JPH0318704Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a plunger pump in which a plunger reciprocates within a cylinder to feed liquid.

[Problems to be solved by conventional techniques and inventions] Plunger pumps have been known in which a plunger reciprocates within a cylinder, thereby pumping liquid within the cylinder. The mechanism that converts the plunger into reciprocating motion is as shown in Figure 1.
It is conceivable to use a pinion connected to the rotating shaft of the motor and a rack meshed with the pinion.

The rack shown in Figure 1 has a tooth groove formed on one side of a square column, and when this rack is used, the meshing state between the rack and pinion is maintained well when the rack is displaced around its axis. This may cause so-called "wobble", resulting in a decrease in liquid feeding accuracy, and wear and tear on the pinion. Therefore, in order to reliably transmit power between the pinion and the rack, it is necessary to equip the rack with a displacement prevention guide.
Therefore, there is a problem that the mechanism becomes complicated.

The present invention was developed in view of the above-mentioned circumstances.The shape of the rack is cylindrical, a plurality of tooth grooves are formed along the circumferential direction, and the tooth tip surface of the pinion is shaped to match the outer peripheral shape of the round rack. It is an object of the present invention to provide a plunger pump with a simplified mechanism, which has high liquid feeding accuracy and does not require a rough displacement prevention guide by forming a concave surface.

[Means for solving problems]

In order to achieve the above object, the present invention forms a liquid passage and a pumping cylinder that communicates with the passage, respectively, and allows liquid to flow only from the inlet to the outlet of the passage. a pump head each provided with a check valve, a plunger having one end inserted fluid-tightly into the pumping cylinder, a rack connected to the other end of the plunger, and a rotating shaft meshing with the rack. A plunger driving motor equipped with a pinion is provided, and the rotating shaft of the motor is periodically rotated in the forward and reverse directions, and this movement is transmitted to the plunger via the pinion and the rack, thereby causing the plunger to reciprocate. In a plunger pump for pumping liquid in a pump head, one end of the plunger is rotatably inserted into a pumping cylinder, and the rack is formed into a cylindrical round rack having a plurality of tooth grooves along the circumferential direction. , the tooth tip surface of the pinion is formed in an arcuate concave shape corresponding to the outer peripheral shape of the round rack from one end in the axial direction to the other end.

[Effect]

In the present invention, one end of the plunger is rotatably inserted into the pumping cylinder, and the rack is made into a cylindrical round rack having multiple tooth grooves along the circumferential direction, so it is easy to rotate the plunger. The meshing state with the pinion is maintained well, and the accuracy of liquid delivery does not deteriorate due to vibration, and the round rack rotates freely and naturally shifts to the part where it is most likely to mesh. In addition to smooth power transmission, the tooth grooves of the rack and pinion are less likely to wear out and can withstand long-term operation.

In addition, because the tooth tip of the pinion is formed into an arcuate concave shape that corresponds to the outer circumferential shape of the round rack, the pinion and the rack come into line contact over a wide range, reducing accuracy even when pumping liquid under high loads. There is no such thing.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings, while comparing it with an example using a rack having a tooth groove formed on one side of a prismatic column and a pinion whose tooth surface is not concave.

〔Example〕

FIG. 1 shows an example using a rack with a tooth groove formed on one side of a prismatic column and a pinion whose tooth surface is not concave, and FIG. 2 shows an embodiment of the present invention.

In the figure, reference numeral 1 denotes a pump head, in which a passage 2 for transporting liquid is formed in a vertical direction. A lower check valve 5 consisting of a valve seat 3 and a ball 4 is disposed at the lower part of the passage 2, and a valve seat 6 and a ball 7 at the upper part.
An upper check valve 8 is provided. Further, a pumping cylinder 9 is bored in the pump head 1 so as to be perpendicular to the transport liquid passage 2, and one end side of a plunger 11 is inserted into the pump head 1 in a liquid-tight manner and can move forward and backward and rotate freely by a gasket 10. There is. A rack 1 is provided on the other end side of the plunger 11.
2 are connected to each other, and motor 1 is connected to this rack 12.
A pinion 14 connected to the rotating shaft of No. 3 is disposed in mesh with each other.

In the pump of the present invention shown in FIG. 2, the rack 12 is formed into a cylindrical round rack having a plurality of tooth grooves along the circumferential direction, and as shown in FIGS. The tooth top surface 14a and the tooth bottom surface 14b of the pinion 14 are each formed in an arcuate concave shape from one end in the axial direction to the other end, so that the tooth surface of the pinion 14 is formed in a concave shape along the axial direction. . When the rack 12 and pinion 14 are engaged as shown in FIG. 6, the pitch circle of the rack 12 and the pitch circle of the pinion 14 are in line contact over a wide range. In addition, in FIG. 6 and FIG. 7 described later,
12a is the tooth tip of rack 12, 12b is rack 1
The bottom surfaces of No. 2 teeth are shown respectively.

In the plunger pump described above, the rotational motion of the motor 13 is converted into the reciprocating motion of the plunger 11 by the pinion 14 and the rack 12. In the example shown in FIG. If the tooth groove is only cut, and the rack 12 is displaced as it is, the meshing state between the pinion 14 and the rack 12 will not be maintained well, causing so-called "runout", which will reduce the accuracy of liquid delivery and cause the rack and pinion to displace. Since this tends to cause wear and the like, it is necessary to provide a guide 15 to prevent displacement of the rack 12, which makes the mechanism complicated. On the other hand, in the pump of the present invention shown in FIG. 2, the rack 11 is cylindrical and the tooth grooves are continuously cut along the circumferential direction, so even if the rack 12 is displaced, the pinion 14 is always Since the meshing condition between the rack 12 and the rack 12 can be maintained well, a guide for preventing displacement of the rack 12 is not required, and high liquid feeding accuracy can be obtained.

Furthermore, since the tooth surface of the pinion is formed into a concave shape corresponding to the tooth surface of the round rack, the pinion and the rack come into line contact over a wider range, making it possible to withstand high loads. In other words, when using a pinion whose tooth surface is not normally concave compared to a round rack,
As shown in FIG. 7, the pitch circle of the rack 12 and the pitch circle of the pinion 14 make only point contact with each other, so the contact range between the pinion 14 and the rack 12 is small, and therefore, if a high load is applied to this location, the power will be reduced. However, in the present invention, such a problem does not occur.

In addition, in the above embodiment, the tooth tip surface 1 of the pinion 14
4a and the tooth bottom surface 14b are both formed in a concave shape, but only the tooth top surface 14a may be formed in a concave shape and the tooth bottom surface 14b may be formed in a flat shape, and the same effect can also be obtained by this. I can do it.

[Effect of idea]

As explained above, in the plunger pump of the present invention, one end of the plunger is rotatably inserted into the pumping cylinder, and the rack is formed into a cylindrical round rack having a plurality of tooth grooves along the circumferential direction. In addition, the tooth tip surface of the pinion is formed into an arcuate concave shape corresponding to the outer peripheral shape of the round rack from one end in the axial direction to the other end, so that the pinion and the rack are in line contact over a wide range. In addition to having high liquid feeding accuracy, it does not require a rigid displacement prevention guide and is mechanically simple, which is advantageous in terms of manufacturing. In addition, since a cylindrical rack with multiple tooth grooves formed along the circumferential direction and a pinion are used for power transmission, the rack can be freely displaced and will naturally shift to the part where it is easiest to engage. Since they mesh together, the transmission of power is smooth, and the tooth grooves of the rack and pinion are less likely to wear out, making them sufficiently durable for long-term operation.

[Brief explanation of the drawing]

Fig. 1 is a partial cross-sectional side view showing a pump using a rack with tooth grooves formed on one side of a prismatic column and a pinion whose tooth surface is not concave as a plunger drive mechanism, and Fig. 2 is a partial cross-sectional side view of a pump using a rack with a tooth groove formed on one side of a prismatic column and a pinion whose tooth surface is not concave. FIG. 3 is a perspective view showing a pinion of the same example, FIG. 4 is a partially omitted enlarged sectional view taken along the line shown in FIG. 3, and FIG. FIG. 6 is an explanatory diagram showing a state of meshing between the pinion and a round rack, and FIG. 7 is an explanatory diagram showing a state of meshing between a normal pinion and a round rack. 9... Pumping cylinder, 11... Plunger, 12... Rack, 13... Motor, 14...
Pinion, 15... Rotation prevention guide.

Claims (1)

[Scope of utility model registration request] A pump head having a liquid passage and a pumping cylinder communicating with the passage formed therein, and provided with check valves in the inflow and outflow parts of the passages to allow liquid to flow only from the inflow part to the outflow part. and a plunger having one end inserted fluid-tightly into the pumping cylinder, a rack connected to the other end of the plunger, and a plunger driving motor having a rotating shaft equipped with a pinion that meshes with the rack. , a plunger pump that periodically rotates the rotating shaft of the motor forward and reverse, and transmits this motion to the plunger via the pinion and rack, thereby causing the plunger to reciprocate and pumping the liquid in the pump head, One end of the plunger is rotatably inserted into a pumping cylinder, and the rack is formed into a cylindrical round rack having a plurality of tooth grooves along the circumferential direction, and the tooth tip surface of the pinion is rotated in the axial direction. A plunger pump characterized in that it is formed in an arc concave shape corresponding to the outer peripheral shape of the round rack from one end to the other end.