JPH0634182U - Variable capacity vane pump - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a vane pump capable of easily forming a passage having a small cross-sectional area for noise reduction with high accuracy and achieving stable noise reduction. [Structure] The cam ring 3 is formed with a beard groove 31 having a small cross-sectional area for communicating a discharge-side closed portion 2c between the suction port 2a and the discharge port 2b with the discharge port 2b.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a variable displacement vane pump applied as a hydraulic power source of an automatic transmission, and more particularly to a variable capacity vane pump having a passage having a small cross-sectional area communicating with a discharge port in order to achieve low noise.

[0002]

[Prior art]

 Conventionally, as a variable displacement vane pump, for example, the one described in Japanese Utility Model Laid-Open No. 63-104689 is known.

This variable displacement vane pump has a structure in which a plurality of whisker grooves (passages having a small cross-sectional area) are formed on a side surface of a casing accommodating a cam ring so as to communicate with the discharge port.

Therefore, when the vane rotates, the negative pressure side and the positive pressure side of the vane communicate in a stepwise manner through the plurality of whisker grooves, and the passage area gradually increases. Therefore, the pressure change from the negative pressure to the positive pressure gradually progresses, and the pressure change becomes smooth. As a result, the generation of overshoot pressure between the vanes can be suppressed and noise can be reduced.

[0005]

[Problems to be solved by the device]

 By the way, in the above-mentioned conventional vane pump, in order to form the beard groove (the passage having a small cross-sectional area), the casing is processed in the following procedure.

First, a casing is manufactured. In this case, the casing is molded. At this time, the discharge port and the suction port are molded. Then, the surface of the casing is ground, and the beard groove communicating with the discharge port is cut with an end mill or the like. After that, the outer peripheral surface of the casing is ground on the mating surface between the casings, and other parts are machined using this surface as a reference.

However, in carrying out the above-mentioned processing, there were the following problems.

When cutting the beard groove (passage), the processing is performed with reference to the discharge port, but since the reference discharge port and the beard groove are located in the rotation direction, they are positioned in the rotation direction. It is difficult and time-consuming to match the pipes, and because of the casting, the dimensional accuracy of the discharge port is low, and the position accuracy of the passage is also poor.

After cutting the beard groove (passage) with an end mill, the casing surface, which serves as a reference, is ground. In this grinding, the periphery of the beard groove is also ground. This is different before and after grinding, which also makes it difficult to maintain high accuracy.

As described above, if the positional accuracy of the beveled groove is low and variations in processing occur, the effect of suppressing the occurrence of overshoot pressure is reduced and the noise reduction capability is reduced.

The present invention has been made in view of the above-mentioned conventional problems, and it is possible to easily form a passage having a small cutting area for noise reduction with high accuracy, and to stably reduce noise. The purpose is to provide a vane pump that can achieve the above.

[0012]

[Means for Solving the Problems]

 Therefore, in the present invention, the above object is achieved by forming a passage having a small sectional area toward the cam ring instead of the casing.

That is, the variable displacement vane pump of the present invention has a plurality of vanes, a rotor, a cam ring, a return spring, an intake port, and a discharge port, and swings the cam ring with respect to the casing to connect the rotor and the cam ring. In a variable displacement vane pump that adjusts the discharge flow rate by changing the eccentricity, a passage with a small cross-sectional area that connects the discharge side confined part between the discharge port and the suction port to the discharge port is formed in the cam ring. It was configured.

The passage may be formed on both sides or either side of the cam ring.

Further, the passage may be formed in a shape in which the cross-sectional area is changed so that the cross-sectional area gradually increases in the vane rotation direction.

[0016]

[Action]

 First, the manufacturing procedure will be described. The casing is molded by casting as usual, and the discharge port and the suction port are also molded at that time. On the other hand, the cam ring is usually formed by sintering, and when the passage is formed on the side surface of the cam ring as in the pump according to claim 2, the passage is also formed when the cam ring is formed. Can be molded together. After that, when the cam ring is attached to the casing, the passage formed in the cam ring is communicated with the discharge port of the casing.

When the passage is not formed by sintering, the cam ring is processed based on the swing center of the cam ring or the like. However, since the cam ring has high dimensional accuracy by sintering, the positional accuracy of the passage is also high. .

Next, the operation of the pump will be described. At the discharge side closing portion, the vane first reaches the passage having a small cross-sectional area formed in the cam ring along with the rotation of the vane, and passes through this passage. The negative pressure side of the vane communicates with the discharge port on the positive pressure side. When the vane rotates further, the vane reaches the discharge port, and the negative pressure side and the pressure suppression side are in complete communication.

Therefore, since the pressure change from the negative pressure to the positive pressure gradually progresses, the occurrence of pressure overshoot is suppressed, and the noise is reduced.

Further, in the vane pump according to the second aspect, when the passage is formed on both side surfaces of the cam ring, when the pressure of the discharge port is applied to the passage, the passage is evenly applied from both sides.

Further, in the third aspect, the cross-sectional area of the passage is gradually increased in the vane rotation direction, and the cross-sectional area of the passage for communicating the negative pressure side and the positive pressure side with the rotation of the vane is gradually increased. As the pressure increases, the pressure change gradually progresses, the pressure change becomes smooth, and the pressure overshoot suppressing capability is improved.

[0022]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a cross-sectional view showing a variable displacement vane pump P according to an embodiment. The casing of the variable displacement vane pump P is composed of a housing 1 and a housing 2, and the space formed by these is shown. There are provided a cam ring 3, a rotor 4, a plurality of vanes 5, a vane ring 8 and the like. The rotor 4 is rotationally driven by a rotary shaft (not shown).

FIG. 3 is a view taken along the line S3-S3 in FIG. 2. As shown in FIG. 3, the cam ring 3 swings around a pivot 6 fixed to the housing 1 and the housing 2. It is movably provided, and is further urged by the return spring 7 in a direction in which the amount of eccentricity with the rotor 4 increases.

A lever-shaped piston 9 is provided along the outer circumference of the cam ring 3. The piston 9 is swingably provided with a pin 10 as a fulcrum so that the cam ring 3 is pressed. An oil chamber 11 is formed on the back side of the piston 9.

As shown in the explanatory view of FIG. 1, the housing 2 is formed with an intake port 2 a and a discharge port 2 b along the inner peripheral portion of the cam ring 3. That is, the opening area of each of the ports 2a and 2b is changed by rotating the cam ring 3 around the pivot 6.

Further, in the cam ring 3, at a position of the closing portion 2c on the discharge side between the ports 2a and 2b of the housing 2, one end portion overlaps the discharge port 2b so that a beard groove (having a small cross-sectional area) ( A passage 31 is formed, and the beard groove 31 is formed in a shape in which the cross-sectional area gradually increases toward the discharge port 2b side from the tip on the suction port 2a side to the position overlapping the discharge port 2b. . As shown in the cross-sectional view of FIG. 4, the beard grooves 31 are symmetrically formed and have the same size on both side surfaces of the cam ring 3.

As shown in FIG. 1, the distance L between the suction port 2a side tip of the beard groove 31 and the suction port 2a is set to be slightly smaller than the pitch P of the vanes 5. ing.

Next, the operation of the embodiment will be described.

A) Manufacturing The manufacturing procedure will be described. The housings 1 and 2 are molded by casting, and the suction port 2a and the discharge port 2b are also molded at that time.

On the other hand, the cam ring 3 is formed by sintering, and the beard groove 31 is also formed at the time of this forming.

After that, when the cam ring 3 is assembled to the housing 2 by the pivot 6, the beard groove 31 is arranged at a position communicating with the discharge port 2b as shown in FIG.

As described above, the cutting process is not required to form the beard groove 31.

B) During Pump Operation When the pump P is operated, the vane 5 reaches the beard groove 31 formed in the cam ring 3 in the closing portion 2c as the vane 5 rotates (see FIG. 1). (State), the negative pressure side of the vane 5 communicates with the discharge port 2b, which is the positive pressure side, through the beard groove 31. Then, when the vane 5 rotates, the cross-sectional area of the portion that connects the negative pressure side and the positive pressure side of the beard groove 31 gradually increases, and finally, the vane 5 reaches the discharge port 2b and the negative pressure side. And the control side are in complete communication.

As described above, the bevel groove 31 gradually changes the pressure from the negative pressure to the positive pressure, so that the overshoot of the pressure is suppressed and the noise is reduced.

Further, when the negative pressure side and the positive pressure side of the vane 5 are communicated with each other by the beard groove 31, the beard grooves 31 and 31 on both side surfaces of the cam ring 3 are in communication at the same time, and both are symmetrical and have the same shape. Because of the dimensions, the oil pressure acting on the cam ring 3 when the oil passes through the beveled grooves 31, 31 is evenly applied to the cam ring 3 from both sides, and the cam ring 3 is attached to the housings 1 and 2. On the other hand, it is possible to prevent one-sided contact. Therefore, it is possible to prevent uneven wear and burn due to one-sided contact of the cam ring 3.

As described above, in this embodiment, the effects listed below can be obtained.

Since the beard groove 31 is formed by sintering the cam ring 3, the cutting process is unnecessary, the labor of the process is saved, and the positional accuracy is improved.

As described above, since the positional accuracy of the beveled groove 31 is high and processing variations are unlikely to occur, it is possible to reliably suppress the generation of overshoot hydraulic pressure and obtain high noise reduction performance.

Since the beard groove 31 is formed in a shape in which the cross-sectional area gradually increases from the tip on the suction port 2a side toward the discharge port 2b, the pressure change from negative pressure to positive pressure gradually progresses. However, high performance of suppressing overshoot hydraulic pressure is obtained.

Since the beard grooves 31 are formed on both surfaces of the cam ring 3 in a symmetrical shape and with the same size, the oil pressure acting on the cam ring 3 when the oil passes through the beard grooves 31, 31 is equal to that on both surfaces of the cam ring 3. Therefore, it is possible to prevent the cam ring 3 from being in one-sided contact with the housings 1 and 2, so that uneven wear and burn due to one-sided contact of the cam ring 3 can be prevented.

Although the embodiment of the present invention has been described above with reference to the drawings, the specific configuration is not limited to this embodiment.

For example, in the embodiment, the whisker groove 31 is provided on both side surfaces of the cam ring 3, but it may be provided on only one side surface.

Further, in the embodiment, both the suction port 2a and the discharge port 2b are formed only on the one housing 2, but both or one of the ports 2a and 2b are provided on the housings 1 and 2. Both ports may be formed, or each port 2a, 2b may be formed in a separate housing 2a, 2b. When either one or both of the ports 2a and 2b are formed in both housings 1 and 2, the passages are preferably provided on both side surfaces of the cam ring 3.

Further, in the embodiment, the whisker groove 31 formed on the side surface of the cam ring 3 is shown as a passage, but, for example, a hole that penetrates from the inner circumference of the cam ring 3 to the inside of the cam ring 3 and reaches the discharge port 2b. It may be formed, and the number thereof may be arbitrarily set from 1 to a plurality.

[0046]

[Effect of device]

 As explained above, in the variable displacement vane pump of the present invention, the passage with a small cross-sectional area for noise reduction is formed in the cam ring with high dimensional accuracy, so the passage position accuracy is improved and stable noise reduction performance is obtained. The effect of being able to be obtained is obtained.

Further, in the variable displacement vane pump according to the second aspect, since the passage is formed on the side surface of the cam ring, the passage can be molded at the same time when the cam ring is formed, and the cutting process is unnecessary, and the passage is formed. The machining accuracy can be improved and the labor required for machining can be saved.In addition, if the passages are formed on both sides of the cam ring, the fluid flow pressure will be received evenly from both sides, and the cam ring will On the other hand, it is possible to prevent a one-sided contact state, which prevents uneven wear and burn due to one-sided contact of the cam ring.

Further, in the variable displacement vane pump according to the third aspect, since the passage is formed in a shape in which the cross-sectional area is changed so that the cross-sectional area is gradually increased in the vane rotation direction, the pressure change due to the rotation of the vane is suppressed. Gradually progressing, the pressure change becomes smooth, the pressure overshoot suppression capability is improved, and the noise reduction performance is improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing each port and a cam ring of a variable displacement vane pump according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a variable displacement vane pump according to an embodiment.

FIG. 3 is an S of FIG. 2 showing the variable displacement vane pump of the embodiment.
It is the figure seen along the 3-S3 line.

FIG. 4 is an enlarged cross-sectional view (cross-section taken along line S4-S4 in FIG. 1) showing a main part of the variable displacement vane pump according to the embodiment of the present invention.

[Explanation of symbols]

 1 Housing (Casing) 2 Housing (Casing) 2a Suction Port 2b Discharge Port 3 Cam Ring 4 Rotor 5 Vane 7 Return Spring 31 Beard Groove (Passage)

Claims (3)

[Scope of utility model registration request] 1. A plurality of vanes and rotors, cam rings,
A variable capacity vane pump having a return spring, a suction port, and a discharge port, wherein a cam ring is swung with respect to a casing to change a discharge flow rate by changing an eccentric amount between a rotor and a cam ring. A variable displacement vane pump characterized in that a cam ring is formed with a passage having a small cross-sectional area for communicating a discharge-side closed portion between the discharge port and the discharge port. 2. The variable displacement vane pump according to claim 1, wherein the passage is formed on both sides or one side of the cam ring. 3. The variable displacement vane pump according to claim 1, wherein the passage is formed in a shape in which the cross-sectional area is changed so that the cross-sectional area gradually increases in the vane rotation direction.