JPH04103264U - radial plunger pump - Google Patents

Abstract

(57) [Summary] [Purpose] To alleviate the surge pressure that occurs at the start of the suction stroke,
Reduces vibration and noise caused by surge pressure. [Structure] A bottomed cylindrical plunger 13 housed in a cylinder 11 is reciprocated by a cam 8.
A radial plunger pump configured to pressurize and discharge liquid introduced into a pump chamber 18 through a suction hole 17 formed in a plunger 13 with a plunger 13.
When the plunger 13 moves to a predetermined position, the suction hole 1 of the plunger 13
A liquid reservoir chamber 12 communicating with the cylinder 11 is formed in the cylinder 11. As a result, while the plunger 13 finishes the discharge stroke and moves to the suction stroke, the liquid in the liquid reservoir chamber 12 is supplied to the pump chamber 18 through the suction hole 17, thereby alleviating cavitation.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This idea was developed to supply pressure to automobile power steering systems, suspension systems, etc. It relates to a radial plunger pump used as a supply source.

0002

[Conventional technology]

Conventionally, this type of radial plunger pump has a cylinder 1 as shown in FIG. A bottomed cylindrical plunger 13 housed in 1 is reciprocated by a rotating cam 8, and the plunger The hydraulic fluid is pumped into the plunger chamber (pump chamber) through the suction hole 17 formed in the body 16 of the plunger 13. ), this hydraulic fluid is pressurized and discharged into the discharge passage (for example, (See Japanese Patent Application Laid-Open No. 58-15769).

0003

[Problem that the idea aims to solve]

However, in such a conventional example, the plunger 13 discharges at the top dead center. After completing the stroke, the suction hole 17 of the plunger 13 opens into the suction chamber 9 (i.e., the suction Until the transition to the entry stroke), hydraulic fluid is supplied from the outside into the plunger chamber 18. As a result, the liquid within the plunger chamber 18 causes cavitation. And suck The inlet hole 17 opens into the suction chamber 9, and liquid is introduced into the plunger chamber 18 to fill the cavity. When the vibration disappears, a large surge pressure (impact) is generated, causing vibration and noise. There was a problem with it.

0004

[Means to solve the problem]

This invention was devised to solve the problems of the above-mentioned conventional technology, and A bottomed cylindrical plunger housed in a cylinder is reciprocated by a cam, and the body of the plunger The liquid introduced into the pump chamber through the formed suction hole is pressurized with a plunger and discharged. A radial plunger pump configured to project the plunger, the plunger being in a predetermined position. A liquid reservoir chamber is formed in the cylinder that communicates with the suction hole of the plunger when it is moved to the position. It is characterized by

[0005]

[Effect]

During the pressurization and discharge stroke of the plunger, some of the liquid in the pump chamber passes through the suction hole. and flows into the liquid reservoir chamber. Then, the plunger completes the pressurization and discharge stroke and During the transition to the input stroke, liquid is supplied from the liquid reservoir chamber to the pump chamber through the suction hole. do.

[0006]

【Example】

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

[0007] In FIG. 1, 1 is a housing (cylinder block), and this housing 1 A pump drive shaft 4 is rotatably supported via bearings 2 and 3. This pump drive A cam body 5 is formed on the driving shaft 4, and a bearing 6 is provided on the outer periphery of the cam body 5. A cam seat 7 is fitted thereto to form a cam 8.

[0008] Reference numeral 9 is an annular suction chamber formed in the housing 1, and this suction chamber 9 is driven by a pump. It is formed coaxially with the shaft 4. A predetermined gap is formed between this suction chamber 9 and the cam 8. The hydraulic fluid flows in from a pipe (not shown) through the suction passage 10. It is supposed to be done. A plurality of cylinders are arranged approximately radially on the outer circumferential side of this suction chamber 9. A cylinder 11 is formed. This cylinder 11 is opened to the suction chamber 9, An annular liquid reservoir chamber 12 is formed at a predetermined distance from this opening end. stop A bottomed cylindrical plunger 13 is slidably housed inside this cylinder 11. It has been accommodated. This plunger 13 has its bottom 14 pressed against the cam 8 by a spring 15. A plurality of suction holes 17 are formed in the body portion 16. This suction hole 17 , the suction chamber 9 and the plunger chamber (pump chamber) 18 are connected near the bottom dead center of the plunger 13. The hydraulic fluid in the suction chamber 9 is introduced into the plunger chamber 18. In addition, when the plunger 13 moves a predetermined amount within the cylinder 11, the suction hole 17 closes the cylinder. It opens into the liquid reservoir chamber 12 formed in the plunger chamber 11, and the inside of the liquid reservoir chamber 12 and the plunger chamber 18. communicate with. 19 is a plug screwed onto the end of the cylinder 11; 19 closes the external open end of the cylinder 11. And this plug 19 A retainer 20 is engaged with the lower surface of the head of the spring 15. It is designed to both support and guide its movements. 21 is shaped into housing 1 This is the discharge path created. One end of this discharge passage 21 is a pressure chamber at the end of the cylinder 11. 22, and the other end communicates with a hydraulic pipe line 24 via a check valve 23. It is formed like this.

[0009] In addition, 25 is a sealing device, and this sealing device 25 is located outside the bearing 2. This is a sealing device that seals between the housing 1 and the pump drive shaft 4.

0010 According to the above embodiment structure, the pump drive shaft 4 is powered by a power source not shown (for example, an engine). ), and when the plunger 13 comes to a position near the bottom dead center, the suction hole 17 opens. It opens into the entry chamber 9, and liquid is sucked into the plunger chamber 18. The pump drive shaft 4 is , the plunger 13 is pushed up by a predetermined amount by the cam 8, and the suction hole 1 7 and the suction chamber 9 is cut off, the suction stroke ends, and then the pressurization and discharge stroke begins. Transition. Then, in the middle of this pressurization/discharge stroke, the suction hole 17 opens into the liquid reservoir chamber 12. A part of the liquid in the plunger chamber 18 flows into the liquid reservoir chamber 12 through the suction hole 17. Inflow. Also, the suction hole 17 of the plunger 13 may be blocked by the wall of the cylinder 11. The liquid introduced into the plunger chamber 18 is transferred to the plunger 1 until it reaches the top dead center. 3 to pressurize it, push open the check valve 23, and let the liquid flow from the discharge path 21 to the hydraulic pressure pipe 24. Exhale the body.

[0011] When this discharge stroke is completed and the plunger 13 is moving from the top dead center to the bottom dead center, The suction hole 17 of the plunger 13 opens into the liquid reservoir chamber 12 of the cylinder 11, and Liquid flows from 12 into plunger chamber 18 through suction hole 17 .

0012 In this way, according to this embodiment, from the discharge stroke to the suction stroke, the external Hydraulic fluid is not supplied from the cylinder into the plunger chamber 18, but the plunger 13 When the chamber 11 is moved to a predetermined position, the liquid in the liquid reservoir chamber 12 flows through the suction hole 17. Since it is supplied into the plunger chamber 18, cavitation is alleviated and the suction hole is 17 opens into the suction chamber 9 (at the start of the suction stroke), the surge pressure (shock) that occurs is relaxed. vibration and noise are suppressed.

[0013]

[Effect of the idea]

As explained above, the present invention allows the plunger to move inside the cylinder to a predetermined position. Then, the liquid reservoir formed in the cylinder is pumped through the suction hole in the body of the plunger. Since it is connected to the chamber, the pressurization/discharge stroke shifts to the suction stroke. During the process, hydraulic fluid is supplied from the fluid reservoir chamber to the pump chamber, and cavitation is slowed down. The surge pressure (impact) that occurs at the start of the suction stroke is alleviated. Therefore, this The vibration and noise caused by the surge pressure that occurs at the start of the suction stroke can be reduced. Wear.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a radial plunger pump showing an embodiment of the present invention.

FIG. 2 is a sectional view of main parts of a conventional radial plunger pump.

[Explanation of symbols]

8...Cam 11...Cylinder 12...Liquid reservoir chamber 13...Plunger 16...Torso 17...Suction hole 18...Pump room (plunger room)

Claims (1)

[Scope of utility model registration request] Claim 1: A bottomed cylindrical plunger housed in a cylinder is reciprocated by a cam, and liquid introduced into a pump chamber through a suction hole formed in the body of the plunger is pressurized by the plunger and discharged. In the radial plunger pump, when the plunger moves to a predetermined position,
A radial plunger pump characterized in that a cylinder is formed with a liquid reservoir chamber that communicates with a suction hole of a plunger.