Gear rack hydraulic cylinder for fire fighting truck

Abstract

The invention discloses a gear and rack hydraulic cylinder for a fire fighting truck. The gear and rack hydraulic cylinder comprises a cylinder body assembly, a rack assembly and a gear. The rack assembly is installed in the cylinder body and comprises a rack, a front piston and a rear piston, a welding groove is formed in the bottom of the rack, wear-resistant materials are welded in the welding groove and on the surface, close to the welding groove, of the rack, the wear-resistant materials form a wear-resistant layer, and the wear-resistant layer makes direct contact with the inner wall of the main cylinder body. The wear-resistant material is welded to the bottom of the rack, the wear-resistant layer is constructed to replace a traditional supporting design that a cylinder body is provided with a hole to install a positioning pin, and the design has the advantages that the cylinder body is not provided with the hole, the overall sealing performance of the hydraulic cylinder can be remarkably improved, the oil leakage condition is avoided, meanwhile, external rainwater cannot enter the hydraulic cylinder, and the service life of the hydraulic cylinder is prolonged. Therefore, the inner wall of the cylinder body is effectively prevented from being rusted; the welding groove is formed in the bottom of the rack, so that the welding effect of the wear-resistant material can be improved, and the connection between the constructed wear-resistant layer and the rack is more stable.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic cylinders, and in particular to a rack and pinion hydraulic cylinder for fire trucks. Background Art

[0002] The gear rack hydraulic cylinder is a frequently used actuator in fire trucks. Fire trucks are mainly used for fire fighting and rescue, and their reliability and safety requirements are high during operation. As an important actuator, the hydraulic cylinder has high reliability requirements. Therefore, as an actuator, the hydraulic cylinder must not only meet various travel and angle adjustment requirements, but also ensure the reliability and stability of the hydraulic cylinder at a certain angle or height, which is crucial for the main fire truck.

[0003] In order to prevent the rack from deforming during the reciprocating motion of the rack, most existing rack and pinion hydraulic cylinders have holes in the middle of the cylinder body and insert positioning pins to fix the rack support element inside the cylinder body. This support method requires a hole in the middle of the cylinder body, but due to the high butter pressure in the cylinder body, oil leakage is likely to occur during the movement of the rack and pinion hydraulic cylinder. At the same time, external rainwater is also likely to enter the cylinder body through the hole, causing the inner wall of the cylinder body to rust, resulting in leakage of the rack and pinion hydraulic cylinder. Summary of the invention

[0004] In view of this, the present invention provides a rack and pinion hydraulic cylinder for a fire truck, which can prevent oil leakage and internal leakage of the rack and pinion hydraulic cylinder.

[0005] To achieve the above object, the present invention provides the following technical solutions: A rack and pinion hydraulic cylinder for a fire truck comprises a cylinder assembly, a rack assembly and a gear.

[0006] Among them, the cylinder body assembly includes a front end pressure cover, a rear end pressure cover, a main cylinder body and a sub-cylinder body, the front end pressure cover and the rear end pressure cover are respectively installed on the front and rear ends of the main cylinder body, the main cylinder body is provided with a mounting hole, the sub-cylinder body cover is provided on the mounting hole, the gear is installed in the sub-cylinder body, and part of it extends into the main cylinder body through the mounting hole; the rack assembly is installed in the cylinder body, the rack assembly includes a rack, a front piston and a rear piston, the rack is meshed with the gear, the front piston and the rear piston are respectively installed on the front and rear ends of the rack, a welding groove is provided at the bottom of the rack, wear-resistant material is welded on the surface of the rack in the welding groove and near the welding groove, the wear-resistant material forms a wear-resistant layer, and the wear-resistant layer is in direct contact with the inner wall of the main cylinder body.

[0007] Preferably, a plurality of the welding grooves are provided, and the plurality of welding grooves are spaced apart around the axis of the arc-shaped bottom surface of the rack.

[0008] Preferably, around the axis of the arc-shaped bottom surface, the arc angle of the arrangement of the plurality of welding grooves is 60°-180°.

[0009] Preferably, the welding groove extends along the axial direction of the rack, and the length of the welding groove is greater than half the length of the rack.

[0010] Preferably, a plurality of the welding grooves are provided, and the plurality of welding grooves are spaced apart from each other along the axial direction of the arc-shaped bottom surface of the rack.

[0011] Preferably, the welding groove extends along the circumference of the arc-shaped bottom surface, and the curvature of the welding groove is greater than half of the curvature of the arc-shaped bottom surface.

[0012] Preferably, the wear-resistant material is aluminum bronze, and the aluminum bronze is welded on the surface of the rack in the welding groove and near the welding groove by a surfacing process.

[0013] Preferably, the wear-resistant material is high manganese steel, and the high manganese steel is welded on the surface of the rack in the welding groove and near the welding groove by a surfacing process.

[0014] Compared with the prior art, the present application discloses a rack and pinion hydraulic cylinder for a fire truck, which replaces the traditional support design of opening holes in the cylinder body to install locating pins by welding wear-resistant material at the bottom of the rack and constructing a wear-resistant layer. The advantage of such a design is that the cylinder body has no openings, which can significantly improve the overall sealing performance of the hydraulic cylinder and avoid oil leakage. At the same time, external rainwater cannot enter the interior of the hydraulic cylinder, thereby effectively avoiding rust on the inner wall of the cylinder body. By constructing a welding groove at the bottom of the rack, the welding effect of the wear-resistant material can be effectively improved, so that the connection between the constructed wear-resistant layer and the rack is more stable, effectively avoiding the wear-resistant layer from falling off.

[0015] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a cross-sectional view of a rack and pinion hydraulic cylinder for a fire truck disclosed in an embodiment of the present application; Figure 2 is a front view of a rack of a gear rack hydraulic cylinder for a fire truck disclosed in an embodiment of the present application; Figure 3 is an axial cross-sectional view of a rack of a gear rack hydraulic cylinder for a fire truck disclosed in an embodiment of the present application; Figure 4 It is a front view of a rack (with a wear-resistant layer) of a gear rack hydraulic cylinder for a fire truck disclosed in an embodiment of the present application; Figure 5It is an axial cross-sectional view of a rack (with a wear-resistant layer) of a rack and pinion hydraulic cylinder for a fire truck disclosed in an embodiment of the present application.

[0017] Reference numerals: 1. Cylinder assembly; 11. Front end gland; 12. Rear end gland; 13. Main cylinder; 14. Auxiliary cylinder; 2. rack assembly; 21. rack; 22. front piston; 23. rear piston; 211. welding groove; 3. Gears; 4. Wear-resistant layer. DETAILED DESCRIPTION

[0018] The invention discloses a gear rack hydraulic cylinder for a fire truck, which can prevent the gear rack hydraulic cylinder from leaking oil and internal leakage.

[0019] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0020] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0021] Reference below Figures 1 to 5 A rack and pinion hydraulic cylinder for a fire truck in an embodiment of the present invention is described.

[0022] The embodiment of the present application discloses a rack and pinion hydraulic cylinder for a fire truck, comprising: a cylinder assembly 1, a rack 21 assembly 2 and a gear 3.

[0023] Among them, the cylinder body assembly 1 includes a front end pressure cover 11, a rear end pressure cover 12, a main cylinder body 13 and a sub-cylinder body 14, the front end pressure cover 11 and the rear end pressure cover 12 are respectively installed at the front and rear ends of the main cylinder body 13, a mounting hole is opened on the main cylinder body 13, the sub-cylinder body 14 is covered on the mounting hole, the gear 3 is installed in the sub-cylinder body 14, and part of it extends into the main cylinder body 13 through the mounting hole; the rack 21 assembly 2 is installed in the cylinder body, the rack 21 assembly 2 includes a rack 21, a front piston 22 and a rear piston 23, the rack 21 is meshed with the gear 3, the front piston 22 and the rear piston 23 are respectively installed at the front and rear ends of the rack 21, a welding groove 211 is opened at the bottom of the rack 21, and wear-resistant material is welded on the surface of the rack 21 in the welding groove 211 and near the welding groove 211, the wear-resistant material forms a wear-resistant layer 4, and the wear-resistant layer 4 is in direct contact with the inner wall of the main cylinder body 13.

[0024] In order to ensure that the rack in the gear rack hydraulic cylinder does not deform during the reciprocating motion, most of the existing gear rack hydraulic cylinders adopt a design in which holes are opened on the cylinder body and positioning pins are installed in the holes to support the rack. Although this design can effectively support the rack, the oil pressure inside the gear rack hydraulic cylinder is relatively high when it is moving. The holes on the cylinder body are prone to cause the risk of oil leakage. At the same time, external rainwater can easily enter the cylinder body through the holes, causing corrosion of the inner wall of the cylinder body, and then causing leakage in the hydraulic cylinder.

[0025] In this embodiment, wear-resistant material is welded at the bottom of the rack 21 to construct a wear-resistant layer 4 to replace the traditional support design of the cylinder body opening for installing the positioning pin. The advantage of such a design is that the cylinder body has no openings, which can significantly improve the overall sealing performance of the hydraulic cylinder and avoid oil leakage. At the same time, external rainwater cannot enter the interior of the hydraulic cylinder, thereby effectively avoiding rust on the inner wall of the cylinder body.

[0026] Furthermore, by constructing a welding groove 211 at the bottom of the rack 21, the welding effect of the wear-resistant material can be effectively improved, so that the connection between the constructed wear-resistant layer 4 and the rack 21 is more stable, and the wear-resistant layer 4 can be effectively prevented from falling off.

[0027] In some embodiments, a plurality of welding grooves 211 are provided, and the plurality of welding grooves 211 are spaced apart around the axis of the arc-shaped bottom surface of the rack 21. The provision of the plurality of welding grooves 211 can increase the area of ​​the wear-resistant layer 4 to enhance the support of the wear-resistant layer 4 to the rack 21, and at the same time, can also improve the connection strength between the wear-resistant layer 4 and the rack 21. Figure 2 and Figure 3 As shown, six welding grooves 211 are arranged at the bottom of the rack 21 , and the six welding grooves 211 are arranged on the arc-shaped bottom surface of the rack 21 at even intervals around the axis of the arc-shaped bottom surface.

[0028] In some embodiments, around the axis of the arc-shaped bottom surface, the arrangement arc of the plurality of welding grooves 211 is 60°-180°, and the arrangement arc of the plurality of welding grooves 211 can be adjusted according to actual needs, and is not specifically limited here; for example Figure 2 and Figure 3 As shown, six welding grooves 211 are arranged at 120° on the arc-shaped bottom surface of the rack 21 .

[0029] In some embodiments, for example Figure 2 As shown, the welding groove 211 extends along the axial direction of the rack 21 , and the length of the welding groove 211 is greater than half the length of the rack 21 , so that the wear-resistant layer 4 can cover most of the bottom surface of the rack 21 to provide better support for the rack 21 .

[0030] In some embodiments, a plurality of welding grooves 211 are provided, and the plurality of welding grooves 211 are spaced apart axially along the arc-shaped bottom surface of the rack 21. The provision of the plurality of welding grooves 211 can increase the area of ​​the wear-resistant layer 4 to enhance the support of the wear-resistant layer 4 to the rack 21, and at the same time, can also improve the connection strength between the wear-resistant layer 4 and the rack 21.

[0031] Furthermore, the welding groove 211 extends along the circumference of the arc-shaped bottom surface, and the curvature of the welding groove 211 is greater than half of the curvature of the arc-shaped bottom surface, so that the wear-resistant layer 4 can cover most of the bottom surface of the rack 21 to provide better support for the rack 21.

[0032] In some embodiments, the wear-resistant material is aluminum bronze, which is welded on the surface of the rack 21 in and near the welding groove 211 through a surfacing process.

[0033] In some embodiments, the wear-resistant material is high manganese steel, and the high manganese steel is welded on the surface of the rack 21 in and near the welding groove 211 by a surfacing process.

[0034] The wear-resistant material can also be other wear-resistant and high-temperature resistant materials other than those in the above embodiments, which is not specifically limited here.

[0035] Other structures and operations of the rack and pinion hydraulic cylinder for a fire truck according to the embodiment of the present invention are well known to those skilled in the art and will not be described in detail here.

[0036] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0037] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A rack and pinion hydraulic cylinder for a fire truck, characterized in that: include: Cylinder assembly, rack assembly and gear; The cylinder assembly comprises a front end pressure cover, a rear end pressure cover, a main cylinder body and a sub-cylinder body, wherein the front end pressure cover and the rear end pressure cover are respectively mounted on the front and rear ends of the main cylinder body, a mounting hole is opened on the main cylinder body, the sub-cylinder body cover is arranged on the mounting hole, the gear is mounted in the sub-cylinder body, and part of the gear extends into the main cylinder body through the mounting hole; The rack assembly is installed in the cylinder body, and the rack assembly includes a rack, a front piston and a rear piston. The rack is meshed with the gear, and the front piston and the rear piston are respectively installed at the front and rear ends of the rack. A welding groove is opened at the bottom of the rack, and wear-resistant material is welded on the surface of the rack in the welding groove and near the welding groove. The wear-resistant material forms a wear-resistant layer, and the wear-resistant layer is in direct contact with the inner wall of the main cylinder body.

2. The rack and pinion hydraulic cylinder for a fire truck according to claim 1, characterized in that: A plurality of welding grooves are provided, and the plurality of welding grooves are spaced apart around the axis of the arc-shaped bottom surface of the rack.

3. The rack and pinion hydraulic cylinder for a fire truck according to claim 2, characterized in that: Around the axis of the arc-shaped bottom surface, the arc angle of the arrangement of the plurality of welding grooves is 60°-180°.

4. The rack and pinion hydraulic cylinder for a fire truck according to claim 2, characterized in that: The welding groove extends along the axial direction of the rack, and the length of the welding groove is greater than half the length of the rack.

5. The rack and pinion hydraulic cylinder for a fire truck according to claim 1, characterized in that: A plurality of welding grooves are provided, and the plurality of welding grooves are spaced apart from each other along the axial direction of the arc-shaped bottom surface of the rack.

6. The rack and pinion hydraulic cylinder for a fire truck according to claim 5, characterized in that: The welding groove extends along the circumference of the arc-shaped bottom surface, and the curvature of the welding groove is greater than half of the curvature of the arc-shaped bottom surface.

7. The rack and pinion hydraulic cylinder for a fire truck according to claim 1, characterized in that: The wear-resistant material is aluminum bronze, and the aluminum bronze is welded on the surface of the rack in the welding groove and near the welding groove by a surfacing process.

8. The rack and pinion hydraulic cylinder for a fire truck according to claim 1, characterized in that: The wear-resistant material is high manganese steel, and the high manganese steel is welded on the surface of the rack in the welding groove and near the welding groove by a surfacing process.

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