CN111071224A

CN111071224A - Pure mechanical automatic tensioning device for vehicle parking brake

Info

Publication number: CN111071224A
Application number: CN202010010822.3A
Authority: CN
Inventors: 朱派龙; 郭大伊; 张铛锋; 张东峰; 杜亮
Original assignee: Guangdong Industry Technical College
Current assignee: Guangdong Industry Technical College
Priority date: 2020-01-06
Filing date: 2020-01-06
Publication date: 2020-04-28

Abstract

The application discloses a purely mechanical automatic tensioning device for vehicle parking braking, which comprises a braking mechanism of a vehicle and a base, wherein a rotary pin shaft is arranged on the base, and a fixed wheel disc and a driving gear are assembled on the rotary pin shaft; the driving mechanism is fixed in position through a locking arm, and when the locking arm releases the fixing of the driving mechanism, the driving mechanism drives the gear to rotate, so that the fixed wheel disc is driven to rotate through the rotating pin shaft; when the driver leaves from the main driving seat, the position of the main driving seat rises, and the linkage mechanism drives the locking arm to release the fixing of the position of the driving mechanism. The device adopts a pure mechanical structure to realize automatic braking, and has high reliability, low manufacturing cost and strong universality.

Description

Pure mechanical automatic tensioning device for vehicle parking brake

Technical Field

The application relates to the field of automobile design and manufacture, mechanical engineering and automobile safety, in particular to a purely mechanical automatic tensioning device for vehicle parking brake (hand brake).

Background

Parking brake, commonly called hand brake, as the safety brake tool, the frequency of use is relatively high, and nevertheless, the phenomenon that the hand brake is forgotten to be pulled when the vehicle is stopped also often appears, because some drivers do not have good habits. In recent years, the accident that a driver forgets to pull the hand brake due to parking is frequently seen in the newspaper end and the network, and the driver forgets to pull the hand brake and is rolled by the own vehicle to be killed.

Most automatic transmission automobiles are provided with electronic hand brakes which are electrically controlled hand brakes, and the hand brakes can be pulled up by manually pressing (pulling) a button after the automobiles are stopped. When starting, the button can be released by manually pressing (pulling). It still requires manual manipulation of the buttons and the same can roll over if the driver forgets to do so.

The high-grade vehicle on the market also has an automatic parking function, the infrastructure of the high-grade vehicle is also an electronic hand brake, the manual step is omitted, the vehicle is automatically parked (tensioned) when the vehicle is stopped, and the vehicle is automatically released when the vehicle is started, the automatic parking vehicle is generally provided with an automatic parking vehicle type, whether the vehicle is used or not can be selected by an automatic switch, and a safety belt is generally tied on the premise of using the automatic parking vehicle type.

Some mechanical parking devices are proposed in the prior art, but most of the devices are not realized by a pure mechanical structure and depend on devices such as a power supply, an electric element, a sensor and the like. In the event of a power outage (lack of power), there is no way for any device that relies on a power source to operate.

Disclosure of Invention

The application aims at providing a pure mechanical type automatic tensioning device for vehicle parking braking, which realizes the function of automatically tensioning a hand brake based on a pure mechanical structure and is used for overcoming the problems that the existing device is high in cost and depends on a power supply and the like.

In order to realize the task, the following technical scheme is adopted in the application:

a purely mechanical automatic tensioning device for vehicle parking braking comprises a braking mechanism of a vehicle, wherein the braking mechanism comprises a braking handle, a ratchet wheel, a pawl and a braking kicking pull rope;

the device also comprises a base, the ratchet wheel is fixed on the base, a rotating pin shaft is installed on the base, a fixed wheel disc and a driving gear are coaxially assembled on the rotating pin shaft, wherein the end part of the brake handle is fixed on the fixed wheel disc, the pawl is arranged on the edge of the fixed wheel disc and matched with the ratchet wheel, and the brake kicking pull rope is connected with the fixed wheel disc;

the driving mechanism is fixed in position through a locking arm, and when the locking arm releases the fixing of the driving mechanism, the driving mechanism drives the driving gear to rotate, so that the fixed wheel disc is driven to rotate through the rotating pin shaft, the fixed wheel disc rotates to brake a vehicle by pulling a brake kick pull rope, and drives a brake handle to lift and a pawl to change the occlusion position with a ratchet wheel to realize brake locking;

when the driver leaves from the main driving seat, the position of the main driving seat rises, and the linkage mechanism drives the locking arm to release the fixing of the position of the driving mechanism.

Further, the base includes the bottom plate and sets up four curb plates all around the bottom plate, install in the shaft hole on the left side board of base, the right side board at the both ends of rotatory round pin axle.

Furthermore, the driving mechanism comprises a fixed shaft perpendicular to the rotating pin shaft, mounting holes are symmetrically formed in the front side plate and the rear side plate on the base, and the fixed shaft penetrates through the mounting holes in the front side plate and the rear side plate and can slide in the axial direction of the mounting holes;

a limiting ring is mounted on the fixed shaft, a pressure spring is sleeved on the fixed shaft between the limiting ring and the rear side plate, and a rack matched with the driving gear is laid on the surface of the fixed shaft; when the locking arm releases the fixing of the driving mechanism, the pressure spring pushes the fixed shaft to move axially through the limiting ring, so that the rack drives the driving gear to rotate.

Furthermore, the upper surface of the rear side plate is provided with a guide hole communicated with the mounting hole on the rear side plate, a guide pin is assembled in the limiting hole, and the end part of the guide pin is inserted into a guide groove formed in the surface of the fixed shaft along the axial direction.

Furthermore, a lug is arranged on a bottom plate of the base, and the locking arm is hinged on the lug;

a bolt is vertically arranged at the front end of the locking arm, and a fixing hole matched with the bolt is formed in the fixing shaft; the rear end of the locking arm is provided with a position adjusting mechanism which is used for driving the locking arm to rotate under the driving of the linkage mechanism;

when the positioning mechanism drives the locking arm to rotate, the front end of the locking arm moves downwards to enable the bolt to be separated from the fixing hole in the fixing shaft, and then the locking arm releases the fixing of the driving mechanism.

Furthermore, the position adjusting mechanism comprises a limiting seat arranged on a base plate, the limiting seat comprises a vertical plate and a transverse plate vertically arranged at the top of the vertical plate, an air bag is arranged between the bottom of the transverse plate and the rear end of the locking arm, and a return spring is arranged between the rear end of the locking arm and the base plate of the base;

the linkage mechanism is used for charging air into the air bag or extracting air from the air bag; when the air in the air bag is pumped out, the return spring pushes the rear end of the locking arm to move upwards, so that the front end of the locking arm moves downwards.

Furthermore, the linkage mechanism comprises an air cylinder arranged below the main driving seat, a spring seat is arranged at the bottom of the main driving seat, the upper end of a piston rod of the air cylinder is connected with the spring seat, and a support spring is sleeved on the piston rod between the air cylinder and the spring seat; the rodless cavity of the cylinder is communicated with the air bag in the position adjusting mechanism through a pressure air pipe, and the size of the rodless cavity is adjusted through the change of the position of the piston in the cylinder, so that air is filled into the air bag or is pumped out of the air bag.

Further, a release lever connected to a front end of the lock arm is provided in the vehicle cab.

Furthermore, the locking arm is made of metal, and an electromagnet is arranged on a base bottom plate below the front end of the locking arm.

The application has the following technical characteristics:

1. high reliability of safety guarantee

The realization process of this application is the cooperation of pure mechanical element, does not basically receive the influence of changes such as temperature, humidity, atmospheric pressure, also need not power drive, even the power cuts off the power supply suddenly, and the autobrake's of device function is unchangeable.

2. Compact structure and low manufacturing cost

Besides the original ratchet wheel/pawl structure of the vehicle, pure mechanical elements such as a driving gear rack kinematic pair, a compression spring, an air cylinder/air bag and the like are additionally adopted, and the integral device is compact in structure, small in integral size and easy to adapt and install. Compared with other components, the mechanical components are wide in source and low in purchase or manufacturing cost; the inventor actually measures that the cost of the mass production of the newly added mechanical components does not exceed 60 yuan RMB.

3. Simple and convenient to control

The original manual operation is not influenced, the operation of releasing the hand brake is the same as the original operation, and the locking state is released by pressing down the locking arm when the hand brake is tightened.

4. Reducing or preventing further injury

When the driver is separated from the seat or bounces off the seat by inertia in case of accident, the hand brake is also automatically tightened. Therefore, the automobile cannot be further moved to cause secondary damage to the automobile or more damages to other people and other objects.

5. Good versatility

The device can be used for refitting most of middle and low-grade automobiles at present, can also form a novel independent and perfect product to completely replace the original hand brake part, and is particularly suitable for household popular cars and various trucks. And a safety guarantee measure with low cost and high reliability is provided for parking braking.

Drawings

FIG. 1 is a schematic structural view of the device with the brake handle not lifted;

FIG. 2 is a right side view of the base portion;

FIG. 3 is a schematic view of the device in a brake handle lifted condition;

fig. 4 is a schematic structural diagram of the linkage mechanism and the positioning mechanism.

The reference numbers in the figures illustrate: the brake device comprises a base 1, a bottom plate 101, side plates 102, a brake handle 2, a ratchet wheel 3, a pawl 4, a fixed wheel disc 5, a rectangular key 6, a rotating pin 7, a driving gear 8, a brake kicking pull rope 9, a rack 10, a limiting ring 11, a pressure spring 12, a guide pin 13, a fixed shaft 14, a fixed hole 141, a guide groove 142, a retainer ring 15, a fixed seat 16, a driver 17, a main frame seat 18, a spring seat 19, a supporting spring 20, a cylinder 21, a piston rod 22, a pressure air pipe 23, a limiting seat 24, a transverse plate 241, a vertical plate 242, a reset spring 25, an air bag 26, a locking arm 27, a latch pin 271 and a.

Detailed Description

In view of the problems that the existing automatic parking brake device mostly depends on a power supply, so that the reliability needs to be improved, the cost is high and the like, the problem that the brake device depends on the power supply is fundamentally solved, the influence on the structure of the original brake is avoided, and meanwhile, the refitting cost is low. Therefore, the proposed device structure should be a pure mechanical structure, not containing any electrical components, not requiring a power supply, not requiring a sensor. In addition, the device can not influence the function of the original manual hand brake, namely, when the driver forgets to pull the hand brake and leaves the seat, the hand brake is automatically tensioned to achieve the parking brake, so as to prevent the vehicle from sliding. If the driver does not forget to pull the hand brake, the device does not work, and a protective barrier is added for the driver.

The application provides a purely mechanical automatic tensioning device for vehicle parking braking, which comprises an original braking mechanism of a vehicle, wherein the braking mechanism comprises a braking handle 2, a ratchet wheel 3, a pawl 4 and a braking kicking pull rope 9; the device further comprises a base 1, the ratchet wheel 3 is fixed on the base 1 through a fixing seat 16, as shown in fig. 2, a rotating pin 7 is mounted on the base 1, a fixed wheel disc 5 and a driving gear 8 are coaxially assembled on the rotating pin 7, wherein the end part of the brake handle 2 is fixed on the fixed wheel disc 5, a pawl 4 is arranged at the edge of the fixed wheel disc 5 and matched with the ratchet wheel 3, and a brake kicking pull rope 9 is connected with the fixed wheel disc 5; the base 1 is internally provided with a driving mechanism matched with the driving gear 8, the driving mechanism is fixed in position through a locking arm 27, when the locking arm 27 releases the fixation of the driving mechanism, the driving mechanism drives the driving gear 8 to rotate, so that the fixed wheel disc 5 is driven to rotate through the rotating pin shaft 7, the fixed wheel disc 5 rotates to brake a vehicle by pulling a brake kick pull rope 9 on one hand, and drives the brake handle 2 to lift on the other hand, and drives the pawl 4 to change the meshing position with the ratchet wheel 3 to realize brake locking on the other hand; when the driver 17 moves away from the main seat 18, the position of the main seat 18 is raised, and the lock arm 27 is moved by the link mechanism to release the fixing of the driving mechanism position.

The brake mechanism is the original structure of the vehicle and comprises a ratchet 3, a pawl 4, a brake handle 2, a brake kicking pull rope 9 and other mechanisms, and the structure of the brake mechanism is the prior art and is not described herein. In the application, a base 1, a driving mechanism, a linkage mechanism and the like are added in an original braking mechanism of a vehicle, wherein the base 1 is arranged below a ratchet wheel 3 and a pawl 4 and is fixed on a vehicle frame. In the solution of the present application, the base 1 is composed of a bottom plate 101 and four side plates 102 surrounding the bottom plate 101, preferably, a front side plate is parallel to a rear side plate, a left side plate is parallel to a right side plate, and the front side plate is perpendicular to the left side plate. A fixed wheel disc 5 and a driving gear 8 are arranged on a rotating pin 7 on the base 1, the fixed wheel disc and the driving gear are respectively fixed on the rotating pin 7 through a rectangular key 6, and when the rotating pin 7 rotates, the fixed wheel disc and the driving gear synchronously rotate; in an example of the present application, shaft holes are symmetrically formed on the left side plate and the right side plate of the bottom plate 101, and two ends of the rotating pin 7 are movably assembled in the shaft holes, wherein a shoulder is arranged at the right end of the rotating pin 7 to prevent the rotating pin from moving to the left, and a retaining ring 15 is arranged at the left end to prevent the rotating pin from moving to the right, as shown in fig. 2.

The driving mechanism in the base 1 is matched with the driving gear 8, and when the driving gear 8 rotates under the action of the driving mechanism, the driving gear drives the rotating shaft pin to rotate, so that the fixed wheel disc 5 is driven to rotate. The pawl 4 and the brake kick cord 9 are mounted on the fixed wheel 5, and after the fixed wheel 5 rotates, the brake kick cord 9 is pulled from the position a to the position B in the figure as shown in fig. 1. The end of the brake kicking pull rope 9 is connected with the cam of the brake kicking block, namely, the brake kicking pull rope 9 is pulled backwards to drive the cam to rotate, and the cam pushes the brake kicking block to fold so as to brake the rim of the vehicle wheel. The cam and the brake kicking block are all structures on the vehicle, and the principle is not repeated. When the fixed wheel disc 5 rotates, the end part of the brake handle 2 is fixed on the fixed wheel disc 5, so that the brake handle 2 is driven to be lifted, namely the driver 17 is helped to pull up the brake handle 2; and the position of the brake handle 2 is locked due to the matching of the ratchet wheel 3 and the pawl 4.

In this embodiment, the actuation of the drive mechanism is controlled by a single locking arm 27, and the locking arm 27 is used to limit the position of the drive mechanism. Referring to fig. 1 and 3, the driving mechanism includes a fixed shaft 14 perpendicular to the rotating pin 7, mounting holes are symmetrically formed in the front side plate and the rear side plate on the base 1, and the fixed shaft 14 passes through the mounting holes in the front side plate and the rear side plate and can slide in the axial direction of the mounting holes; the limiting ring 11 is installed on the fixing shaft 14, the pressure spring 12 is sleeved on the fixing shaft 14 between the limiting ring 11 and the rear side plate, and the limiting ring 11 is used for limiting the position of the pressure spring 12 and enabling the pressure ring to be in a compression state. A rack 10 matched with the driving gear 8 is laid on the surface of the fixed shaft 14; when the locking arm 27 releases the fixing of the driving mechanism, the compression spring 12 pushes the fixed shaft 14 to move axially through the limiting ring 11 under the action of elastic potential energy, so that the rack 10 drives the driving gear 8 to rotate, namely, the state of fig. 1 is changed into the state of fig. 3.

Referring to fig. 1, in order to limit the movement of the fixed shaft 14 and prevent the fixed shaft 14 from rotating, and to maintain the meshed state between the driving gear 8 and the rack 10, a guide hole leading to a mounting hole on the rear side plate is formed on the upper surface of the rear side plate, a guide pin 13 is assembled in the limiting hole, the end of the guide pin 13 is inserted into a guide groove 142 formed in the surface of the fixed shaft 14 along the axial direction, and the fixed shaft 14 can only move axially but cannot rotate due to the cooperation of the guide pin 13 and the guide groove 142.

As shown in fig. 1 and 4, a lug 28 is arranged on the bottom plate 101 of the base 1, and the locking arm 27 is hinged on the lug 28; the articulated mounting of the locking arm 27 is achieved, for example, by a rotary shaft passing through correspondingly provided holes in the locking arm 27 and the lug 28. The front end of the locking arm 27 is vertically provided with a bolt 271, and the fixed shaft 14 is provided with a fixed hole 141 matched with the bolt 271; the rear end of the locking arm 27 is provided with a position adjusting mechanism which is used for driving the locking arm 27 to rotate under the driving of the linkage mechanism; when the positioning mechanism drives the locking arm 27 to rotate, so that the front end of the locking arm 27 moves downwards to cause the plug pin 271 to be disengaged from the fixing hole 141 on the fixed shaft 14, the locking arm 27 releases the fixing of the driving mechanism, and at this time, the pressure spring 12 pushes the fixed shaft 14 to drive the rack 10 to move, thereby driving the driving gear 8 to rotate.

Referring to fig. 4, the positioning mechanism provided in this embodiment includes a limiting seat 24 disposed on the bottom plate 101 of the base 1, the limiting seat 24 includes a vertical plate 242 and a horizontal plate 241 vertically disposed on the top of the vertical plate 242, an air bag 26 is disposed between the bottom of the horizontal plate 241 and the rear end of the locking arm 27, and a return spring 25 is disposed between the rear end of the locking arm 27 and the bottom plate 101 of the base 1; the linkage mechanism is used for charging air into the air bag 26 or exhausting air from the air bag 26; when the air in the air bag 26 is exhausted, the return spring 25 pushes the rear end of the lock arm 27 to move upward, thereby moving the front end of the lock arm 27 downward, so that the lock arm 27 releases the fixing of the fixed shaft 14.

In the scheme, the signal for starting the automatic tensioning device is that the driver 17 leaves the main driving seat 18, that is, the driver 17 leaves the main driving seat 18 for any reason, and if the hand brake is not pulled, adverse results can be caused, so that the automatic tensioning device is started after the driver 17 leaves the main driving seat 18. One specific implementation way is as follows:

the linkage mechanism comprises a cylinder 21 arranged below the main driving seat 18, a spring seat 19 is arranged at the bottom of the main driving seat 18, the upper end of a piston rod 22 of the cylinder 21 is connected with the spring seat 19, and a support spring 20 is sleeved on the piston rod 22 between the cylinder 21 and the spring seat 19; the rodless cavity of the cylinder 21 is communicated with an air bag 26 in the positioning mechanism through a pressure air pipe 23, and the size of the rodless cavity is adjusted through the change of the position of a piston in the cylinder 21, so that air is filled into the air bag 26 or air is pumped out of the air bag 26.

When the driver 17 sits on the main seat 18 during driving, the position of the main seat 18 moves downwards, the piston rod 22 of the cylinder 21 pushes the piston to move downwards, the supporting spring 20 compresses, the volume of the rodless cavity becomes smaller, gas is pushed into the air bag 26, and the air bag 26 enables the locking arm 27 to keep a position, which is also a hand brake release state required when the vehicle normally runs. After the driver 17 leaves the main driving seat 18, the main driving seat 18 loses the pressure position and rises, the supporting spring 20 pushes the spring seat 19 to drive the piston rod 22 and the piston to move upwards, at the moment, air in the air bag 26 is sucked into a rodless cavity of the air cylinder 21, the air bag 26 is flattened under the cooperation of the return spring 25, the right end of the locking arm 27 moves upwards and the left end moves downwards, the position fixing of the driving mechanism is released, finally, the braking kicking pull rope 9 is tensioned to realize the braking of the vehicle, and the braking handle 2 is also pulled up and locked.

When a driver 17 needs to drive a vehicle, the driver only needs to press a button at the end part of the brake handle 2 according to conventional operation, after the button is pressed, the pawl 4 is temporarily separated from the ratchet wheel 3, at the moment, the brake handle 2 is put down, the brake handle 2 drives the fixed wheel disc 5 to rotate, then the driving gear 8 is driven to rotate through the rotating pin 7, the driving gear 8 is matched with the rack 10, the fixed shaft 14 moves, and the pressure spring 12 is compressed; since the airbag 26 is inflated while the driver 17 is seated in the main seat 18, the return spring 25 is compressed by the airbag 26, and the latch 271 at the front end of the lock arm 27 is in contact with the surface of the fixed shaft 14; the latch 271 is finally inserted into the fixing hole 141 of the fixed shaft 14 when the fixed shaft 14 moves, and the driving mechanism is reset to the state shown in fig. 1, that is, to the manual brake down state.

Further, a mechanism for disengaging the latch pin 271 provided at the front end of the lock arm 27 from the fixing hole 141 provided in the fixed shaft 14 may be provided so as to perform braking using a handbrake while the driver 17 is still seated in the main seat 18. This mechanism is relatively easy to arrange, for example, a release lever connected to the front end of the lock arm 27 may be provided in the vehicle cabin, so that when the driver 17 presses the release lever downward, the release lever directly pushes the front end of the lock arm 27 to move downward, so that the latch 271 is disengaged from the fixing hole 141 of the fixed shaft 14, and thus the driver 17 can automatically lift the brake lever 2 upward by the driving mechanism without lifting the brake lever 2 upward.

As an extension of this embodiment, in addition to the above-described purely mechanical structure, the latch 271 of the lock arm 27 may be disengaged from the fixing hole 141 by pulling down the front end of the lock arm 27 by an electromagnet provided on the base plate 101 of the base 1 when the buckle is released.

The device is easy to manufacture, the base 1 of the main structure can be formed by punching plates, and the driving gear 8 and the rack 10 can be formed by adopting a powder metallurgy process, so that the manufacturing cost is reduced. The fixing shaft 14 can be milled to form a flat opening after being turned, and then drilling and tapping are carried out.

The above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.

Claims

1. The utility model provides an automatic take-up device of pure mechanical type vehicle parking braking, includes the arrestment mechanism of vehicle, arrestment mechanism includes brake handle (2), ratchet (3), pawl (4) and braking and plays stay cord (9), its characterized in that:

the device further comprises a base (1), the ratchet wheel (3) is fixed on the base (1), a rotating pin shaft (7) is mounted on the base (1), a fixed wheel disc (5) and a driving gear (8) are coaxially assembled on the rotating pin shaft (7), wherein the end part of the brake handle (2) is fixed on the fixed wheel disc (5), a pawl (4) is arranged at the edge of the fixed wheel disc (5) and matched with the ratchet wheel (3), and a brake kicking pull rope (9) is connected with the fixed wheel disc (5);

the base (1) is internally provided with a driving mechanism matched with the driving gear (8), the driving mechanism is fixed in position through a locking arm (27), and after the locking arm (27) releases the fixing of the driving mechanism, the driving mechanism drives the driving gear (8) to rotate, so that the fixed wheel disc (5) is driven to rotate through a rotating pin shaft (7); the fixed wheel disc (5) rotates to brake the vehicle by pulling the brake kicking pull rope (9), and drives the brake handle (2) to lift up and drives the pawl (4) to change the meshing position with the ratchet wheel (3) to realize brake locking;

when the driver (17) leaves the main driving seat (18), the position of the main driving seat (18) rises, and the locking arm (27) is driven by the linkage mechanism to release the fixing of the position of the driving mechanism.

2. The purely mechanical automatic tensioning device for the parking brake of the vehicle as claimed in claim 1, wherein the base (1) comprises a bottom plate (101) and four side plates (102) arranged around the bottom plate (101), and the two ends of the rotating pin shaft (7) are installed in shaft holes on the left side plate and the right side plate of the base (1).

3. The purely mechanical automatic tensioning device for the parking brake of the vehicle as claimed in claim 2, wherein the driving mechanism comprises a fixed shaft (14) perpendicular to the rotating pin (7), the front side plate and the rear side plate of the base (1) are symmetrically provided with mounting holes, and the fixed shaft (14) passes through the mounting holes of the front side plate and the rear side plate and can slide in the axial direction of the mounting holes;

a limiting ring (11) is mounted on the fixed shaft (14), a pressure spring (12) is sleeved on the fixed shaft (14) between the limiting ring (11) and the rear side plate, and a rack (10) matched with the driving gear (8) is laid on the surface of the fixed shaft (14); when the locking arm (27) releases the fixing of the driving mechanism, the pressure spring (12) pushes the fixed shaft (14) to move along the axial direction through the limiting ring (11), so that the rack (10) drives the driving gear (8) to rotate.

4. The purely mechanical automatic tensioning device for the parking brake of the vehicle as claimed in claim 3, wherein the rear side plate is provided with a guide hole on the upper surface thereof, the guide hole is communicated with the mounting hole on the rear side plate, the guide pin (13) is assembled in the limiting hole, and the end of the guide pin (13) is inserted into a guide groove (142) axially formed on the surface of the fixed shaft (14).

5. Purely mechanical automatic vehicle parking brake tensioning device according to claim 2, characterized in that a lug (28) is provided on the base plate (101) of the base (1), the locking arm (27) being hinged on the lug (28);

a plug pin (271) is vertically arranged at the front end of the locking arm (27), and a fixing hole (141) matched with the plug pin (271) is formed in the fixing shaft (14); the rear end of the locking arm (27) is provided with a position adjusting mechanism which is used for driving the locking arm (27) to rotate under the driving of the linkage mechanism;

when the positioning mechanism drives the locking arm (27) to rotate, so that the front end of the locking arm (27) moves downwards to cause the bolt (271) to be disengaged from the fixing hole (141) on the fixing shaft (14), the locking arm (27) releases the fixing of the driving mechanism.

6. The purely mechanical automatic tensioning device for the parking brake of the vehicle as claimed in claim 5, wherein the positioning mechanism comprises a limiting seat (24) arranged on a bottom plate (101) of the base (1), the limiting seat (24) comprises a vertical plate (242) and a horizontal plate (241) vertically arranged on the top of the vertical plate (242), an air bag (26) is arranged between the bottom of the horizontal plate (241) and the rear end of the locking arm (27), and a return spring (25) is arranged between the rear end of the locking arm (27) and the bottom plate (101) of the base (1);

the linkage mechanism is used for charging gas into the air bag (26) or exhausting gas from the air bag (26); when the air in the air bag (26) is exhausted, the return spring (25) pushes the rear end of the locking arm (27) to move upwards, thereby moving the front end of the locking arm (27) downwards.

7. The purely mechanical automatic tensioning device for the parking brake of the vehicle as claimed in claim 6, wherein the linkage mechanism comprises a cylinder (21) installed below the main seat (18), a spring seat (19) is arranged at the bottom of the main seat (18), the upper end of a piston rod (22) of the cylinder (21) is connected with the spring seat (19), and a support spring (20) is sleeved on the piston rod (22) between the cylinder (21) and the spring seat (19); the rodless cavity of the cylinder (21) is communicated with an air bag (26) in the positioning mechanism through a pressure air pipe (23), and the size of the rodless cavity is adjusted through the change of the position of a piston in the cylinder (21), so that air is filled into the air bag (26) or air is pumped out of the air bag (26).

8. Purely mechanical automatic parking brake tensioning device according to claim 1, characterized in that a release lever connected to the front end of the locking arm (27) is provided in the vehicle cab.