Air spring for cab of heavy truck with automatic height adjustment

An air spring for a cab of a heavy truck with automatic height adjustment, in which the air spring is provided between the cab and a frame of a truck and supports the cab with a pressure of air filling in the air spring, includes a canister in which an internal space is formed, and a piston movably mounted in the internal space of the canister and configured to ascend and descend relative to the canister. A port opening unit is provided adjacent to an intake port and an exhaust port of the piston, respectively. When the cab ascends or descends, each of the port opening units comes into contact with guides, each having an inclined surface, formed in the canister to open either the intake port or the exhaust port.

CROSS-REFERENCE(S) TO RELATED APPLICATIONS

The present application claims priority to Korean Patent Application No. 10-2021-0115520, filed on Aug. 31, 2021, the entire contents of which is incorporated herein for all purposes by this reference.

BACKGROUND OF PRESENT INVENTION

Field of Present Invention

The present invention relates to an air spring for a cab of a heavy truck, which cushions a cab for a driver accommodated in the heavy truck, and more particularly, to an air spring for a cab of a heavy truck with automatic height adjustment, which is located in the air spring and controls an internal pressure of the air spring to maintain a constant height when the cab ascends or descends beyond a predetermined range.

Description of Related Art

In a heavy truck, a cab for a driver in the heavy truck is provided in a form of being placed on an upper portion of a frame.

A front end portion of a cab130is hinged to a front end portion of a frame140, as shown inFIG.1and the cab130is supported by a suspension including an air spring100.

The air spring100applies a constant pressure in a space formed by a canister110and a piston120to make the cab130have a constant height.

As shown inFIG.1, the air spring100should be provided with a leveling valve150configured to supply or discharge air in or from the air spring100on one side of the air spring100.

A cab hinge bracket141of the cab130is provided on the frame140of a vehicle, a lower end portion of the rod mounting bracket142is fixed inside a cab hinge bracket141, and an upper end portion of the rod mounting bracket142is connected to a lower end portion of a leveling rod151. An upper end portion of the leveling rod151is hinged to a valve lever152extending laterally from the leveling valve150provided on an upper bracket143.

The air spring100includes the canister110and the piston120and is filled therein with air to serve a buffering function.

When the cab130is positioned at a normal height (seeFIG.3A), the valve lever152blocks a passage communicating with the air spring100in the leveling valve150to maintain the normal height of the cab130.

When the cab130descends from the normal height (see toFIG.3B), a front end portion of the valve lever152descends to open a passage through which air is supplied toward the air spring100within the leveling valve150and to supply air to the air spring100, and thus the cab130is raised.

On the other hand, when the cab130ascends (seeFIG.3C), the front end portion of the valve lever152ascends to open a passage through which the air is discharged from the air spring100within the leveling valve150, and thus the cab130is lowered.

However, according to the related art as described above, due to a structure in which the leveling valve150, the leveling rod151, the rod mounting bracket142, and the leveling rod151are link-connected using bolts, the number of parts is large to cause an increase in production cost.

Furthermore, since movable parts such as the leveling rod151and the valve lever152are exposed to the outside, a malfunction frequently occurs due to exposure to foreign materials.

BRIEF SUMMARY OF PRESENT INVENTION

Various aspects of the present invention are directed to providing an air spring for a cab of a heavy truck with automatic height adjustment, which is configured for maintaining a constant height of a cab without exposing a configuration for introducing air into the air spring or discharging the air therefrom.

Other objects and advantages of the present invention may be understood by the following description and become apparent with reference to the exemplary embodiments of the present invention. Further, it is obvious to those skilled in the art to which various exemplary embodiments of the present invention pertains that the objects and advantages of the present invention may be realized by the means as claimed and combinations thereof.

In accordance with various exemplary embodiments of the present invention, there is provided an air spring for a cab of a heavy truck with automatic height adjustment, which may be provided between a cab and a frame of a truck and may support the cab with a pressure of air filling in the air spring, including a canister in which a space may be formed, and a piston movably mounted in the internal space of the canister and configured to ascend and descend relative to the canister, wherein, a port opening unit may be provided adjacent to an intake port and an exhaust port of the piston, respectively, and when the cab ascends and descends, the port opening unit may come into contact with a guide on which an inclined surface is formed in the canister to open either the intake port or the exhaust port.

The guide may include an intake guide on which an intake guide surface inclined outward the canister toward a lower side of the canister may be formed, and an exhaust guide on which an exhaust guide surface inclined inward the canister toward the lower side of the canister, wherein the intake guide surface may be located at a position which is higher than a position of the exhaust guide surface.

A first support surface formed downward from a lower end portion of the intake guide surface in an ascending and descending direction of the piston may be formed in the intake guide, and a second support surface formed upwards from an upper end portion of the exhaust guide in an ascending and descending direction of the piston may be formed in the exhaust guide.

A lower end portion of the intake guide surface may be spaced from an upper end portion of the exhaust guide surface with a predetermined distance.

The port opening unit may be provided above each of the intake port and the exhaust port.

The port opening units respectively provided on the intake port and the exhaust port side may be located at a same height.

A holder configured to accommodate a corresponding port opening unit may be formed in the piston to intersect the intake port and the exhaust port.

Each of the port opening units may include a rod which is slidably provided in inside of the holder and in which a communication hole configured for fluidically communicating with the intake port or the exhaust port according to the sliding position is formed, a roller disposed at an end portion of the rod and configured to come into contact with the guide, and a spring elastically support the roller toward the guide.

The intake port and the exhaust port may be formed in the piston in an ascending and descending direction of the piston, and each of the port opening units may be provided to be adjacent to an upper end portion of the piston.

The intake guide may be spaced from the exhaust guide by a predetermined interval.

DETAILED DESCRIPTION

Hereinafter, air spring for a cab of a heavy truck with automatic height adjustment according to various exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In an air spring for a cab of a heavy truck with automatic height adjustment according to various exemplary embodiments of the present invention, an air spring1, which may be provided between a cab and a frame of a truck and supports the cab due to a pressure of air filling in the air spring1, may include a canister10in which a space may be formed, and a piston20mounted in inside of the canister10and configured to ascend and descend relative to the canister10. A port opening unit30may be provided adjacent to an intake port21and an exhaust port22formed in the piston20, respectively. In the exemplary embodiment of the present invention, each of the port opening units30may have the same structure. When the cab ascends or descends, each of the port opening units30may come into contact with guides11and12, each having an inclined surface, formed in the canister10to open either the intake port21or the exhaust port22.

The cab in which an occupant rides in the truck is located above the frame, and the air spring1may be provided between the cab and the frame, may maintain the cab at an appropriate position, and prevents a vibration due to traveling from being transferred to the occupant.

The canister10may be formed in a form of a barrel to accommodate components, which will be described below, in inside of the canister10.

The piston20may be inserted upwards from a lower end portion of the canister10and may block the canister10.

The cab may be supported by a pressure of air filling in a space formed by the canister10and the piston20. Furthermore, an intake port21configured to introduce the pressurized air into the air spring1and an exhaust port22configured to discharge the air in the air spring1to the outside are formed in the piston20. The intake port21and the exhaust port22are formed substantially in an ascending and descending direction of the canister10, and the intake port21or the exhaust port22may be opened or closed according to the pressure in the air spring1.

In various exemplary embodiments of the present invention, the pressure of the air spring1may be maintained within a predetermined range, and thus the cab may be automatically maintained at a constant height.

To the present end, in various exemplary embodiments of the present invention, an intake guide11and an exhaust guide12may be provided on the canister10, and the port opening unit30operated by the intake guide11and the exhaust guide12may be provided in the piston20.

When the canister10ascends or descends according to an internal pressure of the air spring1, each of the port opening units30may operate according to profiles of the intake guide11and the exhaust guide12to open the intake port21or the exhaust port22. When the internal pressure of the air spring1is low and the cab descends, the pressurized air from the outside thereof is introduced through the intake port21to the air spring1, and when the internal pressure of the air spring1is high and the cab ascends, the air in the air spring1is discharged to the outside through the exhaust port22. Accordingly, the pressure of the air spring1may be maintained within an appropriate range, and thus the cab may be also maintained at an appropriate height.

A profile may be formed on an internal surface of each of the intake guide11and the exhaust guide12to allow the port opening unit30to be operated in conjunction with the ascending and descending of the canister10.

When the canister10descends, the intake guide11may allow the port opening unit30provided at the intake port21to be operated. To the present end, an intake guide surface11aformed as an inclined surface and a first support surface11bformed as a vertical surface may be sequentially formed from the top portion to the bottom portion of the intake guide11. The intake guide surface11amay be formed as an inclined surface which may be inclined outward toward the canister10from the top portion to the bottom. Furthermore, the first support surface11bmay be formed downward from a lower end portion of the intake guide surface11a. The first support surface11bmay not be formed to be inclined and may be formed in the same direction as the ascending and descending direction of the canister10.

When the canister10ascends, the exhaust guide12may allow the port opening unit30provided at the exhaust port22to be operated. To the present end, an exhaust guide surface12aformed as an inclined surface and a second support surface12bformed as a vertical surface may be sequentially formed from the bottom the top portion of the exhaust guide12. The exhaust guide surface12amay be formed as an inclined surface which may be inclined inward toward the canister10from the top portion to the bottom. The second support surface12bmay be formed upwards from an upper end portion of the exhaust guide surface12a. Even in the exhaust guide12, the second support surface12bmay not be formed to be inclined and may be formed in the same direction as the ascending and descending direction of the canister10.

The intake guide surface11aand the first support surface11bformed in the intake guide11, and the exhaust guide surface12aand the second support surface12bformed in the exhaust guide12may form profiles by which the port opening unit30may be opened or blocked according to the ascending or descending of the canister10on the intake guide11and the exhaust guide12.

The intake guide11may be formed to be spaced from the exhaust guide12. For example, the intake guide11may be formed to be spaced from the exhaust guide12by an interval of 180 degrees.

Each of the port opening units30may be provided to be adjacent to an upper end portion of the piston20to open or block the intake port21and the exhaust port22according to the internal pressure of the air spring1.

Each of the port opening units30may be formed to have the same structure and may be provided in each of a holder23formed in the piston20to open and block the intake port21and the exhaust port22. In the instant case, each of the port opening units30may be preferably located at a same height.

Each of the port opening units30may include a rod31configured to open and block the intake port21or the exhaust port22, a roller32configured to come into contact with the intake guide11or the exhaust guide12at an end portion of the rod31, and a spring33configured to elastically support the roller32to be pressed against the intake guide11or the exhaust guide12.

The rod31may be slidably provided in the holder23formed in the piston20. The holder23may be formed at a position adjacent to the upper end portion of the piston20to accommodate the rod31in a direction perpendicular to the ascending and descending direction of the canister10. Accordingly, the rod31may be slidably provided in the holder23.

A communication hole31aconfigured to communicate with the intake port21or the exhaust port22according to a sliding position of the rod31may be formed in the rod31. The rod31may block the intake port21or the exhaust port22in most sections. However, when the communication hole31ais located to coincide with the intake port21or the exhaust port22, the communication hole31amay communicate with the intake port21or the exhaust port22. When the communication hole31acommunicates with the intake port21, pressurized air may be introduced into the air spring1from the outside, and when the communication hole31acommunicates with the exhaust port22, the air in the air spring1may be discharged to the outside.

The roller32may be located at an end portion of the rod31and may come into contact with the intake guide11or the exhaust guide12. Since the roller32is rotatably provided on an external end portion of the rod31, when the intake guide11or the exhaust guide12ascends and descends together with the canister10, the roller32may move the rod31according to the profile of an internal surface of the intake guide11or the exhaust guide12.

The spring33may elastically support the rod31and the roller32to be pressed against the intake guide11or the exhaust guide12in the holder23. Since the spring33is provided on the innermost side of the holder23, the spring33elastically supports the rod31and the roller32to be pressed to the outside, so that the roller32may be pressed against the intake guide11or the exhaust guide12.

Meanwhile, a stopper23amay be formed in the holder23to prevent the rod31from being separated from the holder23.

When the port opening unit30is located between a lower end portion of the intake guide surface11ain the intake guide11and an upper end portion of the exhaust guide surface12ain the exhaust guide12, the port opening unit30may simultaneously block the intake port21and the exhaust port22, respectively.

When the inside of the air spring1is at an appropriate pressure and thus the cab is located at an appropriate height, the port opening unit30may be located between the lower end portion of the intake guide surface11ain the intake guide11and the upper end portion of the exhaust guide surface12ain the exhaust guide12, respectively (section D inFIGS.5and8A).

Since the lower end portion of the intake guide surface11ais spaced from the upper end portion of the exhaust guide surface12awith a predetermined distance D, the port opening unit30may be moved along the vertical support surface11b(or12b) within the predetermined distance D so that the intake port21and the exhaust port22are remained in a blocked state.

Hereinafter, an operation of the air spring for a cab of a heavy truck with automatic height adjustment according to various exemplary embodiments of the present invention, which has the above-described configuration, will be described below.

Each ofFIG.8A,FIG.8BandFIG.8Cillustrates a state of the air spring1according to a height of the cab.

First,FIG.8Aillustrates a case in which the height of the cab is located within an appropriate range.

When the height of the cab is within the appropriate range, the port opening units30are located in a section D between the lower end portion of the intake guide surface11aand the upper end portion of the exhaust guide surface12a. The port opening units30are in a state of blocking the intake port21and the exhaust port22, and there may be no entry and exit in the air spring1.

FIG.8Billustrates a state in which the cab descends.

The state in which the cab descends is a state in which the pressure inside the air spring1is lowered, and thus the canister10may descend.

When the canister10descends, the intake guide11and the exhaust guide12may also descend together with the canister10.

When the intake guide11descends, the roller32may enter the intake guide surface11afrom the first support surface11bin the port opening unit30on the side of the intake port21. Since the intake guide surface11ais an inclined surface, the intake guide surface11amay press the roller32and the rod31to be moved inward the holder23. As the canister10and the intake guide11descend, the rod31may be further moved inward the holder23, and thus the communication hole31amay communicate with the intake port21. When the communication hole31acommunicates with the intake port21, a passage through which air pressed from an air pump is configured for being introduced into the air spring1may be formed. Accordingly, the pressure of the air spring1may be increased, and thus the canister10and the cab may be raised to an appropriate height.

Meanwhile, when the exhaust guide12descends together with the intake guide11, the roller32may be maintained in a state of coming into contact with the second support surface12bof the exhaust guide12in the port opening unit30on the side of the exhaust port22. Accordingly, the port opening unit30on the side of the exhaust port22consistently may block the exhaust port22.

As described above, when the air is supplied to the inside of the air spring1from the outside thereof through the intake port21, the pressure of the air spring1may be increased, and the canister10may ascend from a descending state.

When the canister10ascends to an appropriate height, the roller32may enter the first support surface11bfrom the intake guide surface11aeven in the port opening unit30on the side of the intake port21, and the rod31may be moved forward to block the intake port21again.

FIG.8Cillustrates a state in which the pressure in the air spring1is higher than an appropriate level, and the cab is raised.

When the pressure of the air spring1is high, the canister10may ascend.

Due to the ascending of the canister10, the intake guide11and the exhaust guide12also may ascend.

Even when the intake guide11ascends, since the roller32of the port opening unit30on the side of the intake port21may travel on the first support surface11b, the roller32may not be moved inward the holder23and may be maintained at its position, being maintained in a state of blocking the intake port21.

On the other hand, when the exhaust guide12ascends, the roller32may enter the exhaust guide surface12afrom the second support surface12bin the port opening unit30on the side of the exhaust port22. Since the exhaust guide surface12ais formed as an inclined surface, when the canister10and the exhaust guide12ascend in a state in which the roller32may come into contact with the exhaust guide surface12a, the roller32may enter the exhaust guide surface12afrom the second support surface12b. When the canister10ascends in the state in which the roller32may come into contact with the exhaust guide surface12a, the exhaust guide surface12amay press the roller32and the rod31toward a center portion of the piston20. Accordingly, the rod31may slide inside the holder23, and when the sliding distance is increased, the exhaust port22may communicate with the communication hole31a. When the exhaust port22and the communication hole31aare connected to each other, a portion of the air in the air spring1may be discharged to the outside through the exhaust port22.

When the air in the air spring1is discharged to the outside to some extent, the pressure in the air spring1may be decreased, and thus the canister10may start to descend again. As described above, as the pressure in the air spring1is decreased, when the canister10descends again and thus the inside of the air spring1reaches an appropriate pressure, the roller32may enter the second support surface12bfrom the exhaust guide surface12a, and the rod31may block the exhaust port22to maintain an appropriate pressure state.

In accordance with an air spring for a cab of a heavy truck with automatic height adjustment according to various exemplary embodiments of the present invention, which has the above-described configuration, a configuration for supplying air into the air spring or discharging air therefrom may be integrated into the air spring so that the number of parts may be reduced.

Furthermore, when a truck is manufactured, a pressure of the air spring and a height of the cab may be automatically adjusted only by installing the air spring and connecting an air line without installing a configuration for supplying or discharging air in the air spring so that an amount of work required may be reduced.

Due to the reduction in the number of parts and the amount of work required, a reduction in production cost may be achieved.

Furthermore, since a configuration for supplying and discharging air is not exposed to the outside, a failure of the air spring1due to foreign materials may be reduced.

In accordance with various aspects of the present invention, a configuration for supplying air into an air spring1or discharging air therefrom may be integrated into the air spring so that there may be an effect in that reduction of the number of parts, a production cost and a failure of the air spring may be achieved.