JPS6214394Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oil pump device that is rotationally driven by a vehicle engine and serves as a hydraulic source for the steering force of a power steering device used in a vehicle.

As shown in FIG. 1A, the conventional oil pump device pumps oil from a reservoir a (not shown) to an oil pump b.
The hydraulic fluid sucked in through the suction ports b′ and b′ of
High pressure is created by the vaned rotor and the discharge port
b″, b″ are supplied to the spool chamber 1 of the flow control valve d via the high-pressure side oil passage c, and the discharge flow rate Q _p is from the spool chamber 1 through the orifice 2 and from the discharge chamber 3 to the power steering controller (not shown). The flow rate Q supplied to the gearbox and the flow rate _Qs bypassed to the bypass port 4 communicating with the low-pressure side oil passage e returning to the suction port b' of the oil pump b', and the oil pressure _P2 of the discharge chamber 3. is supplied to the back pressure chamber 6 of the spool 5 through a communication path, and the spool 5 adjusts the opening of the bypass port 4 by receiving the hydraulic pressure P ₂ in the back pressure chamber 6 and a spring bias from a built-in spring 6'. The pressure difference P 1 - P 2 between the oil pressure P ₁ in the spool chamber ₁ and _the oil pressure P ₂ in the discharge chamber 3 in the flow control valve d hardly changes, and the supply flow rate Q is always approximately It is supposed to be kept constant.

Further, the oil pump b is rotationally driven by a vehicle engine (not shown), and the rotation speed of the oil pump b is proportional to that of the vehicle engine, so that the discharge flow rate Q _p of the oil pump b changes depending on the rotation speed. ing.

However, in the conventional oil pump device as described above, as _shown in FIG. The supply flow rate Q from the discharge chamber 3 of d is kept approximately constant as shown by the dotted line in FIG _.
The increase in is transferred to the oil pump b via the low pressure side oil passage e.
This results in unnecessary pumping action being returned to the suction port b' side of the engine, causing the oil pump b to rotate at an unnecessary high speed when the vehicle engine is rotating at high speed, and causing a large load to be borne from the oil pump b side to the vehicle engine side. be.

This project is an invention that solves the above-mentioned difficulties in conventional oil pump devices for power steering, and reduces the engine load received from the oil pump by reducing the discharge flow rate of the oil pump when the engine rotates at high speed. The present invention provides an oil pump device for power steering, in which a main suction port, an auxiliary suction port, an auxiliary discharge port, and a main discharge port are provided in the order of the vane rotation direction of the oil pump, and an auxiliary suction port and an auxiliary A discharge port is arranged on the front and rear sides of the vane rotation direction at the cam major radius position, closer to the main suction port and the main discharge port, and the communication path between the main suction port and the auxiliary suction port is opened from closed during high-speed rotation. It is characterized in that it is provided with control valves that simultaneously switch the communication path between the main discharge port and the auxiliary discharge port from open to closed.

An embodiment of the present invention will be described below with reference to FIGS. 2, 3, and 4. In the figures, a indicates a reservoir (not shown), b an oil pump (not shown) rotated by a vehicle engine, c is oil pump b
High pressure side oil passage communicating with main discharge port b″, b″ of
d is a flow control valve, e is a low-pressure side oil passage communicating from reservoir a and flow control valve d to both main suction ports b', b' of oil pump b, and f is a housing; A main suction port b', an auxiliary suction port 10, an auxiliary discharge port 11, and a main discharge port b'' are provided in the illustrated lower half of the pump b in the order of the vane rotation direction, and the auxiliary suction port 10 and the auxiliary discharge port 11 are arranged near the main suction port b' side and the main discharge port b'' side at the front and rear sides of the vane rotation direction at the cam major radius position R ₃ , and the spool 6 is slidably inserted into the spool hole 16, and the spool 6 forms chambers 17, 18, 19, and 20 inside the spool hole 16 from the left side in the figure, and the left chamber 17 is an oil pump. The chamber 20 on the right side has a built-in spool spring 21 and is in direct communication with the high-pressure side oil passage c of b, and is an oil passage that introduces hydraulic pressure from the downstream side of the orifice c' provided in the high-pressure side oil passage c. It is connected to 23, and
One chamber 19 on the center side has an oil passage 1 extending from the end side of the main suction port b' of the oil pump b.
2, and an oil passage 13 extending from the auxiliary suction port 10.
The other chamber 18 on the center side has an oil passage 15 extending from the end side of the main discharge port b'' of the oil pump b and an oil passage extending from the auxiliary discharge port 11. The spool hole 16, the spool 6 and the spool spring 21 are provided so as to be able to communicate with each other.
The control valve g is configured such that its spool 6 controls the discharge side pressure P of the oil pump b applied in the chamber 17.
_p and the decreasing hydraulic pressure P ₁ through the orifice c′
Hydraulic pressure P ₁ in the right chamber 20, which is given
Under the action of the spool spring 21 and the spool spring 21, when the vehicle engine is rotating at a low speed, that is, when the oil pump b is rotating at a low speed, the spool 6 is moved between the oil pressure P ₀ in the left chamber 17 and the oil pressure P ₁ in the right chamber 20.
The position shown in Fig. 1 is reached, where the spring pressure and F become P ₀ = P ₁ + F, and the main suction port b' and the auxiliary discharge port 10
Oil passage 12, chamber 19 and oil passage 13 between
The communication path is closed, and the main discharge port
b'' and the auxiliary discharge port 11, the communication path consisting of the oil passage 15, the chamber 18 and the oil passage 14 is opened, and when the vehicle engine is rotating at high speed, that is, when the oil pump b is rotating at a high speed, the oil pump b is discharged. As the side oil pressure P ₀ increases and the oil pressure difference P ₀ −P ₁ between the upstream and downstream sides of the orifice c′ increases, the spool 6 of the control valve g moves to the right as shown in FIG. The communication path between the suction port b' and the auxiliary suction port 10 is switched to open, and the communication path between the main discharge port b'' and the auxiliary discharge port 11 is switched to closed, and in this state, the lower half of the oil pump b Main discharge port
Even if the discharge flow rate from the b'' side is reduced, it is maintained by the influence from the main discharge port b'' in the upper half.

The illustrated embodiment has the above-mentioned structure, and to explain its operation, when the vaned rotor of the vehicle engine, that is, the oil pump b, is rotating at a relatively low speed, the spool of the control valve g 6 is in the position shown in Figure 2, and the oil pump b
Since the communication path (oil passages 12, 13, chamber 19) between the main suction port b'' and the auxiliary port 10 is closed, there is no suction from the auxiliary suction port 10, while the main discharge port b'' and the auxiliary port 10 are closed. Communication path between discharge ports 11 (oil paths 14, 15, chamber 1
8) is opened and the oil is discharged from both discharge ports b'' and 11. In this state, the pumping action of the space _b1 formed by the opposing vanes, rotor, and cam of the oil pump b is caused by the cam minor radius of
When the volume expands from point R ₁ to the major radius R ₃ , it communicates only with the main suction port b' and sucks in the hydraulic oil from the low pressure side oil passage e, and the space b ₁ reaches the major radius R ₃ of the cam and the volume increases. The main suction port is closed when it reaches approximately the maximum diameter limit.
In this case, the suction amount of hydraulic oil by space b ₁ is almost the maximum because it is separated from b', and as soon as the suction of the hydraulic oil is finished, the volume of space b ₁ decreases and the hydraulic oil inside is raised to high pressure. The auxiliary discharge port 11 is connected to the main discharge port b'', and the maximum amount of hydraulic fluid is discharged.

Therefore, the discharge flow rate per unit of the above space _b Q _A
Ignoring the vane thickness, Q _A ≒2πB(R ₃ ² −R ₁ ² )...(1) where B: is expressed by the vane spacing.

Next, when the vaned rotor of the vehicle engine, that is, the oil pump b, rotates at high speed, the spool 6 of the control valve g moves to the right as shown in FIG. It is connected to the suction port b' so that hydraulic oil can be supplied to the space b ₁ , and the space b ₁ is connected to the cam at the middle radius R ₂ which is slightly shorter than the long radius R ₃ of the cam, that is, the volume of the space b ₁ . When it becomes a little smaller, the auxiliary suction port 10
The amount of suctioned hydraulic oil decreases by the volume reduction, and the suctioned hydraulic oil is made high pressure and discharged from the main discharge port b''.

Therefore, the discharge flow rate Q _{B per} unit of space b in this case is Q _B ≒ 2πB (R ₂ ² − R ₁ ² )...(2) However, R ₁ < R ₂ < R ₃ Therefore, the vehicle When the engine, that is, the oil pump b, rotates at high speed, the control valve g automatically operates, and from the above equations (1) and ( ₂ ), the basic discharge amount per unit of the space b between the vanes in the oil pump b is On the other hand, the driving torque T of oil pump b is related to the basic discharge amount, and if the discharge pressure is P and the basic discharge amount is Q, then T=PQ/2π
Since Q _B <Q _A , the load on the vehicle engine is significantly reduced.

Therefore, as shown in Fig. 5, compared to the discharge flow rate characteristic Q ₀ in the conventional device, which increases as the rotation speed of the vehicle engine, that is, the oil pump b, increases, in this case, the discharge flow rate increases due to the decrease in the basic discharge amount and the increase in the rotation speed. The increase in volume becomes almost contradictory, and the total discharge volume remains almost unchanged even if the number of times increases, resulting in a discharge flow rate Q ₀ ′, which eliminates wasted energy (discharge volume) in the hatched area in the same figure. You can save money.

FIG. 4 shows another operating mechanism of the control valve g, and in this embodiment, a detection device 34 for electrically detecting the rotation speed of the vehicle engine or oil pump b; It is composed of a battery 35 that serves as a power source, and a solenoid 30 that is excited by the detection device 34 to slide and switch the spool 6 of the control valve g. 6, low pressure oil is introduced into the chamber 20 on the right side through the oil passage 31 from the oil passage 12 extending from the main suction port b' on the low pressure side of the oil pump b, and Chamber 1 on the left side from the chamber 20
The structure is such that low-pressure oil is also introduced into the left chamber 17 by an oil passage 32 provided in the spool 6 that reaches 7.

Therefore, in the embodiment of the control valve g' shown in FIG. 4, substantially the same effect as the control valve g shown in FIG. It has the advantage of being able to be set to
Main suction port in the upper half of oil pump b
The above-mentioned auxiliary suction port and auxiliary discharge port can also be provided on the b' and main discharge port b'' sides, and the effect can be further improved.

[Brief explanation of drawings]

FIG. 1A is a vertical sectional view showing a conventional power steering oil device, FIG. 1B is a special view of FIG. 1A, FIG. 2 is a longitudinal sectional view showing an embodiment of the present invention, The drawings are an explanatory diagram of the operation of FIG. 2, FIG. 4 is a longitudinal sectional view showing another embodiment of the control valve, and FIG. 5 is a characteristic diagram of the embodiment of the present invention. b: Oil pump, b': Main suction port, b'': Main discharge port, g, g': Control valve, 6: Subur,
7: Spool spring, 10: Auxiliary suction port, 11: Auxiliary discharge port, 12, 13, 14,
15: Oil path, 16: Spool hole, 17, 18, 1
9,20: Chiyamba.

Claims (1)

[Scope of utility model registration request] A main suction port, an auxiliary suction port, an auxiliary discharge port, and a main discharge port are provided in this order along the vane rotation direction of the oil pump, and the auxiliary suction port and the auxiliary discharge port are located on the front and rear sides of the vane rotation direction at the cam major radius position. The communication path between the main suction port and the auxiliary suction port is switched from closed to open during high speed rotation, and at the same time, the communication path between the main suction port and the auxiliary suction port is switched from closed to open. An oil pump device for power steering, characterized in that it is provided with control valves that respectively switch communication paths between auxiliary discharge ports from open to closed.