And on the side of both gears,
As shown in FIG. 2, the side plate 16 having the shaft holes 24 and 25 is provided.
(17) is in sliding contact, and seals the tooth side surfaces of the drive gear 12 and the driven gear 14.

On the gear side of the side plate 16, high pressure introduction grooves 19 and 20 for introducing pressure oil from the discharge port 26 are formed on the gear surface of the side plate 16. On the other hand, a high-pressure introduction groove 21 for introducing pressure oil from the discharge port 26 is also formed on the counter gear surface of the side plate, and a three-letter gasket (seal material) 23 is fitted into the high-pressure introduction groove, so that suction is performed. Mouth 18
The low pressure area on the side is clearly defined.

Furthermore, a shaft hole 24 in the gear surface of the side plate,
Hydraulic oil introduction regions 30 and 31 are formed around the circumference of the cylinder 25, and a part of the hydraulic oil introduced between the teeth is configured to flow into the hydraulic oil introduction regions 30 and 31. .

Next, the operation of such a gear pump will be described. When a drive source (not shown) rotates, the drive shaft 11 connected to the drive source rotates, and the driven gear 14 and the driven shaft 13 Rotates. Then, hydraulic oil is introduced between the teeth of the drive gear 12 and the driven gear 14 from the suction port 18, and is conveyed to the discharge port 26. At this time, the hydraulic pressure of the hydraulic oil introduced between the teeth acts on the side plate. By forming such a hydraulic oil introduction region where the hydraulic pressure becomes low, the gear between the apparent side plates with a small capacity between the teeth is provided. It is possible to prevent the high pressure area of the sliding surface from increasing.

FIG. 5 shows the relationship between the forces applied to the side plates. As shown in FIG.
F1, a force F2 pressed by the working oil pressure between the teeth through the high-pressure introduction groove 19, and a force F3 pressed by the squeeze allowance of the three-letter gasket act to maintain the resultant force F = F1 + F2 + F3 within a predetermined range. By the side plate 1
The pressure balance between the gears 12 and 14 and the side plate 16 is maintained without the 6 being pressed against the gears 12 and 14 more than necessary, and an appropriate sealing effect by the side plate 16 is obtained.

In particular, when a gear having a small gear width is used, the apparent size of F2 becomes larger than a predetermined value by shortening the time required for the hydraulic oil between the teeth to reach a predetermined pressure. , The gap between the gear and the side plate becomes large, and the hydraulic oil leaks.
6, the hydraulic oil introduction areas 30, 31 are formed on the gear surface,
By reducing the oil pressure and changing the area of the hydraulic oil introduction regions 30 and 31 according to the pump size (by increasing the area of the hydraulic oil introduction regions 30 and 31 as the capacity of the pump becomes smaller), the tooth width of the gear is increased. , The pressure between the side surfaces of the gears and the surface of the side plate can be prevented from increasing.
Leakage of hydraulic oil due to an increase in the gap between the side plates 16 and 14 can be prevented.

In this embodiment, the hydraulic oil introduction region 3
0, 31 with shaft holes 24, 25 in the gear face of the side plate 16.
Since it is formed by chamfering around, for example, when used as a side plate of a pump with a large capacity, simply cut out the side plate from the gear sliding surface side of the side plate according to the tooth width of the gear to be used Therefore, the areas of the hydraulic oil introduction regions 30, 31 are simultaneously reduced, and the optimal hydraulic oil introduction regions 30, 31 are reduced.
Can be obtained.

[0017]

As described above, according to the gear pump or motor of the present invention, the hydraulic oil introduction region is formed on the side of the side plate on which the gear slides, and the low-pressure region is set. By adjusting the thickness of the side plate using the chamfered portion made in the hole and adjusting the low pressure area, even if the shape parameters other than the thickness of the side plate and gear are the same, the appropriate hydraulic balance acting on the side plate Is obtained, and leakage of hydraulic oil from a gap between the gear and the side plate can be reduced, and vibration can be suppressed. Further, even if the pump capacity, that is, the gear width of the gear is different, by setting the side plate thickness of the width adapted to the gear width, other parts such as the casing and the mounting bolt use the same one. It does not cause an increase in man-hours or cost.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a gear pump or a motor of the present invention.

FIG. 2 is a schematic view showing a side plate of the gear pump or the motor of the present invention.

FIG. 3 is a schematic diagram showing a conventional gear pump or motor.

FIG. 4 is a schematic view showing a side plate of a conventional gear pump or motor.

FIG. 5 is a diagram showing a pressure balance of a side plate.

[Explanation of symbols]

 12, 14 Gear 16, 17 Side plate 18 Suction port 23 3-shaped gasket 24, 25 Shaft hole 26 Discharge port 30, 31, Hydraulic oil introduction area

Claims (1)

[Claims] 1. A gear pump or motor configured to convey hydraulic oil sucked from a suction port by a pair of gears and discharge the hydraulic oil to a discharge port. A gear pump having a side plate that slides and cuts off the suction port side, and a three-shaped gasket that partitions the discharge port side and the suction port side on the opposite gear surface of the side plate. A gear pump or a motor, wherein a hydraulic oil introduction region is provided on a gear side surface of a shaft hole provided.