JPS5985492A - Flow control device of oil pump - Google Patents

Abstract

PURPOSE:To allow the working oil with little pulsation to be fed when the rotation irregularity of an engine occurs by operating a control plunger to close variable orifices and utilize a fixed orifices by means of the pressure difference between the upstream and downstream sides of the fixed orifices. CONSTITUTION:When the rotation irregularity of an engine occurs and the pump discharge quantity is changed, if the pressure difference between the upstream and downstream sides of fixed orifices 5a, 5b becomes a predetermined value or higher, a control plunger 7 is lowered against a spring 13, then variable orifices 6a, 6b are closed and the working oil is fed only through the fixed orifices 5a, 5b. In addition, when the said pressure difference is further increased, a flow control valve 14 is lowered, a chamber 10 is communicated to bypass holes 20a, 20b, then an excess other than the working oil flowing to a feed oil passage 7c direction through the fixed orifices 5a, 5b is fed to the bypass hole 20a from the chamber 10 and returned to the suction side of an oil pump. Therefore, the working oil with little pulsation can be fed from a discharge port 12 to a power steering gear mechanism.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flow rate control device for an oil pump (for example, an oil pump for power steering).

Conventional oil pump flow rate control device, for example, JP-A-56-
The oil pump flow control device described in Publication No. 35567 will be explained with reference to FIG. 1. (a) shows the pump housing, and (2) shows the supply extending from the discharge side of the oil pump (not shown) driven by the engine. Oil passage, (C) is constricted,
(dl is a fixed orifice, (81 is a variable orifice, (
'ff11 is a control plunger, (gl is a spring, Y) is a discharge port connected to the gear mechanism of the power steering, and (i) is the supply oil path (extending from b3 to the side opposite to the spring of the control plunger (1). In the pilot oil passage, the hydraulic oil discharged from the oil pump is guided to the downstream side through the supply oil passage (b), the throttle (C), and the fixed orifice (d),
Further, it is guided from the hole next to the fixed orifice (dl) to the downstream side of the fixed orifice (dl) through the variable orifice (e) from the hole next to the variable orifice (d).

It is further led to the power steering gear mechanism via the discharge port. In addition, if uneven rotation occurs in the engine and the oil pump discharge amount changes, and the pressure difference between the pressure on the upstream side of the throttle (C) and the pressure on the downstream side of the throttle (C) increases, the control plunger (0 is the spring The variable orifice (el) descends against the gl, and the opening of the variable orifice (el) is narrowed to control the flow rate of the hydraulic fluid that is guided from the downstream side of the fixed orifice (d) to the power steering gear mechanism via the discharge port (hl). It has become.

In the oil pump flow control device, a control plunger (1) for controlling a variable orifice (e) is connected to a flow control valve (not shown) and a variable orifice (not shown).
The throttle installed upstream of el (operated by the differential pressure between the upstream and downstream sides of cl) had the disadvantage of causing variations in the flow rate discharged to the power steering gear mechanism. Conventionally, the hydraulic oil passing through a variable orifice (a recirculating orifice (d) provided in parallel with el) is bypassed by a passage provided separately from the control plunger (f) and discharged to the gear mechanism of the chisel power steering. This increases the size of the device, weight, and cost.

In addition, in the same conventional device, a spring (g
The spring force must be set small.

In other words, the differential pressure between the upstream and downstream sides of the throttle (C) is very small, and the spring force of the spring (g) must be set small. Therefore, the sliding resistance of the control plunger (D) could not be ignored, and the control of the variable orifice (e) was unstable.

The present invention addresses the above-mentioned problems, and includes a fixed orifice and a variable orifice that are provided in parallel in the middle of a supply oil path extending from the discharge (Ill) of an oil pump driven by an engine, and the pressure on the upstream side of the fixed orifice. A control plunger controls the opening of the variable orifice when the pressure difference between the pressure on the downstream side of the fixed orifice and the pressure on the downstream side of the fixed orifice exceeds a predetermined value, and a control plunger that opens the bypass hole and opens the fixed orifice when the pressure difference becomes even larger. An excess flow valve of the hydraulic oil that has flowed into the upstream side is returned to the suction side of the oil pump. The object of the present invention relates to a flow rate control device for an oil pump, characterized in that it is provided with a supply oil passage that communicates with the oil pump, and a large-diameter pressure receiving portion that protrudes radially outward from the outer circumferential surface of a sylanger and communicates with the upstream side of a fixed orifice. By doing so, there is no variation in the discharged flow rate.

The device can be made smaller, reducing weight and cost. Another object of the present invention is to provide an improved oil pump flow rate control device that can stably control the opening of a variable orifice.

Next, the oil pump flow rate control device of the present invention will be explained with reference to an embodiment shown in FIGS. 2 to 5. (1) is a pump housing, (2) is an oil pump driven by an engine (not shown). ), the supply oil passage extending from the discharge side of (
3) is a connector fixed to the pump housing (11), (4) is a plug fixed to the lower end of the connector (3), and (5aX5b) is a connector fixed to the connector (3) so that the plug is inclined with respect to the axis of the connector (3). (4) is a fixed orifice provided in the connector (3), (6aX6b) is a variable orifice provided in the connector (3) such that their positions are different from each other along the axis of the connector (3), and (7) is a variable orifice provided in the connector (3). ) The control plunger (7a) slidably inserted into the control plunger (7) is connected to the connector (3) provided on the outer circumference of the control plunger (7), and (7b) is the outer circumference of the control plunger (7). The large diameter pressure receiving part (8) is the same pressure receiving part (7b).
A chamber in the connector (3) opposite to the chamber e-+8) is connected to the supply oil path (2) via a pilot oil path (9). (7C) passes through the control plunger (7) in the axial direction to form a fixed orifice (5).
a) (5b) and the supply oil passage communicating with the downstream side of the variable orifice (6aX6b), fixed orifice (5a) (5b) and variable orifice (6a) (6b) whose 0υ is connected to the supply oil passage (2); Upstream chamber, 01) is a chamber connected to the supply oil passage (7C), (121 is a chamber connected to the same chamber (11), (131)
is a spring that urges the control plunger (7) upward; 04) is a flow control valve that is slidably inserted into the pump housing (1); and (15) is a flow control pulp A4 that is attached upwardly. The spring (171) that presses the chamber (171) through the pore (161)
11) A chamber connected to the chamber, a9, is connected to the chamber an through a communication hole, and a chamber below the flow control valve (141, (20a) is larger than the land width (A) of the top of the flow control pulp 0. The bypass hole (20a) is the same diameter as the above-mentioned bypass hole (20a) and extends to the suction side of the oil pump. ).

Next, the operation of the oil pump flow rate control device will be explained. Hydraulic oil discharged from the oil pump driven by the engine flows through the supply oil path (2) → chamber (101 → fixed orifices (5a) (5b) and variable orifice (6).
a) (6b) → Supply oil path (7) in control plunger (7)
C)→chamber (11)→is sent to the gear mechanism of the power steering via the discharge port Oz. However, uneven rotation occurred in the engine, the pump discharge amount changed, and the pressure on the upstream side of the fixed oriice (5aX5b) (chamber (8)
When the pressure difference between the pressure inside the fixed orifice (5a) (5b) and the pressure on the downstream side of the fixed orifice (5a) (5b) (the pressure inside the supply oil passage (7C) and the chamber (111)) exceeds a predetermined value, the control plunger (7) It descends against the spring (13J), narrows the opening of the variable orifices (6a) (6b), and finally closes them to divert the hydraulic oil supply to the fixed orifice (5a) (
5b) only. In addition, the above differential pressure, that is, the pressure on the upstream side of the fixed orifices (5a) (5b) (chamber Q
Pressure inside OI) and pressure downstream of fixed orifice (saX5b) (supply oil passage (7C) chamber (11) pore (
7) When the pressure difference with the communication hole (181channo?- (pressure in 1gI) becomes even larger, the flow control pulse (+4) moves down against the spring (I5), and the chamber (lO) closes to the bypass hole. (2@), and also communicates through the bypass hole (20b), and the excess oil other than the hydraulic oil directed to the supply oil path (7C) via the fixed orifice (saXsb) is removed from the chamber (1υ). It flows into the bypass hole (20a) as shown by the arrow in Fig. 6 and returns to the suction side of the oil pump.Therefore, even if the engine rotation becomes uneven and the oil pump discharge amount changes, the discharge port 02 Hydraulic oil with little pulsation is supplied from the control plunger (7) to the gear mechanism of the power steering.
) The reason for providing the flow control valve (+4) is as follows. Flow control pal,' (+
4) If the followability is good even for high-frequency pulsations, the control plunger (7) is not necessary, but the flow control valve (I4) has a pressure of 80 K9/cm.
Since high-pressure oil also acts on the device, it is constructed to counteract this, resulting in poor response. Therefore, while the pulsation of the discharge flow rate is small, the control plunger (actuating force)
The pulsation is absorbed, and if the pulsation of the discharge flow rate becomes large, the flow control pulp 64) is activated to absorb the pulsation.

Moreover, at that time, the excess amount of hydraulic oil in the chamber QO) is returned directly from the chamber 00) to the binox hole (20a), and also through the bypass hole '(20b),
That is, the oil is returned with two bypass holes provided and discharged from the fixed orifice (saX5b) toward the supply oil path (7c) in a stable state with little pulsation. At this time, assuming that the bypass flow rate Qs flowing through the bypass hole (20a) is Pl, the pressure inside the chamber 00) is +8, the pressure inside the bypass hole (20a) is +8, and the opening area of the bypass hole (20a) is S, then Q8■ Since it is represented by Sof stone 10~, the stroke along the flow control pulp 0 depending on whether there is a bypass hole (20b) or not is as shown in FIG. 10, and xl<I2. That is, the binosu hole (20b)
If there is, the opening area of the bypass hole is S. When trying to, the flow control valve I is stroked x1
However, if there is no bypass hole (20b), the opening area of the pass hole should be set to S. In order to do so, it is necessary to lower the flow control pulp along the 0 line by a stroke x2, and xl<I2. On the other hand, the balance equation of the flow control valve (+4) is as follows: k is the spring constant of the flow control valve, Fo is the spring force of the flow control valve when the stroke is zero, ΔP
woP 1+ Pφ, A is the pressure receiving area of the flow control valve. If there is a bypass hole (20b)...A, aP□=F
If there is no binosu hole (20b) in 0+X1...A
According to ΔP2=Fo+x2, ΔP2>ΔP1.

This means that under the condition that the oil pump rotates at a constant rate, [If there is a bi-no-ξ pass hole (20b) → ΔP is relatively small → the opening area of the no-ξ pass hole is made small → the discharge flow rate is relatively large] Also, if there is no ()2 path hole (20b) →
∆P is relatively large → the opening area of the bypass hole is increased → the discharge flow rate is relatively small], and increasing the opening area of the latter bypass hole increases the bypass flow rate and the discharge flow rate becomes relatively small. It means to decrease. Pi・ξ
No. 11 showing the discharge flow rate characteristics when there is a through hole (20b).
In the figure, the discharge flow rate differs depending on the discharge pressure Pφ.
This is because the stroke X of the flow control valve (14) differs depending on each pressure, and ΔP changes. For reference, FIG. 12 shows the discharge flow rate characteristics when there is no bypass hole (20b). What can be said from the above explanation is that the bypass hole (20b) can reduce changes in the discharge flow rate due to changes in load pressure, and this can make the steering force characteristics of the automobile more stable. Connect. For example, the flow rate change at 20 Q Orpm (3K9/crn” −+ 80 K
9/crn”) is when there is a bypass hole (20b) = 4.1 to 5.2 J3An1n (△Q = 1.1
47m1n), without bypass hole (20b) = 3
．． 2~4.947m1n (△Q = 1.7-e/m
1n) Te. Moreover, the binocular ξ space hole (20b) does not remain in a stable state in discharge flow rate characteristics. That is, the hydraulic pressure (radial load) applied to the runt 9 portion of the flow control valve 04) is balanced, the sliding resistance on the flow control valve side is reduced, and the wear of the sliding portion is reduced.

Figure 6 shows a fixed orifice (5) and a variable orifice (
This is another embodiment in which the fixed orifice (5) is provided in the connector (3) while the connector (3) is provided with one fixed orifice (5). Also, Figure 7 shows
One fixed orifice (5) and one variable orifice (6) each.
This is another embodiment in which a fixed orifice (5) is provided in the plug (4). Figure 8.9 also shows two fixed orifices (5) and two variable orifices (6) ((5)
aX5b) and (6aX6b)), while fixed orifices (5a) and (5b) are provided horizontally in the plug (4). In the embodiment shown in Fig. 6 above, the connector (3) is enlarged as it is necessary to provide an oil path from the chamber aυ to the fixed orifice (5), but in the other embodiments shown in Figs. 2, 7, and 8, the There is no need for an oil passage, and the connector (3) becomes a connector. In addition, the communication hole (16) is a part of the communication hole (18), and hydraulic damping is applied to stabilize the operation of the flow control valve (+41). (16) can be provided on the connector (3), which is advantageous in terms of processing.Also, the reason why the variable orifices (6aX6b) are provided at different levels in the embodiment shown in Fig. 2.8 is because (1)
Control plunger for hydraulic oil after passing through the variable orifice (
7) to reduce hydraulic pry input and make it easier to maintain hydraulic balance. (III. The transient region in which the discharge flow rate is reduced is arbitrarily set. In other words, there is not much freedom in setting the spring force on the spring side, but the diameter of the variable orifice (6a) (6b), This is because a transition region in which the discharge flow rate is reduced can be arbitrarily set by selecting different height dimensions.

In the embodiment shown in FIG. 8, fixed orifices (5a) (5
b) is provided horizontally, because in the case of Fig. 7, the jet after passing through the fixed orifice (5) acts directly on the control plunger (force), causing the control plunger (7) to become inoperable. Although it tends to be stable, if it is provided as shown in Fig. 8, the jets after passing through the fixed orifices (5a) (5b) will interfere with each other, which can eliminate the adverse effect on the control granuler (7). Note that the fixed orifice (5) can also be provided on the pump nozzle (1) side as shown by the broken line in FIG.

The oil pump flow rate control device of the present invention is constructed as described above, and has a variable orifice (6) or a variable orifice (6a).
) (6b) is actuated by the differential pressure between the upstream and downstream sides of the fixed orifice (5) or (5aX5b).
It is possible to more accurately bring the discharge flow rate discharged to the gear mechanism section of the non-gun closer to the set value. Further, in the present invention, the hydraulic oil that has passed through the fixed orifice provided in parallel to the variable orifice is sent to the gear mechanism section of the power steering via the supply oil path (7C) provided at the center of the control plunger (7). Since it is directly discharged, the device can be made compact, processing is easy, and manufacturing costs can be reduced. Mabuko's invention &-! ,, The control plunger (7) for variable orifice refitting is controlled by the pilot oil pressure (pressure in chamber 5-f8) and the restriction (2') of the supply oil path (2).
) and the low pressure after passing through the fixed orifice (5) and the tin link (131
Since the sliding resistance acting on the control plunger (7) can be ignored, the variable orifice (
6) or (6aX6b) can be stably controlled.

Although the present invention has been described above with reference to embodiments, it goes without saying that the present invention is not limited to such embodiments, and that various design modifications can be made without departing from the spirit of the present invention. .

[Brief explanation of drawings]

FIG. 1 is a vertical side view showing a conventional oil pump flow rate control device, FIG. 2 is a vertical side view showing an embodiment of the oil pump flow rate control device according to the present invention, and FIG. FIG. 4 is a cross-sectional plan view taken along line IV-IV in FIG. 2, FIG. 5 is an enlarged longitudinal side view of the control plunger, and FIGS. 6 to 8 are A longitudinal side view showing each of the other embodiments, FIG. 9 is a cross-sectional plan view taken along the line ■-■ in FIG. 8, and FIG. 10 shows the relationship between the opening area of the bypass hole and the stroke of the flow control valve. An explanatory diagram, FIG. 11 is an explanatory diagram showing the discharge flow rate characteristics when there is a main hole (20b), and FIG.
0b) is an explanatory diagram showing the discharge flow rate characteristics in the case where there is no 0b). (2)... Supply oil path, (5) or (5aX5b)
・Fixed orifice, (6) or (6a) (6b)・
... variable orifice, (7) ... control plunger, (
7b)...Pressure receiving part of control plunger (7), (7c)
...Control plunger (7) supply oil path, (14)
...Flow control valve. Sub-Agent Patent Attorney Shigefumi Okamoto and 2 others Figure 2 1 ■ Potato 5 Figure 7 Figure 8 Figure 9 Circle Figure 10

Claims (1)

[Claims] A fixed orifice and a variable orifice are provided in parallel in the middle of a supply oil path extending from the discharge side of an oil pump driven by an engine, and the differential pressure between the pressure upstream of the fixed orifice and the pressure downstream of the fixed orifice is a predetermined value. A control plunger controls the opening degree of the variable orifice when the differential pressure increases further, and an oil pump opens the bypass hole and drains the excess hydraulic oil flowing upstream of the fixed orifice when the differential pressure increases further. a flow control valve that returns to the suction side of the control plunger, and a supply oil passage that extends axially through the control plunger and communicates with the downstream side of the fixed orifice, and a supply oil passage that protrudes radially outward from the outer peripheral surface of the plunger and is fixed thereto. 1. A flow rate control device for an oil pump, characterized in that a large diameter pressure receiving portion communicating with the upstream side of an orifice is provided.