JP3524308B2 - Discharge pressure adjusting device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge pressure adjusting device.

[0002]

2. Description of the Related Art For example, a liquid ejecting apparatus such as a power sprayer is generally provided with a discharge pressure adjusting device for adjusting the discharge pressure of a pump (see, for example, Japanese Utility Model Publication No. 7-21238). The discharge pressure adjusting device has a pressure adjusting valve body that constitutes a pressure adjusting valve, and the pressure adjusting valve body closes a residual liquid port communicating with a liquid flow path downstream of a discharge port of the pump,
Always urged by elastic urging force. When the discharge pressure of the pump exceeds a predetermined value, the pressure regulating valve body is pushed back against the elastic biasing force, and the residual liquid port opens. The liquid flowing out from the residual liquid port is returned to the liquid source side, and the discharge pressure of the pump is maintained at a predetermined pressure. Then, the discharge pressure of the pump can be adjusted by adjusting the elastic biasing force applied to the pressure regulating valve body.

Conventionally, the adjustment of the pressure adjustment value of the pressure adjustment valve is
As disclosed in Japanese Utility Model Publication No. 7-21238, it is performed by manually rotating a pressure adjusting knob which is rotatable in a plane perpendicular to the operation axis of the pressure adjusting valve. .

Further, an electric motor for rotating a rotating member rotatable in a plane perpendicular to the operation axis of the pressure regulating valve in forward and reverse directions, and an operation switch for controlling forward and reverse rotations and stoppage of the motor are provided. What is also proposed by Japanese Utility Model Publication No. 8-4124.

[0005]

However, among the conventional discharge pressure adjusting devices, the one in which the pressure adjusting knob is manually rotated is not good in operability. In particular, in the case of a backpack-type power sprayer, the operator has to turn his / her hand to the back side to rotate the pressure adjusting knob, so that there is a remarkable problem that it is difficult to operate.

[0006] Further, a device provided with the motor and the operation switch has good operability, but has a problem that the structure is complicated and the cost is high.

The present invention has been made in view of these circumstances, and an object thereof is to provide a discharge pressure adjusting device having a simple structure and good operability.

[0008]

In order to solve the above-mentioned problems, a discharge pressure adjusting device according to the present invention rotates along a plane including a pressure adjusting valve for adjusting the discharge pressure and an operating axis of the pressure adjusting valve.
And a rotating member for adjusting the pressure adjusting value of the pressure adjusting valve,
An operating lever for rotating the member is provided.

According to the present invention, since the operator can rotate the rotating member with the operation lever, the operability is good. Furthermore, the structure is simple.

Further, the rotating member is provided rotatably with respect to a pressure regulating valve casing for accommodating the pressure regulating valve, and the rotating member is provided with a cam for contacting the pressure regulating valve and adjusting a pressure regulating value thereof. It is even more preferable if it is provided.

The cam is, for example, an eccentric cam that is eccentric from the center of rotation of the rotating member.

Further, if the pressure regulating value of the pressure regulating valve is made to be adjustable in stages, the operator does not need to be sensitive to delicate adjustment of the pressure regulating value, so the operation is easier. .

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in detail based on an embodiment shown in the accompanying drawings.

FIG. 1 is a sectional view of a main part of a pump 2 integrally provided with a discharge pressure adjusting device 1 according to an embodiment of the present invention.

First, the pump 2 will be described. The pump 2 is a so-called differential type pump known per se, and not only when the piston 4 advances in the cylinder 3, but also when the piston 4 retracts,
It is of a type that ejects liquid.

The pump 2 is provided with a clutch drum 5, and a rotational driving force is transmitted to the clutch drum 5 from a prime mover such as an internal combustion engine (not shown) via a clutch shoe of a centrifugal clutch device (not shown). To be done.

The clutch drum 5 is a reduction gear 6
And a large reduction gear 7 and is drivingly connected to a drive crankshaft 8 that reciprocally drives the piston 4. The piston 4, which is pivotally fixed to the drive crankshaft 8 via a connecting rod 9, slides back and forth in the cylinder 3 in a liquid-tight manner in the left-right direction as viewed in FIG.

A suction port 10 is formed on the head side (the right end side in FIG. 1) of the cylinder 3, and the suction port 10 communicates with a liquid source such as a tank (not shown). The suction valve body 11, which normally closes the suction port 10,
When the piston 4 retracts to the left in the cylinder 3 as viewed in FIG. 1, a negative pressure is generated in the cylinder 3 against the elastic biasing force of the compression coil spring 12 for biasing the intake valve body. The suction port 10 is moved in the opening direction (to the left in FIG. 1).

The piston 4 has a large-diameter portion 4a on the head side of the cylinder 3 and a small-diameter portion 4 extending from the large-diameter portion 4a to the bottom side of the cylinder 3 (the left end side in FIG. 1).
b, and the large-diameter portion 4a slides on the inner circumference of the cylinder 3 in a liquid-tight manner. Between the surface of the large diameter portion 4a of the piston 4 and the inner peripheral surface of the cylinder 3 is a liquid absorption chamber 13, and the surface of the small diameter portion 4b of the piston 4 and the inner peripheral surface of the cylinder 3 are The space is the liquid ejection chamber 14.

A communication passage 15 is formed in the piston 4 to connect the liquid suction chamber 13 and the liquid discharge chamber 14 to each other. The communication passage 15 is normally closed by a discharge valve body 16. There is. The discharge valve body 16 has elasticity of the compression coil spring 17 for urging the discharge valve body due to an increase in the internal pressure of the liquid suction chamber 13 when the piston 4 advances to the right in the cylinder 3 as viewed in FIG. The communication passage 15 is moved in the opening direction (leftward in FIG. 1) against the biasing force.

The liquid discharge chamber 14 communicates with a liquid jet working member such as a spray nozzle (not shown) through a discharge port 18 formed in the cylinder 3.

The pump 2 constructed as described above operates as follows.

When the piston 4 retracts in the cylinder 3 to the bottom dead center (the left end side in FIG. 1), the suction valve body 11 moves in the direction to open the suction port 10 and the inside of the cylinder 3 moves. The liquid is sucked into the liquid suction chamber 13 from the liquid source. In this suction stroke, the discharge valve body 16 blocks the communication passage 15.

Subsequently, the piston 4 is connected to the cylinder 3
When advancing inside to the top dead center (position shown in FIG. 1), the discharge valve body 16 moves in a direction of opening the communication passage 15, and the liquid suction chamber 13 to the liquid discharge chamber 14 and the discharge port. 1
The liquid is pressure-fed to the liquid ejecting work member via the pressure roller 8. When the piston 4 reaches the top dead center, the liquid remains in the liquid discharge chamber 14.

When the piston 4 retreats to the bottom dead center again, the liquid is sucked from the liquid source into the liquid suction chamber 13 in the cylinder 3 and the liquid remaining in the liquid discharge chamber 14 is removed. , Is pumped to the liquid jetting work member.

By the above-described continuous strokes, the pump 2 continuously pumps the liquid.

Next, the discharge pressure adjusting device 1 according to this embodiment will be described.

As shown in FIGS. 1 and 2, the discharge pressure adjusting device 1 adjusts a pressure adjusting valve 20, a pressure adjusting valve casing 21 accommodating the pressure adjusting valve 20, and a pressure adjusting value by the pressure adjusting valve 20. The pressure adjusting and rotating member 22 is provided.

A spill port 23 is branched and formed on the downstream side of the discharge port 18 of the pump 2. A pressure regulating valve seat 24 constituting the pressure regulating valve 20 is fixed to the outer end portion of the residual liquid port 23, and the pressure regulating valve seat 24 has
The pressure regulating valve body 26 is pressed by the compression coil spring 25 as the pressure regulating valve body urging means. The pressure regulating valve element urging spring 25 is accommodated in a spring accommodating hole 27 formed in the pressure regulating valve casing 21. The spring accommodating hole 2
7 communicates with the liquid source via a return port 28 formed in the pressure regulating valve casing 21.

The pressure regulating valve casing 21 has a casing 29 of the pump 2 having the residual liquid port 23.
Is stuck to.

The pressure regulating valve element biasing spring 25 has its one end 25a side pressing the pressure regulating valve body 26 and the other end 2 thereof.
The spring receiving member 30 is pressed on the 5b side. The spring receiving member 30 is formed in the pressure regulating valve casing 21 and communicates with the spring accommodating hole 27.
It is slidable in a liquid-tight manner. The spring receiving member 30 and the pressure regulating valve body 26 constituting the pressure regulating valve 20 are urged by the pressure regulating valve body urging spring 25 in opposite directions on a common operating axis XX.

The spring receiving member 30 is provided with a flange 32 at the end portion on the other end portion 25b side of the pressure regulating valve urging spring 25. The flange 32 comes into contact with a step portion 33 formed between the spring accommodating hole 27 and the spring receiving member sliding hole 31 to prevent the spring receiving member 30 from falling out of the pressure regulating valve casing 21. To prevent.

The pressure adjusting turning member 22 has a disk-shaped turning main body 34. The rotation axis Y-Y of the rotation main body 34 intersects at right angles with the operation axis X-X of the pressure regulating valve 20. A disc-shaped cam 35 having a diameter smaller than that of the rotating main body 34 is provided on a plane on one side of the rotating main body 34.
However, they are formed integrally with each other so as to be eccentric with respect to the rotation center O of the rotation main body 34. Further, on the plane of the eccentric cam 35, a shaft portion 36 having a diameter smaller than that of the eccentric cam 35 is provided.
Are integrally formed concentrically with the rotating body 34.

The pressure adjusting and rotating member 22 accommodates the eccentric cam 35 in a concave portion 37 formed in the pressure regulating valve casing 21 and having a circular cross section, and at the same time, the concave portion 37.
The outer peripheral surface of the rotating main body 34 is fitted to the circular fitting stepped portion 38 formed around the inlet side of, and is rotatably attached to the pressure regulating valve casing 21. The shaft portion 36 of the pressure adjusting / rotating member 22 is fitted and inserted into a bearing hole 39 which is formed in the pressure adjusting valve casing 21 and communicates with the recessed portion 37, and is inserted into an outer end portion of the shaft portion 36. Is
A stopper 40 is attached from the outside of the pressure regulating valve casing 21.

The eccentric cam 35 is in contact with the outer end portion 30a of the spring receiving member 30 constituting the pressure regulating valve 20 at its circular outer peripheral surface 35a serving as a cam surface, so that the pressure regulating valve 2
The pressure regulation value by 0 is regulated, and the rotation main body 3
By eccentrically rotating around the rotation axis Y-Y of 4, the pressure adjusting value by the pressure adjusting valve 20 can be adjusted.
On the circular outer peripheral surface 35a of the eccentric cam 35, an appropriate number (three in the illustrated example) of smooth depressions 41a, 41 are formed in order to adjust the pressure adjustment value by the pressure adjustment valve 20 stepwise.
b and 41c are formed side by side in the circumferential direction of the circular outer peripheral surface 35a with an appropriate interval corresponding to a predetermined set pressure therebetween. The outer end portion 30a of the spring receiving member 30 is smoothly formed so as to fit the recesses 41a, 41b, 41c, and the pressure regulating valve element biasing spring 25 and the recesses 41a, 41b, 41c are formed. And with
It constitutes the click-stop mechanism.

The pressure adjusting / rotating member 22 is also provided with an operating lever 42 for operating the rotating main body 34 about its rotation center O. When the operating lever 42 is operated up and down along the plane of FIG. 3, the rotating body 34 rotates along a plane including the operation axis XX of the pressure regulating valve 20, and in response thereto. The eccentric cam 35 moves, and the position of the spring receiving member 30 on the operation axis XX is changed. As a result, the pressure regulating valve seat 24
The pressing force of the pressure regulating valve body 26 with respect to is adjusted, and the discharge pressure of the pump 2 is adjusted.

According to the discharge pressure adjusting device 1 according to the present embodiment having the above-mentioned configuration, since the operating lever 42 is provided, it is easy to operate. In particular, it is suitable for use with a backpack-type power sprayer that requires an operator to rotate his / her hand to operate.

Further, since the pressure adjusting value by the pressure adjusting valve 20 can be adjusted stepwise, the operator does not need to focus on the fine adjustment of the discharge pressure of the pump 2, and the operability is further improved. .

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a main part of a pump including a discharge pressure adjusting device according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken along the line II-II of FIG.

FIG. 3 is an explanatory diagram showing an operation of the pressure-regulating rotating member in FIG.

[Explanation of symbols]

20 Regulator 21 Pressure regulating valve casing 22 Rotating member 35 cams (eccentric cams) 42 Operation lever XX Operating axis of pressure regulating valve O Center of rotation

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-62-167939 (JP, A) Jikkouhei 8-4124 (JP, Y2) (58) Fields investigated (Int.Cl. ⁷ , DB name) B05B 9/03 A01M 7/00 B05B 12/00 F16K 17/04 F16K 31/122

Claims (4)

(57) [Claims] 1. A pressure regulating valve (20) for regulating discharge pressure , and
Along a plane including the operating axis (XX) of the pressure regulating valve (20)
To adjust the pressure adjustment value of the pressure adjusting valve (20)
The member (22) and the rotating member (22) are rotated.
And an operating lever (42) for adjusting the discharge pressure. 2. The pressure regulating valve (2) for connecting the rotating member (22).
0) is provided rotatably with respect to the pressure regulating valve casing (21), and the rotating member (22) is provided with the pressure regulating valve (2).
Cam (35) that abuts 0) to adjust the pressure adjustment value
The discharge pressure adjusting device according to claim 1, further comprising: 3. The discharge pressure adjusting device according to claim 2 , wherein the cam is an eccentric cam (35) which is eccentric from a center (O) of rotation of the rotating member (22). 4. The discharge pressure adjusting device according to claim 1, 2 or 3 , wherein the pressure adjusting value of the pressure adjusting valve (20) can be adjusted stepwise.