JP2000087875A - Vane pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vane pump preventing a fluid from becoming high in temperature inside a pump by friction caused by the rotation of a shaft. SOLUTION: A vane pump is provided with a body 1; a cam ring 3 mounted inside the body 1; a rotor 4 rotatably accommodated in the cam ring 3; a plurality of vanes 5 provided in the protrudable state around the rotor 4; a shaft 14 for rotating the rotor 4; and a cover 2 fixed to the side face of the body 1. The shaft 14 is formed of a hollow member. One end 14d provided in the cover 2 or the body 1, out of the ends of the shaft 14 is closed with closing members 19, 20, while the other end 14c is opened to the atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vane pump for moving a vane provided on a rotor along a cam ring.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional vane pump. The vane pump has a body 1 covered with a cover 2 and a cam ring 3 having an elliptical inner wall. A rotor 4 is provided in the cam ring 3, and a plurality of vanes 5 are protruded from the rotor 4 and are radially incorporated. Further, a shaft hole 6 is formed in the body 1 and the cover 2.
A bush 7 is provided on the inner periphery of the shaft hole 6 on the body 1 side, and a bush 8 is provided on the inner periphery of the cover 2 side. The shaft 9 is rotatably supported by the bushes 7 and 8. The shaft 9 penetrates a central portion of the rotor 4 and is fixed to the rotor 4 through serrations formed in the penetrating portion.
Therefore, this shaft 9 becomes a drive shaft of the rotor 4. The body 1 is provided with an oil seal 10 around the shaft 9 to prevent oil from leaking out of the body 1 along the shaft 9.

Next, the operation of the vane pump will be described. When the shaft 9 is rotated by a drive source (not shown), the rotor 4 rotates. At this time, the vane 5 protrudes from the rotor 4 by centrifugal force due to the rotation of the rotor 4, but since the inner wall of the cam ring 3 has an elliptical shape, the vane 5 moves in and out along this inner wall surface. In other words, the tip of each vane 5 rotates while being in close contact with the cam ring 3, and each of the vanes 5 forms an independent chamber. Then, as each vane 5 moves in and out along the wall surface of the cam ring 3, the volume of each chamber changes. Here, when the process enters a process of increasing the volume of the chamber, a suction process for sucking oil is performed. On the other hand, when each chamber enters a stroke of contraction, it becomes an oil discharge stroke. As described above, the high-pressure oil is discharged while repeating the suction stroke and the discharge stroke. The high-pressure oil is discharged from the discharge port through the flow path in the body 1 and is sent to the actuator (not shown). Can be

[0004] Side plates 11 are provided on the side surfaces of the rotor 4 and the cam ring 3. A high-pressure chamber 12 is formed on the back side of the side plate 11, and a pump discharge pressure is guided to the high-pressure chamber 12. Then, the side plate 11 is pressed against the rotor 4 by the oil pressure in the high-pressure chamber 12 to maintain the loading balance. In addition, oil leaks from the high-pressure chamber 12 around the shaft 9 through the space between the side plate 11 and the rotor 4. The oil leaking from around the shaft 9 flows toward the large-diameter portion 9a along the shaft 9 and flows from the inside of the oil seal 10 to the drain passage 13 formed in the body 1.

[0005]

When the above-described vane pump is operated, frictional heat is generated between the shaft 9 and the bushes 7, 8 and between the tip of the vane 5 and the inner wall surface of the cam ring 3. . This frictional heat is transmitted to the oil and raises the oil temperature. As described above, when the pressure oil becomes high in temperature, energy loss is correspondingly caused, and energy transmission efficiency to the actuator deteriorates. Also, components other than the vane pump to which the pressurized oil is supplied may adversely affect the heat. For example, the characteristics of a valve or the like may change due to thermal expansion. In particular, when the above-described vane pump is used in a power steering device, it is necessary to secure a somewhat larger discharge amount in consideration of the leakage amount. Therefore, the discharge amount itself,
I have to do more. However, the higher the discharge amount, the higher the number of rotations of the shaft 9, and the easier it is to generate heat.

However, even in a power steering system, energy loss due to an increase in the temperature of the system and the influence on the characteristics must be minimized. For this reason, in the current apparatus, a long cooler pipe is provided, and heat is released at that portion. Therefore, there is a problem that extra space is required for the cooler pipe. SUMMARY OF THE INVENTION It is an object of the present invention to provide a vane pump that prevents fluid from becoming hot inside a pump due to friction caused by rotation of a shaft.

[0007]

According to a first aspect of the present invention, there is provided a body, a cam ring housed in the body, a rotor rotatably accommodated in the cam ring, and a plurality of protruding members provided around the rotor. A vane, a shaft for rotating the rotor, and a cover fixed to a side surface of the body, wherein the shaft is formed of a hollow member, and the shaft is provided within the cover or the body among the ends of the shaft. It is characterized in that one end is closed by a closing member, the other end is opened, and this opening is opened to the atmosphere. According to a second aspect of the present invention, there is provided a body, a cam ring provided in the body, a rotor rotatably housed in the cam ring, a plurality of vanes provided rotatably around the rotor, and a rotor for rotating the rotor. In a vane pump having a shaft to be closed and a cover fixed to the side surface of the body, the shaft is formed of a hollow member having both ends opened, and when the shaft is incorporated into the body and the cover, both ends are exposed to the atmosphere. The feature is that it is configured to be open.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The first embodiment shown in FIG. 1 differs from the prior art in that a hollow shaft 14 penetrates the center of the rotor 4 and serves as a drive shaft. The shaft 14 includes a large diameter portion 14a and a small diameter portion 14b, and is incorporated in the shaft hole 6 formed in the body 1 and the cover 2.
A bearing 15 is provided in the shaft hole 6 of the body 1,
The large diameter portion 14 of the shaft 14 is
a. A bush 16 is provided on the cover 2 to support the small diameter portion 14b. The end 14c on the large diameter portion 14a side is opened, and the opening is opened to the atmosphere. On the other hand, a plug 19 is fitted into the small-diameter portion 14b, and an O-ring 20 is mounted around the plug 19, so that the end 14
d is sealed. In the first embodiment, the plug 1
9 and the O-ring 20 form the closing member of the present invention. However, only the plug 19 is used, and the end 1
If the 4d can be sealed, the O-ring 20 need not be used.

A pipe-shaped stopper 17 is fixed to the outer periphery of the large-diameter portion 14a of the shaft 14, and the bearing 15 is fixed by the stopper 17 and the ring member 27.
Is sandwiched between them. Therefore, the shaft 14 is rotatably supported by the bush 16 and the bearing 15. Further, an oil seal 18 is provided on the outer periphery of the stopper 17. Other configurations are the same as in the conventional example. The same components as those in the conventional example are denoted by the same reference numerals.

Next, the operation of the vane pump according to the first embodiment will be described. When the large diameter portion 14a of the shaft 14 is rotated in association with a drive source (not shown), the rotor 4 rotates. When the rotor 4 rotates, the vanes 5 provided therein come in and out, and repeat the suction stroke and the discharge stroke to discharge the pressure oil. This mechanism is the same as the above-mentioned conventional example.
On the other hand, the oil leaked from the rotor 4 flows through the passage 28 along the outer periphery of the shaft 14 toward the large-diameter portion 14a, and flows into the drain passage 13 from just before the oil seal 18. In the course of the flow of the drain oil, the drain oil also enters between the bush 16 on the small diameter portion 14b side and the small diameter portion 14b, and this drain oil is
It also functions as a lubricating oil for rotation 4. However, since the small-diameter end portion 14d of the shaft 14 is sealed, the drain oil does not flow into the shaft 14. That is, the drain oil does not flow through the shaft 14 and leak outside the pump.

Further, during the operation of the vane pump, the shaft 14 rotates.
Friction heat is generated around 4. That is, the small diameter portion 14
Friction heat is generated between the bush 16 and the small diameter portion 14b on the b side, and between the oil seal 18 and the stopper 17 on the large diameter portion 14a. The frictional heat generated in these portions is transmitted to the entire shaft 14 and also to the oil. Further, frictional heat is generated between the vane 5 and the cam ring 3. This frictional heat is also transmitted to the oil.

However, since the large-diameter end 14c of the shaft 14 is open, the frictional heat is released from the inside of the shaft 14 to the atmosphere. In this way,
If the friction heat generated in the shaft 14 is released, a rise in the temperature of the shaft 14 can be suppressed. Vane 5
Is transmitted to the shaft 14 via the oil and the rotor 4 and is released to the atmosphere. By radiating heat from the inside of the shaft 14 as described above, it is possible to suppress an increase in the temperature of frictional portions such as the shaft 14 and the vane 5, and also to suppress an increase in the oil temperature in the pump. Therefore, it is possible to reduce the energy loss due to the heat generation and to prevent the characteristic change due to the heat generation of the other elements to which the pressure oil is supplied from the vane pump.

The second embodiment shown in FIG. 2 uses a hollow shaft 21 having a uniform outer diameter. And body 1
Is provided with a bush 22 and an oil seal 10, and the cover 2
Is provided with a bush 16. These bushes 22
The shaft 21 is rotatably supported by the shafts 16 and 16. The end 21a in the cover 2 of the shaft 21 is connected to the plug 19, as in the first embodiment.
And an O-ring 20 provided therearound. Therefore, the pressure oil flows through the shaft 21 and
It does not leak outside. The end 21b on the opposite side of the shaft 21 is opened to open the inside of the shaft 21 to the atmosphere. Other configurations are the same as those of the first embodiment.
The vane pump of the second embodiment as described above can also release frictional heat generated during driving from the hollow portion in the shaft 21 to the atmosphere.

The third embodiment shown in FIG. 3 differs from the other embodiments in that both ends of a hollow shaft 23 fixed to the rotor 4 project from the body 1 and the cover 2. The shaft 23 includes a large-diameter portion 23a and a small-diameter portion 23b.
b protrudes from the cover 2. In this state, both ends 23c and 2c of the shaft 23 are assembled.
3d is open to the atmosphere. As in the first embodiment, a bearing 15 is provided on the body 1 to support the large-diameter portion 23a. The bearing 15 is fixed by being sandwiched between the stopper 17 and the ring member 27. The oil seal 1 is provided on the outer periphery of the stopper 17.
8 are provided. Further, a driven gear 24 is fixed to the protruding portion of the large diameter portion 23a.
, The driving force is transmitted.

On the other hand, the cover 2 is formed with a shaft hole 6 penetrating the cover 2, a bush 16 is provided therein to support the small-diameter portion 23 b, and the distal end of the small-diameter portion 23 b is placed outside the cover 2. To protrude. An oil seal 25 is provided on the small-diameter portion 23b on the cover 2 side as described above. The small-diameter portion 23 protruding from the cover 2
An output flange 26 is provided using b as an output shaft.
If another device such as a compressor is connected to the output flange 26, the compressor can be driven in conjunction with the vane pump. The vane pump of the third embodiment as described above can also release the frictional heat generated by the rotation of the shaft 23 to the atmosphere via the space inside the shaft 23. Therefore, it is possible to suppress an increase in the temperature of the apparatus and an increase in the temperature of the discharged oil, thereby eliminating energy loss and other problems caused by the increase in the temperature.

In the third embodiment, the output flange 26 does not need to be attached to the small-diameter portion 23b protruding from the cover 2, and the small-diameter portion 23b does not have to protrude. In short, it is sufficient that the small-diameter portion side is open to the atmosphere through the opening of the end 23d. Since both ends 23c and 23d of the hollow shaft 23 are opened to the atmosphere as described above, heat can be more efficiently dissipated than when only one end is opened. However, the first,
Naturally, even if one end is closed as in the second embodiment, a large heat radiation effect can be expected as compared with the conventional device. Therefore, when attaching the driven gear 24 and the output flange 26 to the shaft 23, the shaft 2
If it is more convenient for the inside of 3 to be closed, one end may be closed as in the first and second embodiments. However, in this case, the ends need not necessarily be sealed as in the other embodiments. Because the shaft 23 projects from the cover 2 in the third embodiment shown in FIG. 3, the oil in the body 1 and the cover 2 does not flow into the shaft 23. Therefore, there is no fear that oil leaks outside through the inside of the shaft 23.

Further, the vane pumps of the first to third embodiments can be reduced in weight by making the shaft for rotating the rotor 4 hollow, thereby saving energy.
In the above-described embodiment, the shaft is supported by the bearing and the bush, and the shaft is supported only by the bush. However, only the bearing may be used. However, in the case where a bush is used, it is desirable that the drain oil is guided around the bush so as to function as a lubricating oil.

[0018]

According to the first aspect of the present invention, the frictional heat generated by the rotation of the shaft can be released to the atmosphere to prevent the device and the fluid from becoming hot.
Therefore, efficient operation can be performed by reducing energy loss due to the oil temperature and the high temperature of the equipment. In addition, by making the shaft hollow, the weight of the rotating part can be reduced, so that more energy can be saved. Further, in an apparatus using such a vane pump, heat does not adversely affect components other than the vane pump to which the pressurized oil is supplied, for example, an actuator operated by the discharge oil of the pump. Even when such a vane pump is used in a device that dislikes heat, such as a power steering device of an automobile, it is possible to suppress an increase in fluid temperature in the vane pump. Therefore, a cooler pipe for cooling the discharged fluid whose temperature has increased can be dispensed with, and the device space can be reduced. According to the second invention,
By opening both ends of the shaft and opening it to the atmosphere, the heat radiation effect is further enhanced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a first embodiment.

FIG. 2 is a sectional view of a second embodiment.

FIG. 3 is a sectional view of a third embodiment.

FIG. 4 is a sectional view of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Body 2 Cover 3 Cam ring 4 Rotor 5 Vane 14 Shaft 14c End 14d End 19 Plug 20 O-ring 21 Shaft 21a End 21b End 23 Shaft 23c End 23d End

Claims (2)

[Claims] 1. A body, a cam ring provided in the body, a rotor rotatably accommodated in the cam ring, a plurality of vanes protrudably provided around the rotor, and rotating the rotor. In a vane pump including a shaft and a cover fixed to a side surface of the body, the shaft is formed of a hollow member, and one end of the shaft provided in the cover or the body is closed with a closing member. A vane pump that is closed and has the other end opened, and this opening is open to the atmosphere. 2. A body, a cam ring provided in the body, a rotor rotatably accommodated in the cam ring, a plurality of vanes protrudably provided around the rotor, and rotating the rotor. In a vane pump including a shaft and a cover fixed to a side surface of the body, the shaft is formed of a hollow member having both ends opened, and when the shaft is incorporated into the body and the cover, both ends are open to the atmosphere. Vane pump that is configured.