JP4130071B2 - Flow control valve - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a flow control valve.
[0002]
[Prior art]
The flow control valve is applied in various fields. For example, in a hydraulic power steering apparatus for a vehicle, it is used for a hydraulic pump that supplies a predetermined hydraulic oil to the system. It acts to keep the supply (oil supply) amount of hydraulic oil supplied constant.
[0003]
Here, as this type of flow control valve, as shown in FIGS. 7A to 7C, a union 72 having an orifice 74, an upstream side of the orifice 74 provided opposite to the union 72, and 2. Description of the Related Art A flow control valve 70 having a configuration in which a spool valve 76 to which a downstream fluid pressure is applied is disposed in a valve housing is known. In this flow control valve 70, the flow rate of the fluid returning to the hydraulic pump main body is controlled by opening and closing the outflow hole of the fluid (hydraulic oil) supplied to the inner cavity of the valve housing by the operation of the spool valve 76. Thus, the flow rate of the fluid sent through the flow path 78 of the union 72 is controlled to be constant.
[0004]
Incidentally, in recent years, hydraulic power steering devices to which such a flow control valve 70 is applied tend to be applied particularly to large vehicles, and small and large capacity hydraulic pumps are used. Along with this, there is a problem that the control flow rate characteristic (pump rotation speed N−control flow rate Q · characteristic) of the flow rate control valve 70 deteriorates. Here, in FIG. 8, the control flow rate characteristic (pump rotation speed N-control flow rate Q · characteristic) in such a conventional flow rate control valve is shown by lines X and Y, which are ideal (target and target). The control flow characteristics are indicated by line Z.
[0005]
As a result of studying this problem, the present applicant has found that the fluid in the union 72 of the flow control valve 70 becomes an unnecessary swirling flow as shown in FIGS. 7A and 7B, or FIG. As shown in FIG. 7 (C), the flow was found to be deflected.
[0006]
That is, when the fluid in the union 72 is unnecessarily swirled or the flow is deflected, the fluid pressure on the upstream side of the orifice 74, that is, the fluid pressure applied to the rear end side of the spool valve 76 ( Feedback pressure) increases, and the displacement of the spool valve 76 becomes smaller than the original displacement. For this reason, the degree of opening and closing of the outflow hole of the fluid supplied to the lumen of the valve housing is less than the original (ideal) one, and the flow rate of the fluid returning to the hydraulic pump body is reduced. The flow rate of the fluid delivered through the flow path 78 of the union 72 will increase.
[0007]
As described above, in the conventional flow control valve 70, the fluid in the union 72 is unnecessarily swirled or the flow is deflected, so that the control flow characteristics of the flow control valve 70 (pump rotation speed N-control flow (Q · characteristic) has deteriorated, and there has been a negative effect on controlling the flow rate of the fluid to be sent out to be constant.
[0008]
[Problems to be solved by the invention]
In view of the above facts, an object of the present invention is to obtain a flow rate control valve that can be more reliably controlled so as to keep the flow rate of a fluid to be delivered constant.
[0009]
[Means for Solving the Problems]
The flow control valve of the invention according to claim 1 is provided in the valve housing, and is provided in the union having a flow path that is formed in a cylindrical shape and communicates with a lumen of the valve housing, and the flow path of the union, An orifice that restricts the flow path, a communication lateral hole that is formed along the radial direction in the union upstream of the orifice, and that communicates the flow path with the lumen of the valve housing; and a downstream side of the orifice A feedback port that opens to the flow path of the union and a front end opening of the flow path of the union are provided in the valve housing, and fluid pressure on the upstream side of the orifice is applied to the front end side, and A spool valve to which a fluid pressure downstream of the orifice is applied to the rear end side through the feedback port, and the inside of the valve housing The outlet hole of the fluid supplied to reflux opened and closed by the spool valve by controlling the flow rate of a fluid, in the flow control valve for controlling the flow rate of the fluid delivered through the flow path of the union, the Even if the pressure distribution in the circumferential direction of the union of the fluid in the vicinity of the opening of the feedback port becomes non-uniform due to the swirling and deflection of the fluid flowing through the flow path of the union, the spool valve can be connected via the feedback port. The number of the feedback ports, the outer diameter D of the union, and the outer diameter Ds of the spool valve are set so that the fluid pressure applied to the rear end side is averaged .
[0010]
In the flow rate control valve according to the first aspect, a union and a spool valve are provided in the valve housing, and a flow path of the union communicates with a lumen of the valve housing and is restricted by an orifice. A feedback port is opened in the union flow path downstream of the orifice, and this feedback port communicates with the rear end side of the spool valve. Further, a communication horizontal hole is formed in the union upstream of the orifice along the radial direction, and the flow path of the union communicates with the inner cavity of the valve housing.
[0011]
When fluid is supplied to the lumen of the valve housing from a hydraulic pump or the like, the supplied fluid flows into the flow path from the opening at the tip of the union and also flows into the flow path from the communication lateral hole, and the flow of the union Sent over the path. At this time, fluid pressure on the upstream side of the orifice is applied to the front end side of the spool valve, and fluid pressure on the downstream side of the orifice is applied to the rear end side of the spool valve via the feedback port. When the spool valve moves (displaces) so that the two are balanced, the fluid outlet hole of the valve housing is opened and closed by the spool valve. By opening and closing the outflow hole by the spool valve, the flow rate of the fluid returning to the hydraulic pump or the like is controlled, and thereby the flow rate of the fluid sent through the union flow path is kept constant.
[0012]
Here, in the flow rate control valve according to the first aspect, the openings of the feedback port are provided at a plurality of locations in the immediate vicinity of the orifice and at equal intervals along the circumferential direction of the union. Therefore, even if the union circumferential pressure distribution in the vicinity of the opening becomes non-uniform due to the swirling and deflection of the fluid flowing through the union flow path, the spool valve is connected to the rear end side of the spool valve via the feedback port. The applied fluid pressure is averaged as a result.
[0013]
Accordingly, the fluid pressure (feedback pressure) applied to the rear end side of the spool valve via the feedback port does not rise unnecessarily due to the swirling and deflection of the fluid flowing through the union flow path. Can be moved (displaced) accurately. For this reason, the opening / closing degree of the outflow hole of the fluid supplied to the lumen of the valve housing becomes the original (ideal), and the flow rate of the fluid returning to the hydraulic pump or the like, that is, the union flow path is sent out. The flow rate of the fluid can be kept constant.
[0014]
Thus, in the flow rate control valve according to the first aspect, the flow rate of the fluid to be delivered can be controlled more reliably so as to be kept constant.
[0015]
The flow rate control valve according to a second aspect of the present invention is the flow rate control valve according to the first aspect, wherein two or more feedback ports are provided, and the relationship between the outer diameter D of the union and the outer diameter Ds of the spool valve. D / Ds = 0.71 to 0.77 is satisfied .
[0016]
In the flow rate control valve according to claim 2 , two or more feedback ports are provided, and the relationship between the outer diameter D of the union and the outer diameter Ds of the spool valve satisfies D / Ds = 0.71 to 0.77. It can be more reliably controlled to keep the flow rate of the delivered fluid constant.
[0033]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 schematically shows the overall configuration of a hydraulic power steering device 50 for a vehicle to which a flow control valve 10 according to an embodiment of the present invention is applied.
[0034]
The hydraulic power steering apparatus 50 includes a gear box 54 (steering mechanism) made up of a rack and pinion for steering the left and right steered wheels 52. A steering wheel 56 is connected to the gear box 54 via a steering shaft 55, and the steered wheel 52 can be steered via the gear box 54 by steering the steering wheel 56. Further, the gear box 54 is provided with an assisting power cylinder and a control valve (not shown).
[0035]
The hydraulic power steering apparatus 50 includes a hydraulic pump 58 that generates a steering assist force (assist force) in addition to the gear box 54. The hydraulic pump 58 is, for example, a vane pump, a trochoid pump, or a gear pump, and is driven by an engine. The hydraulic pump 58 communicates with the power cylinder (one cylinder chamber) of the gear box 54 via the flow control valve 10 and also the power cylinder (the other cylinder chamber) of the gear box 54 via the reservoir tank 60. It becomes the composition communicated with. The pressure fluid (hydraulic oil) discharged from the hydraulic pump 58 is metered by the flow control valve 10 and then supplied to the control valve of the gear box 54, and the pressure fluid is supplied to one chamber of the power cylinder according to the steering torque. Is supplied, and a steering assist force (assist force) is obtained.
[0036]
Here, the flow control valve 10 includes a valve housing 12. An inflow hole 14 and an outflow hole 16 for pressure fluid (hydraulic oil) are formed in the valve housing 12, and each is connected to a hydraulic pump 58. A union 18 is disposed in the valve housing 12. As shown in FIGS. 2A and 2B, the union 18 has a flow path 20 that is formed in a cylindrical shape and communicates with the lumen (the inflow hole 14 and the outflow hole 16) of the valve housing 12. is doing. An orifice 22 is provided in the flow path 20 of the union 18 to partially restrict the flow path 20. A communication lateral hole 24 is formed along the radial direction at the tip of the union 18 upstream of the orifice 22 (outflow hole 16 and outflow hole 16 side), and the flow path 20 is formed in the valve housing 12. Communicating with the cavity.
[0037]
Further, the flow control valve 10 includes a spool valve 26. The spool valve 26 is provided in the valve housing 12 so as to face the union 18 (the front end opening of the flow path 20), and is always attached to the union 18 (the front end opening of the flow path 20) by the spring 28. It is energized.
[0038]
Further, the valve housing 12 and the union 18 are provided with a feedback port 30. One end of the feedback port 30 opens downstream of the orifice 22 and opens in the flow path 20 of the union 18, and the other end opens in the lumen of the valve housing 12 on the rear end side of the spool valve 26. is doing. As a result, the fluid pressure on the upstream side of the orifice 22 is applied to the front end side of the spool valve 26, and the fluid pressure on the downstream side of the orifice 22 is applied to the rear end side of the spool valve 26 via the feedback port 30. To be granted.
[0039]
As described above, the flow rate control valve 10 controls the flow rate of the fluid returned to the hydraulic pump 58 by opening and closing the outflow hole 16 of the fluid supplied to the inner cavity of the valve housing 12 by the spool valve 26. In this configuration, the flow rate of the fluid delivered to the gear box 54 via the flow path 20 can be controlled.
[0040]
Further, in this flow control valve 10, the length along the radial direction of the union 18 with respect to the communication lateral hole 24 formed in the union 18 as described above is set to the length of the distal end opening of the flow path 20 of the union 18 and the communication horizontal hole. The length is set such that the swirling and deflection of the fluid flowing into the flow path 20 through the flow path 24 through the flow path 20 is suppressed. Moreover, at least one of the formation position, the number of formations, and the diameter dimension of the communication horizontal hole 24 along the circumferential direction of the union 18 is also the same as that of the tip opening of the flow path 20 of the union 18 and the communication. It is set so that swirling and deflection of the fluid flowing into the flow path 20 through the horizontal hole 24 and flowing through the flow path 20 are suppressed.
[0041]
In addition, the axial position of the communication lateral hole 24 from the tip of the union 18 is such that the flow of the union 18 is at a position where the pressure rise caused by the swirling and deflection of the fluid flowing through the flow path 20 of the union 18 does not reach the opening of the feedback port 30. The fluid flowing through the passage 20 is set to be deflected.
[0042]
Furthermore, the openings of the feedback port 30 described above are provided at a plurality of locations in the immediate vicinity of the orifice 22 and at equal intervals along the circumferential direction of the union 18, and the rear end of the spool valve 26 is provided via these feedback ports 30. The rise of the fluid pressure applied to the side due to the swirling and deflection of the fluid flowing through the flow path 20 of the union 18 is suppressed.
[0043]
2A and 2B, in the present embodiment, for example, the outer shape and the like of the spool valve 26 and the union 18 are set as follows.
1) Spool valve 26
Diameter (outer diameter) _DS
2) Union 18
Outer diameter D / D _S : 0.71
Inner diameter D ′ / D _S : 0.35
3) Communication side hole 24
Diameter φ / D _S : 0.18
Forming location (distance in the axial direction from the tip of the union 18) L / D _S : 0.35
4) Feedback port 30
Number: Four locations at regular intervals (every 90 degrees) in the circumferential direction Next, the operation of this embodiment will be described.
[0044]
In the flow control valve 10 of the power steering device 50 configured as described above, the union 18 and the spool valve 26 are provided in the valve housing 12, and the flow path 20 of the union 18 communicates with the lumen of the valve housing 12 and the orifice 22. It is squeezed by. A feedback port 30 is opened in the flow path 20 of the union 18 on the downstream side of the orifice 22, and the feedback port 30 communicates with the rear end side of the spool valve 26. Further, a communication lateral hole 24 is formed along the radial direction in the union 18 upstream of the orifice 22, and the flow path 20 of the union 18 is communicated with the lumen of the valve housing 12.
[0045]
When pressure fluid (hydraulic oil) is supplied from the hydraulic pump 58 to the lumen of the valve housing 12, the supplied fluid flows into the flow path 20 from the tip opening of the union 18 and also flows from the communication lateral hole 24. It flows into the passage 20 and is sent to the control valve of the gear box 54 via the passage 20 of the union 18. At this time, the fluid pressure upstream of the orifice 22 is applied to the front end side of the spool valve 26 and the fluid pressure downstream of the orifice 22 is applied to the rear end side of the spool valve 26 via the feedback port 30. The spool valve 26 moves (displaces) so that the moving force due to the fluid pressure (and the urging force of the spring 28) is balanced, so that the outflow hole 16 of the valve housing 12 is opened and closed by the spool valve 26. By opening / closing the outflow hole 16 by the spool valve 26, the flow rate of the fluid returning to the hydraulic pump 58 is controlled, whereby the flow rate of the fluid sent to the gear box 54 through the flow path 20 of the union 18 is made constant. Kept.
[0046]
Here, in the flow control valve 10 according to the present embodiment, the communication lateral hole 24 formed in the union 18 has a length along the radial direction of the union 18 such that the end opening and the communication of the flow path 20 of the union 18 are connected. The length is set such that the swirling of the fluid flowing into the flow path 20 through the horizontal hole 24 and flowing through the flow path 20 is suppressed. For example, when the length of the communication lateral hole 24 is set to be suitably long, the fluid flowing into the flow path 20 through the communication horizontal hole 24 is turned in the axial direction of the flow path 20 (the force for turning is suppressed). ), The swirling of the fluid flowing through the flow path 20 is suppressed. Moreover, in this flow control valve 10, the communication lateral hole 24 formed in the union 18 is similarly connected to at least one of the formation position, the number of formations, and the diameter dimension along the circumferential direction of the union 18. It is set so that the swirling and deflection of the fluid flowing into the flow channel 20 and flowing through the flow channel 20 through the front end openings and the communication lateral holes of the 18 flow channels 20 are suppressed. For example, when the formation position along the circumferential direction of the union 18 is suitably set, the inflow amount of the fluid flowing into the flow path 20 through the communication lateral holes 24 is set to the respective communication lateral holes 24 along the circumferential direction of the union 18. And the deflection of the fluid flowing into the flow path 20 is suppressed.
[0047]
Moreover, in this flow control valve 10, the opening portions of the feedback port 30 are provided at a plurality of locations in the immediate vicinity of the orifice 22 and at equal intervals along the circumferential direction of the union 18. Therefore, even if the pressure distribution in the circumferential direction of the union 18 in the vicinity of the opening is uneven due to the swirling and deflection of the fluid flowing through the flow path 20 of the union 18, the spool valve 26 is connected via the feedback port 30. As a result, the fluid pressure applied to the rear end side is averaged.
[0048]
As a result, the fluid pressure downstream of the orifice 22, that is, the fluid pressure (feedback pressure) applied to the rear end side of the spool valve 26 via the feedback port 30, causes the swirling of the fluid flowing through the flow path 20 of the union 18. The spool valve 26 can be accurately moved (displaced) without unnecessarily rising due to the deflection. For this reason, the opening / closing degree of the outflow hole 16 of the valve housing 12 becomes the original (ideal) level, and is sent to the gear box 54 through the flow rate of the fluid returning to the hydraulic pump 58, that is, the flow path 20 of the union 18. The flow rate of the fluid can be kept constant.
[0049]
Thus, in the flow control valve 10 according to the present embodiment, it is possible to more reliably control the flow rate of the fluid to be sent out so as to be kept constant.
[0050]
Next, the result of experimental analysis of the influence on the control flow rate characteristics (pump rotation speed N−control flow rate Q · characteristic) such as the outer shape of the spool valve 26 and the union 18 as described above will be described.
A) Study on the number of feedback ports 30 The results of studying the control flow rate characteristics (pump rotation speed N-control flow rate Q · characteristics) based on the following conditions are shown in FIGS. 3 (A) to 3 (C). Has been.
[0051]
1) Spool valve 26
Diameter (outer diameter) _DS
2) Union 18
Outer diameter D / D _S : 0.71
Inner diameter D ′ / D _S : 0.35
3) Communication side hole 24
Diameter φ / D _S : 0.18
Forming location (distance in the axial direction from the tip of the union 18) L / D _S : 0.35
4) Feedback port 30
In the case of two places, it is formed at an interval of 180 degrees in the circumferential direction, and in the case of four places, it is formed at equal intervals every 90 degrees in the circumferential direction. As is apparent from FIGS. It is understood that the feedback ports 30 are preferably provided at a plurality of locations at equal intervals along the circumferential direction of the union 18.
B) Examination of the location where the communication lateral hole 24 is formed (axial distance L from the tip of the union 18) Based on the following conditions, the results of examining the control flow characteristics (pump rotation speed N-control flow Q and characteristics) are shown in FIG. 4.
[0052]
1) Spool valve 26
Diameter (outer diameter) _DS
2) Union 18
Outer diameter D / D _S : 0.71
Inner diameter D ′ / D _S : 0.35
3) Communication side hole 24
Diameter φ / D _S : 0.18
4) Feedback port 30
As shown in FIG. 4, the formation of the communication lateral hole 24 (the axial distance L / D _S from the tip of the union 18) is formed based on the above conditions. It is understood that 0.35 or less is good.
C) Examination of outer diameter D of union 18 The result of examining the control flow rate characteristic (pump rotation speed N-control flow rate Q · characteristic) based on the following conditions is shown in FIG.
[0053]
1) Spool valve 26
Diameter (outer diameter) _DS
2) Union 18
Inner diameter D ′ / D _S : 0.35
3) Communication side hole 24
Diameter φ / D _S : 0.18
Forming location (distance in the axial direction from the tip of the union 18) L / D _S : 0.35
4) Feedback port 30
As shown in FIG. 5, it is understood that the outer diameter D / D _S of the union 18 is preferably 0.77 or less under the above conditions, as is apparent from FIG. .
D) Examination of inner diameter D ′ of union 18 The result of examining the control flow rate characteristic (pump rotation speed N−control flow rate Q · characteristic) based on the following conditions is shown in FIG.
[0054]
1) Spool valve 26
Diameter (outer diameter) _DS
2) Union 18
Outer diameter D / D _S : 0.71
3) Communication side hole 24
Diameter φ / D _S : 0.18
Forming location (distance in the axial direction from the tip of the union 18) L / D _S : 0.35
4) Feedback port 30
As shown in FIG. 6, it is understood that the inner diameter D ′ / D _S of the union 18 is preferably 0.35 or less.
[0055]
【The invention's effect】
As described above, the flow rate control valve according to the present invention has an excellent effect that the flow rate of the fluid to be delivered can be controlled to be kept constant.
[Brief description of the drawings]
FIG. 1 is a configuration diagram schematically showing a configuration of a flow control valve according to an embodiment of the present invention and a hydraulic power steering device for a vehicle to which the flow control valve is applied.
FIG. 2 is a cross-sectional view showing the union configuration of the flow control valve according to the embodiment of the present invention.
FIG. 3 is a diagram showing a control flow rate characteristic (pump rotation speed N−control flow rate Q · characteristic) with respect to the number of feedback ports in the flow rate control valve according to the embodiment of the present invention.
FIG. 4 is a line showing a control flow rate characteristic (pump rotational speed N−control flow rate Q · characteristic) with respect to a location where a communication horizontal hole is formed (axial distance L from the tip of the union) in the flow rate control valve according to the embodiment of the present invention; FIG.
FIG. 5 is a diagram showing a control flow rate characteristic (pump rotation speed N−control flow rate Q · characteristic) with respect to the outer diameter D of the union in the flow rate control valve according to the embodiment of the present invention.
FIG. 6 is a diagram showing a control flow rate characteristic (pump rotation speed N−control flow rate Q · characteristic) with respect to an inner diameter D ′ of the union in the flow rate control valve according to the embodiment of the present invention.
FIG. 7 is a cross-sectional view showing a swirling flow and a deflection flow in a union in a conventional flow control valve.
FIG. 8 is a diagram showing a control flow rate characteristic (pump rotation speed N−control flow rate Q · characteristic) in a conventional flow rate control valve in comparison with an ideal (target) control flow rate characteristic.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Flow control valve 12 Valve housing 14 Inflow hole 16 Outflow hole 18 Union 20 Flow path 22 Orifice 24 Communication side hole 26 Spool valve 30 Feedback port 50 Power steering apparatus 54 Gear box 58 Hydraulic pump

Claims (2)

A union having a flow path provided in the valve housing and formed in a cylindrical shape and communicating with the lumen of the valve housing;
An orifice provided in the flow path of the union and restricting the flow path;
A communication lateral hole formed along the radial direction in the union upstream of the orifice and communicating the flow path with the lumen of the valve housing;
A feedback port that opens into the flow path of the union downstream of the orifice;
Opposite the front end opening of the flow path of the union, provided in the valve housing, the fluid pressure on the upstream side of the orifice is applied to the front end side, and the fluid pressure on the downstream side of the orifice passes through the feedback port. A spool valve applied to the rear end side via
With
The flow rate of the fluid delivered through the flow path of the union is controlled by opening and closing the outflow hole of the fluid supplied to the lumen of the valve housing by the spool valve and controlling the flow rate of the fluid flowing back. In the flow control valve,
Even if the pressure distribution in the circumferential direction of the union of the fluid in the vicinity of the opening of the feedback port becomes non-uniform due to the swirling and deflection of the fluid flowing through the flow path of the union, the spool is passed through the feedback port. The number of the feedback ports, the outer diameter D of the union, and the outer diameter Ds of the spool valve were set so that the fluid pressure applied to the rear end side of the valve was averaged.
A flow control valve characterized by that. Two or more feedback ports are provided,
The relationship between the outer diameter D of the union and the outer diameter Ds of the spool valve satisfies D / Ds = 0.71 to 0.77.
The flow control valve according to claim 1 .

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