KR20110073889A - Axle apparatus of heavy construction equipment equipped with a parking brake - Google Patents

Abstract

PURPOSE: An axle apparatus for construction equipment with a parking brake is provided to easily release a release plate rubbing with a brake disc by applying torque to a release push rod. CONSTITUTION: An axle apparatus for construction equipment with a parking brake comprises an axle shaft(3), a brake disk unit(7), a release plate(10), a brake piston cover(30), a parking piston cover, a parking piston(50), a brake sliding body, a brake piston, a return spring, a push pin member, and a push rod. The axle shaft is rotated inside a housing. The brake disk unit has a pressing plate(5) and a disk(6). The brake piston cover has an inner cover(31), a brake piston mounting unit, and a brake hydraulic port(33). The parking piston cover has a parking piston outer flange(41), a parking piston mounting unit, and a parking hydraulic port. The parking piston has a parking sliding body, a plate pressing unit, and an insert hole.

Description

Axle apparatus of heavy construction equipment equipped with a parking brake}

The present invention relates to an axle device for a construction machine incorporating a parking brake, and more particularly, a parking brake that can manually release a parking brake installed on an axle in an emergency, and can be independently operated and released for a brake brake. It relates to an axle device for a construction machine with a built-in.

In general, a brake unit including a brake disc, a pressure plate, a brake piston, and the like is built in a housing of an axle device for a construction machine to perform a function of deceleration or braking based on a rotational force transmitted from an axle connected to an engine.

In the conventional axle device for construction machinery, when hydraulic pressure is supplied to the brake hydraulic port mounted on the brake piston cover during braking of the user to brake the axle shaft coupled to the wheel, it is initially restrained by the elastic force of the return spring. While the brake piston slides along the central axis of the axle shaft to induce friction of the brake unit including the brake disc and the compression plate, when the brake is released, the brake piston regenerates the elastic force of the return spring when the hydraulic pressure is released. By returning to the initial state, the friction action of the brake disc and the pressing plate is eliminated. Accordingly, the rotation of the axle shaft and the wheel mounting portion of the axle shaft is decelerated or braked.

Some technologies that can be combined with the parking brake device on the outside of the axle housing for parking and stopping of construction machinery are disclosed, but the technical configuration for attaching the axle housing outside is complicated, long-term stop The brake pedal operation is always required regardless of braking for a limited time or stopping for a short time, and a brake pedal operation of the driver is required even when a construction machine is parked for a short time or stopped on a slope. There was this.

In particular, in case of emergency or maintenance, the parking brake must be released without a pedal operation outside the axle housing. However, in the related art, there is a problem in that disassembly of the entire axle or some parts related to the parking brake is required to release the parking brake.

Accordingly, an object of the present invention is to provide an axle device for a construction machine incorporating a parking brake capable of releasing the parking brake with a simple operation outside of the axle housing even in the event of an emergency or disassembly of some parts related to the parking brake. .

It is also an object of the present invention to provide an axle device for a construction machine incorporating a parking brake that can be independently activated and released with respect to the operation of a brake piston inside an axle housing.

In order to achieve the above object, axle device for a construction machine incorporating a parking brake according to the present invention,

An axle shaft having a disc mounting portion and a release plate mounting portion formed at one side of the outer circumference thereof and connected to the wheel mounting portion and the axle connecting portion, respectively, and rotating inside the housing by a rotational force transmitted to the axle connecting portion;

A brake disc unit having a compression plate and a disk axially coupled to the disk mounting portion, the brake disc unit constraining rotation of the axle shaft by friction between the compression plate and the disk;

A release plate axially coupled to the release plate mounting portion so as to be adjacent to the pressing plate;

A brake piston cover having an inner cover fixed to the housing, a brake piston seat formed inside the inner cover, and a brake hydraulic port communicating from an outer side of the inner cover to the brake piston seat;

A parking piston outer flange fixed to the housing, a parking piston seating portion formed inside the parking piston outer flange, and a parking hydraulic port communicating from the outside to the parking piston seating portion, and installed adjacent to the brake piston cover. Parking piston cover;

A parking sliding body slidably mounted in the parking piston seat and a plate pressing part extending from the parking sliding body and selectively grounded on one side of the release plate And an insert hole formed through the plate pressing part, wherein the parking sliding body slides in a direction in which the parking sliding body is spaced apart from the pressing plate by hydraulic pressure through the parking hydraulic port when the parking operation is released.

A brake sliding body that is slidably mounted inside the brake piston seat and a brake piston that slides so that the brake sliding body approaches the pressing plate side by hydraulic pressure through the brake hydraulic port when the brake is operated;

A return spring supported by a fixing member fastened to one side of the brake piston cover and supporting one side of the brake piston in a direction away from the pressing plate;

A push pin member slidably installed in an insert hole of the parking piston, the one end of which pushes the pressing plate at one end thereof in contact with the brake sliding body by brake operation; And

A pitch-join body coupled to the housing so as to be close to one side of the release plate and a ground part contacting one side of the release plate, and when the charge adjustment body is charged by applying an external force, the parking piston is far from the pressing plate. And a parking release push rod which pushes the release plate to the ground portion.

In addition, the construction machine axle device with a built-in parking brake according to the present invention,

An external force receiving head is formed at the front end of the pitch adjusting body, and an adjusting nut is further formed to fix the pitch adjusting body.

In addition, the axle device for a construction machine incorporating a parking brake according to the present invention further comprises a parking spring installed between the brake piston cover inside and the parking piston, the parking spring each of the brake piston cover and the parking piston It is mounted on the mounting groove formed on one side of the.

In addition, in the construction machine axle device with a built-in parking brake according to the present invention, the sealing member is mounted on the outer periphery of the sliding body of the parking piston and the sliding body of the brake piston, respectively.

In addition, the construction machine axle device with a built-in parking brake according to the present invention, the parking piston is provided with a first hydraulic inner flange extending on the outer periphery of the parking piston sliding portion, the first hydraulic inner flange is a parking hydraulic port The hydraulic pressure introduced through is accommodated in a direction opposite to the elastic force of the parking spring.

In addition, the construction machine axle device with a built-in parking brake according to the present invention, the brake piston is provided with a knuckle flange which is a second hydraulic pressure extending on the outer circumference of the brake piston sliding portion, the second hydraulic pressure inner flange is brake hydraulic pressure The hydraulic pressure introduced through the port is characterized in that for receiving in a direction opposite to the elastic force of the return spring.

The construction machine axle device with a built-in parking brake according to the present invention applies an additional pedal operation or parking by easily releasing the release plate in friction with the brake disc by applying a rotational force to the release push rod in an emergency or outside the maintenance axle housing. There is an advantage that the parking brake can be released without disassembling the brake related parts.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a partial cross-sectional view of an axle device for a construction machine incorporating a parking brake according to an embodiment of the present invention, Figure 2 is a main part perspective view of the axle device for a construction machine incorporating a parking brake according to the present invention, FIG. Fig. 4 is a main sectional view showing the parking brake releasing operation state manually operated by the release push rod in accordance with the present invention.

In the present embodiment, reference numeral 3 denotes an axle shaft, 4 a disc mounting portion, 7 a brake disc unit, 8 an axle housing, 20 an unparking push rod, 21 a pitch adjusting body, 30 a brake piston cover, and 32 Brake piston seat, 33 is brake hydraulic port, 34 is return spring, 38 is parking spring, 40 is parking piston cover, 42 is parking piston seat, 43 is parking hydraulic port, 50 is parking piston, 51 is parking piston pressurization Part 60 represents a brake piston.

Construction machine axle device with a built-in parking brake according to the present embodiment,

A disk mounting portion 3 and a release plate mounting portion 9 formed on one side of the outer circumference thereof, each of which is connected to the wheel mounting portion 1 and the axle connecting portion 2, and a rotational force transmitted to the axle connecting portion 2; An axle shaft 4 which rotates inside the housings 8a and 8b by means of;

And a disk 6 and a compression plate 5 axially coupled to the disk mounting portion 3, and restrains rotation of the axle shaft 4 by friction between the compression plate 5 and the disk 6. Brake disc unit 7;

A release plate 10 which is axially coupled to the release plate mounting portion 9 so as to be adjacent to the pressing plate 5;

Inner cover 31 fixed to the housing 8a and the brake piston seat 32 formed inside the inner cover 31 and the inner cover 31 from the outside to the brake piston seat 32. A brake piston cover 30 having a brake hydraulic port 33 in communication therewith;

The parking piston outer flange 41 fixed to the housing 8b and the parking piston seating portion 42 formed inside the parking piston outer flange 41 and the parking piston communicating with the parking piston seating portion 42 from the outside. A parking piston cover 40 having a hydraulic port 43 and installed adjacent to the brake piston cover 30;

A parking sliding body 52 slidably mounted in the parking piston seat 42 and a plate pressing part 51 extending from the parking sliding body 52 and selectively grounded on one side of the release plate 10. ) And an insert hole 53 formed through the plate pressing part 51, and the parking sliding body 52 is hydraulically pressed through the parking hydraulic port 43 when the parking operation is released. Parking piston 50 that slides in a direction spaced from);

When the brake sliding body 62 is slidably mounted in the brake piston seat 32 and the hydraulic pressure is applied through the brake hydraulic port 33 when the brake is operated, the brake sliding body 62 is pressed by the compression plate 5. A brake piston 60 that slides toward the side;

A return supported by the fixing member 35 fastened to one side of the brake piston cover 30 and supporting the one side of the brake piston 60 in a direction away from the pressing plate 5. A spring 34;

The push pin member 36 is installed in the insert hole 53 of the parking piston 50 so as to be slidable, and the one end of the push pin member 36 pushes the pressing plate 5 when the brake sliding body 62 comes into contact with the brake sliding body 62. ); And

A pitch adjusting body 21 coupled to the housing 8b so as to be close to one side of the release plate 10, and a ground part 22 contacting one side of the release plate 10. A parking release push rod 20 in which the ground portion 22 pushes the release plate 10 so that the parking piston 50 moves away from the pressing plate 5 when the pitch adjusting body 21 is inserted; It is configured to include.

Preferably, the pitch adjusting body 21 is provided with a screw portion on the outer circumference, and the screw hole is formed in the housing 8b to enable the pitch movement of the pitch adjusting body 21. In addition, an external force receiving head 23 is formed at the front end of the pitch adjusting body 21, and an adjusting nut 24 is further formed to fix the pitch adjusting body 21.

In the embodiment of the present invention, the external force receiving head 23 is composed of a groove portion 25 for receiving the rotational force of the screwdriver, but other power tools or hand tools including a torque wrench or tongs well known to those skilled in the art Of course, it can be variously modified to a structure suitable to accommodate the rotational force.

In the embodiment of the present invention, the return spring 34 is pressed by the head portion of the fixing member 35 in the arrangement fitted on the outer periphery of the fixing member 35, the brake piston 60 It is mounted inside the insert hole 63, so that the elastic force of the return spring 34 is always away from the pressing plate (5), for example, the arrangement state spaced apart from the parking piston 50 by a predetermined distance It serves to support the brake piston 60 to the brake piston cover 30 side.

This is because when the hydraulic pressure in the brake hydraulic port 33 decreases below the elastic force of the return spring 34 during the brake release operation, the position of the brake piston 60 is reduced by the elastic force of the return spring 34. By returning to), it means that the friction action of the pressing plate 5 and the disk 6 is released, so that the rotational force of the axle shaft 3 is maintained without braking.

On the other hand, the construction machine axle device with a built-in parking brake according to the present invention further comprises a parking spring 38 installed between the brake piston cover 30 and the parking piston 50, the parking The spring 38 is mounted in a pressing recess 37a and 37b formed at one side of each of the brake piston cover 30 and the parking piston 50 so that the pressing plate 5 and the disk 6 during the parking operation. The plate presser 51 of the parking piston 50 performs a function of elastically supporting one side of the parking piston 50 so as to push the pressing plate 5 for friction.

In addition, seal members 39a and 39b are mounted on outer peripheries of the sliding body 52 of the parking piston 50 and the sliding body 62 of the brake piston 60, and the seal members 39a and 39b. They respectively perform the airtightness and leakage prevention function of the parking piston seating part 42 and the brake piston seating part 32, respectively.

On the other hand, according to an embodiment of the present invention, the parking piston 50 has a first hydraulic inner flange 54 extending on the outer periphery of the parking piston sliding portion 52, the first hydraulic inner flange 54 The hydraulic pressure introduced through the parking hydraulic port 43 receives in the direction opposite to the elastic force of the parking spring 38.

In addition, the brake piston 60 includes a second hydraulic inner flange 64 extending on the outer circumference of the brake piston sliding part 62, and the second hydraulic inner flange 64 opens the brake hydraulic port 33. The hydraulic pressure introduced through is received in a direction opposite to the elastic force of the return spring 34.

The parking spring 38 is preferably mounted in each of the mounting recesses 37b and 37a formed in the first hydraulic inner flange 54 and the second hydraulic inner flange 64, respectively.

The mounting portion 42 of the parking piston cover 40 may further include a hydraulic chamber or a space portion communicating with the parking hydraulic port 43 and adjacent to the first hydraulic inner flange 54, and similarly to the brake piston cover. The seating portion 32 of the 30 may further form a hydraulic chamber or a space portion communicating with the brake hydraulic port 33 and adjacent to the second hydraulic inner flange 64, which is the first hydraulic inner flange (each). 54) and the water pressure corresponding to the longitudinal direction of the axle shaft 3 of the second hydraulic inner flange 64, and the sliding movement performance of each of the parking piston 50 and the brake piston 60 moving accordingly are considered.

In the configuration of the present invention, each of the above-described brake piston cover 30 and brake piston 60, the parking piston cover 40 and the parking piston 50 can be assembled on the outer periphery of the axle shaft (3) An opening 27 having a predetermined size is formed through the center portion, and the arrangement is variously modified in consideration of the diameter of the axle shaft 3 or the pressing performance required for the frictional force between the pressing plate 5 and the disk 6. Of course you can.

In the implementation of the axle device for a construction machine incorporating a parking brake according to the present invention, the above-described components may be configured to be symmetrically with respect to the wheel connecting portion 2 for braking and parking of the right wheel and the left wheel. Since it will be apparent to those skilled in the art will not be described in detail.

Hereinafter, the operating principle of the construction machine axle device with a built-in parking brake according to the present invention.

Axle device for a construction machine with a built-in parking brake according to the present invention can independently drive the parking piston (50) and the brake piston (60) so that the brake braking and parking brake braking can be performed independently. First, the parking brake braking principle is explained.

Referring to FIG. 5, when a user performs a parking brake operation, for example, an adjustment of a parking brake pedal or a parking lever (not shown), the hydraulic pressure formed in the parking hydraulic port 43 of the parking piston cover 40 In this case, the elastic force of the parking spring 38 acts as an axial load on the left side of the drawing corresponding to the longitudinal direction of the axle shaft 3 to press the sliding body 52 of the parking piston 50 to the pressing plate 5. Move closer to

Ultimately, the pressing portion 51 of the parking piston sliding body 52 when the sliding body 52 of the parking piston 50 approaches the crimp plate 5 due to the axial load caused by the elastic force of the parking spring 38. ) Pushes one side of the pressing plate 5, whereby the pressing plate 5 and the disk 6 are brought into close contact and friction with each other and the rotation of the axle shaft 3 is braked to decelerate or stop.

The above-mentioned parking spring 38 acts so that the parking piston 50 receives continuous elasticity against the brake piston cover 30 fixed to the housing 8 in the mounting recesses 37a and 37b. maintain.

On the other hand, when the parking brake release operation, the hydraulic pressure is applied to the parking hydraulic port 43 of the parking piston cover 40, wherein the hydraulic pressure is introduced to the parking piston sliding portion 52 and the first hydraulic pressure flange (54) Corresponding to the longitudinal direction of the axle shaft 3 acts as an axial load on the right side of the drawing.

Ultimately, when the clearance between the parking piston sliding portion 52 and the hydraulic pressure received by the first hydraulic inner flange 54 exceeds the elastic force of the parking spring 38, the pressing portion 51 of the parking piston 50 is pressed onto the pressing plate. Departed from (5), the friction force between the disk (6) and the pressing plate (5) is removed and the axle shaft (3) can maintain the rotation freely. This means that the parking brake is completely released.

On the other hand, the construction machine axle device with a built-in parking brake according to the present invention can release the parking brake without emergency parking brake pedal or parking brake release operation by the lever.

That is, in the absence of the parking brake release operation, the elastic force of the parking spring 38 acts as an axial load on the left side of the drawing corresponding to the longitudinal direction of the axle shaft 3, thereby sliding the body 52 of the parking piston 50. And the pressing plate 5 and the disk 6 maintain close contact and friction with each other, but the user applies a rotational force of a screwdriver to the external force receiving head 23 exposed to the outside of the axle housing 8b so that the parking piston ( The sliding body 52 and the pressing plate 5 of the 50 may be separated.

If the user rotates the screwdriver coupled to the recess 25 in a clockwise or counterclockwise direction after releasing the adjusting nut 24, the pitch adjusting body 21 acts as an axial load on the right side of the drawing. It has a pitch of and is moved.

Therefore, the ground portion 22 pushes the release plate 10 in a direction opposite to the spring force of the return spring 34 by the pitch movement of the parking release push rod 20, and one side of the release plate 10. The sliding body 52 of the parking piston 50 grounded at is spaced apart from the pressing plate 5 corresponding to the pitch moving distance.

Ultimately, the construction machine axle device with a built-in parking brake according to the present invention does not require the disassembling process of the parking brake release operation and some parts related to the parking brake through a simple operation by the user. Through the friction between the parking piston 50 and the pressing plate (5) can be easily released.

The brake actuation and release principle according to the present invention will be described.

The construction machine axle device with a built-in parking brake according to the present invention independently performs deceleration and stop control of the axle shaft 3 in a state in which the parking brake is released.

When the brake is operated, hydraulic pressure is applied to the brake hydraulic port 33 of the brake piston cover 30, and at this time, the hydraulic pressure is introduced to the brake piston sliding part 62 and the second hydraulic inner flange 64 to extrude the axle shaft. It acts as an axial load on the left side of the drawing, corresponding to the longitudinal direction of 3).

When the clearance between the brake piston sliding portion 62 and the hydraulic pressure received by the second hydraulic inner flange 64 exceeds the elastic force of the return spring 34, the brake piston 60 moves to contact the push pin member 36. In addition, the push pin member 36 is pushed by the brake piston 60, slides in the insert hole 53, and moves to the pressing plate 5 side.

When the pushpin member 36 and the pressing plate 5 are in contact, the pressing plate 5 and the disk 6 are brought into close contact with each other by the axial load of the axle shaft 3 applied to the brake piston 60. The friction action occurs and the rotation of the axle shaft 3 is braked to decelerate or stop. This means that the brake is completely locked for rotational braking of the axle shaft 3.

On the other hand, by means of the return spring 34 the brake piston 60 receives a constant resilience towards the brake piston cover 30 fixed to the housing 8, which causes the brake piston 60 to be the length of the axle shaft 3. It means to receive the axial load on the right side of the figure corresponding to the direction.

When the elastic force of the return spring 34 exceeds the clearance of the brake piston sliding part 62 and the hydraulic pressure accommodated in the second hydraulic inner flange 64, the brake piston 30 is separated from the push pin member 36 and braked. It returns to the inside of the seating part 32 of the piston cover 30, and accordingly, the pressing force of the push pin member 36 is removed, and the contact and friction state of the crimping plate 5 and the disk 5 are released and the axle is released. The shaft 3 can freely maintain rotation.

The parking brake manual release principle according to the present invention will be described.

When the parking brake is operated, hydraulic pressure is applied to the brake hydraulic port 33 of the parking piston outer flange 41, and the hydraulic pressure is introduced to the brake piston sliding part 62 and the second hydraulic inner flange 64 to extrude the axle. Corresponding to the longitudinal direction of the shaft 3 acts as an axial load on the left in the drawing.

When the clearance between the brake piston sliding portion 62 and the hydraulic pressure received by the second hydraulic inner flange 64 exceeds the elastic force of the return spring 34, the brake piston 60 moves to contact the push pin member 36. In addition, the push pin member 36 is pushed by the brake piston 60, slides in the insert hole 53, and moves to the pressing plate 5 side.

When the pushpin member 36 and the pressing plate 5 are in contact, the pressing plate 5 and the disk 6 are brought into close contact with each other by the axial load of the axle shaft 3 applied to the brake piston 60. The friction action occurs and the rotation of the axle shaft 3 is braked to decelerate or stop. This means that the brake is completely locked for rotational braking of the axle shaft 3.

The foregoing description of the embodiments of the present invention has been described as illustrative in order to assist those skilled in the art with respect to the present invention, and the scope of the present invention is set forth in the appended claims. It is to be interpreted accordingly, and the scope includes various modifications, alternatives, and equivalents by those skilled in the art.

1 is a partial cross-sectional view of an axle device for a construction machine incorporating a parking brake according to an embodiment of the present invention;

2 is a perspective view of a main part of an axle device for a construction machine incorporating a parking brake according to the present invention;

Figure 3 is a sectional view of the main part showing the operating state of the parking piston during the parking brake operation according to the present invention,

Fig. 4 is a sectional view showing the main parts of the parking brake release operation state manually operated by the release push rod according to the present invention;

Explanation of the main symbols for the main parts of the drawings

3: axle shaft 4: disc mounting portion

7: brake disc unit 8: axle housing

20: parking release push rod 21: pitch adjustment main body

30: brake piston cover 32: brake piston seat

33: Brake hydraulic port 34: Return spring

38: parking spring 40: parking piston cover

42: parking piston seat 43: parking hydraulic port

50: parking piston 51: parking piston pressing portion

60: brake piston 62: brake piston sliding body

Claims (6)

An axle shaft having a disc mounting portion and a release plate mounting portion formed at one side of the outer circumference thereof and connected to the wheel mounting portion and the axle connecting portion, respectively, and rotating inside the housing by a rotational force transmitted to the axle connecting portion; A brake disc unit having a compression plate and a disk axially coupled to the disk mounting portion, the brake disc unit constraining rotation of the axle shaft by friction between the compression plate and the disk; A release plate axially coupled to the release plate mounting portion so as to be adjacent to the pressing plate; A brake piston cover having an inner cover fixed to the housing, a brake piston seat formed inside the inner cover, and a brake hydraulic port communicating from an outer side of the inner cover to the brake piston seat; A parking piston outer flange fixed to the housing, a parking piston seating portion formed inside the parking piston outer flange, and a parking hydraulic port communicating from the outside to the parking piston seating portion, the parking being installed adjacent to the brake piston cover Piston cover; A parking sliding body slidably mounted in the parking piston seat and a plate pressing part extending from the parking sliding body and selectively grounded on one side of the release plate And an insert hole formed through the plate pressing part, wherein the parking sliding body slides in a direction in which the parking sliding body is spaced apart from the pressing plate by hydraulic pressure through the parking hydraulic port when the parking operation is released. A brake sliding body that is slidably mounted inside the brake piston seat and a brake piston that slides so that the brake sliding body approaches the pressing plate side by hydraulic pressure through the brake hydraulic port when the brake is operated; A return spring supported by a fixing member fastened to one side of the brake piston cover and supporting one side of the brake piston in a direction away from the pressing plate; A push pin member slidably installed in an insert hole of the parking piston, the one end of which pushes the pressing plate at one end thereof in contact with the brake sliding body by brake operation; And A pitch adjusting body coupled to the housing so as to be close to one side of the release plate and a ground part contacting one side of the release plate, and the parking piston moves away from the pressing plate when the pitch adjusting body is applied by applying an external force. Axle device for a construction machine with a built-in parking brake, characterized in that it comprises a; parking release push rod for the ground portion to push the release plate. The method according to claim 1, An external force receiving head is formed at the front end of the pitch adjustment main body, and an axle device for a construction machine with a built-in parking brake, characterized in that an adjustment nut is further formed to fix the pitch adjustment main body. The method according to claim 1, And a parking spring installed between the brake piston cover inside and the parking piston, wherein the parking spring is mounted in a seating recess formed at one side of each of the brake piston cover and the parking piston. Axle device for construction machinery. The method according to claim 1, Axle device for a construction machine with a built-in parking brake, characterized in that the sealing member is mounted on the outer periphery of the sliding body of the parking piston and the sliding body of the brake piston. The method according to claim 1, The parking piston includes a first hydraulic inner flange extending on an outer circumference of the parking piston sliding part, and the first hydraulic inner flange receives hydraulic pressure introduced through the parking hydraulic port in a direction opposite to the elastic force of the parking spring. Axle device for construction machinery with a built-in parking brake, characterized in that. The method according to claim 1, The brake piston has a second hydraulic inner flange extending on the outer circumference of the brake piston sliding part, and the second hydraulic inner flange receives the hydraulic pressure introduced through the brake hydraulic port in a direction opposite to the elasticity of the return spring. Axle device for construction machinery with a built-in parking brake, characterized in that.

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