JPH04103268U - plunger type pump - Google Patents

Abstract

(57) [Summary] [Purpose] To discharge air bubbles in a pressurized chamber with a simple structure and without reducing the effective stroke of the plunger piston. [Structure] A groove is provided on the outer periphery of the plunger piston, and a gas vent hole that communicates with the cam chamber is provided in the plunger case. The groove portion communicates with the pressurizing chamber near the bottom dead center, and communicates with the gas vent hole near the top dead center.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

The present invention relates to plunger type pumps, particularly for vehicle anti-lock brake systems. Control systems that require high hydraulic pressure, such as systems and traction control systems It is mixed in the pressurizing chamber of a radial plunger type pump that generates high liquid pressure, which is suitable for use in This allows the air bubbles that enter to escape easily.

0002

[Conventional technology]

Conventionally, for example, systems that suppress brake fluid pressure in vehicles (anti-lock blocks) have been used. When high hydraulic pressure is required as a power source for a rake system), a pressurized chamber is used. A radial plunger type pump with suction and discharge valves is used.

0003 As the above-mentioned radial plunger type pump, for example, There is a type described in Japanese Utility Model Application Publication No. 63-048543.

0004 The above radial plunger type pump has a cam filled with hydraulic fluid as shown in Figure 5. An eccentric cam 2 is rotatably arranged in a chamber 1, and an eccentric cam 2 is arranged in the plunger case 3 in the direction of the axis L1. is housed so as to be slidable in the direction, and one end is elastically biased and abuts against the eccentric cam 2, The suction flow is reciprocated according to the rotation of the eccentric cam 2 and is provided along the axis L1. A plunger piston 5 with a passage 4 is provided.

[0005] Inside the plunger case 3, hydraulic fluid is pressurized at the bottom of the plunger piston 5. A pressurized chamber 6 is provided between the upper end of the pressurized chamber 6 and the suction liquid path 4, and the suction liquid path 4 is closed with a spring. The suction valve 9 is biased in the closing direction between the lower end of the pressurizing chamber 6 and the discharge port. The discharge valve 10 is equipped with a discharge valve 10 energized.

[0006] During operation, the plunger piston 5 moves toward one side (arrow A) as the eccentric cam 2 rotates. side), the hydraulic fluid in the cam chamber 1 passes through the suction flow path 4 and the suction valve 9. The fluid is sucked into the pressurizing chamber 6, and at this time, the cam chamber 1 filled with hydraulic fluid and the pressurizing chamber 6 are The gap is sealed by substantially the entire outer surface of the plunger piston 5. Also, When the plunger piston 5 moves to the other side (arrow B side in the figure), the hydraulic fluid in the pressurizing chamber 6 It is compressed and becomes a high-pressure liquid, which opens the discharge valve 10 and is discharged to the discharge port.

[0007]

[Problem that the idea aims to solve]

Generally, the high fluid pressure generated by plunger-piston type pumps, such as those described above, It is stored in a gas-filled pressure accumulator and used in small doses. In this case, inside the pressure accumulator The filled gas passes through the partition wall made of rubber plastic that partitions the inside of the pressure accumulator, and reaches high pressure. It is known that it melts into liquid. As mentioned above, the sealed gas melts into the liquid In the middle of the hydraulic fluid circulation cycle, that is, after using high pressure, the hydraulic fluid is at atmospheric pressure. When returning to the working fluid, the volume of the melted gas expands based on Boyle's law Then, it becomes bubbles and flows into the reservoir together with the reflux liquid.

[0008] As mentioned above, bubbles of melted gas that flowed into the reservoir diffuse into the atmosphere and settle down. If the air bubbles are sucked back into the pressurized chamber 6 before, the hydraulic pump will normally Since the design is based on the assumption that the pressure inside the pressurizing chamber 6 will not increase, This will lead to a serious situation where the pump function will be interrupted.

[0009] In contrast, for example, as shown in Japanese Utility Model Application Publication No. 63-170578, the present applicant A bubble removal passage is provided inside the plunger piston, and the plunger piston is at top dead center. When the pressurized chamber is in the vicinity, the pressurized chamber is communicated with the atmosphere-open liquid storage chamber through the air bubble passage. The company provides a plunger pump that discharges air bubbles from a pressurized chamber.

0010 However, in the above configuration, there is a complex-shaped gas inside the plunger piston. Processing is somewhat complicated because it is necessary to drill a bubble blowing passage. Also, in a short time However, since the pressurized chamber and the atmosphere-open reservoir chamber communicate with each other, the plunger piston There is a problem that the effective stroke becomes smaller.

[0011] This invention was made to solve the problems with conventional pumps as described above. It has a simple structure and reduces the effective stroke of the plunger piston. A plunger-type port that allows air bubbles mixed into the pressurized chamber to be discharged without causing any damage. The purpose is to provide a sample.

0012

[Means to solve the problem]

Therefore, the present invention has a cam chamber filled with hydraulic fluid and a cam chamber formed in communication with the cam chamber. The plunger case mounting hole, the eccentric cam rotatably arranged in the cam chamber, and the Plunger case installed in the plunger case mounting hole and the above plunger case The plunger is slidably housed in the sliding part of the plunger, and its tip is brought into contact with the eccentric cam. It slides in the axial direction according to the rotation of the eccentric cam, and the suction penetrating through the axial direction A plunger piston with an inflow passage and the above plunger piston are connected from the pressurized chamber side. When moving to the eccentric cam side, the valve opens and the hydraulic fluid in the cam chamber flows through the suction flow path. The suction valve that supplies water into the pressurized chamber and the plunger piston move toward the pressurized chamber. A plunger type equipped with a discharge valve that opens when the pressure is applied and discharges the hydraulic fluid in the pressurized chamber. In the pump, the cam chamber side of the plunger case is connected to the plunger case mounting hole. The diameter is smaller than the inner circumferential surface of the cam chamber, and a passage communicating with the cam chamber is formed between the inner circumferential surface and the cam chamber. The plunger piston slide is attached to the cylindrical neck. A gas vent hole is provided to communicate the moving part and the passage, while the outer periphery of the plunger piston is A groove is provided in the portion, and the groove is such that the plunger piston is moved by the eccentric cam. When it is pushed all the way to the pressurized chamber side, it communicates with the pressurized chamber, but it does not communicate with the gas vent hole. On the other hand, gas is released when the plunger piston protrudes the most from the pressurized chamber. A plunger characterized in that it communicates with the hole but does not communicate with the pressurizing chamber. This provides a portable type pump.

[0013] The groove is, for example, a circle formed around the outer circumference of the plunger piston. It is circular.

[0014]

[Effect] Since the plunger type pump according to the present invention has the above-mentioned configuration, melting When gas bubbles enter the pressurizing chamber, the plunger piston is moved to its maximum position by the eccentric cam. When the pressurized chamber is pushed in, the groove and the pressurized chamber communicate with each other, and air bubbles in the pressurized chamber enter the groove. Then he was arrested. The trapped air bubbles are removed when the plunger piston moves toward the cam chamber. During this period, the plunger piston is hermetically sealed in the groove and protrudes the most from the pressurized chamber. When the groove communicates with the gas vent hole, the cam chamber is opened from the gas vent hole through the passage. Exit to. Therefore, while the eccentric cam is rotating for a while, the pressurized chamber All the air bubbles escape into the cam chamber.

[0015]

【Example】

Next, the present invention will be described in detail based on embodiments shown in the drawings. The overall configuration of the plunger type pump according to the embodiment of the present invention shown in FIGS. 1 to 4 is as follows: It is similar to the conventional example disclosed in Japanese Patent Application Laid-Open No. 63-048543.

[0016] That is, the cam chamber 20 constituting the hydraulic pressure release section is filled with hydraulic fluid, and the eccentric The cam 21 is rotatably arranged. A plunger case mounting hole formed in communication with the lower end of the cam chamber 20 having a circular cross section. A plunger case 23 is fitted and fixed to 22. Diagram of the plunger case 23 A small hole is formed in the middle upper part to provide a passage 24 between the plunger mounting hole 22 and the inner circumferential surface of the plunger mounting hole 22. A cylindrical neck portion 23a having a diameter is formed. In addition, the plunger case 23 includes A plunger sliding part 26 is bored in the direction of the axis L2 from the upper end of the cylindrical neck part 23a, A plunger piston 27 is slidably disposed within the plunger piston sliding portion 26. are doing.

[0017] The plunger piston is connected to the lower end of the plunger piston sliding portion 26. A pressurizing chamber 28 having an inner diameter slightly larger than the inner diameter of the sliding part 26 is provided, as shown in FIG. , the plunger piston 27 is in a protruding state. A gap portion 30 is formed between the outer peripheral portion 27a and the outer peripheral portion 27a.

[0018] Inside the pressurizing chamber 28 is a suction valve made of a ball valve biased by a spring 31. 32 is provided, and the suction valve 32 penetrates the plunger piston 27 in the direction of the axis L2. The lower end opening of the suction flow path 33 is opened and closed.

[0019] Further, the opening 28a at the lower end of the pressurizing chamber 28 is connected to a ball biased by a spring 34. The opening 28a is opened and closed by a discharge valve 35 consisting of a plunger valve. It communicates with a discharge port 36 formed in the base 23. The lower end of the cylindrical neck portion 23a communicates the plunger sliding portion 26 with the passage 24. A gas vent hole 38 consisting of a horizontal hole is provided.

[0020] The plunger piston 27 has a lock provided on the tip end 27b side on the cam chamber 20 side. 39 and the spring support portion 23b of the plunger case 23, the cylindrical neck is A return spring 40 wound around the outer periphery of the portion 23a is compressed and inserted. The plunger piston 27 is elastically moved upward in the figure (in the direction of arrow C) by the spring 40. is biased so that the tip portion 27b is always in contact with the eccentric cam 21. Ru. Further, the plunger piston 27 is provided with the suction flow passing through the plunger piston 27 in the direction of the axis L2. An inflow passage 42 communicating with the vicinity of the upper end of the passage 33 is provided to penetrate in the radial direction, and the inflow passage 42 is open to a passage 24 communicating with the cam chamber 20.

[0021] Furthermore, the plunger piston 27 is used to remove air bubbles that have entered the pressurized chamber 28. An annular groove portion 44 that goes around the outer peripheral portion 27a in the circumferential direction is recessed. The groove portion 44 is the distance T1 from the tip 27b on the cam chamber 20 side to the upper end 44a in the figure, and the The distance T2 and width W from the tip 27c on the pressure chamber 28 side to the lower end 44b in the figure are as follows. It is set as follows.

[0022] That is, the plunger piston 27 is moved closest to the pressurizing chamber 28 by the eccentric cam 21. In the pushed-in state (bottom dead center), the groove 44 communicates with the pressurizing chamber 28, but the gas It does not communicate with the extraction hole 38, and the plunger piston 27 is located on the eccentric cam 21 side. In the vicinity of the most protruding state from the pressurizing chamber 28 (top dead center), the groove 44 is a gas vent hole. 38 but does not communicate with the pressurizing chamber 28, and the plunger piston 27 is In the state between the top dead center and the bottom dead center, the groove 44 prevents the plunger piston from sliding. It is set to be hermetically sealed by the plunger piston sliding surface 26a of the portion 26. There is.

[0023] Next, the operational features of the above embodiment will be explained. As shown in FIGS. 3 and 4, according to the rotation of the eccentric cam 21, the plunger piston The stone 27 slides upward (arrow C) in the figure by the return spring 40. Then, the biasing force of the spring 31 weakens, and the hydraulic fluid in the cam chamber 20 flows into the plunger. The air flows into the pressurizing chamber 28 through the suction passage 33 of the piston 27 . from this state When the eccentric cam 21 further rotates, the plunger piston is rotated as shown in FIGS. 1 and 2. The stone 26 moves downward in the figure (in the direction of arrow D) and pressurizes the hydraulic fluid in the pressurizing chamber 28. Pressure, compress. The pressure of the hydraulic fluid in the pressurizing chamber 28 is applied to the spring 34 of the discharge valve 35. , the discharge valve 35 opens the opening 28a and the hydraulic fluid under high pressure is supplied to the outside from the opening 28a via the discharge port 36.

[0024] In the plunger type pump described above, if air bubbles enter the pressurizing chamber 28, The plunger piston 27 shown in FIGS. 1 and 2 has been pushed into the pressurizing chamber 28 the most. Near the state where the plunger piston 27 is located on the side, the groove 44 of the plunger piston 27 is connected to the pressurizing chamber 28. communicate. Therefore, some or all of the air bubbles mixed in the pressurized chamber 28, It enters the groove 44 through the gap 30 between the groove 44 and the inner peripheral surface of the pressurizing chamber 28. and is caught in the groove 44.

[0025] The eccentric cam 21 rotates further, and the plunger piston 27 moves upward in the figure (in the direction of arrow C). direction), the groove portion 44 is airtightly sealed by the plunger sliding surface 26a. be chained. Therefore, the gas bubbles captured in the groove 44 are trapped in the groove 44. Move in the direction of arrow C while being held in place.

[0026] As shown in FIGS. 3 and 4, the plunger piston 27 is the most protruding from the pressurizing chamber 28. When it reaches the extended state (top dead center), the groove 44 communicates with the gas vent hole 38, as described above. Pass. Therefore, the air bubbles trapped in the groove 44 are removed from the gas vent hole 38 and It exits into the cam chamber 20 via a passage 24 .

[0027] At this time, the positions T1, T2 and width W of the groove portion 44 are set to satisfy the above conditions. Therefore, when the groove portion 44 is in communication with the gas vent hole 38, the pressurized chamber 28 Therefore, the effective stroke of the plunger piston 27 is 44 and the gas vent hole 38, it does not decrease.

[0028] By continuing the above operation once or multiple times as the eccentric cam 21 rotates, All the air bubbles that have entered the pressurizing chamber 28 escape into the cam chamber 20 and are discharged from the pressurizing chamber 28. can do.

[0029] Note that the present invention is not limited to the above embodiment; for example, the shape of the groove may be For example, the cross-sectional shape may be semicircular or the like. Also, above The suction valve and discharge valve are not limited to those mentioned above, but other appropriate types may be used. can do.

[0030]

【effect】

As is clear from the above explanation, the plunger type pump according to the present invention A groove is provided on the outer periphery of the plunger piston, and the cylindrical neck of the plunger case is Since there is a gas vent hole that communicates the plunger piston sliding part and the cam chamber, Air bubbles that have entered the pressurized chamber near the bottom dead center of the plunger piston are trapped in the groove. It can be discharged to the gas vent hole near top dead center.

[0031] In particular, the position and width of the groove can be adjusted so that the groove is located either in the pressurizing chamber or in the gas vent hole. Since it is configured so that when it communicates with one, it does not communicate with the other, so the inside of the pressurized chamber is covered. There is no communication with the pressurized chamber, and the pressure inside the pressurized chamber does not drop. Therefore, the effective stroke of the plunger piston can be maintained. Therefore, Used as a power source to generate high fluid pressure to control vehicle brake fluid pressure. Effective when used with radial plunger pumps that can

[0032] In addition, in the present invention, a groove is formed on the outer periphery of the plunger piston, and a groove is formed on the outer circumference of the plunger piston. It has a simple configuration, just providing a horizontal gas vent hole in the plunger case. It has various advantages such as being easy to process and reducing manufacturing costs. It has points.

[Brief explanation of drawings]

FIG. 1 is a partially cross-sectional schematic diagram showing an embodiment of the present invention.

FIG. 2 is a schematic partial cross-sectional view of the plunger piston in FIG. 1;

FIG. 3 is a partially cross-sectional schematic diagram showing an embodiment of the present invention.

4 is a schematic partial cross-sectional view of the plunger piston in FIG. 3; FIG.

FIG. 5 is a sectional view showing a conventional plunger type pump.

[Explanation of symbols]

20 Cam room 21 Eccentric cam 23 Plunger case 23a Cylindrical neck 24 Passage 26 Plunger piston sliding part 27 Plunger piston 28 Pressurized chamber 30 Gap 32 Suction valve 35 Discharge valve 38 Gas vent hole 44 Groove

Claims (1)

[Scope of utility model registration request] 1. A cam chamber filled with hydraulic fluid, a plunger case mounting hole formed in communication with the cam chamber, an eccentric cam rotatably disposed in the cam chamber, and a plunger mounted in the plunger case mounting hole. The plunger is slidably housed in the case and the plunger sliding part of the plunger case, and its tip abuts on the eccentric cam so that it slides in the axial direction according to the rotation of the eccentric cam and penetrates in the axial direction. A plunger piston is provided with a suction passage, and a valve opens when the plunger piston moves from the pressure chamber side to the eccentric cam side, and the hydraulic fluid in the cam chamber is drawn into the pressurization chamber through the suction passage. The plunger type pump is equipped with a suction valve that supplies fluid to the pressurizing chamber, and a discharge valve that opens when the plunger piston moves toward the pressurizing chamber and discharges the working fluid in the pressurizing chamber. The cam chamber side has a cylindrical neck having a smaller diameter than the inner circumferential surface of the plunger case mounting hole, and has a cylindrical neck configured to form a passage communicating with the inner circumferential surface to the cam chamber, and the cylindrical neck has the above-mentioned A gas vent hole is provided to communicate the plunger piston sliding part and the passage, while
A groove is provided on the outer periphery of the plunger piston, and the groove communicates with the pressurized chamber when the plunger piston is pushed most toward the pressurized chamber by the eccentric cam, but does not communicate with the gas vent hole. On the other hand, a plunger type pump is characterized in that when the plunger piston protrudes most from the pressurizing chamber, it communicates with the gas vent hole but does not communicate with the pressurizing chamber.