JPS6320265A - Flow divider - Google Patents

Abstract

PURPOSE:To prevent a subflow of a relatively large flow amount to an antipressure chamber passage when the servo valve side is at a low pressure, and to stabilize the flow dividing property, by froming a taper surface at the throttle of an outlet port at the servo valve side of the flow divider, at a valve housing side. CONSTITUTION:A taper surface 82 to form a throttle part A is formed at the valve housing 80 of an outlet port at the servo valve side, that is, the first outlet port 18, and a pressure receiving surface 83 t receive the high pressure side pressure P1 of a pressure chamber 86b is formed at a spool valve 67. In this case, a taper surface 84 may be furnished at the valve housing 80 side also at an anti-pressure chamber side passage B of an outlet, that is, the second outlet port 69.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a flow divider that divides and controls pressure fluid between a servo valve side and a reaction chamber side of a power steering device equipped with a reaction force mechanism. be.

<Prior art> In general, in a power steering device equipped with a reaction force mechanism that changes steering force according to vehicle speed, etc., the flow rate of pressure oil discharged from a supply pump is controlled to a constant flow rate f, and this pressure fluid is The flow is divided into the servo valve side and the reaction force chamber 1 at a constant flow rate by the flow control valve. As shown in FIG. 4, this two-low divider has a subya valve nail that is movable within the bore 65a of the valve housing 80, and this valve housing □□□
A first outlet port 68 introduces a constant flow rate of pressure fluid from the supply pump through the inlet port and allows the flow to flow to the servo valve side, and a second outlet port 69 allows the flow to flow to the reaction force chamber side.
is formed, and the pressure P1 introduced from the inlet port
The tapered surface 8 formed on the spool valve 67 side
1 flows out from the first outlet port 68# through the throttle part A, and also flows out from the orifice through the shaft hole of the spool valve 67 and through the reaction force chamber side passage B to the second outlet port 691. , pressure balance between the pressure chambers and springs provided at both ends of the spool valve 67
7 is slid, and the flow rate is divided at a constant rate between the first and second outlet ports 68 and 691.

<Problems to be Solved by the Invention> In the conventional flow divider described above, the constricted portion A in the first outlet port 68 on the servo valve side is connected to the tapered surface 81 formed on the spool valve 67 and the edge portion of the valve housing 80. formed between. Therefore, when the servo valve side has low pressure and the reaction force chamber side has high pressure, such as when driving at high speed with the steering wheel in the neutral state, the spool valve 67 separates the pressure between the servo valve side and the reaction force chamber side. I so as to limit the opening area of
This works. At this time, since the throttle part A is formed by the tapered surface of the spool valve and the edge of the valve housing as described above, the pressure is high on the upstream side of the minimum throttle area of the throttle part A. The pressure on the downstream side is low. Therefore, a low pressure side pressure acts on a part of the tapered surface 81 (between Di and DQ) (the valve 67 is displaced to the left in FIG. Balanced, a higher flow rate is diverted to the second outlet port 69.

This tendency increases as the gear generation pressure increases, increasing the gap in the throttle section A, and continues until the gear generation pressure square becomes equal to the pressure P1. Therefore, the flow rate on the reaction force chamber side φ is the third for the gear generation pressure.
As shown in the figure, the steering force feels worse due to flow rate fluctuations.

Means for Solving the Problems> The present invention solves the unstable phenomenon of the flow divider characteristics described above, and its configuration allows the pressure fluid introduced from the inlet port to move within the inner hole of the valve housing. In a flow divider equipped with two outlet ports that divide a constant flow rate into a servo valve side and a reaction force chamber side of a power steering device equipped with a reaction force mechanism using a spool valve, the outlet port on the servo valve side is The valve housing is provided with a tapered surface forming a constricted portion, and the spool valve is formed with a pressure receiving surface to which high pressure side pressure is applied to the entire surface regardless of displacement of the spool valve due to pressure changes on the reaction force chamber side.

Function> The present invention is such that regardless of the displacement of the spool valve, high pressure side pressure is always applied to the entire pressure receiving surface formed on the spool valve at the throttle part of the servo valve side outlet port, and the servo valve side is low pressure. Also suppresses the displacement of the spool valve in the direction of opening the reaction chamber side passage.

<Example> An example of the present invention will be described below with reference to FIGS. 1 and 2. In FIG. 1, ω is a supply pump driven by an automobile engine. Reference numeral 61 denotes a flow rate control valve that controls the flow rate QO of the pressure oil discharged from the supply pump (a) to a constant flow rate Q. The flow rate control valve 61 is a metering orifice 62 and a bypass valve that is operated according to the front and rear pressure of the metering orifice 62 and controls the opening of a bypass passage 63 communicating with the low pressure side so as to keep this front and rear pressure constant at all times. 64.

A flow divider is connected to the high pressure side of the flow control valve 61. The flow divider 65 divides a constant flow rate Q of pressure fluid from the supply pump ω into a flow rate ψ toward the servo valve 30 and a flow rate toward the reaction force chamber 56 side of the reaction force mechanism having a separate plunger. Note that 15 is a power cylinder, and 70 is an electromagnetic control valve that controls the flow rate part on the reaction force chamber 56 side in accordance with the vehicle speed and the like to control the reaction oil pressure PBfe.

The flow divider 65 according to the present invention has an inlet port portion that introduces a constant flow rate Q of pressure fluid from a supply pump ω into the valve housing (capital), and a first outlet that allows a flow rate ψ to flow toward the servo valve (9) side. It has a port 68 and a second outlet port 69 that allows the flow portion to flow toward the reaction force chamber 56 side. Further, a spool valve 67 is slidably fitted in the inner hole 65cL of the valve nose 80 between the inlet port 85 and the first and second outlet ports. Pressure chambers 86a186b and 86C are formed in the inner hole 6511. The pressure chamber 86g communicates with the pressure chamber 86 through a communication passage 87 provided in the spool valve 67, and the pressure chamber 86b communicates with the pressure chamber 86' through the orifice 66 and the shaft hole of the spool valve 67. ing. Therefore, the spool valve 67 moves depending on the balance between the back and forth pressure of the orifice 66 and the pressing force of the spring, and the spool valve 67 moves between the first and second outlet ports 68.
．． 69, the flow rate ψ, QRj is divided at a constant rate.

Further, as shown in FIG. 2, the valve housing 80J of the outlet port on the servo valve side, that is, the first outlet port 68
A tapered surface 82 forming the constricted portion A is provided, and the spool valve 67 is formed with a pressure receiving surface 83 that receives the high pressure side pressure P1 of the pressure chamber 86b. Note that the outlet port on the reaction force chamber side, that is, the reaction force chamber side passage B of the second outlet port 69 may also be provided with a single taper surface 84 on the valve housing 80 side.

Since the present invention has the structure as described above, the input port 85
A part of the pressure fluid introduced from the pressure chamber 86b into the pressure chamber 86b is guided to the pressure chamber 86α on one end side of the spool valve 67 via the communication passage 87, and at the same time, is introduced into the shaft hole from the orifice 66 bored in the spool valve 67J. the other pressure chamber 8 through the
Guided by 6C. Therefore, the spool valve 67 is slid by the differential pressure between the pressure chambers 86α and 86C and the pressure balance caused by the spring 891, and the spool valve 67 is connected to the first outlet port 68 through the throttle part A and to the second outlet port 69. is reaction chamber side passage B
The flow rate is diverted at a constant rate through the

Therefore, when the pressure on the servo valve 30 side is low (neutral state), the reaction force chamber 5
6 What is the pressure Pl at high pressure (high speed running state) > P
In the GI case, there is no working surface that allows the low pressure side pressure to act on the spool valve 67 and displace the spool valve 67 freely to open the reaction force chamber side passage B, and the spool valve 671 is less likely to be unbalanced. Therefore, it is suppressed that a large amount of flow is diverted to the reaction force chamber side passage B. Also, the pressure change t on the reaction force chamber side
Regardless of the accompanying displacement of the spool valve 67, the high pressure side pressure P1 is always applied to the entire surface of the pressure receiving surface 83, and the gear generated pressure P1 is always applied to the entire surface of the pressure receiving surface 83.
The spool valve 67 is not influenced by the GI and performs a flow diversion action at a predetermined rate.

<Effects of the Invention> As described above, the flow divider according to the present invention has a constricted part of the outlet port on the servo valve side formed with a tapered surface on the valve housing side. The low-pressure side pressure does not act on the spool valve to displace the spool valve in the direction in which the reaction force chamber side passage opens easily, and a large flow rate is prevented from being diverted to the reaction force chamber passage. Also,
Since the spool valve of the throttle part is formed with a pressure receiving surface that receives the high pressure side pressure on the entire surface, the high pressure side pressure always acts on the entire surface regardless of the displacement of the spool valve due to pressure changes on the reaction force chamber side, and the gear The spool valve is no longer displaced by the generated pressure, the unstable phenomenon of flow divider characteristics is eliminated, and the feeling of power steering is improved.

[Brief explanation of the drawing]

Fig. 1 is a pressure fluid circuit diagram of a power steering device to which the flow divider of the present invention is applied, Fig. 2 is a sectional view of main parts of the flow divider of the present invention, Fig. 3 is a characteristic diagram of a conventional flow divider, FIG. 4 is a sectional view of a main part of a conventional flow divider. 65... Flow divider, 67... Fighting spool valve, name... First outlet port, 691111, Second outlet port, (capital)... 9 valve housing, 82...-Tapered surface, 83... ...Pressure receiving surface, δ...Sun entry port.

Claims (1)

[Claims] Pressure fluid introduced from the inlet port is divided at a constant flow rate into the servo valve side and the reaction force chamber side of a power steering device equipped with a reaction force mechanism by a movable spool valve within the inner hole of the valve housing. In a flow divider equipped with two outlet ports, the valve housing of the outlet port on the servo valve side is provided with a tapered surface forming a constriction part, and the spool valve is provided with a tapered surface that forms a constriction part to prevent displacement of the spool valve due to pressure changes on the reaction force chamber side. A flow divider characterized by forming a pressure receiving surface to which high pressure side pressure is applied to the entire surface.