JPH0444874Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a vane pump that reduces noise generated during startup.

[Conventional technology]

FIG. 1 is a circuit diagram showing an example of how a vane pump is used. That is, a vane pump P driven by an electric motor M is installed to supply hydraulic oil from a head tank T whose oil level is higher than that of the vane pump P and cylinder 1 to the cylinder 1 that drives the slide of the press. The electric motor M is a well-known induction motor, which rotates at a substantially constant speed depending on the power supply frequency and the number of poles, and drives the vane pump P at a constant speed. The cylinder 1 has a piston 1A slidably installed to form working chambers 1B and 1C on the head side and rod side, and a piston 1 fixed on the piston 1A.
D are fitted together to form a working chamber 1E, and the working chamber 1B is connected to the head tank T via the prefill valve 2, and the working chambers 1C and 1E are connected to the switching valve 5 through passages 3 and 4. . Furthermore, passage 4
A counterbalance valve 6 with a check valve is provided, and a switching valve 7 for switching between fast feed and slow feed is provided between the passage 3 and the working chamber 1B.

Then, when the vane pump P is driven in the state shown in FIG. 1 and the switching valve 5 is switched from the neutral position shown in the figure where the vane pump P is in the unloaded state to the right position, hydraulic oil from the vane pump P is supplied to the working chamber 1E. , the hydraulic oil in the working chamber 1C is returned to the head tank T through the counterbalance valve 6, the piston 1A descends in a fast forward state, and hydraulic oil is supplied to the working chamber 1B from the head tank T through the pre-fill valve 2. . The head tank T applies head pressure to the hydraulic oil so that a large amount of oil can be supplied to accommodate the rapid movement of the piston 1A.
During the descent of the piston 1A, when the switching valve 7 is also switched from the normal position shown in the figure, hydraulic oil is supplied from the vane pump P to the working chamber 1B, and at the same time, the prefill valve 2 closes and the supply from the head tank T is stopped, and the piston 1A is in a slow feed state and processing is performed. After the machining is completed, when the switching valve 7 is switched to the normal position shown in the figure and the switching valve 5 is switched to the left position, the working chamber 1
Hydraulic oil is supplied to C from the vane pump P, and the hydraulic oil in the working chamber 1B is opened to the prefill valve 2.
Furthermore, the hydraulic oil in the working chamber 1E is supplied from the switching valve 5.
Each is returned to the head tank T, and the piston rises.

[Problem that the invention attempts to solve]

However, in this case, when the vane pump P was started by the electric motor M in an unloaded state with the switching valve 5 at the neutral position shown in the figure, high noise was generated from the vane pump P for a while after starting.

This is due to the following circumstances. In general, the vane pump P has a discharge passage provided inside the vane for distributing the discharged hydraulic oil inside the vane in a vane groove of a rotor that accommodates the vane, as described in Japanese Utility Model Publication No. 51-25765, for example. By connecting, a pressure higher than that of the suction passage is applied to the inner end of the vane, and in addition to centrifugal force, the vane is pushed outward in the direction of contact with the cam ring. is able to sink into the vane groove due to its own weight, and most of the vanes are separated from the cam ring. Therefore, at the beginning of startup, there are few vanes that can be held in contact with the cam ring and contribute to the pumping action, and the motor M rapidly Although the rotational speed reaches a constant constant speed, since the discharge amount is small, the pressure in the discharge passage caused by the flow resistance does not become very large, and the outward pressing force acting on the vanes is small. In addition, the hydraulic oil to be sucked is given head pressure by the head tank T.
Since head pressure acts on the outer ends of the vanes to move the vanes inward, outward movement of the vanes is inhibited and it is not possible to quickly maintain all the vanes in contact with the cam ring. Furthermore, this means that when the vane, which is away from the cam ring, moves from the suction area to the discharge area of the cam ring as the rotor rotates, the outer end collides with the discharge cam surface of the cam ring and bounces off, and the vane moves away from the cam ring again and into the vane groove. By immersing yourself inside, it is further amplified,
This collision of the vanes that are separate from the cam ring generates noise, and the noise is generated if the collision situation is not resolved quickly. The reason for this noise generation is that as time passes and the number of vanes that are held in contact with the cam ring and can contribute to the pumping action increases, the discharge amount increases, and the pressure in the discharge passage caused by the flow resistance also increases, causing outward pressure. This is a phenomenon peculiar to startup that eventually resolves itself as the pressure increases, forcing the vanes to come into even more contact with the cam ring.At low temperatures, the viscosity of the hydraulic oil is high, and sliding resistance to the vanes increases. It was more noticeable in winter when it grew larger.

The present invention aims to reduce the noise generated by the vane pump during startup by increasing the force that presses the vane outward and holding the vane in contact with the cam ring for a short period of time.

[Means to resolve the problem]

For this reason, the vane pump of the present invention has a casing that is internally equipped with a rotor, a cam ring installed on the outer circumference of the rotor, and vanes that are accommodated in vane grooves provided circumferentially in the rotor and whose outer ends can abut against the cam ring. The suction port connected to the suction path and the discharge port connected to the discharge path are open on the outer surface of the casing, and the suction pipe and the discharge pipe are screwed into the inner periphery of the suction port and the discharge port. A female threaded section is provided that allows connection by attaching the suction pipe to the outer surface of the casing where the suction port and discharge port open, and the suction pipe and discharge pipe can also be connected by attaching a flange that is fixed to each pipe end. A flange attachment part is provided, and the inside of the vane groove is connected to the discharge passage inside the vane.A throttle forming body with a throttle hole formed through it is screwed into the concave part of the discharge port, and the discharge piping is connected to the discharge passage. The connection is made using a flange attachment part.

[Effect]

According to such a configuration, when the vane pump is activated and circulation occurs in the discharge passage, the pressure in the discharge passage increases due to the throttling action of the throttle hole of the throttle forming body screwed onto the discharge port. This increased pressure is introduced inside the vane in the vane groove and acts on the vane, creating a large force that pushes the vane outward, allowing the vane to be held in contact with the cam ring in a short time. Noise during startup is reduced.

〔Example〕

Hereinafter, one embodiment of the vane pump of the present invention, which is used as shown in FIG. 1, will be explained with reference to the drawings.

In Figures 2 to 7, vane pump P
Inside the casing P1, which consists of a main body 10 and end covers 11 and 12, is provided a rotor 13 spline-fitted to a drive shaft 14, and a plurality of vane grooves 15 provided in the circumferential direction of the rotor 13 have an outer end. Cam ring 1
The vane 16 is slidably housed so as to be able to come into contact with the vane 7 . The cam ring 17 has two discharge cam surfaces 17A and two suction cam surfaces 17B, and is installed on the outer periphery of the rotor 13. 18 and 19 are side plates provided on both sides of the cam ring 17 and the rotor 13. Each side plate 18 has two discharge holes 18A.
A suction notch 18B is provided at a position corresponding to the discharge cam surface 17A and the suction cam surface 17B, and an annular recess 18D communicating with the discharge hole 18A through a passage 18C is provided in the vane 16 in each vane groove 15.
It is provided inwardly so as to constantly communicate with the entire circumferential area of the rotor 13 in the rotational direction. Moreover, on the side plate 19,
It has a recess 19A at a position corresponding to the discharge hole 18A, a suction notch 19B at a position corresponding to the suction notch 18B, and an annular recess 19D corresponding to the annular recess 18D. Reference numeral 20 denotes a guide hole that forms a discharge path 21 together with each discharge hole 18A;
A discharge port 22 connected to the main body 10 is opened to the main body 10 . Reference numeral 23 denotes a guide hole that forms a suction passage 24 together with the suction notches 18B and 19B, and a suction port 25 connected to the suction passage 24 opens into the main body 10. The inner periphery of the discharge port 22 and the suction port 25 has a female threaded portion 22 to which a discharge pipe (not shown) and a suction pipe (not shown) can be screwed and connected.
A, 25A. And the discharge port 22,
On the outer surface of the main body 10 where the suction port 25 opens, flanges 26 and 27, which are fixed to the ends of the discharge piping and suction piping by screwing, are screwed into screw holes 28 (see FIG. 7). Discharge piping and suction piping can also be connected by attaching with bolts 29.
Flange attachment parts 22B and 25B are formed. Reference numeral 30 denotes a disk-shaped diaphragm forming body with a diaphragm hole 30A formed therethrough, which is screwed onto the female threaded portion 22A formed for connecting the discharge pipe to the discharge port 22. installed. Note that 30B is a tool engaging portion provided for attaching and detaching the aperture forming body 30. Then, the suction pipe from the head tank T shown in FIG. The discharge piping to the switching valve 5 shown in FIG.
6 to the flange attachment part 22B with bolts 29.
It is connected by attaching it to the

Next, the operation of this embodiment will be explained.

The vane pump P is started by the electric motor M with the switching valve 5 in the neutral state as shown in FIG. At this time,
When stopped, each vane 16 can sink into the vane groove 15 due to its own weight, so only a portion of the vanes 16 are in contact with the cam ring 17, and immediately after starting, all the vanes 16 do not contribute to the pumping action. A pumping action is obtained by some of the vanes 16, and hydraulic oil flows through the discharge passage 21, and the throttle hole 30A
The pressure increases in the discharge passage 21 due to the throttling action. The inside of the vane 16 in each vane groove 15 is
Since it is connected to the discharge hole 18A of the side plate 18 through the annular recess 18D and the passage 18C, this rising pressure is introduced and acts on the inner end of each vane 16 and presses it outward with centrifugal force. Although the head pressure from the cam ring 17 acts to move the vanes 16 inward, each vane 16 is pressed outward with a large force and is quickly held in contact with the cam ring 17. That is, due to the effect of the increased pressure introduced through the annular recess 18D, the vane 16 that is in contact with the cam ring 17, which can contribute to the pumping action, increases and the discharge amount increases, and accordingly, the pressure due to the throttle hole 30A increases. As the rise increases, more and more vanes 16 come into contact with the cam ring 17, so that a state in which all of the vanes 16 are held in contact with the cam ring 17 can be achieved in a short period of time. This prevents the vane 16, which is separated from the cam ring 17, from continuously colliding with the discharge cam surface 17A for a long period of time, and the noise during startup is significantly reduced.

Since the throttle hole 30A exerts a throttling action even after a steady driving state of the vane pump P is obtained in which the entire vane 16 is held in contact with the cam ring 17 and contributes to the pumping action, an extreme throttling action causes a large power loss. This is not desirable, and it is necessary to determine the hole diameter after determining through testing whether the diameter of the aperture hole 30A can provide sufficient noise prevention.
In this example, a sufficient effect could be obtained if the hole diameter was such that a pressure difference of about 2 kg/cm ² was generated when the vane pump P was in a steady state of operation. Regarding the throttle hole 30A, if you understand the relationship between the through flow rate and the hole diameter in advance with respect to the allowable differential pressure, even when selecting electric motors M with different rotational speeds according to various discharge volume requirements. The aperture hole 30A having an appropriate diameter can be easily obtained by simply screwing the aperture forming body 30 with an appropriately determined aperture diameter into the female threaded portion 22A of the discharge port 22. Since it does not require any adjustment work, it is easy to handle. When installing the aperture forming body 30, since the female threaded portion 22A provided to connect the discharge pipe is used, the vane pump P
There is no need for any special processing.

In this embodiment, the inside of each vane groove 15 inside the vane 16 is always connected to the discharge passage 21 by the annular recess 18D over the entire circumference in the rotational direction of the rotor 13. The connection between the inside of the vane in each vane groove and the discharge path is made only in the area corresponding to the discharge cam surface of the cam ring.
It can also be applied to a case where the process is limited to a part of the circumference in the rotational direction of the rotor, as in Japanese Patent No. 16407.

[Effect of idea]

In this way, the present invention has a casing that includes a rotor, a cam ring installed on the outer periphery of the rotor, and vanes that are accommodated in vane grooves provided in a plurality of circumferential directions on the rotor and whose outer ends can come into contact with the cam ring. The suction port connected to the suction path and the discharge port connected to the discharge path are open on the outer surface of the casing, and suction piping and discharge piping are screwed to the inner periphery of the suction port and discharge port. It is also possible to connect the suction piping and discharge piping by attaching flanges that are fixed to the ends of each piping on the outer surface of the casing where the suction and discharge ports open. A flange attachment part is provided to connect the inside of the vane groove to the discharge passage on the inside of the vane, and a diaphragm forming body with a diaphragm hole formed through it is screwed into the female threaded part of the discharge port, and the discharge piping is attached to the flange. This is a vane pump that is connected using a mounting part, and when the vane pump is started and circulation occurs in the discharge path,
The pressure in the discharge passage increases due to the throttling action of the throttling hole in the throttling body screwed onto the discharge port, and this increased pressure is introduced into the vane inside the vane groove, causing a large amount of pressure that pushes the vane outward. Power is obtained, the vane can be held in contact with the cam ring in a short time, and noise during startup is reduced. The diaphragm forming body is easy to handle because it is simply screwed onto the female threaded portion of the discharge port and does not require any adjustment work.
Further, when installing the aperture forming body, since the female threaded portion provided to connect the discharge pipe is utilized, there is no need to perform any special processing on the vane pump.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an example of the use of a vane pump, Figs. 2 to 7 show an embodiment of the present invention, Fig. 2 is a sectional view taken along the line - of Fig. 7, and Fig. 3 is FIG. 4 is a front view of the aperture forming body 30, FIG. 5 is a front view of the side plate 18, and FIG. 6 is a partially enlarged sectional view taken along the line - of FIG. 2. , FIG. 7 is a front view of the vane pump P. 13... Rotor, 15... Vane groove, 16...
Vane, 17...cam ring, 21...discharge path,
22...Discharge port, 22A, 25A...Female thread part,
22B, 25B...flange attachment part, 24...
... Suction path, 25 ... Inlet, 26, 27 ... Flange, 30 ... Throttle forming body, 30A ... Throttle hole,
P... Vane pump, P1... Casing.

Claims (1)

[Scope of utility model registration request] The casing has a rotor, a cam ring installed on the outer periphery of the rotor, and a vane that is housed in a plurality of vane grooves provided in the circumferential direction of the rotor and whose outer end can be brought into contact with the cam ring. The suction port that connects to the passage and the discharge port that connects to the discharge passage are open on the outer surface of the casing, and the suction pipe and the discharge pipe can be connected to the inner periphery of the suction port and the discharge pipe by screwing. A flange attachment part is provided on the outer surface of the casing where the suction port and discharge port open, and the suction pipe and the discharge pipe can also be connected by attaching a flange that is fixed to each pipe end. , the inside of the vane groove is connected to the discharge path inside the vane, and the female threaded part of the discharge port has a
A vane pump in which a diaphragm forming body with a diaphragm hole formed through it is screwed on, and the discharge piping is connected using a flange attachment part.