Forklift speed limiting protection valve

Abstract

The present invention discloses a forklift speed limiting protection valve. It comprises a valve seat, a valve sleeve arranged on the valve seat, a valve core arranged on the valve sleeve, a large spring, and a small spring and a steel ball arranged in the corresponding inner cavity of the valve core, and also comprises a connecting sleeve connected to the corresponding end of the valve seat, the large spring is arranged in the inner cavity of the connecting sleeve, the corresponding end of the valve core is provided with a pressure reducing orifice plate connected to the corresponding end of the large spring, and the valve core is respectively provided with a lubrication hole and a plurality of groove oil holes. The forklift speed limiting protection valve has a simple and reasonable structure, a small volume, and a balanced and reliable operation.

Description

Technical Field

[0001] The invention relates to a forklift, and in particular to a speed limiting protection valve for a forklift. Background Art

[0002] During forklift operation, when the high-position forklift is lowering, it must descend slowly due to the heavy load, so the lifting mechanism of the forklift must be equipped with a speed limit protection mechanism. The structural rationality and operating performance of the limit protection valve directly affect the balance and reliability of the forklift's descent. The existing related speed limit protection valves need to be improved and enhanced in terms of their structural composition and corresponding operating performance, and they are relatively large in size, occupy a large space, are not stable enough, and are prone to safety problems. Summary of the invention

[0003] The purpose of the present invention is to provide a forklift speed limiting protection valve in view of the above-mentioned deficiencies in the prior art. The forklift speed limiting protection valve has a simple and reasonable structure, a small volume, and a balanced and reliable operation.

[0004] The technical solution of the forklift speed limiting protection valve of the present invention includes a valve seat, a valve sleeve arranged on the valve seat, a valve core arranged on the valve sleeve, a large spring, and a small spring and a steel ball arranged in the corresponding inner cavity of the valve core, and also includes a connecting sleeve connected to the corresponding end of the valve seat, the large spring is arranged in the inner cavity of the connecting sleeve, the corresponding end of the valve core is provided with a pressure reducing orifice plate connected to the corresponding end of the large spring, the valve core is respectively provided with a lubrication hole and a plurality of groove oil holes, the valve sleeve is provided with a plurality of valve sleeve inner cavity oil holes respectively connected to the corresponding inner cavity of the valve sleeve and the corresponding cavity of the valve seat, and a plurality of valve sleeve groove oil holes respectively connected to the groove oil holes of the valve core and the corresponding cavity of the valve seat.

[0005] The pressure reducing orifice plate is provided with a plurality of pressure reducing holes located at the center and around the center.

[0006] The invention adopts the structural principle of "differential pressure reducing valve + throttle valve", has balanced operation and good practicality, and can stably limit the descending speed of the heavy-loaded fork when installed in the lifting oil circuit, thereby improving the safety of the heavy-load descending operation of the forklift. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention; Figure 2 for Figure 1 Schematic diagram of the pressure reducing orifice structure. DETAILED DESCRIPTION

[0008] In order to further understand the technical solution of the present invention, the present invention is further described by the following embodiments in conjunction with the accompanying drawings. Figure 1 and 2In this embodiment, the forklift speed limiting protection valve includes a valve seat 1, a valve sleeve 2 disposed in the valve seat 1, a valve core 3 disposed in the valve sleeve 2, a large spring 7 and a relatively small spring 4, and a connecting sleeve 8 connected to the corresponding end of the valve seat. The small spring 4 and a steel ball 5 located at the corresponding end of the small spring 4 are arranged in the inner cavity of the valve core near the oil hole 11 of the inner cavity of the valve sleeve.

[0009] The large spring 7 is arranged in the inner cavity 17 of the corresponding end of the connecting sleeve and the valve sleeve, and the corresponding end of the valve core is provided with a pressure reducing orifice plate 6 connected to the corresponding end of the large spring. The pressure reducing orifice plate 6 is provided with a total of 5 pressure reducing holes 19 located in the center and around the center. The inner cavity 17 of the corresponding end of the connecting sleeve and the valve sleeve can be connected to the inner cavity 16 of the valve core through the pressure reducing holes of the pressure reducing orifice plate.

[0010] The corresponding grooves of the valve core are respectively provided with lubrication holes 12 and 6 groove oil holes 15 distributed around the circumference. The valve sleeve 2 is respectively provided with 8 valve sleeve inner cavity oil holes 11 and 8 valve sleeve groove oil holes 14 distributed around the circumferential wall.

[0011] The eight valve sleeve inner cavity oil holes 11 arranged on the valve sleeve 2 are respectively connected to the valve seat inner cavity 18 and the inner cavity of the corresponding part of the valve sleeve, and the corresponding cavity 13 between the valve seat and the valve sleeve. The eight valve sleeve groove oil holes 14 arranged on the valve sleeve 2 are respectively connected to the groove oil holes 15 of the valve core and the corresponding cavity 13 between the valve seat and the valve sleeve.

[0012] One end of the connecting sleeve of the forklift speed limiting protection valve (the inner cavity of the connecting sleeve) is connected to the multi-way valve, and the inner cavity 18 of the valve seat at the other end of the forklift speed limiting protection valve is connected to the lifting cylinder.

[0013] When the forklift working multi-way reversing valve is in the "lifting" position, the high-pressure oil from the multi-way valve enters the corresponding cavity 13 between the valve seat and the valve sleeve through the inner cavity 17 of the connecting sleeve, the pressure reducing hole 19 of the pressure reducing orifice plate, the inner cavity 16 of the valve core and the groove oil hole 15, and the groove oil hole 14 of the valve sleeve, and then enters the inner cavity 18 of the valve seat through the inner cavity oil hole 11 of the valve sleeve and is connected to the lifting cylinder. At this time, the oil flow does not produce throttling, and the cylinder lifts at a normal working speed;

[0014] When the multi-way valve is in the descending position, the multi-way valve is connected to the oil return line, and the pressure oil from the lifting oil cylinder enters the valve core cavity through the valve seat cavity 18, the valve sleeve cavity oil hole 11, the corresponding cavity between the valve seat and the valve sleeve, the valve sleeve groove oil hole and the groove oil hole 15, and then enters the connecting sleeve cavity through the pressure reducing orifice plate 6, and flows back to the oil tank through the multi-way valve. At this time, due to the pressure reducing hole of the pressure reducing orifice plate, the valve core cavity and the connecting sleeve cavity produce a pressure difference, and the valve core cavity pressure is greater than the connecting sleeve cavity pressure. At the same time, under the action of the valve core cavity pressure, the steel ball 5 compresses the small spring to move to the left, and the pressure oil enters the left end face of the valve core. When the pressure difference between the valve core cavity and the connecting sleeve cavity exceeds the spring force of the large spring, the pressure oil pushes the valve core to move right, so that the number of holes of the valve sleeve groove oil hole connected to the corresponding cavity of the valve seat (i.e., the cavity between the valve seat and the valve sleeve) 13 is reduced, and throttling is achieved to reduce the amount of oil passing through, and the oil cylinder slowly descends.

Claims

1. A forklift speed limiting protection valve, comprising a valve seat, a valve sleeve arranged on the valve seat, a valve core arranged on the valve sleeve, a large spring, and a small spring and a steel ball arranged in the corresponding inner cavity of the valve core, wherein the characteristics are It also includes a connecting sleeve connected to the corresponding end of the valve seat, the large spring is arranged in the inner cavity of the connecting sleeve, the corresponding end of the valve core is provided with a pressure reducing orifice plate connected to the corresponding end of the large spring, and the valve core is respectively provided with a lubrication hole and a plurality of groove oil holes, and the lubrication hole is opened at the bottom of the corresponding end of the inner cavity of the valve core; When the multi-way valve is in the descending position, the pressure oil from the lifting cylinder enters the valve core cavity through the valve seat cavity, the valve sleeve cavity oil hole, the corresponding cavity between the valve seat and the valve sleeve, the valve sleeve groove oil hole and the groove oil hole, and then enters the connecting sleeve cavity through the pressure reducing orifice plate, and flows back to the oil tank through the multi-way valve. At this time, due to the effect of the pressure reducing hole of the pressure reducing orifice plate, a pressure difference is generated between the valve core cavity and the connecting sleeve cavity, and the pressure in the valve core cavity is greater than the pressure in the connecting sleeve cavity. At the same time, under the action of the valve core cavity pressure, the steel ball compresses the small spring to move to the left, and the pressure oil enters the left end face of the valve core. When the pressure difference between the valve core cavity and the connecting sleeve cavity exceeds the spring force of the large spring, the pressure oil pushes the valve core to move right, reducing the number of holes in the valve sleeve groove oil holes connected to the corresponding cavity of the valve seat, thereby achieving throttling to reduce the amount of oil passing through and the oil cylinder slowly descends.

2. The forklift speed limiting protection valve according to claim 1 is characterized in that The pressure reducing orifice plate is provided with a plurality of pressure reducing holes located at the center and around the center.

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