JP2004150442A - Variable displacement type vane pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress an oscillation phenomenon of a variable displacement type vane pump, to reduce the pulsation or the like, and to dissolve noise problems. <P>SOLUTION: A metering orifice 40 is provided in the middle of a discharge side passage of pressure fluid. First and second fluid pressure chambers 36, 37 are formed between a cam ring 17 and an adaptor ring 19. The variable displacement type vane pump is provided with a spool type control valve 30 working by the fluid pressure on the upstream and downstream sides of the metering orifice and fluid passages 19b, 35 for communicating this control valve to the first fluid pressure chamber. The control valve selectively leads the fluid pressure on the upstream side of the metering orifice and the fluid pressure on the pump suction side to the first fluid pressure chamber by movement of a spool 32. The fluid passages 35, 19b communicate the control valve to the first fluid pressure chamber through a throttle part (throttle 52) provided on the adaptor ring. <P>COPYRIGHT: (C)2004,JPO

Description

  The present invention relates to a variable displacement vane pump used for various pressure fluid utilization devices, for example, a power steering device for reducing a steering operation force of an automobile.

  Generally, a displacement vane pump directly driven and rotated by an automobile engine is used as a power steering device pump. Such a displacement pump increases or decreases the discharge flow with respect to the engine speed, so that the steering assist force is increased when the vehicle is stopped or running at a low speed, and the steering assist force is reduced when the vehicle is running at a high speed. Has a characteristic that is inconsistent with the steering assist force required for the vehicle. Therefore, it is necessary to use a large-capacity pump capable of securing a discharge flow rate such that a necessary steering assist force can be obtained even during low-speed running at a low rotational speed. In addition, a flow control valve for controlling the discharge flow rate to a certain amount or less is essential for high-speed running at a high rotation speed. 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 a discharge flow rate (cc / rev) per rotation in proportion to an increase in the rotation speed is disclosed in, for example, Patent Documents 1 to 4. 4 and the like. According to these variable displacement pumps, a flow control valve unlike the displacement type is not required, the driving horsepower is prevented from being wasted, the energy efficiency is excellent, and there is no return flow to the tank side. The problem of rise can be reduced, and the problem of leakage inside the pump and reduction in volumetric efficiency can be prevented.

  For example, in a variable displacement pump disclosed in Patent Document 2 or the like, a cam ring is movably provided in a pump casing, and a pair of fluid pressure chambers serving as a control chamber is formed in a gap between the cam ring and the pump casing. The pressure around the orifice provided in the middle of the discharge passage is guided to each chamber, and the differential pressure is applied directly to the cam ring to move it against the urging force of the spring. It is trying to make it.

An example of such a variable displacement vane pump will be briefly described with reference to FIG. 6. In the drawing, reference numeral 1 denotes a pump body, 1a denotes an adapter ring, and 2 denotes an elliptical space formed in the adapter ring 1a of the body 1. The cam ring is provided so as to be swingably displaceable within the portion 1b via the support shaft portion 2a, and is provided with a biasing force by a pressing means in a direction indicated by a white arrow F in the drawing. Numeral 3 denotes a rotor for allowing a vane 3a which is housed eccentrically to the other side so as to form a pump chamber 4 on one side in the cam ring 2 and is rotatably driven by an external drive source so as to move in and out of the vane 3a which can be moved forward and backward in the radial direction. It is.
3b is a drive shaft of the rotor 3, and the rotor 3 is driven to rotate in a direction indicated by an arrow in the figure.

  Reference numerals 5 and 6 denote a pair of high-pressure and low-pressure fluid pressure chambers formed on both sides of the outer periphery of the cam ring 2 in the elliptical space 1b of the adapter ring 1a of the body 1. In addition, passages 5a and 6a for guiding a control pressure for swingingly displacing the cam ring 2, for example, a fluid pressure before and after a variable orifice provided in a pump discharge side passage are provided. By introducing fluid pressure before and after the variable orifice in the pump discharge side passage through these passages 5a and 6a, the cam ring 2 is swung in a required direction to change the volume in the pump chamber 4 and pump discharge. The discharge flow rate is variably controlled according to the flow rate on the side. That is, the discharge-side flow rate control is performed such that the discharge-side flow rate is decreased as the pump rotation speed increases.

Reference numeral 7 denotes a pump suction side opening that opens toward the pump suction side area 4A of the pump chamber 4, and reference numeral 8 denotes a pump discharge side opening that opens toward the pump discharge side area 4B of the pump chamber 4. , 8 are formed on either a pressure plate or a side plate (not shown) which is a fixed wall for holding and holding a pump component comprising the rotor 3 and the cam ring 2 from both sides.
Here, as shown by F in the figure, a biasing force is applied to the cam ring 2 from the fluid pressure chamber 6 side, so that the volume in the pump chamber 4 is always maintained at a maximum. In the drawing, reference numeral 2b denotes a seal member provided on the outer peripheral portion 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.

Reference numeral 8a denotes a beard-shaped notch formed continuously at the end of the pump discharge side opening 8 in the direction of pump rotation. The notch 8a allows the tip of each vane 3a to be connected to the cam ring 2 as the rotor 3 rotates. When the pumping action is performed by sliding the inner peripheral portion of the vane, the fluid pressure is set between the space between the vanes approaching the ends of the openings 7 and 8 and the space between the vanes adjacent thereto. Is gradually released from the high pressure side to the low pressure side, and serves to prevent surge pressure and pulsation problems caused by the surge pressure.
In the variable displacement pump having the above-described configuration, a relief valve for relieving the excessive fluid pressure is provided at a part of the pump discharge side.
The applicant was not able to find prior art documents closely related to the present invention by the time of filing, except for the prior art documents specified in the prior art document information described in this specification. .
JP-A-53-130505 JP-A-56-143383 JP-A-58-93978 Japanese Utility Model Publication No. 63-14078

  According to the conventional variable displacement vane pump described above, in the pump cartridge (pump action section) including the pump components such as the rotor 3 and the cam ring 2, the start of the discharge side opening 4B from the end point of the suction side opening 4A in the pump chamber 4. The pump chamber (the vane 3a and the vane 3a) is located in an intermediate region (portions indicated by reference numerals 9A and 9B in FIG. 6) corresponding to a region from the end point of the discharge side opening 4B to a start point of the suction side opening 4A. The chamber partitioned by the vane 3a) alternates between a pump discharge pressure and a pump suction pressure.

This is because when the leading vane 3a in the rotation direction of the rotor 3 reaches the opening 4B or 4A on the tip side in the rotation direction, the vane 3a becomes the port pressure on the pump discharge side or the suction side at the opening 4B or 4A, and follows. This is because when the vane 3a is in the opening 4A or 4B on the rear end side in the rotation direction, a port pressure is generated by the subsequent opening.
In particular, when an odd number of vanes 3a are employed in this type of variable displacement vane pump, since the vanes 3a are unevenly arranged in the rotation direction of the rotor 3, the rotation shaft 3b of the rotor 3 is The space sandwiched between the vanes 3a, 3a passing through the opposing intermediate regions 9A, 9B at the center becomes asymmetric, and the pressure balance tends to be lost.

  Then, the thrust due to the mutual difference between the pump chambers of the opposed intermediate regions 9A and 9B acts on the inner surface of the cam ring 2 due to such pressure fluctuation and pressure imbalance, and the cam ring 2 vibrates. As a result, on the pump discharge side. There has been a problem that a flow rate fluctuation and a hydraulic pulsation phenomenon occur, which also causes a noise problem. Such a pulsation phenomenon appears, for example, as shown in the characteristic diagram of FIG.

  For this reason, in the above-described variable displacement pump, a variable metering orifice is provided in the middle of the pump discharge side passage, and a spool type control valve is switched and operated by fluid pressure on the orifice and on the downstream side, and on the orifice and on the downstream side There has been proposed an apparatus which suppresses the oscillation phenomenon of the cam ring 2 by selectively supplying the fluid pressure or the pump suction side to the chambers 5 and 6 on both sides of the outer periphery of the cam ring 2, but it is still insufficient. It is hoped that some measures will be taken.

In particular, the operation on the device to be used, to which the fluid pressure is supplied from the variable displacement pump, increases the fluid pressure in the main supply path, whereby the variable metering provided in this path or in the middle of the pump discharge side path. An increase in the differential pressure on the downstream side of the orifice and the downstream side causes a significant change in the pressure on the pump discharge side, so that such a problem needs to be solved.
For example, when the device to be used is a power steering, a large flow rate or a small flow rate flows to the power cylinder side, so that the steering handle suddenly becomes heavy or light, and such instability is resolved. It is desired.

Further, in the above-described conventional variable displacement pump, the control valve for controlling the supply fluid pressure to the high pressure side and the low pressure side fluid pressure chamber for moving and displacing the cam ring also has a problem that the oscillation phenomenon of the spool occurs. is there.
That is, in this control valve, the pump discharge side fluid upstream of the variable metering orifice is guided to one chamber of the spool, and the pump discharge side fluid downstream of the variable metering orifice is guided to the other chamber having a spring. You are being led. Then, as the flow rate of the discharge-side fluid increases, the pressure difference on the downstream side of the variable metering orifice increases, and the spool of the valve moves to the other chamber side. Pressure is introduced to move and displace the cam ring to reduce the flow rate of the discharge-side fluid.

However, in such a control valve, when the fluid pressure on the pump discharge side fluctuates due to the above-described load on the device to be used, the spool in the valve also vibrates, which may cause a so-called oscillation phenomenon. It is desired to take such points into consideration.
In such a conventional variable displacement pump, a damper orifice is formed in a fluid passage for guiding fluid pressure downstream of the metering orifice to the other chamber having a control valve spring, thereby stabilizing the movement of a spool in the valve. I am trying to make it. However, simply providing such a damper orifice has a small throttle effect because the flow rate of the fluid is small, and the spool in the valve easily oscillates. As a result, each fluid controlled by this valve is controlled. The fluid pressure in the pressure chamber becomes unstable, and the cam ring also oscillates, which cannot be suppressed. It is desired to eliminate these problems.

  The present invention has been made in view of such circumstances, and it is intended to suppress an oscillation phenomenon in a control valve and a cam ring, thereby reducing a large flow rate fluctuation and pulsation on a pump discharge side, and also eliminating a noise problem. The purpose is to obtain a variable displacement pump that can perform pressure reduction.

  A variable displacement vane pump according to the present invention includes a pump body, a rotating shaft rotatably supported by the pump body, a rotor connected to the rotating shaft, and a slit provided in the rotor, which can move forward and backward freely. A vane provided, an annular adapter ring provided inside a storage space formed in the pump body, and a pump chamber formed between the rotor outer peripheral portion and the rotor and the adapter ring. A cam ring provided eccentrically with respect to the rotation shaft; an urging means for applying an urging force to the cam ring so that the pump chamber volume is maximized; and a pressure fluid discharged from the pump chamber. The first and second eccentrically-moving cam rings are formed between a metering orifice provided in the middle of the discharge-side passage and the cam ring and the adapter ring. And a second fluid pressure chamber, a spool type control valve operated by fluid pressure on the metering orifice and downstream side, and a fluid passage communicating the control valve with the first fluid pressure chamber. The control valve selectively guides the fluid pressure on the metering orifice upstream side and the fluid pressure on the pump suction side to the first fluid pressure chamber by the movement of a spool, and the fluid passage includes the fluid passage, The control valve communicates with the first fluid pressure chamber through a throttle provided in the adapter ring.

According to the present invention, when the pump is started, the cam ring is urged to one side in the pump body so that the volume of the pump chamber between the rotor and the rotor is maximized. On the suction side, a second fluid pressure chamber is connected to the pump discharge side downstream of the metering orifice.
When the pump rotation speed gradually increases, the control valve is switched by the pressure difference between the fluid pressure on the upstream side of the orifice and the fluid pressure on the downstream side at the pump discharge side, whereby the first fluid pressure on both sides of the cam ring is changed. Fluid pressure on the downstream side of the variable metering orifice on the pump discharge side is introduced into the chamber and the second fluid pressure chamber, and the cam ring is displaced in a direction to decrease the volume of the pump chamber. At this time, since the throttle portion is provided in the fluid passage from the control valve to the first fluid pressure chamber, the fluid is sent in a state in which the fluid pressure fluctuation on the pump discharge side is reduced, and the spool and cam ring of the control valve are moved. Oscillation is suppressed.

That is, according to the present invention, the pressure fluctuation is suppressed by the throttle function by providing the throttle portion in the fluid passage from the control valve to the first fluid pressure chamber on the outer periphery of the cam ring. The oscillation at the spool and the oscillation of the cam ring can be suppressed or prevented. As a result, a large flow rate fluctuation and pulsation occurring at the pump discharge side can be reduced, and a quiet variable displacement vane pump can be obtained.
Such a variable displacement vane pump has an advantage that it is possible to suppress problems such as generation of noise on a vehicle and generation of slight vibration of a steering wheel due to a decrease in hydraulic pulsation.

  Further, according to the present invention, even if a relief valve is built in the spool of the control valve, the throttle valve can suppress the movement of the control valve and suppress oscillation, so that it is not necessary to consider the incorporation of the relief valve. There is also an advantage that the entire pump can be made compact.

  FIGS. 1 to 3 show an embodiment of a variable displacement vane pump according to the present invention. In these drawings, the embodiment describes a case of a vane type oil pump serving as a hydraulic pressure source of a power steering device. I do.

  The variable displacement vane pump indicated by reference numeral 10 as a whole is provided with a front body 11 and a rear body 12 that constitute a pump body, as is clear from FIGS. As is clear from FIG. 2, the front body 11 has a substantially cup shape as a whole, and a storage space 14 for storing and arranging a pump component 13 as a pump cartridge is formed therein. The rear body 12 is combined and integrated so as to close the open end. It should be noted that bearings 16a, 16b, 16c (16b is a rear body 12 side, while a drive shaft 16 for externally driving a rotor 15 as a rotor of the pump component 13 is penetrated through the front body 11 are provided. 16c is disposed on the pressure plate 20 side described later) and is rotatably supported.

Reference numeral 17 denotes a cam ring which has an inner cam surface 17a fitted and arranged on the outer peripheral portion of the rotor 15 having the vane 15a, and forms a pump chamber 18 between the inner cam surface 17a and the rotor 15. As will be described later, the cam ring 17 is arranged so as to be movable and displaceable within an adapter ring 19 provided in the storage space 14 so as to be fitted to an inner wall portion of the space so as to change the volume of the pump chamber 18.
The adapter ring 19 is for holding the cam ring 17 movably and displaceably in the storage space 14 of the body 11.

  Reference numeral 20 denotes a pressure plate which is laminated by being pressed against the front body 11 side of a pump cartridge (pump component 13) constituted by the rotor 15, the cam ring 17 and the adapter ring 19, and on the opposite side of the pump cartridge. The end face of the rear body 12 is pressed against the side plate as a side plate, and a required assembled state is obtained by integrally assembling the front body 11 and the rear body 12. The pump component 13 is constituted by these members.

  Here, the pressure plate 20 and the rear body 12 serving as a side plate laminated thereon via the cam ring 17 are provided with a seal pin 21 which also functions as a pivot support for the swing displacement of the cam ring 17 and a positioning pin. Or by a suitable rotation preventing means (not shown), and is integrally fixed in a state of being positioned in the rotational direction.

  Reference numeral 23 denotes a pump discharge side pressure chamber formed on the bottom side in the storage space 14 of the front body 11, and the pump discharge side pressure acts on the pressure plate 20 by the pressure chamber 23. Reference numeral 24 denotes a pump discharge side opening formed in the pressure plate 20 so as to guide pressure oil from the pump chamber 18 to the pump discharge side pressure chamber 23.

  Reference numeral 25 denotes a pump suction port provided in a part of the front body 11 as shown in FIG. 2, and a suction side fluid flowing from this port 25 passes through a valve hole 30a of a control valve 30, which will be described later, and is connected to the front body. The air is supplied into the pump chamber 18 from a pump suction side opening 26 opened at the end face of the rear body 12 through a pump suction side passage 25a formed in the inside 11 and passages 25b and 25c formed continuously in the rear body 12. Is done.

Here, in this embodiment, in order to guide the suction-side fluid from the suction port 25 to the pump chamber 18, a suction-side passage 25a that straddles the control valve 30, that is, penetrates the valve hole 30a is used. This is because, in the pump used for steering force control as in this embodiment, the flow rate to be fed is as small as 7 l / min, whereby the suction side fluid sucked from the tank T into the suction port 25 is passed through the control valve 30. This is because there is no practical problem.
When such a configuration is adopted, the length of the pump 10 in the axial direction is reduced as compared with the conventional structure in which the suction port 25 is provided between the control valve 30 of the front body 11 and the suction side passage 25b of the rear body 12. The pump 10 can be shortened, and the pump 10 can be downsized. This is because the rear body 12 can be made particularly compact in view of the passage structure, and the mounting position of the pump 10 to the tank T can be performed on the front body 11 side, so that a stable mounting state can be obtained.

  Reference numeral 28 denotes a pump discharge side passage 24, a pump discharge side pressure chamber 23, a fluid passage hole 29 formed at a different position of the pressure plate 20, a second fluid pressure chamber 37, and a cam ring 17, which will be described later. A pump discharge side fluid supplied through a spring chamber 42a formed by a plug 42 for accommodating a biasing spring 41, a notch groove 43 formed in the front body 11, and passage holes 44, 45, 28b formed in the body 11. A discharge port for supplying pressure to a hydraulic device such as a power steering device (indicated by PS in the figure) such as a power steering device (not shown). The discharge port 28 is opened by a plug 28 a provided on the side of the front body 11. Is provided.

  Here, in the above-mentioned pump discharge side passages (24, 23, 29, 42a, 43, 44, 45, 28b), the fluid passage hole 29 opening to the second fluid pressure chamber 37 and the side surface of the cam ring 17 Thus, a variable metering orifice 40 capable of increasing or decreasing the opening area is formed. Here, the variable metering orifice 40 is configured such that the passage hole 29 is opened and closed on the side wall portion in accordance with the movement displacement of the cam ring 17. When the orifice 40 is formed in an appropriate shape whose opening and closing amount is controlled in accordance with the magnitude of the fluid pressure on the pump discharge side, the displacement of the cam ring 17 can be controlled to a desired state, and various flow characteristics can be obtained. Can be achieved.

  Reference numeral 30 denotes a variable meter which is disposed substantially orthogonally above the storage space 14 in the front body 11 and which controls a fluid pressure for moving and displacing the cam ring 17 with respect to the rotor 15 in the pump body 11 (adapter ring 19). The control valve 30 is controlled by a ring orifice 40. The control valve 30 is disposed in a valve hole 30a formed in the body 11 and has the pump discharge side passages (24, 23, 29, 42a, 43, 44, 45, 28b). On the variable metering orifice 40 provided in the middle, a spool 32 that slides by a pressure difference on the downstream side and the urging force of a spring 31 is provided.

  In the control valve 30, the variable metering orifice is connected to one chamber (left chamber in FIG. 1) 32a of the spool 32 via fluid passages 46 and 47 extending from the pressure chamber 23 on the pump discharge side. The fluid pressure upstream of 40 is introduced. In the figure, reference numeral 33 denotes a plug for closing the valve hole 30a having a rod 33a for locking the leftward movement position of the spool 32 in the valve hole 30a at a position where the opening end of the fluid passage 47 is not closed.

A spring 31 is provided in the other chamber (the right chamber in FIG. 1) 32b of the spool 32, and the fluid pressure downstream of the variable metering orifice 40 described above causes the fluid pressure to reach the discharge port 28 in the middle of the passage. That is, the fluid is guided from the second fluid pressure chamber 37 through the fluid passage 19 a formed between the body 11 and the adapter ring 19 and the fluid passage 34 formed in the body 11.
Further, a pump suction side passage 25a continuous with the suction port 25 is formed through the substantially central portion of the valve hole 30a as described above. Fluid is supplied.

A first fluid pressure chamber 36 (described later) formed between the adapter ring 19 and the cam ring 17 is provided between the opening of the suction-side passage 25a and the opening of the fluid passage 47 on the discharge side. The fluid passage 19b of the adapter ring 19 and the fluid passage 35 formed in the body 11 are opened, and normally communicate with the pump suction side passage 25a through the land portion 32d as shown in FIG. A fluid pressure is introduced into the first fluid pressure chamber. Further, when the spool 32 moves to the right by a predetermined amount or more, it is separated from the pump suction side as apparent from FIG. 4, and the fluid pressure on the pump discharge side is supplied to the first fluid pressure chamber 36.
In the drawing, reference numeral 34a denotes a damper orifice portion.

  Reference numerals 36 and 37 denote left and right divided portions of the outer peripheral portion of the above-described cam ring 17 and the seal pin 21 provided between the inner peripheral portion of the body 11 (adapter ring 19) and the seal member 38 provided at a position substantially symmetrical to the axis thereof. In the first and second fluid pressure chambers, the first fluid pressure chamber 36 is connected to the pump suction side or the pump discharge side fluid pressure upstream of the variable metering orifice 40 in accordance with the operation of the control valve 30 described above. However, a pump discharge-side fluid pressure downstream of the variable metering orifice 40 is introduced into the second fluid pressure chamber 37.

Here, on the outer peripheral portion of the cam ring 17, a concave groove or the like of approximately half a circumference may be formed along the circumferential direction so that the first fluid pressure chamber 36 can be secured even when contacting the adapter ring 19. .
Reference numeral 39 in FIG. 3 denotes a relief valve provided to face a part of the pump discharge side passage. In this embodiment, the relief valve is provided by using a part of a fluid passage 44 formed in the body 11. I have. Further, a passage hole 39a connected to the relief valve 39 is a passage for returning the relief fluid to the pump suction side.

  Further, the opening of the fluid passage hole 29 constituting the variable metering orifice 40 is changed by closing the cam ring 17 so that a predetermined flow rate can be obtained when the rotation speed is low. When it becomes high, the flow rate is reduced, and at a predetermined rotational speed or more, a flow rate of about half of the initial flow rate is obtained. Here, such a discharge amount control is obtained by the variable metering orifice 40 formed by the fluid passage hole 29 and the side surface of the cam ring 17 for controlling the opening amount. For example, the shape of the hole 29 is arbitrarily changed. It is possible to change the characteristics by adjusting the opening / closing control amount by the cam ring 17.

  In the variable displacement vane pump 10 described above, the configuration other than that described above is conventionally known, and a specific description thereof is omitted.

  In the variable displacement vane pump 10 having the above configuration, the fluid pressure in the pump discharge side pressure chamber 23 is controlled by the control valve 30 and the first fluid pressure via the valve 30 in order to displace the cam ring 17. In leading to the chamber 36, the fluid passages 46 and 47 between the pump discharge side pressure chamber 23 and the valve hole 30a and the fluid passages 35 and 19b between the valve hole 30a and the first fluid pressure chamber 36 First, second and third apertures 50, 51, 52 are provided.

  That is, conventionally, in the variable displacement vane pump 10, a damper for stabilizing the movement of the spool 32 is provided in the fluid passages 19a and 34 for guiding the fluid pressure downstream of the variable metering orifice 40 to the other chamber 32b of the control valve 30. Although the orifice 34a is provided, in this type of variable displacement vane pump 10, since the flow rate of the fluid is small, the throttling effect is small, the spool 32 oscillates, and thereby the first and second fluid pressure chambers 36 are provided. , 37 become unstable, the cam ring 17 also oscillates, and these cannot be suppressed.

  Therefore, according to the variable displacement vane pump 10, in order to suppress the oscillation phenomenon of the control valve 30 (spool 32) and the cam ring 17, the throttle 50 is provided in the fluid passages 46, 47, 35 (19b) on the pump discharge side. , 51, 52, when the fluid pressure on the discharge side is introduced into the left chamber 32a and the first fluid pressure chamber 36 for operating the spool 32 and the cam ring 17 of the control valve 30, the introduction is smooth. In addition, a predetermined amount of flow is appropriately obtained, and as a result, a damper effect is exerted.

Here, according to this embodiment, at least one, two, or all three of the three apertures 50, 51, 52 described above may be provided.
For example, the first throttle 50 and the second throttle 51 can simultaneously suppress the oscillation of the spool 32 of the control valve 30 and the oscillation of the cam ring 17, and an effect can be obtained in either one of them, but both of them are effective. , It is possible to further increase the aperture effect. Further, as is clear from the arrangement position of the third throttle 52, only oscillation at the cam ring 17 can be suppressed.
If the first, second and third diaphragms 50, 51 and 52 are provided in all three places, the maximum diaphragm effect can be expected.

In particular, according to the variable displacement vane pump 10, the conventionally required fluid passages 46, 47, and 45 (19b) from the pump discharge side pressure chamber 23 to the control valve 30 and the first fluid pressure chamber 36 are provided. By merely providing a throttle section, the fluid pressure guided through these passages becomes less susceptible to excessive fluid pressure fluctuations due to external influences, and as a result, oscillation of the valve spool 32 and the cam ring 17 can be suppressed. And the advantage is great.
In other words, in this embodiment, the supply amount of the fluid pressure to both the chambers 32a and 32b of the control valve 30 and the first fluid pressure chamber 36 on the outer periphery of the cam ring 17 is ensured stably, and the fluid pressure is increased. The oscillation of the valve spool 32 and the cam ring 17 is suppressed by exhibiting a damper effect that does not cause fluctuations in the flow of air.

  When the first, second, and third throttles 50, 51, and 52 are provided to suppress oscillation of the valve spool 32 and the cam ring 17 in the variable displacement vane pump 10, as a result, the pump 10 Pulsation due to the pump discharge-side fluid pressure can be reduced, and it is possible to suppress noise problems on the vehicle, generation of micro-vibration of the steering wheel, and oscillation when the relief valve 3 is operated.

  That is, according to such a configuration, as shown in FIG. 5A, it is possible to obtain a discharge flow rate characteristic with respect to the pump rotational speed without any trouble such as pulsation. Note that a in the figure shows that when the pump rotation speed increases, the discharge flow rate is made smaller than the peak value so that steering control during high-speed running can be performed in a required state. Such control is variable. The opening can be easily controlled by the metering orifice 40. Of course, the control as shown in FIG.

  Here, in the above-described throttles 50, 51, and 52, when only the third throttle 52 is provided, the fluctuation of the pump discharge side flow rate due to the oscillation phenomenon becomes about 1/15 compared to the case where the third throttle 52 is not provided. When only the first and third diaphragms 50 and 52 are provided, the ratio is reduced to about 1/20, and when the first, second and third diaphragms 50, 51 and 52 are disposed, the ratio is reduced to approximately 1/22. Has been confirmed by experiments.

  Further, according to the pump 10 according to the above-described embodiment, the relief valve 39 for preventing the pump discharge side fluid pressure from excessively increasing faces the pump discharge side fluid passage 44 different from the control valve 30 so that the body 11, Although a relief discriminator-installed type disposed inside the control valve 30 is adopted, the present invention is not limited to this, and a relief valve built-in type valve incorporating a relief valve in the spool 32 of the control valve 30 may be used. Good. Adopting such a built-in relief valve has the advantage that the entire pump including the valve 30 can be made compact.

The present invention is not limited to the structure of the embodiment described above, and the shape, structure, and the like of each part can be freely modified and changed as appropriate, and various modified examples are conceivable.
For example, in the above-described embodiment, the first and second throttles 50 and 51 are provided in the fluid passages 46 and 47 from the pump discharge side pressure chamber 23 to the one chamber 32a of the control valve 30, but the present invention is not limited thereto. Without limitation, three or more throttles are provided in the fluid passages 46 and 47 described above, and two or more throttles are provided in the fluid passages 35 and 19b from the control valve 30 to the first fluid pressure chamber 36. Alternatively, a plurality of stops at four or more locations may be provided.

In the above-described embodiment, the case where the annular gap space for holding the cam ring 17 so as to be movable and displaceable is formed between the adapter ring 19 and the present invention is not limited to this. The cam ring 17 may be held so as to be movable.
Further, the vane-type variable displacement vane pump 10 having the above-described configuration is not limited to the structure of the above-described embodiment, but may be applied to various devices and apparatuses other than the power steering device described in the above-described embodiment. Needless to say, this may be done.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view showing one embodiment of a variable displacement vane pump according to the present invention and showing a main structure of the pump. FIG. 2 is a sectional view taken along line II-II in FIG. 1. FIG. 3 is a diagram illustrating an upper half section taken along a line III-III in FIG. 1. FIG. 2 is a schematic diagram for explaining a state in which the variable displacement vane pump of FIG. 1 is operated. (A) is a characteristic diagram showing the relationship between the pump speed and the discharge flow rate in the variable displacement vane pump according to the present invention, and (b) is a characteristic diagram showing the relationship between the pump speed and the discharge flow rate in the conventional example. . It is the schematic for demonstrating the principal part structure of the conventional variable displacement pump.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 10 ... Variable displacement vane pump, 11 ... Front body (pump body), 12 ... Rear body, 13 ... Pump component, 14 ... Storage space, 15 ... Rotor, 15a ... Vane, 16 ... Drive shaft (rotary shaft), 17 ... Cam ring, 17a: cam surface, 18: pump chamber, 19: adapter ring, 20: pressure plate, 21: seal pin (cam ring shaft support), 23: pump discharge side pressure chamber, 24: passage serving as pump discharge side opening, 25 ... Suction ports, 25a, 25b ... Pump suction side passages, 26 ... Pump suction side openings, 28 ... Pump discharge ports, 28a, 28b ... Pump discharge side passages, 29 ... Hole portions constituting variable metering orifices, 30 ... Spool Type control valve, 31 ... spring, 32 ... spool, 32a ... one chamber, 32b ... other chamber, 34 ... fluid communication , 34a: damper orifice, 35: fluid passage, 36, 37 ... first and second fluid pressure chambers, 40: variable metering orifice, 44, 45 ... pump discharge side passage (downstream of the variable metering orifice), 46, 47 ... pump discharge side passage (upstream of the variable metering orifice), 50, 51, 52 ... first, second, and third throttles.

Claims (1)

A pump body,
A rotating shaft rotatably supported by the pump body;
A rotor connected to the rotating shaft;
A vane provided to be able to advance and retreat in a slit provided in the rotor,
An annular adapter ring provided inside a storage space formed in the pump body;
A cam ring provided between the rotor and the adapter ring and eccentrically provided with respect to the rotation shaft so as to form a pump chamber between the rotor ring and the outer peripheral portion;
Biasing means for biasing the cam ring so that the pump chamber volume is maximized;
A metering orifice provided in the middle of the discharge side passage of the pressure fluid discharged from the pump chamber,
First and second fluid pressure chambers formed separately between the cam ring and the adapter ring for eccentrically moving the cam ring;
A spool-type control valve actuated by a fluid pressure on the metering orifice and on the downstream side,
A fluid passage communicating the control valve and the first fluid pressure chamber,
The control valve selectively guides a fluid pressure on an upstream side of the metering orifice and a fluid pressure on a suction side of the pump to the first fluid pressure chamber by a movement of a spool, and the fluid passage is connected to the adapter ring. A variable displacement vane pump characterized in that the control valve communicates with the first fluid pressure chamber via a restrictor provided in the pump.

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