JPH085348Y2 - Piston pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a piston pump that sucks and discharges a fluid by reciprocating motion of a piston accompanying rotation of a rotary shaft.

[Conventional technology]

An example of a conventional piston pump will be described with reference to FIG. In the figure, reference numeral 2 denotes a pump body, which is composed of a main body 4 and a head 6 which is joined to and integrated with an upper portion of the main body 4, and in the main body 4, a rotary shaft 8 which is rotationally driven by being connected to an engine or a motor of a vehicle. Are rotatably supported via bearings (not shown). An eccentric cam 10 is fixed to the tip of the rotary shaft 8 by a key.
Reference numeral 10 projects into the oil reservoir 12 of the main body 4.

A through hole 4a is formed in the upper portion of the main body 4, and the through hole 4a is formed.
The cylindrical portion 6a formed in the lower portion of the head 6 is inserted in the 4a. The hole 6b in the cylindrical portion 6a of the head 6 extends upward to form a cylinder, and the piston 14 is slidably inserted into the cylinder 6b from below to form the cylinder 6b.
A pump chamber 16 is formed above.

This piston 14 has a flange 14a formed at the bottom.
And a spring arranged between the step of the head 6 and
It is constantly urged downward by 18 and its lower end surface is in contact with the outer peripheral surface of the ball bearing 20 fitted on the outer peripheral surface of the eccentric cam 10. Therefore, when the rotary shaft 8 rotates, the eccentric cam 10 and the ball bearing 20 rotate with their centers of rotation eccentric from the axis of the rotary shaft 8, and the bearing 20
Piston pressed against the outer peripheral surface of the outer race of
The cylinder 14 reciprocates in the cylinder 6b in a direction orthogonal to the axis.

Inside the piston 14, the axial passage 22a and the reservoir 12
A suction passage 22 is formed, which is composed of a diametrical passage 22b that is close to the suction passage 22. The suction passage 22 is opened and closed by a ball valve 24 housed in the pump chamber 16. This ball valve 24
A pin 26 inserted into the upper end of the piston 14 across the pump chamber 16 prevents the piston 14 from coming off.

The pump chamber 16 has a discharge check valve through the discharge port 6c.
Connected to 28. The discharge check valve 28 is provided in a plug 30 screwed and fixed to the valve hole 6d of the head 6, and has a valve seat 32 crimped at the tip of the plug 30, a ball valve 34, and the ball valve 34. And a spring 36 for seating on the valve seat 32.

In the piston pump having the above-described configuration, when the rotating shaft 8 rotates, the piston 14 press-contacted to the outer peripheral surface of the ball bearing 20 fitted around the eccentric cam 10 moves into the cylinder.
The pump is operated by moving up and down in 6b to increase or decrease the volume of pump chamber 16. That is, when the piston 14 descends, the volume of the pump chamber 16 increases, the ball valve 24 that closes the suction passage 22 opens, sucks the fluid in the reservoir 12 into the pump chamber 16, and the piston 14 moves. When rising, the volume of the pump chamber 16 is reduced, the ball valve 4 is closed, and the ball valve 34 of the discharge check valve 28 is opened to discharge the fluid in the pump chamber 16 to the outside.

[Problems to be solved by the device]

The above-mentioned conventional piston pump uses the pin 26 to prevent the ball valve 24 that opens and closes the suction passage 22 from coming off, and this pin 26 discharges to the discharge check valve 28 formed on the side wall of the cylinder 6b. If the pump chamber 16 is arranged so as not to reach the outlet 6c, the volume of the pump chamber 16 at the top dead center of the piston 14 becomes unnecessarily large, resulting in a problem that the compression ratio becomes small.

Further, the cylinder 6b formed on the head 6 is
Cylinder where piston 14 slides because it has a bottom
There was also a problem that the workability of the inner peripheral surface of 6b was not good.

In addition, at the tip of the piston 14, the ball valve
Since a through hole for inserting the retaining pin 26 of 24 must be formed, there is a drawback that the structure of the piston 14 is complicated and the workability is not good.

The present invention has been made in order to eliminate the above-mentioned drawbacks, and an object of the present invention is to provide a piston pump capable of achieving a large compression ratio by reducing the volume of the pump chamber at the top dead center as much as possible. To do.

A second object of the present invention is to provide a piston pump capable of easily processing the inner peripheral surface of the cylinder on which the piston slides.

A third object of the present invention is to provide a piston pump having a simple structure and good workability, since it is not necessary to attach a pin for retaining a ball valve that opens and closes a suction passage to a piston.

[Means for solving the problem]

A piston pump according to the present invention includes an eccentric cam fixed to a rotating shaft, a piston that reciprocates in a cylinder by the rotation of the eccentric cam, a large-diameter passage formed inside the piston, and a large-diameter passage. A valve seat provided at a step between the diameter passage and the suction passage, and a ball valve that opens and closes the valve seat, and reciprocates the piston to increase or decrease the volume of the pump chamber in the cylinder to reduce the fluid Intake and discharge are performed, and in particular, a spacer is arranged in the cylinder, and a projection formed at the tip of the spacer is opposed to the ball valve to prevent the ball valve from coming off.

[Action]

In the piston pump having the above structure, the spacer is arranged in the cylinder, and the projection formed at the tip of the spacer is opposed to the ball valve to prevent the ball valve from coming off and reduce the volume of the pump chamber to compress it. The ratio can be increased.

〔Example〕

The present invention will be described below with reference to the embodiments shown in the drawings. FIG. 1 shows a main part of a piston pump according to an embodiment of the present invention, and is a part corresponding to part A in FIG. The other parts have the same structure as the above-described conventional piston pump, and therefore, illustration and description thereof will be omitted. The hole 106b formed in the head 106 of the pump body is
It is penetrated to the upper end of 06 and the piston 114 is
The O-ring from the upper opening.
A spacer 117 is inserted through 115 and screwed and fixed to the head 106.

Inside the piston 114, a suction passage 122 including an axial passage 122a and a diametrical passage 122b is formed as in the conventional piston pump. This axial passage 122
A large-diameter passage 122c is partially formed on the upper end side (discharging side) of a. A ball valve 124 is provided in this large-diameter passage 122c.
And is seated on a valve seat formed in a step portion between the axial passage 122a and the large-diameter passage 122c.
The suction passage 122 between the 116 and the reservoir 112 is opened and closed. A discharge port 106c is formed on the side wall of the pump chamber 116 and is connected to a discharge check valve (not shown).

Further, a protrusion 117a is formed on the lower end surface of the spacer 117 inserted into the cylinder 106b from the upper surface of the head 106, and extends into the large diameter passage 122c of the piston 114. This projection 117a has the piston 114 at the top dead center and the ball valve 1
When 24 is seated on the valve seat, the ball valve 12
Even when the piston 114 is not at the bottom dead center, the tip surface of the protrusion 117a of the piston 114 has a large diameter passage 1 of the piston 114.
It is located within 22c. This prevents the ball valve 124 from coming out of the large diameter passage 122c of the piston 114.

In the piston pump according to the above configuration, as in the conventional case,
The piston 114 is moved up and down in accordance with the rotation of the ball bearing fitted to the eccentric cam, and the volume of the pump chamber 116 is increased and decreased to suck and discharge the fluid. Since the projection 117a provided on the spacer 117 is used instead of the pin, the volume in the pump chamber 116 at the top dead center of the piston 114 can be made extremely small, and the compression ratio can be increased to improve pump efficiency. . Further, it is not necessary to form a through hole for inserting the pin for preventing the ball valve 124 from coming off in the piston 114, and the structure is simple and the process is easy. Moreover, since the cylinder hole 106b is formed so as to pass through the head 106 in the vertical direction, the workability of the inner surface of the cylinder on which the piston 114 slides is improved.

[Effect of device]

As described above, according to the present invention, the spacer is inserted into the cylinder, and the projection formed at the end of the spacer prevents the ball valve that opens and closes the suction passage from coming off. The volume of the pump chamber can be made extremely small, and a piston pump having a simple structure and good workability can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a main part of a piston pump according to an embodiment of the present invention, and FIG. 2 is a vertical sectional view of a conventional piston pump. 106b ... Cylinder 114 ... Piston 116 ... Pump chamber 117 ... Spacer 117a ... Spacer protrusion 122 ... Suction passage 124 ... Ball valve

Claims (1)

[Scope of utility model registration request] 1. An eccentric cam fixed to a rotating shaft, a piston that reciprocates in a cylinder by the rotation of the eccentric cam, a suction passage formed inside the piston, and a suction passage inside the cylinder. With a large diameter passage formed,
A valve seat provided at a step between the large-diameter passage and the suction passage and a ball valve for opening and closing the valve seat are provided, and the volume of the pump chamber in the cylinder is increased or decreased by the reciprocating motion of the piston. A piston pump for sucking and discharging fluid, wherein a spacer is arranged in the cylinder, and a projection formed at the tip of the spacer is opposed to the ball valve to prevent the ball valve from coming off.