JPH0356456Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] The present invention is a power steering device that increases the steering force applied to the steering wheel and transmits it to the wheels using pressure fluid discharged by a pump driven by a power source. (hereinafter referred to as the PS device), to prevent the occurrence of abnormal noise, especially when the temperature of the operating oil for the PS device is low, such as when starting the engine.
Regarding hydraulic pumps for PS equipment.

[Conventional technology]

FIG. 3 shows a conventional hydraulic pump 1 disclosed in Japanese Unexamined Patent Publication No. 56-146472, and its configuration will be explained below.

Reference numeral 2 designates a pump housing. A valve housing hole 3 is passed through the pump housing 2, and a union 4 is screwed into one end of the valve housing hole 3, and a stopper 5 is fitted into the other end. The union 4 has a substantially cylindrical shape, one end of which is inserted into the valve housing hole 3, and a pressurized fluid outlet 6 connected to a gearbox (not shown) opened at the other end.

The valve storage hole 3 has a supply passage 8 and a bypass passage 1.
The supply passage 8 and the bypass passage 10 are opened and spaced apart from each other in the axial direction, and the supply passage 8 and the bypass passage 10 communicate with a discharge chamber and a suction chamber (both not shown) of the oil pump, respectively. The supply passage 8 is constantly communicated with the valve storage hole 3 through a restriction passage 11 formed in the union 4. The restriction passage 11 is configured such that when the pump discharge amount supplied to the supply passage 8 increases, a pressure difference is generated between the upstream side and the downstream side, that is, between the supply passage 8 and the valve housing hole 3 due to the fluid resistance. It's summery. The bypass passage 10 includes a suction port 12 for sucking oil from a reserve tank (not shown) and sending it to the suction chamber of the oil pump.
is formed with an opening.

Further, in the valve storage hole 3, a flow rate adjustment spool valve 1 is provided in order to close the communication path between the supply path 8 and the bypass path 10 and to adjust the opening degree of the communication path.
3 is slidably inserted, and a first valve chamber 15 and a second valve chamber 16 are formed on both sides of this spool valve 13. The second valve chamber 16 is provided with a compression spring 18 that presses the spool valve 13 toward the first valve chamber 15. The elastic force of the compression spring 18 normally pushes the spool valve 13 toward one end of the union 4. The supply passage 8 is held in a position where it abuts against the supply passage 8 and opens into the first valve chamber 15.
The communication between the bypass passage 10 and the bypass passage 10 is cut off.

A throttle member 20 is fitted into the union 4 in proximity to the outlet 6, and the center of the throttle member 20 communicates with the first valve chamber 15 and the outlet 6 via a fluid passage 24, which will be described later. A throttle passage 21 is formed. The union 4 also has a control spool 22.
is slidably inserted into the control spool 22, and a fluid passage 24 that communicates the first valve chamber 15 and the throttle passage 21 passes through the control spool 22. At one end of the control spool 22, there is a control shaft portion 2 that controls opening and closing of the throttle passage 21.
5 is provided protrudingly. A compression spring 26 is inserted between the control spool 22 and the throttle member 20 in a resilient state, and the resilient force of the compression spring 26 causes the control spool 22 to move against the stepped portion 28 formed in the union 4. The control shaft portion 25 of the control spool 22 is thus spaced apart from the throttle member 20 and opens the throttle passage 21.

When the above-mentioned hydraulic pump 1 is rotated by an engine, working oil in a suction chamber of the oil pump is sucked into the pump chamber, and pressure oil is discharged into a discharge chamber. The pressure oil discharged into the discharge chamber is
From the control passage 11 through the supply passage 8 to the valve storage hole 3
The fluid is supplied to the first valve chamber 15 from which the fluid passes through the fluid passage 24 and the throttle passage 21 to the gearbox (not shown).

While the pump rotation speed is low, the pump discharge flow rate is also small, so the spool valve 13 is connected to the bypass passage 1.
0 is closed, and the entire pump discharge flow rate flows through the throttle passage 2.
1 to the gearbox, but as the pump rotation speed increases, the discharge flow rate also increases.
The spool valve 13 is slid to open the bypass passage 10 so as to keep the pressure difference before and after the throttle passage 21 constant, and excess oil flows from the bypass passage 10 into the suction chamber of the oil pump.

[Problem that the invention attempts to solve]

In such a pump for a PS device, when the temperature of the working oil decreases and the viscosity of the working oil is high, the bypass passage 10 is removed from the suction port 12.
It is difficult for working oil to enter from the reserve tank, and the excess oil that has flowed into the bypass passage 10 creates a negative pressure in the bypass passage 10 near the suction port 12. This causes a phenomenon in which the molten air contained in the hydraulic oil for the PS device comes out in the form of bubbles, so-called cavitation. When this working oil containing air bubbles is sucked into the oil pump, the air bubbles are compressed and locally become extremely high pressure, which hits the flow path and generates noise and vibration, which is a problem. It was hot. Such abnormal noises cause discomfort to the driver and passengers.
The ride wasn't very comfortable either.

This invention prevents abnormal noise by collapsing cavitation bubbles that occur near the suction port of the bypass passage when the temperature of the operating oil for the PS device is low, such as when starting the engine. The purpose of the present invention is to provide a hydraulic pump for PS equipment.

[Means for solving problems]

In order to achieve this objective, the hydraulic pump of the present invention is provided with a throttle valve on the bypass passage wall facing the suction port, so that the throttle valve protrudes into the bypass passage only when the engine is started.

[Effect]

According to the above configuration, as when starting the engine,
When the temperature of the operating oil for the PS device is low, the throttle valve protrudes into the bypass passage to narrow the throttle opening area near the suction port, and the atomizing effect causes the operation from the reserve tank to flow from the suction port into the bypass passage. By increasing the oil flow rate and increasing the pressure in the bypass, air bubbles in the cavitation are crushed and abnormal noise is suppressed.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings. Note that in FIGS. 1 and 2, the same components as those shown in FIG. 3 are given the same reference numerals, and explanations thereof will be omitted.

The hydraulic pump 31 according to the present invention includes a throttle valve 32.
However, the suction port 1 opened to the bypass passage 10
The bypass passage 10 is arranged opposite to the bypass passage 10.
It is slidably inserted into a sliding hole 33 formed in.

A flange portion 32a is formed at the rear of the throttle valve 32, and the flange portion 32a is connected to the sliding hole 3.
3 is slidably inserted into a spring chamber 33a formed in the spring chamber 33a through a sealing member such as a Teflon seal 34, and is pressed by a compression spring 35 housed in the spring chamber 33a. Therefore, the throttle valve 32 is biased in the direction of arrow A by the compression spring 35.

The sliding hole 33 is connected to a switching valve 38 through a pipe 36, and the switching valve 38 is connected to an engine 40 through a pipe 39. Also, the switching valve 38
is connected to a timer 43 by a wiring 41, and the timer 43 is connected to an ignition 46 by a wiring 45.

Next, the operation of one embodiment of the present invention will be explained.

As explained in FIG. 3, when the engine is started, the inside of the bypass passage 10 near the suction port 12 becomes negative pressure, and cavitation bubbles are generated. At this point, the ignition 46 is turned on, the timer 43 is activated, the switching valve 38 is opened, and engine oil flows from the engine 40 into the sliding hole 33 through the pipes 39 and 36. Then, the throttle valve 32 protrudes into the bypass passage 10 against the spring pressure of the compression spring 35, the throttle opening area near the suction port 12 becomes narrower, and the mist flows from the suction port 12 into the bypass passage 10 due to the atomizing effect. The flow rate of working oil from the reserve tank increases. This increases the pressure near the suction port 12 and collapses the cavitation bubbles. Therefore, abnormal noise due to cavitation is eliminated.

After the timer 43 operates for several seconds, the timer 43 stops and the switching valve 38 closes. Then, the flow of engine oil into the sliding hole 33 is stopped, and the throttle valve 32
is returned to the position shown in FIGS. 1 and 2 by the restoring force of the compression spring 35.

At this point, the temperature of the working oil for the PS device is high and the viscosity is low, so the working oil from the reservoir tank smoothly flows into the bypass passage 10 from the suction port 12, and the working oil flows into the vicinity of the suction port 12. does not become a negative pressure, so cavitation does not occur.

[Effect of idea]

As mentioned above, according to the present invention, when the temperature of the working oil for the PS device is low, such as when starting the engine, the cavitation bubbles generated near the suction port of the bypass passage are collapsed by the operation of the throttle valve. As a result, no abnormal noise is generated and therefore no discomfort is given to the driver and fellow passengers, resulting in a comfortable ride.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a hydraulic pump according to the present invention;
FIG. 2 is an enlarged vertical cross-sectional view of the throttle valve and its vicinity of the pump shown in FIG. 1, and FIG. 3 is a vertical cross-sectional view of a conventional hydraulic pump. 8... Supply passage, 10... Bypass passage, 12
...Suction port, 21... Throttle passage, 32...
Throttle valve, 40...engine.

Claims (1)

[Scope of utility model registration request] Pressure oil is sent to the gearbox from a supply passage communicating with the discharge side of the oil pump via a throttle passage, and surplus flow is returned to the suction side of the oil pump via a bypass passage, and is reserved in the bypass passage. A hydraulic pump for a power snake removal device is provided with a suction port that sucks oil from a tank and sends it to the suction side of the oil pump, and a throttle valve is provided on the bypass passage wall facing the suction port, and the engine A hydraulic pump for a power steering device, characterized in that the throttle valve projects into the bypass passage only during startup.