JP2003307185A - Vane pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vane pump equipped with vanes to contact smoothly with the inside surface of a cam ring at all times. <P>SOLUTION: The vane pump is furnished with a cam ring 1 having an inside surface approximately in an elliptical shape, a rotor 2 rotating inside the cam ring 1, slits 3 formed radially in the rotor 2, and vanes 4 which are installed in the slits 3 and whose tips make slide contact with the inside surface of the cam ring 1, wherein a projection 4c in the form of an arc of circle is formed at the tip of each vane 4 on the rotating direction side of the rotor 2. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vane pump, which is suitable as, for example, a hydraulic device for power steering of a vehicle.

[0002]

2. Description of the Related Art FIG. 4 shows a schematic structure of a conventional vane pump, FIG. 4 (a) is a schematic structural view of a side surface inside a vane pump, and FIG. 4 (b) is an enlarged view of a vane portion.

As shown in FIG. 4A, a conventional vane pump has a cam ring 1 having an elliptical inner peripheral surface, a rotor 2 rotating in the cam ring 1, and slits radially provided in the rotor 2. 3 and is disposed in the slit 3,
The tip of the cam ring 1 is provided with a vane 4 that slides in contact with the inner peripheral surface of the cam ring 1, and a space such as the inner peripheral surface of the cam ring 1 and the outer peripheral surface of the rotor 2 is supplied with and discharges a liquid such as oil. Two intake ports 21 and two discharge ports 22 are provided at symmetrical positions with respect to the center of the rotor 2. Further, although not shown, the discharge port 22 communicates with the slit 3 so that the discharge pressure of the liquid serves as the back pressure of the vane 4 in the slit 3.

Since the cam ring 1 has an elliptical inner peripheral surface, as the rotor 2 rotates, the vanes 4 and the slits 3 are formed.
Reciprocate to expand and contract inside. That is, the centrifugal force due to the rotation of the rotor 2 acts on the vane 4, and the back pressure due to the discharge pressure acts on the inner end of the vane 4, so that the tip (outer end) of the vane 4 is always in contact with the inner peripheral surface of the cam ring 1. Thus, the vane 4 is pushed outward in the radial direction. And
Since the inner peripheral surface of the cam ring 1 has an elliptical shape, the tip of the vane 4 slides along the shape and the vane 4
Will expand and contract within the slit 3. Therefore, as the rotor 2 rotates, the inner peripheral surface of the cam ring 1 and the rotor 2
The gap portion 5 formed by the outer peripheral surface and the vane 4 repeatedly increases and decreases its volume.

Utilizing the above-mentioned operating state, the liquid supplied to the suction port 21 as the gap between the inner peripheral surface of the cam ring 1 and the outer peripheral surface of the rotor 2 increases (the volume of the gap 5 increases).
The liquid sucked into the gap 5 and compressed with the decrease in the distance between the inner peripheral surface of the cam ring 1 and the outer peripheral surface of the rotor 2 (reduction of the volume of the gap 5) compresses the liquid to the discharge port 22. To discharge the liquid having an arbitrary pressure to the outside.

The vane pump described above is used as a hydraulic device, but particularly when it is used for power steering, if the inner peripheral surface of the cam ring 1 is a simple elliptical shape,
There is a problem that pulsation occurs when the compressed liquid is ejected and the ejection efficiency is impaired. In addition, vibrations and noises of the piping through which the compressed liquid is passed and the equipment that receives the supply are accompanied. For this reason, the inner peripheral surface of the cam ring is not made to be a simple elliptical shape, but an uneven portion, a concave portion, or a convex portion is provided at an appropriate position to suppress pulsation at the time of discharge, maintain stable discharge pressure, and improve discharge efficiency. Is improving. In addition, the concave portion and the convex portion include a radius change in which the radius of the inner peripheral surface largely changes.

FIG. 4 (b) is an enlarged view of the vane portion of the vane pump, showing the state of the vane in contact with the cam ring having the uneven portion on the inner peripheral surface. For comparison with the uneven portion, the original elliptic curve of the inner surface of the cam ring is shown by the dotted line.

As shown in FIG. 4 (b), the slit 3 provided in the rotor 2 allows a slight clearance (gap) between itself and the vane 4 due to the expansion and contraction movement of the vane 4. Further, the tip end portion of the vane 4 is formed into an arcuate curved surface so as to smoothly contact the inner peripheral surface of the cam ring 1. When the rotor 2 rotates, the sliding resistance between the inner peripheral surface of the cam ring 1 and the tip of the vane 4 causes a force to act on the tip of the vane 4 in the direction opposite to the rotational direction of the rotor 2, and the slit 3 is provided. The amount of clearance is tilted. That is, with respect to the center line 3a of the slit 3,
The center line 4a of the vane 4 at the time of rotation has an inclination δ, and it also comes into contact with the tangent line of the inner peripheral surface of the cam ring 1 at an acute angle, not at a right angle. This inclination is unavoidable structurally and cannot be reduced to zero.

[0009]

When the curvature of the inner peripheral surface of the cam ring 1 is sufficiently large with respect to the curved surface of the tip of the vane 4, the vane 4 tilts with respect to the inner peripheral surface of the cam ring 1 as described above. Even when they come into contact with each other, the curved surface portion comes into contact with the inner peripheral surface of the cam ring 1, so that the tip of the vane 4 smoothly slides on the inner peripheral surface of the cam ring 1.

However, particularly in a vane pump used for power steering or the like, in order to suppress the pulsation at the time of discharge and improve the discharge efficiency, the inner peripheral surface of the cam ring 1 has a concave portion 1a and a convex portion as shown in FIG. 4 (b). Since the portion 1b is provided, the curvature of the inner peripheral surface of the cam ring 1 changes greatly, and a portion where the inner peripheral surface of the cam ring 1 contacts the vane 4 at an acute angle occurs. As described above, when the rotor 2 rotates,
Due to the sliding resistance with the cam ring 1 and the clearance in the slit 3, the vane 4 is inclined with respect to the slit 3, and at the above-mentioned location, the vane 4 and the inner peripheral surface of the cam ring 1 contact at a more acute angle when the rotor 2 rotates. It will be. or,
The curved end of the vane 4 is not chamfered, and has a corner 4b.

In such a state, that is, when the vane 4 and the inner peripheral surface of the cam ring 1 are in contact with each other at an acute angle, and the vane 4 has a corner 4b at the tip, the inclination of the vane 4 causes the corner of the tip of the vane 4 to be inclined. 4b is caught on the inner peripheral surface of the cam ring 1 and cannot slide smoothly, which causes an abnormal noise (a metallic friction noise) to slide. Further, the curvature of the curved portion of the concave and convex portion of the inner peripheral surface of the cam ring 1 and the curvature of the curved surface of the tip of the vane 4 are matched and hooked, so that smooth sliding is not possible,
It may slide due to abnormal noise (metal friction noise). This phenomenon causes wear of the inner peripheral surface of the cam ring 1 and the vanes 4, is not preferable in terms of durability of the vane pump, and may shorten the life of the vane pump.

In a vane pump used for power steering of a vehicle, the above phenomenon is caused and an abnormal noise is generated when the steering wheel is operated at a low speed (particularly when the steering wheel is stationary steering). It is considered that the above phenomenon is related to the hydraulic pulsation, and there is a problem in the stability of the discharge pressure of the vane pump.

In view of the above problems, the present invention provides a vane pump having a vane which is always in smooth contact with the inner peripheral surface of the cam ring.

[0014]

SUMMARY OF THE INVENTION A vane pump according to the present invention for solving the above-mentioned problems is a vane which is disposed in a slit radially provided in a rotor and whose tip is slid in contact with an inner peripheral surface of a cam ring. An arcuate convex portion is formed on the rotor rotation side of the tip of the.

The vane pump according to the present invention for solving the above-mentioned problems is characterized in that a curved surface having a large radius of curvature is formed at the tip end portion of the vane on the rotor rotation side.

The vane pump according to the present invention which solves the above-mentioned problems is characterized in that the inner peripheral surface of the cam ring is provided with at least one of irregularities.

The vane pump according to the present invention for solving the above-mentioned problems is characterized in that the slit is capable of accommodating the convex portion at the tip of the vane and is provided with a notch portion for accommodating the convex portion.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The basic structure of a vane pump according to the present invention is the same as that of the vane pump shown in FIGS. 4 (a) and 4 (b). That is, the cam ring 1 having the concave and convex portions 1a and 1b on the inner peripheral surface thereof, and the rotor 2 rotating inside the cam ring 1.
And a vane 4 disposed in the slit 3 and having its tip in contact with the inner peripheral surface of the cam ring 1 and sliding. However, the present invention is characterized by the shape of the vane, particularly the shape of the tip of the vane.

(Embodiment 1) FIG. 1 is a schematic view of a vane shape of a vane pump showing an example of an embodiment according to the present invention. In FIG. 1, the same numbers are given to the same components as those of the conventional technique, and the duplicated description will be omitted. For comparison with the uneven portion, the original elliptic curve of the inner peripheral surface of the cam ring is shown by a dotted line.

As shown in FIG. 1, the vanes 4 are
Arc-shaped convex portion 4c on the side of the rotor 2 in the direction of rotation of the rotor 2
Are formed. That is, even if the inner peripheral surface of the cam ring 1 has a portion contacting the vane 4 at an acute angle, the tip of the vane 4 is always contacted with the inner peripheral surface of the cam ring 1 with a smooth curved surface portion. Curved surface (convex portion 4c) protruding from the rotation direction side of the rotor 2
have. In other words, the portion of the tip portion of the vane 4 that comes into contact with the inner peripheral surface of the cam ring 1 has a p-shape (or q-shape) when viewed from the side. The curvature of the curved surface of the arc-shaped convex portion 4c is appropriately determined according to the curvature of the irregularities on the inner peripheral surface of the cam ring 1.

Further, on the rotation direction side of the rotor 2 of the slit 3, a notch portion 3 matching the shape of the convex portion 4c of the vane 4 is formed.
c is formed. That is, when the vane 4 is pushed back into the slit 3, the convex portion 4c is properly accommodated so that the function of the vane pump is not impaired. In addition, in FIG. 1, the state in which the vane 4 is pushed back is shown by a chain line.

Even if the vane 4 is inclined due to the sliding resistance and the inner peripheral surface of the cam ring 1 has irregularities and has a portion contacting the vane 4 at an acute angle, the tip of the vane 4 has the above-mentioned shape. Since it has, that is, there is no corner on the rotational direction side of the tip of the vane 4, the inner peripheral surface of the cam ring 1 and the tip of the vane 4 are always in smooth contact, and the vane 4 contacts the inner peripheral surface of the cam ring 1. Can slide smoothly. Therefore,
It is possible to prevent abnormal noise caused by catching between the inner peripheral surface of the cam ring 1 and the vane 4, and prevent wear of the vane pump itself.

Further, since the vane 4 has the above-described shape, the mass of the tip end portion of the vane 4 increases and the centrifugal force acting on the vane 4 when the rotor 2 rotates also increases, so that the pressing force to the inner peripheral surface of the cam ring 1 is increased. The airtightness between the cam ring 1 and the vanes 4 is improved.

(Embodiment 2) FIG. 2 is a schematic view of a vane shape of a vane pump showing another example of the embodiment according to the present invention. In FIG. 2, the same numbers are given to the same components as those of the conventional technique, and the duplicate description is omitted. For comparison with the uneven portion, the original elliptic curve of the inner peripheral surface of the cam ring is shown by a dotted line.

As shown in FIG. 2, the vanes 4 are
A curved surface portion 4d having a large radius of curvature is formed on the tip end of the above in the rotation direction side of the rotor 2. That is, even if the inner peripheral surface of the cam ring 1 has a portion contacting the vane 4 at an acute angle, the tip of the vane 4 is always contacted with the inner peripheral surface of the cam ring 1 with a smooth curved surface portion. The corner of the portion on the rotation direction side of the rotor 2 is abolished, and an arc-shaped curved surface portion 4d having a large radius of curvature formed from the rotation direction side of the rotor 2 is provided. In the case of this embodiment, the slit 3 may have a conventional shape.

Even if the vane 4 is inclined due to sliding resistance, and the inner peripheral surface of the cam ring 1 has irregularities and has a portion contacting the vane 4 at an acute angle, the tip of the vane 4 has the above shape. That is, since there is no corner on the rotational direction side of the tip of the vane 4, and the curvature of the vane 4 is sufficiently large with respect to the curvature of the inner peripheral surface of the cam ring 1, the curvatures of the cam ring 1 do not match. The inner peripheral surface and the tip of the vane 4 are always in smooth contact, and the vane 4 is attached to the cam ring 1
The inner peripheral surface of can be smoothly slid. Therefore, the cam ring 1
It is possible to prevent abnormal noise caused by the catching of the inner peripheral surface of the vane 4 with the vane 4, and to prevent abrasion of the vane pump itself.

FIG. 3 is a schematic configuration diagram of a power steering of a vehicle showing an example of specific application of the vane pump.

The power steering is used to assist the steering force when steering the vehicle, and in particular,
It is effective in reducing the steering force at low speeds and greatly reduces the burden on the driver. The hydraulic pressure of oil compressed by an oil pump is used as the power source of the steering force, and a vane pump is applied as this oil pump.

As shown in FIG. 3, the power steering includes a steering wheel 12 used by a driver to steer tires 11, and a steering shaft 14 for transmitting a steering force applied to the steering wheel 12 to a steering gear box 13. A steering gear box 13 for steering the tire 11 by assisting the steering force from the steering wheel 12 by using hydraulic pressure,
An oil pump (vane pump) 15 for supplying hydraulic pressure to the steering gear box and an oil tank 16 serving as a reservoir thereof are provided. The oil pump 15 utilizes the rotation of the engine 17, and the engine 17 and the oil pump 1
The oil pump 1 using the belt 18 provided between the five
8 rotors are rotating. The oil flows as shown by the arrow in FIG. 3, and when it is supplied from the oil pump 15 to the steering gear box 13, it is pressurized by the oil pump 15 and becomes a power source for steering.

In the vane pump according to the present invention, the inner peripheral surfaces of the vane and the cam ring slide smoothly. Therefore, if the vane pump is used in the power steering having the above-mentioned structure, it is possible to prevent an abnormal noise which is conventionally generated during stationary steering. It is also possible to prevent wear of the vane pump itself. Further, since the sliding resistance is reduced, the load of the vane pump on the engine can be reduced, and the response and fuel consumption of the engine itself can be improved.

The drive source for the rotation of the rotor of the oil pump 15 is not limited to the engine 17, but may be driven by an electric motor in some cases, for example, in a light vehicle because of the installation space. However, by reducing the sliding resistance, it is possible to reduce the load on the electric motor and reduce the power consumption.

Although the above-described embodiment is one in which the present invention is applied to a vane pump for power steering, the present invention is not limited to that used for power steering, and can be applied to other hydraulic devices. .

Further, the present invention has a great effect on the vane pump having an uneven portion on the inner peripheral surface of the cam ring, but is also applicable to a vane pump having no uneven portion on the inner peripheral surface of the cam ring, and sliding. It can be expected to reduce resistance.

[0034]

According to the invention of claim 1, even if the vane is inclined, the tip of the vane and the inner peripheral surface of the cam ring are always in smooth contact with each other, so that no abnormal noise is generated. As a result, wear on the cam ring and vanes is reduced, extending the life of the vane pump. In particular, when the drive source of the rotor of the vane pump is an engine, the sliding load is reduced, the engine load is also reduced, and the engine response and fuel consumption are improved. Further, since the weight of the tip of the vane is increased, the inertial force (centrifugal force) is also increased, the pressing force of the vane is improved, and the airtightness is also improved.

According to the second aspect of the invention, since the tip of the vane and the inner peripheral surface of the cam ring are always in smooth contact with each other even when the vane is inclined, no abnormal noise is generated. As a result, wear on the cam ring and vanes is reduced, extending the life of the vane pump. In particular, when the drive source of the rotor of the vane pump is an engine, the sliding load is reduced, the engine load is also reduced, and the engine response and fuel consumption are improved.

According to the invention of claim 3, the effects of claims 1 and 2 work particularly effectively.

According to the invention of claim 4, the convex portion at the tip of the vane can be housed in the slit, and the performance as the vane pump is not impaired.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a vane shape of a vane pump showing an example of an embodiment according to the present invention.

FIG. 2 is a schematic view of a vane shape of a vane pump showing another example of the embodiment according to the present invention.

FIG. 3 is a schematic configuration diagram of a power steering showing an example of specific application of the vane pump according to the present invention.

FIG. 4 is a schematic configuration diagram of a conventional vane pump,
(A) is a schematic block diagram inside a vane pump, (b)
Is an enlarged view of a portion of a vane.

[Explanation of symbols] 1 cam ring 1a Recessed portion (portion where the radius of the inner peripheral surface greatly changes) 1b Convex part (portion where radius of inner peripheral surface changes greatly) 2 rotor 3 slits 3c Notch 4 vanes 4b corner 4c convex part 4d curved surface 5 Gap

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 3H040 AA03 BB05 BB11 CC06 CC09                       CC10 CC14 DD11                 3H044 AA02 BB05 CC05 CC11 CC12                       CC19

Claims (4)

[Claims] 1. A cam ring, a rotor rotating in the cam ring, a slit radially provided in the rotor, and a vane disposed in the slit, the tip of which is in contact with an inner peripheral surface of the cam ring. A vane pump comprising: a vane pump, wherein an arcuate convex portion is formed on a tip end portion of the vane on a rotation direction side of the rotor. 2. A cam ring, a rotor rotating in the cam ring, a slit radially provided in the rotor, and a vane disposed in the slit, the tip of which is in contact with the inner peripheral surface of the cam ring. A vane pump provided with a vane pump, wherein a curved surface having a large radius of curvature is formed at a tip end portion of the vane on a rotation direction side of the rotor. 3. The vane pump according to claim 1, wherein the inner peripheral surface of the cam ring is provided with at least one of irregularities. 4. The vane pump according to claim 1, wherein the slit is capable of accommodating a convex portion of a tip portion of the vane.