JPH05240156A - Reciprocating type piston pump - Google Patents

Abstract

PURPOSE:To significantly improve the wear resisting strength of a part forming the sliding part of a piston pump to greatly prolong the life of the pump, and extremely simplify the maintenance and management of the pump. CONSTITUTION:A reciprocating type piston pump has a cylinder pipe 3 connected to a suction hole 1 and a discharge hole 2, and a piston rod 4 reciprocating in the cylinder pipe 3, and a piston 5 inserted to the top end part of the piston rod 4 in such a manner as to be capable of reciprocating is reciprocated together with the piston rod 4 to deliver a pressurized fluid. On at least one surface of the inner surface of the cylinder pipe 2 and the outer surface of the piston rod 4, wear resisting layers 11a-11c are formed, respectively. The wear resisting layers 11a-11c are formed of hard chromium plating layers 12a-12c formed on a base material surface and chromium oxide coating layers 13, 13a-13c formed on the hard chromium plating layers 12a-12c.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reciprocating piston pump, and particularly, to improve the wear resistance of sliding parts to significantly extend the life of the pump and to make maintenance of the pump extremely easy. A reciprocating piston pump capable of

[0002]

2. Description of the Related Art A reciprocating piston pump is equipped in a control machine for spraying liquid pesticides to control pests, a cleaning machine for spraying high-pressure water on vehicles, and a coating machine for spraying paint on the surface of a workpiece. Has been done.

A reciprocating piston pump used in, for example, a pest control machine is generally constructed as shown in FIG. That is, a cylinder pipe 3 connected to the suction port 1 and the discharge port 2 and a piston rod 4 that reciprocates in the cylinder pipe 3 are provided, and the piston rod 4 is reciprocally fitted and inserted into the tip end portion of the piston rod 4. By reciprocating the piston 5 together with the piston rod 4, the pesticide solution is pressurized and delivered in the direction of the injection nozzle.

Another type of reciprocating piston pump is a piston rod 4 which reciprocates in a cylinder pipe 3 having a suction port 1 and a discharge port 2 as shown in FIG.
A valve body 6 provided at the tip of the piston rod 4, a stopper body 8 provided at a distance from the valve body 6 on the piston rod 4 and having a through hole 7, the valve body 6 and the stopper body. A sleeve 9 having a length smaller than the distance between the sleeve 9 and the piston rod 4 between the valve body 6 and the stopper body 8, and the sleeve 9 fixed to the inner wall of the cylinder pipe 3. There is also one configured with a packing 10 that holds airtightly and slidably.

In this case, when the piston rod 4 returns (moves to the right in FIG. 3), the sleeve 9 moves together with the movement of the piston rod 4 to suck the liquid and at the same time to discharge it from the discharge port 2. Do again, piston rod 4
When the piston rod 4 moves to the left in the drawing even during the forward movement of, the liquid corresponding to the moving amount of the piston rod 4 and the sleeve 9 is discharged from the discharge port 2.
Therefore, it is possible to always perform the discharge stroke both when the piston rod 4 is moving forward and when it is moving backward.

In such a reciprocating piston pump, there are many parts constituting the sliding portion such as the cylinder pipe 3, the piston rod 4 and the sleeve 9, so that the parts are damaged due to wear over time. For this reason, it is necessary to periodically replace parts, maintenance of the pump is complicated, and the life of the pump itself is short.

Therefore, a hard chrome plating layer is formed on the sliding portion of the above-mentioned component by an electrolytic method or the like, and surface treatment is applied.
It has also been devised to improve wear resistance.

[0008]

However, in the hard chrome plating surface treatment by the conventional electrolysis method, adjustment control of the electrolysis temperature, current density, etc. is complicated, and it is difficult to obtain a good quality hard chrome plating layer, while electrolysis is difficult. Since the internal stress generated in the hydrogen and the deposited layer that occurs at some time and a large number of needle holes and cracks occur on the surface of the hard chrome plating layer due to heat treatment in the subsequent process, the base metal surface of the part is completely covered with the hard chrome plating layer. In addition, since the adhesion strength is low, there is a problem that the abrasion resistance is deteriorated due to frequent peeling due to vibration and frictional force during pump operation.

In particular, needle holes and cracks have a problem in that the notch effect causes the cracks to propagate and mechanical properties such as fatigue strength of the component base material to be easily deteriorated and the life of the piston pump to be shortened.

The present invention has been made to solve the above-mentioned problems, and significantly improves the wear resistance strength of the parts constituting the sliding portion of the piston pump, thereby significantly extending the life of the pump. An object of the present invention is to provide a reciprocating piston pump that can greatly simplify pump maintenance management.

[0011]

To achieve the above object, a reciprocating piston pump according to the present invention comprises a cylinder pipe connected to a suction port and a discharge port, and a piston rod reciprocating in the cylinder pipe. A reciprocating piston pump comprising a piston rod reciprocally fitted at the tip of the piston rod to reciprocate together with the piston rod to deliver a pressurized fluid, the cylinder pipe inner surface and the piston rod outer surface. A wear-resistant layer is formed on at least one surface of the hard-chrome plated layer formed on the surface of the base material and a chromium oxide coating layer formed on the hard-chrome plated layer. Is characterized by.

As another pump type, a piston rod reciprocating in a cylinder pipe having a suction port and a discharge port, a valve element provided at the tip of this piston rod, and a piston rod spaced apart from this valve element A stop body provided with a through hole, a sleeve having a length smaller than the distance between the valve body and the stop body, and a sleeve loosely fitted to the piston rod between the valve body and the stop body, In a reciprocating piston pump fixed to the inner wall of the cylinder pipe, and a packing that holds the sleeve in a watertight manner and slidably,
A wear resistant layer is formed on the outer surface of the sleeve, and the wear resistant layer is composed of a hard chromium plating layer formed on the surface of the sleeve base material and a chromium oxide coating layer formed on the hard chromium plating layer. Good.

[0013]

According to the reciprocating piston pump having the above-mentioned structure, the wear resistant layer is formed on the inner surface of the cylinder pipe, the outer surface of the piston rod or the outer surface of the sleeve which constitutes the sliding portion. Is composed of a hard chrome plating layer formed on the surface of each base material and a chrome oxide coating layer formed on the hard chrome plating layer. Since it is filled, cracks are less likely to occur even if stress is applied to the notches such as needle holes and cracks.

Further, the chromium oxide coating layer in which chromium oxides are strongly bonded has a rigid and dense structure and exhibits excellent wear resistance. In particular, among the chromium oxides that compose the coating layer, the chromium oxides filled in the needle holes and cracks of the hard chromium plating layer react at the boundary with the iron-based base material, and spinel type such as FeO ・ Cr ₂ O ₃ Therefore, the bond strength between the base material and the hard chrome plating layer is increased and the risk of peeling is reduced.

The chromium oxide coating layer has a particle size of 1
Since it is a fine ceramic particle having a size of μm or less, it has a high hardness with almost no pores, and a dense and smooth surface layer can be obtained. Therefore, the friction coefficient between parts is reduced, the sliding characteristics are improved, and the wear resistance is greatly improved, which makes it possible to extend the life of the piston pump significantly and maintain the equipment used. Will also be extremely easy.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. The reciprocating piston pump of the present invention,
It is characterized in that a surface treatment is applied to the cylinder pipe, piston rod or sleeve that constitutes the sliding part to form a wear resistant layer as shown in Fig. 1. The basic structure of the piston pump itself is 2 and that shown in FIG.

Therefore, the constituent elements of the piston pump itself are designated by the same reference numerals as those shown in FIGS. 2 and 3, and the illustration thereof is omitted.

That is, the reciprocating piston pump according to this embodiment, as shown in FIGS. 1 and 2, reciprocates in the cylinder pipe 3 connected to the suction port 1 and the discharge port 2 and in the cylinder pipe 3. With piston rod 4,
In a reciprocating piston pump for reciprocatingly moving a piston 5 inserted into the tip of the piston rod 4 together with the piston rod 4 to deliver a pressurized fluid, the inner surface of the cylinder pipe 3 and the piston Wear-resistant layers 11a,
11b. The wear resistant layers 11a and 11b are adhered to the hard chrome plating layers 12a and 12b formed on the surfaces of the base materials of the cylinder pipe 3 and the piston rod 4 and the hard chrome plating layers 12a and 12b, respectively. It is composed of the formed chromium oxide coating layers 13a and 13b.

As an embodiment of a reciprocating piston pump having another type, as shown in FIGS. 1 and 3, a piston rod 4 reciprocating in a cylinder pipe 3 having a suction port 1 and a discharge port 2, A valve body 6 provided at the tip of the piston rod 4, a stopper body 8 disposed at the piston rod 4 at a distance from the valve body 6 and having a through hole 7, the valve body 6 and the stopper body 8. Has a length l less than the distance L of
A sleeve 9 which is loosely fitted to the piston rod 4 between the valve body 6 and the stopper body 8, and a packing 10 which is fixed to the inner wall of the cylinder pipe 3 and holds the sleeve 9 in a watertight and slidable manner. In the reciprocating piston pump including the above, a wear-resistant layer 11c is formed on the outer surface of the sleeve 9, and the wear-resistant layer 11c includes a hard chromium plating layer 12c formed on the surface of the base material of the sleeve 9 and the hard chromium-plated layer 12c. It may be composed of a chromium oxide coating layer 13c formed on the chromium plating layer 12c.

Such wear resistant layers 11a, 11b, 11
c is manufactured by the manufacturing method as described below. First, the hard chrome plating layers 12a, 12b, 12c are formed by electrolytic plating, PVD (physical vapor deposition), thermal spraying, or CV.
It is formed by a general-purpose surface treatment method such as D (chemical vapor deposition) method. For example, in the case of the electrolytic plating method, the base metal such as the cylinder pipe 3, the piston rod 4 or the sleeve 9 is connected to the negative electrode, while the positive electrode is formed by a metal rod having a large ionization tendency, and then the chromic acid compound solution is used. A predetermined voltage is applied between the electrodes by using this as an electrolytic solution, and by the electrolytic action, chromium metal is deposited and adhered on the surface of the base metal to form hard chromium plating layers 12a, 12b, 12c. The thickness of the plating layers 12a, 12b, 12c can be easily controlled by the applied voltage and the energization time, and usually 30 to
It is set to about 70 μm.

Next, the chromium oxide coating layers 13a, 1
In the step of forming 3b and 13c, first, a solution containing a chromium compound such as CrO ₃ is attached to the surface of the base material by means such as coating or dipping, and then the base material to which the solution is attached is heated to a temperature of 500 to 600 ° C. (Preferably near 550 ° C)
Hard chrome plating layer 12
Chromium oxide (Cr ₂ O ₃ ) on the surface of a, 12b, 12c
A coating layer containing as a main component is formed.

The firing temperature is set in the range of 500 to 600 ° C. in order to change CrO ₃ to Cr ₂ O ₃ . In this temperature range, there is no risk of degrading the base metal. As the chromium compound to be used, in addition to the above-mentioned chromic anhydride (CrO ₃ ), chromic acid (H ₂ CrO ₄ ) combined with water, chromium chloride (CrCl ₃ · nH)
₂ O), chromium nitrate [Cr (NO ₃ ) ₃ .6H ₂ O],
Chromium acetate _{[Cr (OAC) 3 · 4H} 2 O], using a chromium sulfate _{[Cr 2 (SO 4) 3} · 15H 2 O] , zinc or soluble complex chromium compound combined with magnesium.

As described above, the step of depositing the chromium compound solution and the firing step are combined to form one cycle, and this operation is repeated for a plurality of cycles to oxidize the surfaces of the hard chromium plating layers 12a, 12b, 12c. Dense and strong coating layers 13a, 13b, 13c containing chromium (Cr ₂ O ₃ ) as a main component are formed. The thickness of the chromium oxide coating layers 13a, 13b, 13c is controlled by the number of times the operation cycle is repeated, and is usually set to 1 to 10 μm.

In this way, wear resistant layers 11a, 11b, 11c are formed on the surfaces of the base materials of the cylinder pipe 3, the piston rod 4, and the sleeve 9 which form the sliding portion of the piston pump, and the hard chrome plated layer 12a, 12b, 12
Chromium oxide is filled in the needle holes and cracks 14 formed in c, so that even if stress acts on the notch portions such as the needle holes and cracks 14, there is little risk of cracking.

Further, the chromium oxide coating layers 13a, 13b and 13c in which the chromium oxides are firmly bonded to each other have a hard and dense structure and exhibit excellent wear resistance. In particular, among the chromium oxides forming the coating layer, the chromium oxides filled in the needle holes and cracks 14 of the hard chromium plating layer react at the boundary with the iron-based base material, and FeO.Cr ₂ O
To form spinel-type crystallite compounds such as ₃
The bonding strength between the base material and the hard chrome plated layers 13a, 13b, 13c is increased, and the risk of peeling is reduced.

Further, the chromium oxide coating layers 13a, 1
Since 3b and 13c are fine ceramic particles having a particle size of 1 μm or less, they have high hardness with almost no pores, and a dense and smooth surface layer can be obtained. Therefore, the friction coefficient between parts is reduced, the sliding characteristics are improved, and the wear resistance is greatly improved, which makes it possible to extend the life of the piston pump significantly and also to maintain the equipment used. It becomes extremely easy.

Next, the effect of the reciprocating piston pump according to this embodiment will be described more specifically.

A reciprocating piston pump having a connection diameter of 3/4 B as shown in FIG. 2 (discharge pressure 50 kg / cm ² , discharge amount 3
(0 l / min) was prepared, and a hard chrome plating layer having a thickness of 30 μm was formed on the inner surface of the cylinder pipe by an electrolysis method as Example 1, and then a chrome oxide coating layer having a thickness of 5 μm was further deposited to form wear resistance. A reciprocating piston pump with layers was prepared.

Here, the chromium oxide coating layer is the base metal on which the hard chromium plating layer is formed, CrO ₃ being 20
It was formed by repeating 15 cycles of immersing in an aqueous solution containing wt% to adhere CrO ₃ to the surface of the base metal and then firing at a temperature of about 550 ° C.

Further, as Example 2, a reciprocating piston pump having the same wear resistant layer as that of Example 1 formed on the outer surface of the piston rod was prepared.

Further, as a third embodiment, a piston pump having the same wear resistant layer as the specifications of the first embodiment formed on both the inner surface of the cylinder pipe and the outer surface of the piston rod was prepared.

As Comparative Examples 1 to 3, piston pumps were prepared in which only the hard chromium plating layer having a thickness of 30 μm was formed instead of the wear resistant layer formed in Examples 1 to 3.

The reciprocating piston pumps of Examples 1 to 3 and Comparative Examples 1 to 3 prepared in this way were mounted on a pesticide sprayer, and the wear amount of each part after running for a total of 300 hours was measured. The measurement was performed and the results shown in Table 1 below were obtained.

[0034]

[Table 1] As is clear from the results in Table 1, in the reciprocating piston pumps of Examples 1 to 3 in which the chromium oxide coating layer was formed, it was proved that the wear amount was extremely low as compared with Comparative Examples 1 to 3, It can be seen that the life of the reciprocating piston pump can be greatly extended.

Next, two reciprocating piston pumps (discharge pressure 50 kg / cm ² , discharge amount 2.3 l / min) having a connection port diameter of 1/2 B as shown in FIG. A piston pump having the same wear-resistant layer as the specifications of No. 1 is formed on the outer peripheral surface of the sleeve, while as Comparative Example 4, a piston pump having only a 30 μm thick chromium oxide plating layer is prepared. The operation was performed under the same conditions as in No. 3, and the wear amount of the sleeve was measured, and the results shown in Table 2 below were obtained.

[0036]

[Table 2] As is clear from the results in Table 2, in Example 4 as well, peeling of the hard chromium plating layer is not observed, and it is understood that the life of the piston pump can be extended. On the other hand, in Comparative Example 4, peeling of the hard chromium plating layer and wear of the sleeve were remarkable, and it was found that replacement was required at an early stage.

[0037]

As described above, according to the reciprocating piston pump of the present invention, the wear resistant layer is formed on the inner surface of the cylinder pipe, the outer surface of the piston rod or the outer surface of the sleeve which constitutes the sliding portion. This wear-resistant layer is composed of a hard chrome plating layer formed on the surface of each base material and a chrome oxide coating layer formed by depositing on this hard chrome plating layer. Since chromium oxide is filled in cracks and cracks, there is little risk of cracking even when stress acts on notches such as needle holes and cracks.

Further, the chromium oxide coating layer in which chromium oxides are strongly bonded has a hard and dense structure and exhibits excellent wear resistance. In particular, among the chromium oxides that compose the coating layer, the chromium oxides filled in the needle holes and cracks of the hard chromium plating layer react at the boundary with the iron-based base material and spinel type such as FeO · Cr ₂ O ₃ Therefore, the bond strength between the base material and the hard chrome plating layer is increased and the risk of peeling is reduced.

The particle size of the chromium oxide coating layer is 1
Since it is a fine ceramic particle having a size of μm or less, it has a high hardness with almost no pores, and a dense and smooth surface layer can be obtained. Therefore, the friction coefficient between parts is reduced, the sliding characteristics are improved, and the wear resistance is greatly improved, which makes it possible to extend the life of the piston pump significantly and maintain the equipment used. Will also be extremely easy.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view showing a wear resistant layer which is a main part of an embodiment of a reciprocating piston pump according to the present invention.

FIG. 2 is a cross-sectional view showing a structural example of a reciprocating piston pump.

FIG. 3 is a sectional view showing a structural example of another reciprocating piston pump.

[Explanation of symbols]

1 Suction Port 2 Discharge Port 3 Cylinder Pipe 4 Piston Rod 5 Piston 6 Valve Body 7 Through Hole 8 Stopper 9 Sleeve 10 Packing 11a, 11b, 11c Wear Resistant Layer 12a, 12b, 12c Hard Chrome Plated Layer 13, 13a, 13b, 13c Chromium oxide coating layer 14 Needle holes and cracks

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kosuke Kawaguchi 1554-3, Inuma, Togane-shi, Chiba Maruyama Manufacturing Co., Ltd. Togane factory (72) Ino, Adachi, Inugata, Togane-shi, Chiba 1554 -3 Maruyama Manufacturing Co., Ltd. Togane Factory

Claims (2)

[Claims] 1. A piston rod provided with a cylinder pipe connected to a suction port and a discharge port, and a piston rod reciprocating in the cylinder pipe, wherein a piston reciprocally fitted in a tip end portion of the piston rod is a piston rod. In a reciprocating piston pump that reciprocates together to deliver a pressurized fluid, a wear resistant layer is formed on at least one surface of the inner surface of the cylinder pipe and the outer surface of the piston rod. A reciprocating piston pump comprising a hard chromium plating layer formed on the surface and a chromium oxide coating layer formed on the hard chromium plating layer. 2. A piston rod that reciprocates in a cylinder pipe having a suction port and a discharge port, a valve body provided at the tip of the piston rod, and a piston rod disposed at a distance from the valve body. A stop body having a through hole, a sleeve having a length smaller than the distance between the valve body and the stop body and loosely fitted to the piston rod between the valve body and the stop body;
In a reciprocating piston pump fixed to the inner wall of the cylinder pipe and provided with a packing that holds the sleeve in a watertight manner and slidably, a wear resistant layer is formed on an outer surface of the sleeve, and the wear resistant layer is formed. A reciprocating piston pump comprising a hard chromium plating layer formed on the surface of the sleeve base material, and a chromium oxide coating layer formed on the hard chromium plating layer.