JPH094570A - Pump device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of seizure without feeding the lubricant such as grease to a coupling joint between a rotor shaft and a motor shaft, and to facilitate the machining of a pump housing. SOLUTION: A pump device comprises a gear pump 11 and a motor 12, the gear pump 11 is provided with an outer rotor 24, an inner rotor 23, a rotor shaft 25, pump housings 26a, 26b, a suction flow passage 27, and a discharge flow passage 28, and the driving force is transmitted by Oldham's coupling 52 in which the rotor shaft 25 is engaged with the motor shaft 42 in the rotational direction. The rotor shaft 25 is provided with a leaked liquid flow passage 32 piercing in the axial direction, and the pump housings are provided with a return flow passage 33 which communicates the Oldham's coupling 52 with the suction flow passage 27, and returns the leaked oil to the suction flow passage 27.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pump device in which a pump and a motor are integrally connected to form a unit.

[0002]

2. Description of the Related Art FIG. 2 is a sectional front view of a conventional pump device 80. The pump device 80 is an inscribed type gear pump 81.
And a motor 82 that rotationally drives the gear pump 81.

The gear pump 81 includes an outer rotor 83,
A pump housing 8 that rotatably houses the inner rotor 84, a rotor shaft 85 that rotates integrally with the inner rotor 84, the outer rotor 83, and the inner rotor 84, and that also rotatably supports the rotor shaft 85.
6a, 86b, 86c, and pump housing 86
suction passage 87 and discharge passage 8 provided in b and 86c
Eight. Bearings 89a and 89b are mounted on the pump housings 86a and 86b, and an oil seal 90 for preventing external leakage of oil is provided on the pump housing 86b.

Rotor shaft 85 and motor shaft 91
Are engaged with each other in the rotational direction by the Oldham coupling 92, whereby the rotational driving force of the motor 82 is generated by the pump 8.
1 is transmitted. The Oldham coupling 92 is provided with a two-sided width at the tip of the rotor shaft 85, which is fitted into a slit provided at the tip of the motor shaft 91 and engaged in the rotational direction.

Further, the rotor shaft 85 and the bearing 89
Return passages 95 and 96 are provided in order to return the oil leaking from between a and 89b to the suction passage 87. When the motor 82 rotates, the rotor shaft 85 rotates via the Oldham coupling 92, and the inner rotor 84 and the outer rotor 83 rotate. As a result, the oil in the oil tank (not shown) is sucked from the suction passage 87 and discharged from the discharge passage 88. By the operation of the pump 81, hydraulic pressure is generated in each portion including the discharge flow passage 88, but a part of the hydraulic fluid leaks from the sliding surfaces of the pump housings 86a and 86b and the inner rotor 84 and the outer rotor 83, It passes between the rotor shaft 85 and the bearings 89a and 89b, and returns to the suction passage 87 through the return passages 95 and 96.

[0006]

In the conventional pump device 80 described above, the leaked oil passes through the peripheral surface of the rotor shaft 85, so that the sliding surface of the rotor shaft 85 is lubricated and cooled. However, since the leaked oil does not pass through the Oldham joint 92, the Oldham joint 92 is not lubricated and cooled by the leaked oil. Therefore, the Oldham coupling 92 is filled with grease for lubrication and cooling. However, since the grease needs to be replenished regularly, the maintenance for that is troublesome. If replenishment of the grease is neglected, the Oldham coupling 92 will be severely worn and may cause seizure. When seizure occurs, the rotor shaft 85 and the motor shaft 91 cannot be separated, so the gear pump 8
1 and the motor 82 cannot be disassembled and cannot be repaired.

Further, since the return flow paths 95 and 96 are obliquely provided in the pump housings 86a and 86b, the processing thereof is not easy. The present invention has been made in view of the above problems, and there is no risk of seizure even if a lubricant such as grease is not supplied to the engaging joint portion between the rotor shaft and the motor shaft. An object of the present invention is to provide a pump device in which the housing can be easily processed.

[0008]

An apparatus according to the invention of claim 1 comprises an inscribed gear pump and a motor for rotationally driving the gear pump, the gear pump comprising an outer rotor, an inner rotor and the inner rotor. A rotor shaft that rotates integrally with the pump, a pump housing that rotatably accommodates the outer rotor and the inner rotor, and rotatably supports the rotor shaft,
And a motor housing having a suction flow passage and a discharge flow passage provided in the pump housing, the motor being formed separately from the pump housing, and the motor being formed separately from the rotor shaft. A pump device having a shaft, wherein the rotational driving force of the motor is transmitted to the pump by an engagement joint formed by the rotor shaft and the motor shaft engaging with each other in the rotational direction. The rotor shaft is provided with a leaking liquid flow passage that penetrates in the axial direction, and the pump housing communicates between the engaging joint portion and the suction flow passage to prevent the leaking liquid from flowing. A return flow path for returning to the suction flow path is provided.

[0009]

When the pump is operated, hydraulic pressure is generated in each part including the discharge flow passage. However, a part of the hydraulic oil leaks from the sliding surface between the pump housing and the inner rotor, and the pressure between the rotor shaft and the bearing is increased. To reach both end surfaces of the rotor shaft.

The leaked oil that reaches one end surface of the rotor shaft reaches the other end surface of the rotor shaft via the leaking liquid flow path of the rotor shaft, passes through the engaging joint portion, and returns to the suction flow path. During this process, the leaking oil lubricates and cools the portion of the engagement joint.

[0011]

1 is a sectional front view showing a pump device 1 according to the present invention. In FIG. 1, the pump device 1 includes an inscribed type gear pump 11 and a motor 12 that rotationally drives the gear pump 11.

The gear pump 11 includes an outer rotor 23,
A pump housing 2 that rotatably houses the inner rotor 24, a rotor shaft 25 that rotates integrally with the inner rotor 24, the outer rotor 23, and the inner rotor 24, and that rotatably supports the rotor shaft 25.
6a, 26b, and a suction passage 27, a discharge passage 28, and a suction port 27a provided in the pump housing 26b. Pump housing 26a, 26b
Bearings 29a and 29b are mounted on the. The suction flow passage 27 includes an inner rotor 24 and an outer rotor 23.
Open from the side to the suction pump chamber formed between
The discharge flow path 28 includes an inner rotor 24 and an outer rotor 2.
3 is opened from the side surface to the discharge pump chamber formed between the discharge pump chamber and the discharge pump chamber 3.

The pump housing 26b includes a motor 12
Holes 36a, 36 for detachably attaching
b and 36c are provided. A packing 37 is mounted in the hole 36b in the middle step, and a bearing 38 is fitted in the hole 36c in the upper step. Further, between the bottom surface of the hole 36b in the middle part and the suction flow path 27, the leak oil is sucked in the flow path 27.
A return flow path 33 for returning to the above is provided.

The pump housing 26a and the pump housing 26b are fixed by a bolt 35. The motor 12 is a known induction motor with a reducer, which has a motor housing 41 and a motor shaft 42, and has a stator, a rotor, a reduction gear, and the like (not shown).

Rotor shaft 25 and motor shaft 42
Are engaged with each other in the rotational direction by the Oldham coupling 52, whereby the rotational driving force of the motor 12 is generated by the pump 1.
1 is transmitted. The Oldham joint 52 includes an engaging protrusion 53 having a width across flats that protrudes from the tip of the rotor shaft 25, and a slit 54 provided at the tip of the motor shaft 42. The engaging protrusion 53 is formed in the slit 54. By being fitted, they are engaged with each other in the rotational direction.

Further, the rotor shaft 25 and the inner rotor 24 are engaged with each other in the rotational direction and integrally rotated by a key groove provided in each of them and a key 31 fitted over the key grooves. .

The rotor shaft 25 is provided with a leaking liquid flow path 32 that penetrates in the axial direction at the center position of its radial cross section. Motor 12 and gear pump 11
Means that when the flange surface of the motor housing 41 is fitted to the flange surface of the pump housing 26b, the bolt 3
They are fixed to each other by 9. In that state, the engaging protrusion 53 of the rotor shaft 25 is fitted into the slit 54 of the motor shaft 42, and the peripheral surface of the tip end portion of the motor shaft 42 has a gap between it and the hole 36a in the lower step. The space between the peripheral surface of 42 and the hole 36b in the middle section is sealed by a packing 37, and the motor shaft 42 is rotatably supported by a bearing 38.

Next, the operation and action of the pump device 1 configured as described above will be described. When the motor 12 rotates, the rotor shaft 25 rotates via the Oldham coupling 52, and the inner rotor 24 and the outer rotor 23 rotate. As a result, the oil in the oil tank (not shown) is sucked through the suction port 27a and the suction flow passage 27 and discharged from the discharge flow passage 28.

By the operation of the pump 11, the discharge passage 28
However, part of the pressure oil leaks from the sliding surfaces of the pump housings 36a and 36b and the inner rotor 24, passes between the rotor shaft 25 and the bearings 29a and 29b, The upper and lower end surfaces of the rotor shaft 25 are reached.

The leaked oil reaching the upper end surface of the rotor shaft 25 fills the gap between the hole 36a in the lower stage and the motor shaft 42, and once flows into the hole 36b in the middle stage, and then the return flow path. It returns to the suction flow path 27 through 33.

The leaked oil that has reached the lower end surface portion of the rotor shaft 25 reaches the uppermost end surface of the engagement convex portion 53 via the leak liquid flow path 32 of the rotor shaft 25, and the engagement convex portion 53.
Through the slit 54 and between the lower end surface of the motor shaft 42 and the upper end surface portion of the rotor shaft 25 to fill the gap between the motor shaft 42 and the hole 36a in the lower step. Then, after once flowing into the hole 36 b in the middle stage portion, it returns to the suction flow passage 27 through the return flow passage 33. Even if the leaked oil flows into the hole 36b in the middle section, the packing 37
Since it is sealed by, it does not leak outside.

In this way, the pump housings 36a, 3a
The oil leaked from the sliding surface between 6b and the inner rotor 24 is
It flows out from the upper end of the rotor shaft 25 via the leaking liquid flow path 32, and lubricates the sliding portions between the motor shaft 42 and the rotor shaft 25 including the engagement convex portion 53 and the slit 54. Cooling. Therefore, the sliding portion is automatically lubricated and cooled by the operation of the gear pump 11 without using grease or the like as in the conventional case, and seizure of the sliding portion is prevented.

Further, since the leaked oil is used for lubrication, the driving force of the motor 12 is effectively used and the power loss is reduced. The structure is simple because no special power is required for lubrication. As the load on the gear pump 11 increases and the temperature rise of the Oldham coupling 52 increases, the amount of leaked oil increases, and as a result, the amount of lubrication increases, so that the amount of lubrication is automatically adjusted.

Further, since the return passage 33 provided in the pump housing 26b is parallel to the axial direction, its processing is easy. Since the pump housings 26a and 26b do not need the holes in the oblique direction as in the conventional case, the processing is easy.

In the above-described embodiment, the pump device 1 having the structure in which the motor shaft 42 and the rotor shaft 25 are connected by the Oldham joint 52 has been described, but various other engaging joints such as a key joint or a spline joint. It can also be applied to the above pump device.

For example, in the case of a key joint, a cylindrical hole and a key groove are provided in the tip end portion of the motor shaft 42, and the tip end portion of the rotor shaft 25 has a diameter that can be fitted into the hole and the key groove is provided. The tip end portion of the rotor shaft 25 is fitted in the hole of the motor shaft 42 and the key is fitted in the key groove. The leaked liquid flow path 32 opens at the uppermost end surface of the rotor shaft 25, and the leaked oil flows out from the most distal end surface, and the sliding surface between the hole of the motor shaft 42 and the rotor shaft 25 and the sliding contact between the key and the key groove. Lubricate the moving surface.

In the embodiment described above, the leaking liquid flow path 3
2, the hole diameter of the return channel 33 is, for example, 1 mm, 1.5 m
m, 2 mm, 3 mm, etc. may be appropriately set according to the discharge pressure and flow rate of the gear pump 11. Gear pump 11
The form, structure, shape, dimensions, etc. of can be changed appropriately. As the motor 12, an electric motor, a pneumatic motor, an internal combustion engine, or the like may be used.

[0028]

According to the first aspect of the present invention, there is no risk of seizure without supplying a lubricant such as grease to the engaging joint between the rotor shaft and the motor shaft. Further, since it is not necessary to provide the pump housing with the oblique hole, the processing is easy.

[Brief description of drawings]

FIG. 1 is a sectional front view showing a pump device according to the present invention.

FIG. 2 is a sectional front view of a conventional pump device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pump device 11 Gear pump 12 Motor 23 Outer rotor 24 Inner rotor 25 Rotor shaft 26a, 26b Pump housing 27 Suction channel 28 Discharge channel 32 Leakage liquid channel 33 Return channel 41 Motor housing 42 Motor shaft 52 Oldham coupling (engagement Joint)

Claims (1)

[Claims] 1. An inscribed type gear pump, and a motor for rotationally driving the gear pump, wherein the gear pump is an outer rotor, an inner rotor,
A rotor shaft that rotates integrally with the inner rotor, a pump housing that rotatably accommodates the outer rotor and the inner rotor and rotatably supports the rotor shaft, and a suction passage provided in the pump housing, The motor has a discharge flow path, the motor has a motor housing formed separately from the pump housing, and a motor shaft formed separately from the rotor shaft. A pump device configured to transmit the rotational driving force of the motor to the pump by an engagement joint formed by engaging a motor shaft with each other in a rotation direction, wherein the rotor shaft has an axial direction. A leaking liquid flow path is provided therethrough, and the pump housing is provided with a portion of the engaging joint. Pump apparatus characterized by return channel for returning to the suction passage leakage fluid communicating between said intake passage is provided, comprising Te a.