JPH09195929A - Oil pressure pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce pulsation of discharge pressure by providing a pulsation/ noise reducing extended chamber to either a suction passage extended from the suction port of a pump caging assembly to a pump chamber or a discharge passage extended from the pump chamber to the discharge port. SOLUTION: A suction passage 49 through which a suction port 7 and a pump chamber 13 are communicated with and connected to each other, and a discharge passage 51 through which a discharge port 9 and the pump chamber 13 are communicated with and connected to each other, are formed as internal passages in a casing main body 1. Pulsation/noise reducing extended chambers 53, 55 are respectively arranged on the way the suction passage 49 and the discharge passage 51, that is, on the way of internal channels between the suction port 7 and the pump chamber 13 and the pump chamber 13 and the discharge port 9. The extended chambers 53, 55 are equipped with end members 61, 63 for varying the capacities of the extended chambers 53, 55 and extended chamber capacity adjusting screws 65, 67 for regulating a position in a depth direction. Hereby, the extended chambers 53, 55 reduce pulsation in a specific frequency range in a pump casing assembly 1 by mutual interference action between incident pressure wave and reflective pressure wave.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic pump, and more particularly to a hydraulic pump used as a hydraulic pressure generator in a hydraulic system such as construction machinery, industrial machinery and machine tools.

[0002]

2. Description of the Related Art Hydraulic pumps used as hydraulic pressure generators in hydraulic systems such as construction machinery, industrial machinery, machine tools, etc.
There are piston pumps, vane pumps, trochoid pumps, and gear pumps. Any of these hydraulic pumps causes pulsation in the discharge pressure, which causes vibration and noise from the hydraulic pump due to pulsation during pump operation.

This noise / vibration deteriorates the working environment and also affects the machining accuracy in a machine tool. Especially in a super-precision machine tool, in order to maintain the required accuracy, noise / vibration generated by a hydraulic pump is used. It is essential to take measures to reduce it.

Conventionally, noise and vibration of a hydraulic pump have been reduced by covering the hydraulic pump with a soundproof cover or attaching an accumulator.

[0005]

In order to reduce the noise and vibration as described above, a soundproof cover, an accumulator, etc.
A separate member and device are required, and it also takes up space for installing the soundproof cover and the accumulator, which also increases the cost.

In addition, none of them reduces the pulsation of the discharge pressure, which causes noise and vibration, at the source, so that noise and vibration cannot be effectively reduced.

The present invention has been made by paying attention to the above-mentioned problems, and effectively reduces the pulsation of the discharge pressure near the source, and eliminates the need for a separate material or device. -The purpose is to provide a hydraulic pump with vibration reduction measures.

[0008]

To achieve the above object, a hydraulic pump according to claim 1 of the present invention comprises a suction passage extending from a suction port formed in a pump casing assembly to a pump chamber and a pump chamber. It is characterized in that an expansion chamber for reducing pulsation and noise is formed in at least one of the discharge passages reaching the discharge port.

In this hydraulic pump, the expansion chamber has the suction passage formed between the suction port and the pump chamber formed in the pump casing assembly, and / or the discharge passage formed between the pump chamber and the discharge port. The pulsation in a specific frequency range is reduced in the pump casing assembly by the same principle as that of the expansion silencer.

Examples of hydraulic pumps into which this expansion chamber can be incorporated include piston pumps, vane pumps, trochoid pumps and gear pumps.

According to a second aspect of the present invention, in the hydraulic pump according to the first aspect, the expansion chamber has a bore chamber formed in the pump casing assembly, and a depth direction of the bore chamber. An end member that movably engages to variably set the volume of the expansion chamber, and an expansion chamber volume adjusting screw that is screwed into the pump casing assembly to define the position of the end member in the depth direction by the screwing amount. It is characterized by being.

In this hydraulic pump, the position of the end member in the depth direction can be changed by the screwing amount of the expansion chamber volume adjusting screw, so that the expansion chamber volume is variably set and the pulsation reducing frequency range is set to the optimum value. Can be tuned to.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows one embodiment in which the hydraulic pump according to the present invention is applied to a swash plate type piston pump. The swash plate type piston pump has a pump casing assembly 5 composed of a casing body 1 and a cover member 3, an intake port 7 and a discharge port 9 are formed in the casing body 1, and a crank chamber 11 is defined inside the cover member 3. ing.

A cylinder block 15 having a pump chamber (cylinder chamber) 13 in the crank chamber 11, and a pump chamber 1
3, a piston 17 reciprocally arranged, a port plate 19 having a pump valve (not shown), a valve body 23 having a pressure adjusting spool valve 21 incorporated therein, and the like are arranged.

The pump casing assembly 5 includes the crank chamber 1
A rotary drive shaft 25 extending across the inside of the bearing member 2
It is rotatably supported by 7, 29. The swash plate 33 is attached to the rotary drive shaft 25 by the pivot 31.
Are connected so that the mounting angle can be changed. The swash plate 33 is connected to the piston 17 by a spherical joint type connecting portion 35, and is rotationally driven by the rotary drive shaft 25 to reciprocally drive the piston 17 with a stroke determined by an attachment angle.

The swash plate 33 is engaged with a mounting angle setting yoke member 37. The mounting angle setting yoke member 37 has a valve body 23 at the upper end in FIG.
The operation rod 39 provided on the
1 is urged to the left by the discharge amount adjusting screw 43
By adjusting the axial position of the operating rod 39, the tilt angle is changed and the mounting angle of the swash plate 33 is variably set.

A pressure adjusting screw 47 for changing the set pressure of the spring 45 acting on the pressure adjusting spool valve 21 is attached to the pump casing assembly 5.

The casing body 1 is provided with an intake passage 49 for connecting the suction port 7 and the pump chamber 13 to each other and a discharge passage 51 for connecting the discharge port 9 and the pump chamber 13 to each other as internal passages. .

In the middle of the suction passage 49 and the discharge passage 51,
In other words, expansion chambers 53 and 55 for reducing pulsation and noise are respectively provided in the internal flow paths between the suction port 7 and the pump chamber 13 and between the pump chamber 13 and the discharge port 9. Has been formed.

The expansion chambers 53, 55 are engaged with bore chambers 57, 59 formed in the casing body 1 and end members for variably setting the expansion chamber volume by movably engaging in the depth direction of the bore chambers 57, 59. 61 and 63, and expansion chamber volume adjusting screws 65 and 67 that are screwed into screw holes 65 and 67 formed in the casing body 1 to define the depth direction positions of the end members 61 and 63 by screwing amounts. ing.

The expansion chambers 53 and 55 include the suction port 7, the discharge port 9, the suction passage 49 and the discharge passage 51 in the normal part.
Has a cross-sectional area sufficiently larger than the cross-sectional area of the passage of the end member 61, by the expansion chamber volume adjusting screws 65, 67.
The expansion chamber volume (cavity volume) is variably set by defining the position of 63 in the depth direction.

The expansion chambers 53 and 55 reduce the pulsation in a specific frequency range in the pump casing assembly 1 by the same principle as that of the expansion silencer, that is, by the mutual interference action of the incident pressure wave and the reflected pressure wave. .

As a result, the pulsation of the discharge pressure is effectively reduced near the source, and noise and vibration are reduced without the need for a separate material such as a soundproof cover or accumulator, or a device.

Further, the expansion chamber volumes of the expansion chambers 53 and 55 are variably set by the screwing amounts of the expansion chamber volume adjusting screws 65 and 67. Therefore, the pulsation reducing frequency is adjusted by adjusting the screwing amounts of the expansion chamber volume adjusting screws 65 and 67. The range can be easily tuned to the optimum value.

The hydraulic pump according to the present invention is not limited to the piston hoop as described above, but can be applied to a vane pump, a trochoid pump, a gear pump and the like.

In the above, the present invention has been described in detail with respect to a specific embodiment. However, the present invention is not limited to this, and various embodiments may be made within the scope of the present invention. The possibilities will be clear to the skilled person.

[0028]

As can be understood from the above description, according to the hydraulic pump of the first aspect, the expansion chamber reduces the pulsation in the specific frequency range within the pump casing assembly by the same principle as that of the expansion silencer. The pulsation of the discharge pressure is effectively reduced near the source, and noise and vibration are reduced without the need for a soundproof cover, a separate material such as an accumulator, or a device.

According to the hydraulic pump of the second aspect,
Since the expansion chamber volume is variably set according to the screwing amount of the expansion chamber volume adjusting screw, the frequency range of pulsation reduction can be easily tuned to the optimum value.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment in which a hydraulic pump according to the present invention is applied to a swash plate type piston pump.

[Explanation of symbols]

 5 Pump casing assembly 7 Suction port 9 Discharge port 11 Crank chamber 13 Pump chamber 17 Piston 21 Pressure adjustment spool valve 25 Rotation drive shaft 33 Swash plate 37 Mounting angle setting yoke member 43 Discharge amount adjusting screw 47 Pressure adjusting screw 49 Intake Passage 51 Discharge passage 53,55 Expansion chamber 57,59 Bore chamber 61,63 End member 65,67 Expansion chamber volume adjusting screw

Claims (2)

[Claims] 1. An expansion chamber for reducing pulsation and noise is formed in at least one of a suction passage extending from a suction port formed in a pump casing assembly to a pump chamber and a discharge passage extending from the pump chamber to a discharge port. A hydraulic pump characterized by 2. The expansion chamber, a bore chamber formed in the pump casing assembly, an end member movably engaged in the depth direction of the bore chamber to variably set the volume of the expansion chamber, The hydraulic pump according to claim 1, further comprising: an expansion chamber volume adjusting screw that is screwed into the pump casing assembly to define the position of the end member in the depth direction according to the screwing amount.