JP2001059481A - Vibration control structure of variable displacement vane pump - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To reduce the occurrence of pump vibration caused by the vibration of a side plate, and to reduce the occurrence of seizure at the sliding contact portion between the side plate and the rotor and the sliding contact portion between the rotor and the cover plate. And a vibration control structure for a variable displacement vane pump. SOLUTION: A rotor 8 rotatably accommodated in a pump housing 2 and having a plurality of vane grooves 13 radially directed at equal intervals in a circumferential direction, and disposed so as to be movable and displaceable in the pump housing 2. A cam ring 7 fitted so as to form a pump chamber 17 with the outer peripheral portion of the rotor 8 and provided with an urging force to maximize the volume of the pump chamber 17; The side plate 5 which is non-rotatably accommodated in the bottom of the cartridge accommodating space 4 and slidably contacts one side of the rotor 8 and the cam ring 7, closes the opening of the pump housing 2, and slidably contacts the other side of the rotor 8 and the cam ring 7. In the variable displacement vane pump 1 including the cover plate 3, a shim 52 is interposed between the bottom wall surface 50 of the pump cartridge housing space 4 and the side plate 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration control structure for a variable displacement vane pump, and more particularly to a vibration control structure for a variable displacement vane pump which suppresses vibration of a side plate to reduce pump vibration and prevent seizure. For vibration structure.

[0002]

2. Description of the Related Art In a pressure balanced vane pump, there are two pairs of a pump suction section and a pump discharge section, and the pump suction sections in both sets and the pump discharge sections in both sets are arranged to face each other. I have.

[0003] For this reason, even if a gap is formed between the side plate and the rotor and between the cover plate and the rotor when the discharge section is at a high pressure (discharge state), the gap is symmetric with respect to the pump drive shaft. Since there are two places, the side plate and the rotor and the cover plate and the rotor are in equilibrium with each other, and because oil enters therein, they are lubricated, and there is no problem such as seizure.

However, the variable displacement vane pump has a structure in which there is only one pair of a pump suction part and a pump discharge part. In addition, since the cam ring is displaced and the discharge part is at a high pressure, the discharge part is On the suction side, there are gaps between the side plate and the rotor and between the cover plate and the rotor. On the suction side, the side plate is pressed against the rotor and the rotor is pressed against the cover plate. See JP-A-9-273487).

[0005]

Therefore, on the suction side of the pump, lubrication between the side plate and the rotor and between the cover plate and the rotor is insufficient, and there is a possibility that seizure may occur at this portion. Was. In particular, since the side plate is merely inserted into the bottom of the pump cartridge accommodating space in the pump housing in such a manner that the side plate does not rotate, the risk described above is further increased.

Further, when the side plate, the outer case, the cam ring and the rotor constituting the pump cartridge are accommodated in the pump cartridge accommodating space in the pump housing and the cover plate is assembled,
Since the design considering the dimensional variation of each of these parts is performed, after assembling these parts, the space between the annular bottom wall at the bottom of the pump cartridge housing space and the side plate,
A gap is left between the side plate and the rotor, between the cover plate and the rotor, and the like.

[0007] This gap further increases the tendency of one side contact between the side plate and the rotor and between the rotor and the cover plate as described above, and further increases the risk as described above. It may cause. In particular, the side plate is non-rotatably accommodated at the bottom of the pump cartridge accommodating space in the pump housing, but only a seal member such as an O-ring is interposed between the side plate and the bottom wall. It easily vibrated, which was a major cause of pump vibration and seizure. However, it is difficult to eliminate such a gap from the limit of processing accuracy.

The present invention solves the above-mentioned problems of the conventional variable displacement vane pump, in particular, suppresses the generation of pump vibration caused by the vibration of the side plate, and slides the side plate with the rotor. It is an object of the present invention to provide a vibration control structure for a variable displacement vane pump in which the occurrence of seizure in a contact portion and a sliding contact portion between a rotor and a cover plate is reduced.

[0009]

SUMMARY OF THE INVENTION The present invention relates to a vibration damping structure for a variable displacement vane pump which solves the above-mentioned problems, and the invention described in claim 1 is provided within a pump housing. A pump chamber rotatably housed and having a plurality of vane grooves radially directed at equal intervals in the circumferential direction and disposed in the pump housing so as to be movable and displaceable, and a pump chamber between the rotor and an outer peripheral portion of the rotor; A cam ring fitted to form a pump chamber and provided with an urging force such that the volume of the pump chamber is maximized, and the cam ring is non-rotatably housed in the bottom of a pump cartridge housing space in the pump housing. A side plate that slides on one side of the rotor and the cam ring; and a cover plate that closes an opening of the pump housing and slides on the other side of the rotor and the cam ring. And a shim is interposed between the bottom wall surface of the pump cartridge accommodating space and the side plate, the variable displacement vane pump having a damping structure. .

According to the first aspect of the present invention, as described above, the control of the variable displacement vane pump including the rotor, the cam ring, the side plate, and the cover plate in the above-described manner is provided. The vibration structure is configured by interposing a shim between the bottom wall surface of the pump cartridge housing space and the side plate.

As a result, no gap remains between the bottom wall surface of the pump cartridge accommodating space and the side plate and between the side plate and the rotor, so that the vibration of the side plate is suppressed and the vibration of the side plate is reduced. The occurrence of pump vibrations is greatly reduced. Further, since the tilting of the side plate is suppressed, the occurrence of seizure in the sliding contact portion between the side plate and the rotor and the sliding contact portion between the rotor and the cover plate is reduced.

Further, according to the second aspect of the present invention, the shim is provided between the bottom wall surface of the pump cartridge accommodating space and the side plate so as to surround the seal member. You.

As a result, the sealing member also acts to suppress the vibration of the side plate, so that the occurrence of pump vibration caused by the vibration of the side plate is further reduced, and the sliding contact portion between the side plate and the rotor, and the rotor, Seizure of the sliding contact portion with the cover plate is further reduced. Further, the sealing member itself is not excessively deformed, so that the durability is improved.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the invention described in claims 1 and 2 of the present application shown in FIGS. 1 to 7 will be described below. FIG. 1 is a front view of a variable displacement vane pump to which the vibration damping structure according to the present embodiment is applied, FIG. 2 is a vertical sectional view taken along line II-II of FIG.
2 is a cross-sectional view taken along line III-III of FIG. 2, FIG. 4 is a rear view of a cover plate of the variable displacement vane pump of FIG. 1, FIG. 5 is a rear view of the same side plate, and FIG.
7 is a front view of the shim, FIG. 8 is a side view of the shim, and FIG. 9 is a characteristic diagram of the variable displacement vane pump of FIG.

As shown in FIGS. 1 to 3, a variable displacement vane pump 1 to which the vibration damping structure according to the present embodiment is applied has a front opening (rightward in FIG. 2) of a pump housing 2 which is a pump body main body. Is covered by a cover plate 3, and a pump cartridge housing space 4 inside the pump housing 2 covered by the cover plate 3 has a side plate 5, an outer case 6, a cam ring 7, The rotor 8 is accommodated.

The side plate 5 is inserted into the bottom of the housing space 4 and the outer case 6 is inserted from above the side plate 5.
Is inserted, and a cam ring 7 is housed in the outer case 6 so as to be swingable with the seal pin 9 as a shaft support. One end of the seal pin 9 is inserted into a pin receiving hole formed in the side plate 5, and the other end is inserted and fixed in a pin receiving hole formed in the cover plate 3.

A seal portion 10 for sealing a sliding portion between the inner peripheral surface of the outer case 6 and the outer peripheral surface of the cam ring 7 is provided at a position where the cam ring 7 is pivotally supported by the seal pin 9 and a position substantially symmetrical with respect to the pump axis. The space between the inner peripheral surface of the outer case 6 and the outer peripheral surface of the cam ring 7 is formed by the seal pin 9 and the seal portion 10.
11 and a second fluid pressure chamber 12. Although the first fluid pressure chamber 11 is illustrated in FIG. 3 as being divided into two chambers, these two chambers are communicated with each other by a groove formed on the sliding surface of the side plate 5.

The cam ring 7 is always directed toward the first fluid pressure chamber 11 by a spring 36 housed over the second fluid pressure chamber 12 and a chamber 47 communicating with the second fluid pressure chamber 12. It is urged to swing. The chamber 47 is closed by a screw plug (plug) 49.

Inside the cam ring 7, a rotor 8 is housed. As shown in FIG. 3, the rotor 8 has a plurality of vane grooves directed radially at equal intervals in the circumferential direction. When the rotor 8 is rotated by being driven by the pump drive shaft 15, the vane 14 accommodated in the vane groove 13 is formed according to the cam surface of the cam ring 7.
Reciprocating sliding inside 13. Each vane 14 is constantly urged toward the cam surface of the cam ring 7 by a pump discharge pressure supplied to a back pressure hole 16 formed in the rotor 8 along the axial direction of the rotor 8.

In this way, each vane 14 is constantly urged toward the cam surface of the cam ring 7, so that two adjacent vanes 14, 14, the cam surface of the cam ring 7, and the outer peripheral surface of the rotor 8 are provided. And the pump chamber 17 formed by being surrounded by the side plate 5 and the cover plate 3 acts as a pump to pressurize the hydraulic oil sucked from the suction part 18,
It discharges to the discharge chamber 20 via the discharge part 19.

As shown in FIGS. 4 and 5, the suction portion 18 has a suction through groove 18a formed on the cover plate 3 and a suction recess formed on the side plate 5 as a suction groove. And a groove 18b. As shown in FIGS. 4 and 5, the discharge portion 19 includes a discharge groove 19a which is a discharge groove formed in the cover plate 3 and a discharge through groove which is a discharge groove formed in the side plate 5. 19b. The suction through groove 18a and the discharge through groove 19b penetrate the cover plate 3 and the side plate 5, respectively.

A suction through groove formed in the cover plate 3
The suction groove 18b formed in the side plate 5 communicates with the suction groove 18b and faces the pump chamber 17 in the suction stroke. Further, the ejection groove 19a formed in the cover plate 3 is formed.
The discharge through groove 19b formed in the side plate 5 communicates with each other, and faces the pump chamber 17 in the discharge stroke.

Only one set of the suction through groove 18a and the discharge groove 19a on the cover plate side is provided on the cover plate 3.
Also, the suction groove 18b and the discharge groove 19 on the side plate side
As for b, only one set is provided on the side plate 5.

The hydraulic oil is supplied from a pump suction port 21 to a suction-side fluid passage 26a formed in the pump housing 2 through a control valve.
22 of spool 23 accommodated in spool accommodation hole 22a of 22
The annular chamber 26b sandwiched between the lands 24 and 25, the suction-side fluid passage 26c formed in the pump housing 2, and the suction-side fluid passage 26d formed in the cover plate 3 are guided to the suction section 18.

On the other hand, the hydraulic oil pressurized by the pump action of the pump chamber 17 exits the discharge section 19 as described above, and
After entering the pump 20, it exits through a pump outlet (not shown) and is sent to various fluid pressure utilizing devices such as a power steering device in a vehicle.

Some of the pressurized hydraulic oil is also shown in FIGS.
As shown in FIG. 5, a back pressure groove formed of one semicircular arc-shaped groove formed in the side plate 5 from the discharge chamber 20 through a back pressure side fluid passage 27 formed in the side plate 5.
3a, and from there is led to the upper half back pressure hole 16 in FIG. 3, and then to the lower half back pressure hole 16 via the annular back pressure groove 29 formed in the cover plate 3. To the back pressure groove 28b formed by the other semicircular groove formed in the side plate 5.

The back pressure side fluid passage 27, one semicircular back pressure groove 28a, upper half back pressure hole 16, annular back pressure groove 29, lower half back pressure hole 16, and the other semicircular back pressure groove 28b. Constitutes a dead-end flow path for the back-pressure oil, and the back-pressure oil filled in the dead-end flow path urges each vane 14 toward the cam surface of the cam ring 7 and at the same time, The sliding contact between the cover plate 3 and the rotor 8 and the sliding between the side plate 5 and the rotor 8 are also performed through a gap between the cover plate 3 and the rotor 8 and a gap between the side plate 5 and the rotor 8 together with a part of the hydraulic oil. It reaches the contact portion and lubricates each of these sliding contact portions.

Finally, the oil seeps into the bearing portion of the drive shaft 15 and lubricates it, passes through the lubricating oil return passage 30 and the suction-side fluid passage 26d formed in the pump housing 2 and passes through the pump suction side. Refluxed.

The pressurized hydraulic oil is further decompressed from the discharge chamber 20 through a variable orifice 31 (see FIG. 3) formed in the side plate 5 and guided to the second fluid pressure chamber 12. The pressurized hydraulic oil upstream of the variable orifice 31 is
The spool of the control valve 22 passes through a fluid passage formed in the pump housing 2 (not shown) and through an end opening 32 thereof.
A first valve chamber (high-pressure side) 33 defined by one land 24 of 23 is entered.

The pressurized hydraulic oil that has flowed into the first valve chamber 33 flows when one of the lands 24 opens a fluid passage 34 formed in the pump housing 2, and then flows into the outer case. The pressure is reduced through the orifice 35 formed in 6 and guided to the first fluid pressure chamber 11.

The cam ring 7 acts on the urging force of the spring 36 by the differential pressure between the pressure of the hydraulic oil guided to the first fluid pressure chamber 11 and the pressure of the hydraulic oil guided to the second fluid pressure chamber 12. 3 to the left around the seal pin 9 in FIG.

Then, since the side surface of the cam ring 7 on the side in contact with the side plate 5 gradually closes the variable orifice 31, the hydraulic oil pressure in the second fluid pressure chamber 12 is further reduced, and the cam ring 7 It swings further to the left around 9. Then, at a position where the pressure of the hydraulic oil in the first fluid pressure chamber 11 is balanced with the resultant force of the pressure of the hydraulic oil in the second fluid pressure chamber 12 and the urging force of the spring 36.

The pressure of the hydraulic oil guided to the first fluid pressure chamber 11 is controlled by the control valve 22 as follows.
A spring 38 is contracted to a second valve chamber (low pressure side) 37 defined by the other land 25 of the spool 23 of the control valve 22 so that the spool 23 is constantly biased toward the first valve chamber 33. Has been established.

The second valve chamber 37 is provided in the pump housing 2.
And an orifice 40 formed in the second fluid pressure chamber 12 through a fluid passage 39 formed across the pump housing 2 and the outer case 6. Orifice 40
The pressure pulsation of the hydraulic oil flowing into the second fluid pressure chamber 12 is smoothed and guided to the second valve chamber 37.

On the other hand, since the pressurized hydraulic oil upstream of the variable orifice 31 flows into the first valve chamber 33 as described above, the spool 23 applies the pressure of the pressurized hydraulic oil. Then, it moves to a position where the resultant force of the urging force of the spring 38 in the second valve chamber 37 and the reduced pressure of the hydraulic oil is balanced and stopped. In this way, the opening amount of the fluid passage 34 is controlled, and the pressure of the hydraulic oil guided to the first fluid pressure chamber 11 via the fluid passage 34 and the orifice 35 is controlled.

Therefore, now, when the pump is started,
When the pump rotation speed gradually increases (idling state), the pump discharge amount gradually increases and the variable orifice 31
The differential pressure before and after increases. Then, the pressure of the hydraulic oil in the first valve chamber 33 increases, and the spool 23 is moved leftward in FIG. 3 to increase the opening amount of the fluid passage 34.

Then, the pressure of the hydraulic oil guided to the first fluid pressure chamber 11 through the fluid passage 34 and the orifice 35 gradually increases, and eventually the pressure of the hydraulic oil in the second fluid pressure chamber 12 is increased. And the resultant force of the spring 36 and the biasing force of the spring 36.

During this time, the cam ring 7 is stationary at the position shown in FIG. 3, the eccentricity with the rotor 8 is maximum, and the pump discharge is maximum. Therefore, as the pump rotation speed increases as described above, the pump discharge amount sharply increases (see the line oa in FIG. 9).

When the pump rotation speed increases and reaches the low speed rotation speed from the idling rotation speed of the vehicle, the differential pressure across the variable orifice 31 further increases, and the first fluid pressure chamber
Since the pressure of the hydraulic oil in the first fluid pressure chamber 11 exceeds the sum of the pressure of the hydraulic oil in the second fluid pressure chamber 12 and the urging force of the spring 36, the cam ring 7 3 and gradually swings to the left in FIG.
The amount of eccentricity between the rotor and the rotor 8, the area of the suction part 18 facing the pump chamber 17 and the area of the discharge part 19 facing the pump chamber 17 gradually decrease, but the pump discharge amount is maintained at a substantially constant high level ( (See the line ab in FIG. 9).

When the rotational speed of the pump further increases and reaches the rotational speed at the time of medium / high speed of the vehicle, the differential pressure across the variable orifice 31 further increases, and the cam ring 7 moves into the first fluid pressure chamber 11. Is pushed by the pressure of the hydraulic oil, and swings further to the left. Thereby, the amount of eccentricity between the cam ring 7 and the rotor 8,
Since the area of the suction part 18 facing the pump chamber 17 and the area of the discharge part 19 facing the pump chamber 17 are reduced, the pump discharge amount is gradually reduced (see the line bc in FIG. 9).

During this time, the variable orifice 31 is gradually closed by the swing of the cam ring 7 to the left.
The minimum opening area is maintained, and the leftward swing of the cam ring 7 stops.

Therefore, even if the pump rotation speed further increases, the cam ring 7 does not swing leftward any more.
The amount of eccentricity between the cam ring 7 and the rotor 8 is maintained at a constant minimum amount, and the pump discharge amount is maintained at a substantially constant low level (see the line cd in FIG. 9).

As described above, in the variable displacement vane pump 1 according to the present embodiment, the cam ring 7 moves so as to reduce the amount of eccentricity with the rotor 8 in accordance with an increase in the pump rotation speed, and is shown in FIG. Such a pump discharge amount characteristic (o-a-b-c-d) can be obtained.

Here, as described above, the side plate 5 is non-rotatably inserted into the bottom of the pump cartridge housing space 4 in the pump housing 2 and housed therein. The manner of housing the side plate 5 will be described in further detail. . As shown in FIGS. 2 and 6, an O-ring 51 serving as a seal member is interposed between the annular bottom wall 50 forming the bottom wall of the pump cartridge housing space 4 and the side plate 5. A shim 52 is provided so as to surround the O-ring 51.

As shown in FIGS. 7 and 8, the shim 52 is formed of a circular ring manufactured using a thin metal plate, and fills a gap between the bottom wall 50 and the side plate 5. The vibration of the side plate 5 is suppressed by being inserted into the gap. By inserting the shim 52 into the gap between the bottom wall 50 and the side plate 5 in this manner, the gap between the side plate 5 and the rotor 8 is also eliminated. As described above, these gaps are inevitably formed as a result of the design in consideration of the dimensional variation of the components of the pump cartridge and because of the necessity of securing an insertion space for the O-ring 51.

Since the present embodiment is configured as described above, the following effects can be obtained according to the vibration damping structure of the variable displacement vane pump 1. A rotor 8 rotatably accommodated in the pump housing 2 and having a plurality of vane grooves 13 directed radially at equal intervals in the circumferential direction;
And is disposed so as to be movable and displaceable within the pump housing 2,
A cam ring 7 fitted so as to form a pump chamber 17 with the outer peripheral portion of the rotor 8 and provided with an urging force to maximize the volume of the pump chamber 17; The side plate 5, which is non-rotatably accommodated in the bottom of the cartridge accommodating space 4 and slidably contacts one side of the rotor 8 and the cam ring 7, closes the opening of the pump housing 2, and slidably contacts the other side of the rotor 8 and the cam ring 7. In the variable displacement vane pump 1 including the cover plate 3, a shim 52 is interposed between the annular bottom wall 50 at the bottom of the pump cartridge housing space 4 and the side plate 5.

As a result, the pump cartridge housing space 4
Between the annular bottom wall 50 at the bottom of the shaft and the side plate 5 and between the side plate 5 and the rotor 8,
The gap that generates the vibration of
The vibration of the side plate 5 is suppressed, and the occurrence of pump vibration caused by the vibration of the side plate 5 is greatly reduced. Also, since the tilting of the side plate 5 is suppressed,
The occurrence of burn-in at the sliding contact portion between the side plate 5 and the rotor 8 and at the sliding contact portion between the rotor 8 and the cover plate 3, particularly on the pump suction side, is reduced.

Further, a shim 52 is provided between the annular bottom wall 50 at the bottom of the pump cartridge accommodating space 4 and the side plate 5 so as to surround the O-ring 51. Acting to suppress the vibration, the occurrence of pump vibration caused by the vibration of the side plate 5 is further reduced, and the sliding contact between the side plate 5 and the rotor 8 and the sliding contact between the rotor 8 and the cover plate 3 are performed. Is further reduced. Further, the O-ring 51 itself is not excessively deformed, so that the durability is improved.

[Brief description of the drawings]

FIG. 1 is a front view of a variable displacement vane pump to which a vibration damping structure according to an embodiment of the invention described in claims 1 and 2 of the present application is applied.

FIG. 2 is a vertical sectional view taken along line II-II of FIG.

FIG. 3 is a cross-sectional view taken along line III-III of FIG. 2;

FIG. 4 is a rear view of a cover plate of the variable displacement vane pump of FIG. 1;

FIG. 5 is a rear view of the side plate.

FIG. 6 is an enlarged view of a main part of FIG. 2;

FIG. 7 is a front view of the shim.

FIG. 8 is a side view of the shim.

FIG. 9 is a characteristic diagram of the variable displacement vane pump of FIG. 1;

[Explanation of symbols]

1 ... Variable displacement vane pump, 2 ... Pump housing,
3 ... cover plate, 4 ... pump cartridge storage space, 5 ... side plate, 6 ... outer case, 7 ... cam ring, 8 ... rotor, 9 ... seal pin, 10 ... seal part,
11 ... first fluid pressure chamber, 12 ... second fluid pressure chamber, 13 ... vane groove, 14 ... vane, 15 ... pump drive shaft, 16 ... vane back pressure hole, 17 ... pump chamber, 18 ... suction part, 18a… suction through groove, 18
b ... suction groove, 19 ... discharge part, 19a ... discharge groove, 19b ... discharge through groove, 20 ... discharge chamber, 21 ... pump suction port, 22 ... control valve, 22a ... spool storage hole, 23 ... spool, 24 ,twenty five…
Land, 26a: suction side fluid passage, 26b: annular chamber, 26c,
26d ... suction side fluid passage, 27 ... back pressure side fluid passage, 28a, 28
b: semicircular back pressure groove, 29: annular back pressure groove, 30: lubricating oil return passage, 31: variable orifice, 32: end opening, 33: first valve chamber (high pressure side), 34: fluid passage, 35 ... orifice, 36 ... spring, 37 ... second valve chamber (low pressure side), 38 ... spring,
39 ... fluid passage, 40 ... orifice, 47 ... chamber, 49 ... screw stopper,
50 ... bottom wall, 51 ... O-ring, 52 ... shim.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kiyoshi Ando 112-1 Hagadai, Haga-cho, Haga-gun, Tochigi Prefecture F-term in Showa Tochigi Development Center Co., Ltd. 3H040 AA03 BB01 BB11 CC10 CC14 CC22 DD01 DD06 DD07 DD39 3H044 AA02 BB05 CC11 CC12 CC22 DD01 DD04 DD05 DD27 DD35

Claims (2)

[Claims] A rotor rotatably housed in a pump housing and having a plurality of vane grooves radially directed at equal intervals in a circumferential direction; and a rotor disposed movably displaceable in the pump housing. A cam ring fitted to form a pump chamber between the pump ring and the outer periphery of the cam ring, and a biasing force applied to maximize the volume of the pump chamber. A bottom plate that is non-rotatably accommodated and slides in contact with one side of the rotor and the cam ring; and a cover plate that closes an opening of the pump housing and slides in contact with the other side of the rotor and the cam ring. In the variable displacement vane pump, a shim is interposed between the bottom wall surface of the pump cartridge accommodating space and the side plate. Damping structure for a variable displacement vane pump, characterized in that. 2. The variable displacement vane pump according to claim 1, wherein a shim is provided between the bottom wall surface of the pump cartridge accommodating space and the side plate so as to surround a seal member. Swing structure.