JP2587640B2 - Vane pump with flow control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vane pump provided with a flow control device for controlling a flow supplied to a power steering device according to a vehicle speed.

(Prior Art) In the conventional apparatus shown in FIGS. 3 and 4, a bore 2 is formed in an aluminum body 1, a side plate 3 and a cam ring 4 are provided inside the bore 2, and the cam ring 4 side is covered with a cover 5. It is blocking.

The cam ring 4 houses a rotor 7 provided with a number of vanes 6, and a drive shaft 8 of the rotor 7 is linked to an engine (not shown).

When the engine is driven, the rotor 7 rotates together with the drive shaft 8. With the rotation of the rotor 7, the tip of the vane 6 moves while sliding on the cam ring 4. By rotating the rotor 7 in this manner, the chamber defined by each vane 6 becomes a suction chamber or a discharge chamber, and discharges high-pressure fluid to the discharge chamber 9.

The fluid discharged into the discharge chamber 9 is supplied to a flow control device F. The flow control device F is housed in a valve mounting hole 10 formed in the aluminum body 1 as shown in FIG. . This valve mounting hole 10 blinds one end,
The other end is open.

In the valve mounting hole 10 as described above, a spring 11, a spool 12, and a hollow connector are arranged in this order from the deepest part.
Insert 13.

The connector 13 has a large diameter portion 14 protruding outward from the aluminum body 1 and a male screw portion 15 mating with a female screw portion formed in the valve mounting hole 10.

The small diameter portion 16 further inside the male screw portion 15 forms an annular gap 17 with the mounting hole 10, and the annular gap 17 has an inflow port 18 communicating with the discharge chamber 9. Is opened.

Further, a cap 19 is fitted to the tip of the small diameter portion 16, and a fixed orifice 20 is formed in the cap 19. Inside this cap 19 is a hollow control member
21 is slidably mounted, and a spring 22 is interposed between the cap 19 and the control member 21.

The control member 21 thus configured includes first and second step portions 23 and 24.
Is formed, and at the normal position, the second step portion 24 is pressed against the step portion 25 formed on the inner periphery of the connector 13. And
When the control member 21 is in the normal position, the control member 21
The first step portion 23 and the step portion 25 of the connector 13 together form a pilot chamber 26. This pilot room 26
Is always in communication with the annular gap 17 through the through hole 27.

A variable orifice 28 is formed in the small diameter portion 16 of the connector 13. When the control member 21 is at the normal position shown in the drawing, the variable orifice 28 keeps the fully open state, and when the control member 21 moves against the spring 22, the control member 21 causes the variable orifice 28 to gradually move. Closed. That is, the variable orifice 28
The degree of opening of the control member 21 is changed in accordance with the amount of movement.

The spool 12 is normally pressed against the cap 19 by the action of the spring 11. In a normal state in which the cap 19 is pressed against the cap 19, the communication between the annular gap 17 and the bypass port 29 is cut off. And the annular gap 17
When the internal pressure increases, the spool 12
And the above-mentioned annular gap 17 and bypass port 29
And communicate.

The bypass port 29 communicates with the suction port 30 of the vane pump.

The center portion of the spool 12 as described above is hollow, and the hollow portion 31 covers the spring chamber 32 provided with the spring 11 on the seat plug 34 holding the filter 33. Further, the hollow portion 31 is provided with a spring receiver 36 for holding one end of the spring 35,
A ball poppet 37 is interposed between the spring receiver 36 and the seat plug 34. The hollow portion 31 communicates with the bypass port 29 through a flow hole 38 and an annular groove 39 formed in the spool 12, and the configuration of the spool 12 inside the hollow portion 31 is a relief valve.

A passage 41 is formed in the aluminum body 1 in parallel with the valve mounting hole 10. One end of the passage 41 is closed with a plug 42, and the spring chamber 32 and the connector are connected through the passage 41. 13 communicates with the opening 13a side.

When the engine is driven, the drive shaft 8 linked to the output shaft rotates to drive the vane pump. When the vane pump is driven in this manner, the discharged fluid is supplied to the inflow port 18 → the annular gap 17 → the fixed orifice 20.
The power is supplied to a power steering device (not shown) via the variable orifice 28 → the opening 13a.

At this time, if the vehicle is running at a low speed, the discharge amount of the vane pump is small, so that the pressure loss of the fluid passing through the orifices 20, 28 is also small.

Therefore, there is almost no relative difference between the pressure in the pilot chamber 26 where the pressure on the upstream side of the orifices 20 and 28 acts and the pressure on the opening 13a side downstream of these orifices, and the control member 21 maintains the illustrated position. Will remain. When the control member 21 holds the position shown in the drawing, the variable orifice 28 is maintained in the fully open state,
A flow rate corresponding to the total opening area of 0 and 28 is supplied to the power steering apparatus.

When the vehicle speed gradually increases from the above state to reach the medium speed range, the discharge flow rate increases accordingly, and the pressure loss of the fluid passing through the orifices 20, 28 also increases.

For this reason, the pressure difference between the pilot chamber 26 and the opening 13a side is slightly increased, and the control member 21 moves to a position where it is balanced with the spring force of the spring 22, and slightly closes the variable orifice 28. When the variable orifices 28 are slightly closed in this way, the total opening area with the fixed orifices 20 is also reduced, so that the flow rate passing through them is also reduced.

When the vehicle speed further increases and reaches the high-speed range, the pressure difference between the two orifices 20 and 28 further increases, so that the control member 21 strokes to the maximum and the variable orifice 28 is fully closed.

Therefore, in this case, only the flow rate determined by the fixed orifice 20 is supplied to the power steering device.

The flow rate supplied to the power steering device is controlled in accordance with the vehicle speed as described above. When an excess flow rate exceeding the control flow rate is generated, the pressure in the annular gap 17 naturally increases. Due to the pressure action at this time, the spool 12 moves against the spring 11, and the annular gap 17 and the bypass port
The excess flow rate is returned to the suction port 30 via the bypass port 29 because of communication with the suction port 29.

Further, when the pressure on the power steering device side becomes equal to or higher than the set pressure, the ball poppet 37 opens, so that the pressure on the power steering device side is suppressed within the set pressure.

(Problems to be solved by the present invention) In the conventional vane pump as described above, the body 1
Is made of aluminum, so when you slide the spool 12,
There has been a problem that the inner circumference of the valve mounting hole 10 is significantly worn.

An object of the present invention is to improve the wear resistance of a body made of aluminum so as to reduce its weight.

(Means for Solving the Problems) According to the present invention, a cam ring is provided in a bore formed in an aluminum body, the rotor is rotated together with a drive shaft, and the tip of a vane provided in the rotor is slidably contacted with the cam ring. It is assumed that the vane pump is configured to discharge the high-pressure fluid to the discharge chamber and guide the high-pressure fluid to the flow control device provided in the aluminum body.

On the premise of the vane pump described above, the present invention is configured such that an iron-based sleeve is fitted to a mounting hole in a flow control device, and an iron-based spool of the control device is slidably provided in the sleeve. An outlet is formed in the iron-based sleeve, and the outlet is characterized in that its shape is elliptical and the major axis of the ellipse is parallel to the axis of the spool.

(Operation of the Present Invention) Since the present invention is configured as described above, the iron-based spool also slides in the iron-based sleeve.

In addition, the outlet formed in the iron-based sleeve is made elliptical and its long axis is parallel to the axis of the spool, so even when the spool moves and the outlet opens, it gradually opens and suddenly opens. It does not reach the fully open state. Since the outlet gradually opens in this way, the jetting power at the time of the opening is increased, and the fluid is momentarily increased accordingly.

Furthermore, by making the outflow port elliptical as described above, it is possible to shorten the length in the short axis direction while securing the same opening area as in the case of a circular port. Since the length in the short axis direction is short, the leading end of the spool does not fall into the outlet and tilt.

(Effect of the present invention) Since the iron-based spool slides inside the iron-based sleeve,
Wear of the sleeve that is the sliding part of the spool can be prevented,
While eliminating the drawbacks of the aluminum body, it can fully demonstrate its light weight features.

In addition, since the outlet is elliptical, a supercharge effect can be exhibited, and the suction efficiency can be improved accordingly.

Furthermore, since the inclination of the spool can be prevented, problems such as inconvenience when the spool is inclined, for example, problems such as the engagement between the spool and the sleeve do not occur.

(Embodiment of the Present Invention) The embodiment of the present invention shown in FIGS. 1 and 2 is a conventional valve mounting hole 10 in which an outlet 44 is formed in advance in a portion where a spool 43 slides. The most important feature is that the sleeve 43 is fitted and the spool 43 is also made of iron.

The outlet 44 communicates with the bypass port 29. However, since the outlet 44 is formed in the sleeve 45 in advance as described above, there is an advantage that the shape can be freely selected.

In this embodiment, as shown in FIG. 2, the shape of the outlet 44 is elliptical, and the major axis of the ellipse is parallel to the axis of the spool 43.

The outlet 44 is made elliptical in this way in order to exhibit the supercharge effect and to prevent the spool 43 from tilting.

The supercharge effect refers to improving the suction efficiency of the suction port 30 by energizing the flow from the bypass port 29 to the suction port 30.

If the outlet port 44 is made elliptical as described above, even when the spool 43 moves and the outlet port 44 opens, the outlet port 44 gradually opens and does not suddenly reach the fully open state. If the outlet 44 is gradually opened, the ejection power at the beginning of the opening becomes large, and the fluid becomes more vibrant.

Also, if the outlet 44 is a perfect circle, when the corner of the spool 43 reaches the outlet 44, the corner is
Since it will be in a shape that falls into the 44 part, the relevant spool 43
Tilts. When the spool 43 is inclined, the contact force of the corner of the spool 43 with the sleeve 45 increases, and the sleeve 45 wears with the corner.

However, if the outlet 44 is made elliptical as in this embodiment, the length in the short axis direction can be shortened even if the opening areas are equal. If the length in the short axis direction is reduced in this way, the corners of the spool 43 will not fall into the outlet 44, and as a result, the spool 43 will not tilt. Since the inclination of the spool 43 can be prevented, the wear of the sleeve 45 caused by the inclination can also be prevented.

Further, in this embodiment, as described above, the spool 43
Is made of iron, so that the sheet member 47 provided in the hollow portion 46 of the spool 43 can be made of iron. Since the iron-based sheet member 47 is used as described above, the sheet member 47 can be pressed into the hollow portion 46 with a strong force.

Therefore, the seat member 47 can be held at an arbitrary position in the hollow portion 46, but the spring force of the spring 35 is adjusted according to the position of the seat member 47, and the set pressure of the relief valve is adjusted. It is also possible to do.

Further, in this embodiment, a ball 48 is press-fitted into one end of the passage 41 to close the opening, and a push nut 49 is fitted outside the ball 48 to prevent the ball 48 from coming off. I have.

If the plug 42 is used in the passage 41 as in the conventional case, the cost is inevitably increased.
In this case, it is not necessary to cut a screw on the passage 41 side, and the cost merit increases accordingly.

Further, since the body 1 is made of aluminum, it is not possible to withstand high pressure just by press-fitting the ball 48. Therefore, the push nut 49 is attached to the outside of the ball 48 as described above to prevent the ball 48 from coming off.

Since the configuration other than the above is exactly the same as the conventional one, the detailed description thereof uses the conventional description as it is,
In the drawings, the same components are denoted by the same reference numerals.

[Brief description of the drawings]

1 and 2 show an embodiment of the present invention.
FIG. 2 is a sectional view of a flow control device, FIG. 2 is an enlarged sectional view of a portion where a sleeve is fitted in a mounting hole, FIG. 3 is a sectional view of a conventional vane pump, and FIG. 4 is a sectional view of a flow control device. . 1 ... aluminum body, 2 ... bore, 4 ... cam ring,
6 Vane, 7 Rotor, 9 Discharge chamber, F Flow control device, 10 Mounting hole, 43 Spool, 45 Sleeve.

Claims (1)

(57) [Claims] A cam ring is provided in a bore formed in an aluminum body, and the rotor is rotated together with a drive shaft to bring the tip of a vane provided in the rotor into slidable contact with the cam ring. And a high-pressure fluid is guided to a flow control device provided in the aluminum body. In the vane pump, an iron-based sleeve is fitted into a mounting hole of the flow control device, and the control device is inserted into the sleeve. The iron-based spool is slidably provided, and the iron-based sleeve has an outlet formed therein. The outlet has an elliptical shape, and the major axis of the ellipse is the axis of the spool. A vane pump provided with a flow control device characterized by being parallel to the above.