JPH11294347A - Variable capacity type vane pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the relief flow rate to pass a valve part in the operating time of a relief valve, to suppress the generation of a foreign sound and a pressure variation generated by the relief flow, and to reduce the driving horsepower of a pump. SOLUTION: To the fluid pressure chambers 5 and 6 at both sides of the outer periphery of a cam ring 2 which is supported swayable in the condition to bias a rotor 3 having vanes 3a to one side, the fluid pressures at the upstream side and the downstream side of the first fixed throttle 21 which is provided at a pump discharge side passage 11 are introduced. A pilot passage extending from the downstream part of the fixed throttle to a pump suction side through a fluid pressure chamber at the low pressure side is provided, and the second throttle 23 to detect the flow of the pilot passage is provided between the pump discharge side passage of the pilot passage and the fluid pressure chamber at the low pressure side. A pilot type relief valve 20 is provided to a passage extending from the low pressure side fluid pressure chamber of the pilot passage to the pump suction side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable displacement vane pump used in a pressure fluid utilizing device such as a power steering device for reducing the steering force of a steering wheel of an automobile, and more particularly to a variable displacement vane pump when the fluid pressure reaches a predetermined pressure. The present invention relates to a variable displacement vane pump having a relief valve for relieving a fluid to a pump suction side.

[0002]

2. Description of the Related Art As a pump for a power steering device, a displacement type vane pump directly driven and rotated by an automobile engine has been generally used. Since the displacement flow rate of such a displacement pump increases or decreases in response to the engine speed, the power assisted steering increases the steering assist force when the vehicle is stopped or running at low speed, and decreases the steering assist force during high speed running. It has a characteristic opposite to the steering assist force required for the device. Therefore, it is necessary to use a large-capacity pump capable of ensuring a discharge flow rate such that a necessary steering assist force can be obtained even at a low speed running at a low speed. Moreover, for high-speed driving with high rotation speed,
A flow control valve for controlling the discharge flow to a certain amount or less is essential. For this reason, in the displacement pump, the number of components is increased, the structure and the passage configuration are complicated, and it is inevitable that the overall size and cost increase.

In order to solve such a problem of the displacement pump, a variable displacement vane pump capable of decreasing the discharge flow rate per one rotation (cc / rev) in proportion to an increase in the number of rotations has been proposed. JP-A-5-278622
JP, JP-A-7-243385, JP-A-8-2
It is proposed by, for example, US Pat. According to these variable displacement pumps, a flow control valve unlike a displacement pump is not required, the driving horsepower can be prevented from being wasted, so that energy efficiency is excellent. Does not rise, and it is also possible to prevent problems such as leakage inside the pump and reduction in volumetric efficiency.

An example of such a variable displacement vane pump will be briefly described with reference to FIGS. 24 to 26 showing a pump structure disclosed in Japanese Patent Application Laid-Open No. Hei 8-200399. In FIG. Ring, 2
Is a cam ring provided to be swingable via a support shaft 2a serving as a swing fulcrum in an elliptical space 1b formed in an adapter ring 1a of the body 1. It is urged by urging means (compression coil spring 2b). Reference numeral 3 denotes a rotor, and a pump chamber 4 in the cam ring 2.
Is formed eccentrically toward the other side so as to be formed on one side, and is rotatably driven by an external drive source to advance and retreat the vane 3a held movably in the radial direction. In addition, 3 in the figure
b is a drive shaft of the rotor 3, and the rotor 3 is rotationally driven in a direction indicated by an arrow in the figure.

[0005] Reference numerals 5 and 6 denote a pair of high-pressure and low-pressure fluid pressure chambers formed on both sides of the outer peripheral surface of the cam ring 2 in the elliptical space 1b of the adapter ring 1a of the body 1. 6, passages 5a and 6a for guiding fluid pressure before and after a variable throttle 12 provided in a pump discharge side passage 11 as a control pressure for swinging the cam ring 2 are opened through a spool type control valve 10 described later. doing. In this example, the variable throttle 12 is provided with a hole 12a opened on the side wall surface of the body 1 forming the fluid pressure chamber 6 on the low pressure side, and the hole 1a.
Side edge 1 of cam ring 2 that moves to open and close 2a
2b. Reference numeral 13 denotes a pump discharge side passage downstream of the variable throttle 12 described above.

As described above, the pump discharge side passages 11, 1
24 and 25 by introducing the fluid pressure before and after the variable throttle 12 of FIG.
27, the volume of the pump chamber 4 is changed by swinging the cam ring 2 in a required direction, and the discharge flow rate is controlled in accordance with the flow rate at the pump discharge side as shown in the flow rate characteristic of FIG. Can be. That is, it is possible to perform a flow rate control in which the flow rate on the discharge side is raised to a predetermined flow rate with the increase in the pump rotation speed, the flow is maintained in that state, and the flow rate is reduced in a high rotation speed region of the pump.

[0007] FIG. 24 is a view showing a region B from a region A in FIG.
FIG. 25 shows a state from region B to region C in FIG. In FIG. 25, the cam ring 2 swings to the right in the drawing, and the variable throttle 12 is throttled to reduce the discharge flow rate from the pump in accordance with the throttle amount, and to maintain a constant flow rate at the minimum throttle position. become. FIG. 26 shows a state in which the pump is driven at a low speed.
In region A of No. 7, the state at the time of relief when the pressure fluid utilization device side operates and the fluid pressure on the pump discharge side becomes the relief pressure is shown. Fig. 2 where the pump is driven at high speed
When the relief valve 15 is open in the region C of FIG.
The relief flow rate is controlled in accordance with the open state of No. 2.

7 is a pump suction side area 4 of the pump chamber 4
A pump suction side opening (suction port) opened toward A, and a pump discharge side opening (discharge port) 8 opened toward the pump discharge side area 4B of the pump chamber 4. These openings 7 and 8 are provided in at least one of a pressure plate and a side plate (not shown) which are fixed walls for holding and holding a pump component including the rotor 3 and the cam ring 2 from both sides. Is formed.

The cam ring 2 is provided with the compression coil spring 2.
b from the fluid pressure chamber 6 side, the pump chamber 4
Is pressed in a direction to maintain the internal volume to a maximum. In the drawing, reference numeral 2c denotes a seal member provided on the outer peripheral surface of the cam ring 2 to define the fluid pressure chambers 5 and 6 on both the left and right sides together with the shaft support 2a.

The spool type control valve 10 is provided with differential pressures P1, P2 before and after a variable throttle 12 such as a metering orifice provided in the middle of the pump discharge side passages 11, 13.
And a fluid pressure P3 corresponding to the magnitude of the flow rate on the pump discharge side is introduced into the fluid pressure chamber 5 on the high pressure side outside the cam ring 2, thereby ensuring a sufficient flow rate even immediately after the pump is started. It is configured to be able to. In particular, such a control valve 10 is operated by a variable throttle 12 when the differential pressure across the variable throttle 12 becomes greater than or equal to a predetermined value during a load operation by the operation of a pressure fluid utilization device (indicated by PS in the figure). By introducing the fluid pressure P1 on the more upstream side as the control pressure into the fluid pressure chamber 5 on the high pressure side outside the cam ring 2, the swing of the cam ring 2 can be prevented.

The pump body 1 has a tank T
There is provided a pump suction side passage 14 which extends from the low pressure chamber of the spool type control valve 10 to the pump suction side region 4A of the pump chamber 4. The pump discharge side passage 1
3, a pressure control valve is provided directly at a position where the pressure fluid is relieved to the pump suction side (or the tank T side) via the pump suction side passage 14 when the fluid pressure on the pump discharge side becomes equal to or higher than a predetermined pressure. A dynamic relief valve 15 is provided.

According to such a direct acting relief valve 15, as shown in FIG. 26, when the fluid pressure on the pump discharge side reaches or exceeds a predetermined set pressure during the operation of the pump, the flow of fluid Part or the entire amount can be released to the pump suction side (tank side). In particular, such a direct acting relief valve 15 allows a pressure fluid to be relieved from a pump discharge side to a pump suction side since a variable displacement pump is not provided with a flow control valve unlike a displacement pump. Is what you need.

[0013]

In the conventional variable displacement vane pump having the above-described structure, when the direct-acting relief valve is operated, all the flow for relieving the inside thereof to the pump suction side passes through the entire amount and is discharged. It is necessary to prevent the adverse effect of the fluid flow at the time of the relief from occurring.

That is, in the above-described variable displacement vane pump, a fluid sound such as "shoe" due to a fluid flow during relief during the pump operation, a valve component constituting a relief valve by the fluid flow,
For example, there is a problem that the ball, the ball receiver, and the compression coil spring resonate to cause an abnormal sound such as a beeping sound (vibration sound).

In order to prevent such abnormal noise, the present applicant has proposed a structure in which an elastic member is fitted in a ball receiver to take measures against vibrations, as disclosed in Japanese Patent Application No. 9-351348. I have. However, such a structure requires an anti-vibration measure such as an elastic member, which increases the number of parts and increases the cost.

Further, according to the above-described variable displacement vane pump, all of the relief flow rate is discharged through the direct-acting relief valve at the time of relief, so that the driving horsepower of the pump (displacement volume × fluid pressure × pump rotation speed) Is wasted.

In the variable displacement vane pump described above, if the flow rate of the fluid flowing at the time of relief by the direct acting relief valve is large, the pressure fluctuation becomes large and a surge pressure is easily generated. This is because the direct acting relief valve described above operates intermittently depending on whether or not a predetermined pressure has been reached, and the movement of the ball and the ball receiver and the expansion and contraction of the compression coil spring accompanying this operation are remarkable. This is because the fluctuation increases. Such pressure fluctuation increases as the flow rate passing through the relief valve portion increases.

Further, in the above-described variable displacement vane pump, the direct-acting type relief valve in which the entire flow to be relieved is returned to the pump suction side has a problem that cracking characteristics are not good. Here, the cracking characteristic means a characteristic until the relief pressure is reached. The cracking point is a point at which the relief valve starts to open.

For example, when the flow rate discharged from the pump chamber is 1
At 0 l / min, when the set pressure (relief pressure) of the relief valve is 105 kgf / cm ² , the cracking point at which the relief valve starts opening as shown in FIG.
It becomes 0 kgf / cm ² . Then, as shown by the dashed line in FIG. 28, the relief valve has such characteristics that a predetermined relief flow rate can be obtained at the time when the relief valve starts to open gradually from the cracking point and reaches the relief pressure.

However, as is apparent from the hatched portion in FIG. 28, when the fluid pressure in the pump discharge side passage exceeds the cracking point, the pressure fluid becomes fluid. As the pressure increases, the pump is relieved toward the pump suction side. Therefore, the variable displacement vane pump having such a direct acting relief valve not only consumes unnecessary drive horsepower by the relief flow rate, but also cannot secure the flow rate necessary for the operation of the pressure fluid utilization device. There are cases. For this reason, such a variable displacement vane pump needs to be large enough to secure a flow rate necessary for operating the pressure fluid utilization device.

Further, in the above-described variable displacement vane pump, when the direct acting relief valve is continuously operated,
The fluid temperature may increase, and the fluid may deteriorate. There are also problems such as a decrease in volumetric efficiency due to internal leakage in the pump and seizure between a pump component (pump cartridge), for example, a rotor having vanes and a body or pressure plate sandwiching the rotor from both sides.

The present invention has been made in view of such circumstances, and has been made to reduce noise caused by fluid noise and vibration noise caused by the flow of fluid at the time of relief through a relief valve during operation of a pump, and to reduce pump noise. It is an object of the present invention to obtain a variable displacement vane pump capable of reducing the driving horsepower and the surge pressure of the pump. Another object of the present invention is to provide a variable displacement vane pump capable of suppressing an increase in fluid temperature during continuous relief, preventing seizure in pump components, and improving cracking characteristics.

[0023]

SUMMARY OF THE INVENTION In order to meet such a demand, a variable displacement vane pump according to the present invention has a pump chamber between the vane and a rotor having the vane biased to one side. A cam ring to be formed and a swing pin supported around a swing pin which is fitted around the swing ring and which is disposed along the axial direction on a part of the outer circumferential surface of the cam ring along the axial direction so as to swing so that the volume of the pump chamber fluctuates. A biasing means for biasing the pump chamber in the direction in which the volume of the pump chamber is maximized, and a throttle for detecting a pump discharge side flow rate are provided in a part of the pump discharge side passage, and further, a downstream fluid pressure is introduced. A pump body having a pair of fluid pressure chambers formed on both sides of an outer peripheral portion of a cam ring, a rotating shaft for rotating the rotor, and a relief on a pump suction side when a fluid pressure on a pump discharge side becomes a predetermined pressure or more. Re And a Fubarubu. A pilot passage is provided from a downstream portion of the throttle to a pump suction side via the low pressure side fluid pressure chamber, and a pilot passage is provided between the pump discharge side passage of the pilot passage and the low pressure side fluid pressure chamber. And a pilot type relief valve is provided between the low pressure side fluid pressure chamber of the pilot passage and the pump suction side.

In the variable displacement vane pump according to the present invention, the second throttle is provided as a variable throttle by providing the second throttle in a fluid pressure chamber on the low pressure side and at a position which can be opened and closed at an outer edge of a cam ring. It is.

Further, the variable displacement vane pump according to the present invention is characterized in that a cam ring forming a pump chamber between the rotor having the vane and the rotor is biased to one side, and a cam ring outer periphery fitted around the cam ring. With the swing pin arranged along the axial direction at a part of the circumferential direction of the surface as a fulcrum, the pump chamber is swingably supported so that the volume of the pump chamber fluctuates and biased in the direction in which the volume of the pump chamber becomes maximum Biasing means,
A pump body that forms a pair of fluid pressure chambers on both sides of an outer peripheral portion of the cam ring, and a fixed throttle that is provided in a part of a pump discharge side passageway and that introduces downstream fluid pressure into the pair of fluid pressure chambers. A rotary shaft for rotating the rotor, and a relief valve for relief to the pump suction side when the fluid pressure on the pump discharge side becomes equal to or higher than a predetermined pressure.
A bypass passage is provided from the upstream side of the fixed throttle of the pump discharge side passage to the downstream side of the fixed throttle via the fluid pressure chamber on the low pressure side, and a part of this bypass passage is provided in the fluid pressure chamber on the low pressure side. A check valve is provided in parallel with the fixed throttle by opening the cam ring at a position that can be opened and closed at the outer edge of the cam ring, and further prevents a backflow from a pump discharge side passage downstream of the variable throttle in the bypass passage. And a pilot passage from the fluid pressure chamber on the low pressure side to the pump suction side is provided, and a pilot relief valve is provided in the middle of the pilot passage.

According to the present invention, the relief valve that relieves the discharge flow rate from the pump chamber to the pump suction side is of a pilot type and is provided in the middle of the pilot passage. The flow rate can be greatly reduced.
According to the present invention, by connecting the fluid pressure chamber on the low pressure side to the downstream side of the second throttle in the pilot passage, the cam ring can be displaced in the direction of reducing the volume of the pump chamber during relief. The movement of the cam ring can further reduce the discharge flow rate (displacement volume) from the pump chamber. According to the present invention, the driving horsepower of the pump at the time of relief can be significantly reduced, and can be made substantially closer to “0”.

According to the present invention, the cam ring is swung by the fixed throttle and the variable throttle provided in parallel with the pump discharge side passage to control the discharge flow rate from the pump chamber, and the variable throttle is moved by the cam ring. By opening and closing according to the rocking displacement of the pump, the so-called drooping characteristic of maintaining the discharge flow rate from the pump chamber at a constant flow rate smaller than the maximum flow rate when the pump is rotationally driven in a high rotation range. It can be obtained as the flow characteristics of the pump.

The relief valve attached to the variable displacement vane pump is adapted to transfer the pressure fluid from the pump discharge side to the pump suction side when the pressure fluid on the pump discharge side becomes higher than a predetermined pressure due to the operation of a pressure fluid utilization device or the like. Used for relief.

[0029]

1 to 8 show a first embodiment of a variable displacement vane pump according to the present invention. In these figures, the same or corresponding parts as those shown in FIGS. Are denoted by the same reference numerals, and detailed description is omitted. Further, in the first embodiment, the vane pump according to the present invention is a vane type oil pump serving as a hydraulic pressure source of a power steering device, and a discharge flow rate thereof is constant regardless of an increase or decrease in the rotation speed of the pump. The case of a pump having a flow rate will be described.

According to the present invention, the relief valve 20 for relieving the pump suction side when the fluid pressure on the pump discharge side becomes equal to or higher than a predetermined pressure is changed from the conventional direct acting type to the pilot type. That is, in the pump discharge side passage 11 from the pump discharge side region 4B of the pump chamber 4, a fixed throttle 21 for detecting the flow rate of the pump discharge side flowing through the passage 11 is provided. The fluid pressure on the upstream side and the downstream side of the fixed throttle 21 is guided to a pair of fluid pressure chambers 5 and 6 formed on both sides of the outer peripheral portion of the cam ring 2. It is constituted so that it may be oscillatingly displaced in accordance with.

Fixed throttle 21 of the pump discharge side passage 11
On the downstream side, a passage 22a for guiding the fluid pressure on the downstream side to the low pressure side fluid pressure chamber 6 communicating with the spring chamber provided with the compression coil spring 2b is formed. This passage 22a
Communicates with the passage 22b extending from the spring chamber to the pump suction side passage 14. These passages 22a, 22b
Constitutes a pilot passage 22 extending from the pump discharge side passage 11 to the pump suction side passage 14 via the low pressure side fluid pressure chamber 6 (including a spring chamber).

The passage 22a is provided with a second fixed throttle 23 for detecting the flow in the pilot passage 22. The second fixed stop 23 functions as a stop for providing a damper effect. This second fixed aperture 23
Is a flow rate relieved toward the pump suction side through the pilot passage 22 as will be described later. In the first embodiment, the flow rate is 0.8 l / min.

In the pilot passage 22, a pilot type relief valve 20 is provided in the middle of a passage 22b extending from the low pressure side fluid pressure chamber 6 to the pump suction side.

In such a configuration, the pressure fluid discharged from the pump chamber 4 is supplied to the pressure fluid utilization device PS through the pump discharge side passage 11. At the time of low rotation, the cam ring 2 is at a position where the volume of the pump chamber 4 is maximized, as shown in FIG. This is because the pump suction side fluid is introduced into the high pressure side fluid pressure chamber 5, while the fluid pressure downstream of the first fixed throttle 21 in the pump discharge side passage 11 is supplied to the low pressure side fluid pressure chamber 6. But the pilot passage 22
It is because it is led through.

Then, the flow rate of the pressurized fluid from the pump chamber 4 increases, and the spool of the spool type control valve 10 is pushed by the fluid pressure upstream of the first fixed throttle 21 in the pump discharge side passage 11. 2, the fluid pressure on the upstream side of the first fixed throttle 21 is introduced into the fluid pressure chamber 5 on the high pressure side, and the fluid pressure on the downstream side is introduced into the fluid pressure chamber 6 on the low pressure side. . The cam ring 2 swings rightward in the drawing due to the differential pressure, and the volume of the pump chamber 4 is reduced, so that the flow rate discharged from the pump chamber 4 can be reduced.

According to such a variable displacement vane pump, after the supply flow rate from the pump rises to a predetermined amount in a low rotation range as shown in FIG. Can be maintained.

In the above-described variable displacement vane pump, the pressure fluid utilization device P receiving the feed from the pump is used.
When a load is applied, for example, when S is activated, the fluid pressure in the pump discharge side passage 11 increases, and the fluid pressure chamber 6 on the low pressure side into which the fluid pressure on the downstream side of the first fixed throttle 21 is guided. The fluid pressure in the pilot passage 22 including the pressure rises. When this pressure exceeds the set pressure of the relief valve 20, as shown in FIG. 3, the relief valve 20 is opened and the fluid on the pump discharge side is relieved to the pump suction side.

At this time, in the first embodiment, the fluid pressure upstream of the fixed throttle 21 of the pump discharge side passage 11 is guided to the high pressure side fluid pressure chamber 5 on one side of the cam ring 2. Further, a fixed throttle 21 is provided in the other low-pressure side fluid pressure chamber 6.
The fluid pressure on the downstream side is further reduced to the pilot passage 22 by the second fixed throttle 23.
Therefore, the cam ring 2 further swings and displaces in a direction in which the volume of the pump chamber 4 is minimized, so that the discharge flow rate from the inside of the pump chamber 4 can be further reduced so as to substantially approach “0”. . According to such a variable displacement vane pump, the displacement can be reduced to a value close to “0”, so that the driving horsepower of the pump can be reduced.

That is, according to the first embodiment, the first fixed throttle 21 provided in the pump discharge side passage 11 and the second fixed throttle provided in the pilot passage 22 during relief of the variable displacement vane pump. The cam ring 2 is further displaced in the direction in which the volume of the pump chamber 4 is reduced by combining the throttle 23 and the discharge side flow rate flowing through the pump discharge side passage 11 is reduced. Flow rates can be minimized. According to the variable displacement vane pump in the first embodiment, noise and surge pressure as in the related art are hardly generated, and cracking characteristics can be further improved.

In the variable displacement vane pump having such a configuration, the use of the pilot type relief valve 20 can greatly improve cracking characteristics as compared with the conventional one. That is, the pump according to the first embodiment has cracking characteristics shown by the solid line in FIG. 28 described above. To explain this, in the first embodiment, the relief valve 20 is a pilot type, and the relief flow rate passing through the valve 20 at the time of relief may be about 0.8 l / min. The cracking point of the relief valve 20 used for such a pump is 105 kgf / cm ² unlike the conventional about 60 kgf / cm ^2.
The value is about ² to 3 kgf / cm ² lower than the relief pressure of ² kgf / cm ² .

Furthermore, according to the variable displacement vane pump described above, the relief flow rate is small even when the pump is operated continuously through the relief valve 20 during pump operation. (Sequence of the pump cartridge) and deterioration of the fluid can be prevented. Moreover, in the power steering apparatus using such a variable displacement vane pump, since the driving horsepower for driving the pump may be small, it is possible to prevent engine stall due to this.

FIGS. 5 to 8 show specific examples of the variable displacement vane pump according to the present invention described with reference to FIGS. In these figures, a vane type variable displacement pump indicated by the reference numeral 30 as a whole is provided with a front body 31 and a rear body 32 which constitute a pump body.
As shown in FIG. 5, the front body 31 has a substantially cup shape as a whole, and a storage space 34 for storing and arranging a pump component 33 as a pump cartridge is formed therein. The rear body 32 is combined and integrally assembled so as to close the end. It should be noted that bearings 36a, 36b, 36c (36a, 36b are connected to the front body 31) with a drive shaft 36 through which a rotor 35, which is a rotor of the pump component 33, is rotatably driven from the outside. Side, 36c is disposed on the rear body 32 side)
It is rotatably supported by. 36d is an oil seal.

Reference numeral 37 denotes an inner cam surface 37a fitted and arranged on the outer peripheral portion of the rotor 25 having the vane 35a.
And a cam ring that forms a pump chamber 38 between the inner cam surface 37a and the rotor 35.
As described later, is disposed so as to be movable and displaceable within an adapter ring 39 provided in the storage space 34 so as to be fitted to an inner wall portion of the space so as to change the volume of the pump chamber 38. The adapter ring 39 is for holding the cam ring 37 movably in the storage space 34 of the body 31.

Reference numeral 40 denotes the rotor 35 and the cam ring 3 described above.
7 and an adapter ring 39, a pressure plate that is stacked and pressed against the front body 31 side of the pump cartridge (pump component 33), and the end face of the rear body 32 is provided on the opposite side of the pump cartridge. The plates are pressed into contact with each other, and a required assembly state is obtained by integrally assembling the front body 31 and the rear body 32. The pump component 33 is configured by these members. The pressure plate 40 and the rear body 32 serving as a side plate laminated on the pressure ring 40 via the cam ring 37 function as a pivot support and a positioning pin for swing displacement of the cam ring 37, and furthermore, the cam ring 37.
A fulcrum pin 41 having a sealing function for defining a fluid pressure chamber for oscillating the shaft, and appropriate detent means (not shown)
And are integrally fixed while being positioned in the rotation direction.

Reference numeral 43 denotes a pump discharge side pressure chamber formed on the bottom side in the storage space 34 of the front body 31, and the pump discharge side pressure acts on the pressure plate 40 by the pressure chamber 43. Reference numeral 44 denotes a pump discharge side passage formed as a pump discharge side opening formed in the pressure plate 40 so as to guide the pressure oil from the pump chamber 38 to the pump discharge side pressure chamber 43.

Reference numeral 45 denotes the front body 3 as shown in FIG.
1. A pump suction port provided in a part of the pump body 1 and a suction side fluid flowing from the tank T through the port 45 is supplied to a pump suction side passage 45 formed in the front body 31.
a and 45b, which are supplied to the inside of the pump chamber 38 from a pump suction side opening opening at an end face of the rear body 32 through a passage (not shown) formed in the rear body 32 continuously.

Reference numeral 48 denotes the front body 21 as shown in FIG.
Is a plug member having a pump discharge port composed of a passage 48a extending toward the side of the pump chamber and a passage 48b communicating therewith.
4. A part for discharging the pump discharge side fluid pressure supplied through the pump discharge side pressure chamber 43 and supplying it to hydraulic equipment such as a power steering device (not shown).

A nut-like member 49 having the first fixed throttle 21 is provided at a part of the pump discharge side passage, at the inner end of the plug member 48 forming the pump discharge port in the first embodiment. It is provided by screwing. In addition,
The first fixed aperture 21 may be formed by a hole formed in the body 31 as shown in FIG. 7B, for example.

The second fixed stop 23 is formed by a small-diameter hole formed in the plug member 48 in the radial direction. This second fixed stop 23 is provided in FIGS.
As shown in (a), the cam ring 3 is formed by a passage hole (passage 22a) formed in a part of the front body 31.
The second fluid pressure chamber 52 formed outside of the valve 7 is connected to a spring chamber 62a formed by a plug 62 for accommodating a spring 61 for urging the cam ring 37. Further, the spring chamber 62
a through the pilot type relief valve 20 provided on the rear body 32 with a screw plug 70.
It communicates with a pump suction side passage (not shown) provided therein.

In FIG. 6, reference numerals 51 and 52 denote the adapter ring 3.
9, a pair of fluid pressure chambers 51 and 52 formed between the inner peripheral portion of the cam ring 37 and the outer peripheral portion of the cam ring 37. These fluid pressure chambers 51 and 52 support the cam ring 37 so as to swing freely. And a seal member 53 provided at the axially symmetric position, and is formed to be divided into left and right. Here, reference numeral 54 in the figure denotes a passage for supplying the pump discharge pressure upstream of the first fixed throttle 21 on the pump discharge side to the fluid pressure chamber 51 on the high pressure side (left side in the figure). Further, the pump discharge pressure on the downstream side of the first fixed throttle 21 is guided through the passage 22a into the other low pressure side fluid pressure chamber 52, as is apparent from the above-described structure.

A control valve 55 is a spool valve for controlling the fluid pressure guided to a pair of fluid pressure chambers 51 and 52 for swinging the cam ring 37. The valve hole 55a forming the spool type control valve 55 is
As shown in FIGS. 5 and 6, a part of the front body 21 is formed in a direction orthogonal to the axial direction of the rotating shaft 36 so that one end is open to the outer surface. A valve part, a spool 56,
A compression coil spring 57 is incorporated, and the open end is closed by a plug 58.

One end of the control valve 55 (on the plug 58 side) is connected to the first fixed throttle 21 by the passages 59a and 59b shown in FIG.
The pump discharge pressure on the upstream side of
The spring chamber provided with the compression coil spring 57 at the other end of
The pump discharge pressure on the downstream side of the fixed throttle 21 is guided. A passage 45a for guiding the pump suction pressure from the pump suction port 45 toward the rear body 32 penetrates a central portion of the spool 56. In the vane type variable displacement pump 30 as described above, the configuration other than the above is widely known in the related art, and a specific description thereof will be omitted.

The variable displacement vane pump 30 having such a configuration operates as described with reference to FIGS. 1 to 3 described above, and a detailed description thereof will be omitted. Also,
The above-described pilot-type relief valve 20 has a cylindrical portion 7 in a valve installation space 72 that is formed so as to open from the rear end side of the rear body 32 to the joint surface with the front body 31.
3 is provided. As is well known, a valve seat member, a ball, a ball receiver, and a compression coil spring that constitute the relief valve 20 are incorporated in a valve hole 70a formed in the cylindrical portion 73 of the plug member 70. As a structure of such a relief valve 20, a structure other than the above may be adopted.

FIGS. 9 to 15 show a second embodiment of the variable displacement vane pump according to the present invention. In these figures, the same or corresponding parts as those in FIGS. The detailed description is omitted. The second embodiment is a variable displacement vane pump in which the pump discharge flow rate is constant regardless of the increase or decrease in the number of revolutions, as in the above-described first embodiment.

In the second embodiment, a passage 22a from the downstream side of the fixed throttle 21 provided in the pump discharge side passage 11 to the fluid pressure chamber 6 on the low pressure side can be opened and closed by the outer edge of the cam ring 2. The variable aperture 25 is formed by this opening 25a and the outer edge 25b of the cam ring 2 by being opened at the position. The portion forming the variable aperture 25 is shown in an enlarged manner in FIGS. An elliptical concave groove 25c is formed at the opening end of the fluid pressure chamber 6 (including the spring chamber of the spring 2b) on the low pressure side of the opening 25a forming the variable throttle 25, and the outer edge 25 of the cam ring 2 is formed.
The structure is such that the fluid slightly flows even when the opening 25a is closed at b.

The low pressure side fluid pressure chamber 6 is connected to a passage 22b provided with a pilot type relief valve 20 through a spring chamber.
Are connected to the pump suction side passage 14, thereby forming a pilot passage 22. The opening 25a and the hole having the same diameter as the opening 25a are 0.8 l / min, similarly to the second fixed stop 23 in the first embodiment.
This is a throttle through which the flow rate flows.

In such a configuration, when the number of revolutions of the pump is small, the suction pressure from the tank T is led to the fluid pressure chamber 5 on the high pressure side, and the suction pressure from the fixed throttle 21 is supplied to the fluid pressure chamber 6 on the low pressure side. The fluid pressure P2 (= P4) is led to the state shown in FIG. When the pump rotation speed becomes a predetermined rotation speed or more and the pump discharge side fluid pressure P1 upstream of the fixed throttle 21 becomes a certain value or more, the spool constituting the spool type control valve 10 moves, The pressure is guided to the fluid pressure chamber 5 on the high pressure side (P3 = P1). On the other hand, the fluid pressure P2 on the downstream side of the fixed throttle 21 is guided through the variable throttle 25, and the fluid pressure P4 (<P2)
Therefore, the cam ring 2 is displaced in the direction to reduce the pump chamber 4 as shown in FIG. Therefore, the discharge flow rate from the pump is maintained at a constant flow rate regardless of the pump speed.

Further, when the fluid pressure in the pump discharge side passage 11 becomes equal to or higher than a predetermined pressure (relief pressure) due to the operation of the pressure fluid utilization device PS or the like, the variable throttle 25 is closed (flow through the concave groove 25c). The passage is secured), and the relief valve 20 is opened to perform relief to the pump suction side. The state at this time is shown in FIG. 11, where P4 is smaller than P2. When such a relief state is established, the cam ring 2 further reduces the fluid pressure P4 on the low-pressure side.
In this case, the pump chamber 4 is further displaced in a direction to reduce the size, and the discharge flow rate from the pump chamber 4 is further reduced. According to the second embodiment, the same operation and effect as those of the first embodiment can be obtained.

FIGS. 12 to 14 have substantially the same structure as FIGS. 5 to 7 described above, and the diagram corresponding to FIG. 8 in the second embodiment is substantially the same as that of FIG. Omitted. The second embodiment is different from the first embodiment in that a fixed throttle 21 is provided in a part of a passage 44 on the pump discharge side formed in a pressure plate 40, and the passage 44 is The small diameter hole is provided in a position which can be opened and closed by the outer edge 25b of the cam ring 37 substantially in parallel.

Here, the fixed throttle 21 described above is a metering throttle for detecting the flow rate on the pump discharge side flowing through the pump discharge side passage, as described above. The small-diameter hole 25a is a throttle that detects a flow in the pilot passage 22 at the time of relief and has a damper function. The small-diameter hole 25a is formed in the outer edge 25 of the cam ring 27.
It is opened and closed by b, but may be completely closed or slightly open when closed. Here, the relationship between the variable aperture 25 composed of the small diameter hole 25a and the cam ring outer edge 25b is based on the damper effect and the cam ring 3.
The optimum value may be appropriately set in consideration of the response of 7, and the like.

FIGS. 16 to 22 show a third embodiment of the variable displacement vane pump according to the present invention. In these figures, the same or corresponding parts as those in FIGS. Numbers are given and detailed description is omitted. The third embodiment is different from the first and second embodiments described above.
Unlike the embodiment of FIG. 23, as shown in FIG. 23, the pump discharge flow rate is set to a constant flow rate with an increase in the number of rotations, and the flow rate is reduced to a predetermined flow rate in a high rotation speed range to reduce the flow rate. This is a variable displacement vane pump that maintains a so-called drooping characteristic.

In the third embodiment, FIGS.
As shown in FIG. 8, a bypass passage 27 is provided from the upstream side of the fixed throttle 21 provided in the pump discharge side passage 11 to the low pressure side fluid pressure chamber 6, and the low pressure side fluid pressure chamber 6 and the spring 2b are connected. The fixed throttle 2 is inserted through the stored spring chamber.
1 is provided with a bypass passage 28 extending to the downstream side. Then, a portion 25a of the bypass passage 27 facing the low pressure side fluid pressure chamber 6 is opened at a position that can be opened and closed by an outer edge portion 25b of the cam ring 2 so that the fixed throttle 2 can be opened.
A variable stop 25 is provided in parallel with the first stop.

Further, the bypass passage 28 located on the downstream side of the variable throttle 25 is provided with the pump discharge side passage 1.
A check valve 29 for preventing backflow from 1 is provided.
A pilot passage 22b extending from the fluid pressure chamber 6 on the low pressure side to the pump suction side (passage 14) is provided.
0 is provided.

According to such a configuration, when the pump rotation speed is low, the pump discharge side fluid uses the pressure fluid through the pump discharge side passage 11 and the bypass passages 27 and 28 as shown in FIG. It is fed to the device PS. Then, when the rotation becomes high, as shown in FIG. 17, the cam ring 2 is moved in the direction in which the pump chamber 4 is reduced by the fixed throttle 21 and the variable throttle 25 provided in parallel with the pump discharge side passage 11 and the bypass passages 27 and 28. By oscillating displacement,
Control can be performed so that the discharge flow rate from the pump chamber 4 is maintained at a constant amount.

When the pressure fluid utilization device PS is operated, the relief valve 20 is opened as shown in FIG. 18 to relieve the fluid on the pump discharge side to the pump suction side, and the cam ring 2 is further squeezed with a variable throttle. 25 so as to close the pump chamber 4.
The discharge flow rate from the fluid can be reduced, and the relief of useless fluid can be reduced.

FIG. 23 shows such a flow control state. FIG. 22 shows a portion where the above-mentioned variable stop 25 is formed. Here, in this embodiment, the cam ring 2
Of the small-diameter hole 25a can be closed so as to be substantially "0" by the outer edge 25b. In addition, the concave groove 25c secures the flow in the bypass passage 27 and the passage 22b which become the pilot passage 22, and also enables the drooping characteristic, particularly the constant flow rate control when the rotational speed becomes high, to be appropriately performed. Things.

FIGS. 19 to 21 are views showing a state in which the above-described third embodiment is specifically implemented, and FIGS. 5 to 8, FIGS. 12 to 14, FIGS. The same portions are denoted by the same reference numerals, and detailed description thereof will be omitted.
In these figures, the bypass passage 28 and the check valve 29 are formed in a part of the front body 31 by simple drilling and assembling balls as shown in FIG. FIG. 21B shows a case where the fixed aperture 21 is formed on the body 31 side.

The present invention is not limited to the structure of the above-described embodiment, and the shape, structure, etc. of each part of the variable displacement pump 30 including the relief valve can be freely modified or changed as appropriate. Yes, various modifications are possible. Further, in each of the embodiments described above, the fixed aperture and the variable aperture are simply described as “apertures”, but these may be orifices or chokes.

[0069]

As described above, according to the variable displacement vane pump according to the present invention, the relief valve is changed from the so-called direct-acting type, in which all the relief flow is performed, to the pilot type, as in the prior art. The relief flow rate that passes through the relief valve at the time of relief can be greatly reduced, making it difficult to generate noise and surge pressure as in the related art, and can further improve cracking characteristics. According to the present invention, the displacement volume of the pump can be reduced to a minimum and almost "0". Therefore, the conventional drive horsepower of the pump is not wasted, and the useless drive horsepower is almost unnecessary.

Further, according to the present invention, since the relief flow rate is small even when the relief is continuously performed via the relief valve during the operation of the pump, the rise in the fluid temperature is suppressed to prevent the seizure of the pump components and the deterioration of the fluid. Can be prevented.

Further, according to the present invention, a throttle for obtaining a differential pressure by a pilot flow is arranged at a position interrupted by a cam ring to be a variable throttle, and a pilot-type relief valve is arranged downstream of the variable throttle. Thereby, the throttle can be shut off at the time of relief, and the cam ring can be displaced so as to minimize the pump chamber. Therefore, the above-described discharge flow control and relief flow control of the pump can be appropriately performed.

Further, according to the present invention, it is possible to more easily control the discharge flow rate of the pump to have a drooping characteristic.

[Brief description of the drawings]

FIG. 1 is a first view of a variable displacement vane pump according to the present invention.
FIG. 7 is an operation explanatory view showing the embodiment and showing a state at the time of low rotation.

FIG. 2 is an operation explanatory view showing a state at the time of high rotation in the variable displacement pump of FIG. 1;

FIG. 3 is an operation explanatory view showing a state at the time of relief in the variable displacement pump of FIGS. 1 and 2;

FIG. 4 is a characteristic diagram illustrating a supply flow rate with respect to a pump rotation speed in the pumps of FIGS.

FIG. 5 is a longitudinal sectional view of a pump showing a specific example of the variable displacement vane pump of FIGS. 1 to 3;

6 is a sectional view taken along line VI-VI of FIG.

7A is a sectional view taken along the line VII-VII in FIG. 6, and FIG. 7B is a view showing a modified example thereof.

8 is a sectional view taken along line VIII-VIII in FIG.

FIG. 9 shows a second example of the variable displacement vane pump according to the present invention.
FIG. 7 is an operation explanatory view showing the embodiment and showing a state at the time of low rotation.

FIG. 10 is an operation explanatory view showing a state at the time of high rotation in the variable displacement pump of FIG. 9;

11 is an operation explanatory view showing a state at the time of relief in the variable displacement pump of FIGS. 9 and 10. FIG.

FIG. 12 is a longitudinal sectional view of a pump showing a specific example of the variable displacement vane pump of FIGS. 9 to 11;

13 is a sectional view taken along line XIII-XIII in FIG.

14 is a sectional view taken along line XIV-XIV of FIG.

FIGS. 15A and 15B are detailed views of the variable stop described with reference to FIGS. 9 to 11, wherein FIG. 15A is a diagram showing holes and grooves, and FIG.

FIG. 16 is an operation explanatory view showing a third embodiment of the variable displacement vane pump according to the present invention, showing a state at the time of low rotation.

17 is an operation explanatory view showing a state at the time of high rotation in the variable displacement pump of FIG. 16;

FIG. 18 is an operation explanatory view showing a state at the time of relief in the variable displacement pump of FIGS. 16 and 17;

FIG. 19 is a longitudinal sectional view of a pump showing a specific example of the variable displacement vane pump shown in FIGS. 16 to 18;

20 is a sectional view taken along line XX-XX in FIG.

21 (a) is a sectional view taken along line XXI-XXI of FIG. 19,
(B) is a figure which shows the modification.

FIGS. 22A and 22B are detailed views of the variable stop described with reference to FIGS. 16 to 18, wherein FIG. 22A is a view showing holes and grooves, and FIG.

FIG. 23 is a characteristic diagram illustrating a supply flow rate with respect to a pump rotation speed in the pumps of FIGS. 16 to 18;

FIG. 24 is an operation explanatory view showing a conventional variable displacement vane pump and showing a state at the time of low rotation.

FIG. 25 is an operation explanatory view showing a state at the time of high rotation in the variable displacement pump of FIG. 24;

26 is an operation explanatory view showing a state at the time of relief in the variable displacement pump of FIGS. 24 and 25. FIG.

FIG. 27 is a characteristic diagram illustrating a supply flow rate with respect to a pump rotation speed in the pumps of FIGS.

FIG. 28 is a characteristic diagram showing a discharge flow rate from a pump chamber with respect to a fluid pressure (relief pressure) in order to explain cracking characteristics.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Pump body, 1a ... Adapter ring, 2 ... Cam ring, 2b ... Spring, 3 ... Rotor, 3a ... Vane, 4 ... Pump chamber, 4A ... Pump suction side area, 4B ... Pump discharge side area, 5, 6 ... Fluid Pressure chamber, 7: Pump suction side opening, 10
... Spool type switching valve, 11, 13 ... Pump discharge side passage, 14 ... Pump suction side passage, 21 ... Fixed throttle, 22
(22a, 22b) ... pilot passage, 23 ... second fixed throttle, 25 ... variable throttle, 25a ... opening (passage hole), 2
5b: cam ring outer edge, 25c: concave groove, 27, 28 ...
Bypass passage, 29 ... check valve, 30 ... vane type variable displacement pump (variable displacement vane pump),
31: front body (pump body), 32: rear body (pump body), 33: pump components, 34:
Storage space, 35: rotor, 36: drive shaft (rotating shaft), 37: cam ring, 38: pump chamber, 40: pressure plate, 41: fulcrum pin, 43: pump discharge side pressure chamber, 44: pump discharge side passage, 45: Pump suction port, 45a, 45b: Pump suction side passage, 48: Plug member forming pump discharge port, 48a, 48b
... A fluid passage hole on the pump discharge side, 49 ... Nut member, 5
1, 52: first and second fluid pressure chambers, 55: control valve,
61: spring, 62a: spring chamber.

Claims (3)

[Claims] 1. A cam ring which forms a pump chamber between a rotor having a vane and a rotor which is deflected to one side, and a cam ring which is fitted around the cam ring and has a circumferential direction on an outer peripheral surface of the cam ring. Biasing means for pivotally supporting the pump chamber such that the volume of the pump chamber fluctuates around a pivot pin disposed along the axial direction on the portion and biasing the pump chamber in a direction in which the volume of the pump chamber is maximized. Forming a pair of fluid pressure chambers on both sides of an outer peripheral portion of the cam ring above a throttle for detecting a pump discharge side flow rate provided in a part of a pump discharge side passage from the pump chamber and for introducing a fluid pressure on a downstream side. A pump body that rotates the rotor by being supported in the body, and a relief valve that relieves the pump suction side when the fluid pressure on the pump discharge side exceeds a certain pressure. A pilot passage extending from a downstream portion of a throttle of the pump discharge side passage to a pump suction side via the low pressure side fluid pressure chamber; and a pump discharge side passage of the pilot passage and the low pressure side fluid. A second throttle for detecting the flow of the pilot passage is provided between the pressure chamber and the pressure chamber, and a pilot-type relief valve is provided between the fluid pressure chamber on the low pressure side of the pilot passage and the pump suction side. Characteristic variable displacement vane pump. 2. The variable displacement vane pump according to claim 1, wherein the second throttle is provided in the low-pressure side fluid pressure chamber at a position that can be opened and closed at an outer edge of the cam ring. A variable displacement vane pump characterized by comprising. 3. A cam ring forming a pump chamber between the rotor having the vane and the rotor in a state where the rotor is biased to one side, and a cam ring fitted around the cam ring and having a circumferential direction on an outer peripheral surface of the cam ring. Biasing means for pivotally supporting the pump chamber such that the volume of the pump chamber fluctuates around a pivot pin disposed along the axial direction on the portion and biasing the pump chamber in a direction in which the volume of the pump chamber is maximized. A pump body forming a pair of fluid pressure chambers on both sides of an outer peripheral portion of the cam ring; a pump body provided in a part of a pump discharge side passage from the pump chamber, and further increasing the downstream fluid pressure by the pair of fluid pressures. A fixed restrictor introduced into the chamber, a rotary shaft for rotating the rotor by being supported in the body, and a relief for relieving the pump suction side when the fluid pressure on the pump discharge side becomes a certain pressure or more. A bypass passage from the upstream side of the fixed throttle of the pump discharge side passage to the downstream side of the fixed throttle through the fluid pressure chamber on the low pressure side. A variable throttle is provided in parallel with the fixed throttle by opening the fluid throttle chamber at a position that can be opened and closed at an outer edge of the cam ring, and the pump discharge side passage downstream of the variable throttle in the bypass passage. A check valve for preventing backflow from the pump, a pilot passage extending from the fluid pressure chamber on the low pressure side to the pump suction side, and a pilot-type relief valve provided in the middle of the pilot passage. Vane pump.