CN216241958U

CN216241958U - Brake

Info

Publication number: CN216241958U
Application number: CN202122894361.3U
Authority: CN
Inventors: 任艳强; 郑健; 金元; 田鹏
Original assignee: LONGZHONG HOLDING GROUP CO LTD
Current assignee: LONGZHONG HOLDING GROUP CO LTD
Priority date: 2021-11-22
Filing date: 2021-11-22
Publication date: 2022-04-08
Anticipated expiration: 2031-11-22

Abstract

The utility model provides a brake, and belongs to the technical field of brakes. The brake block solves the problems that the installation stability of the brake block on the caliper body in the existing brake is poor and the like. This stopper, including the pincers body and brake block, the installation department has on the pincers body, the locating surface that pastes with the brake block backplate and lean on has on the installation department, fixedly connected with clamp plate on the top of installation department, the top of backplate is connected with the elastic pressing strip, convex be banding horizontal sand grip on the back of backplate, the horizontal constant head tank that corresponds with horizontal sand grip has on the locating surface, horizontal sand grip is embedded into horizontal constant head tank, the top surface of horizontal sand grip pastes and leans on the side of going up in horizontal constant head tank, the clamp plate supports and leans on the bottom surface that makes horizontal sand grip on the elastic pressing strip and closely supports the downside that leans on in horizontal constant head tank. The brake improves the installation stability of the brake block on the caliper body.

Description

Brake

Technical Field

The utility model belongs to the technical field of brakes, and relates to a brake.

Background

The braking system is a system that forcibly reduces the movement speed of the sporting goods. On vehicles, braking is usually performed by a brake, which includes a disc brake, also called a disc brake, a drum brake, also called a drum brake, and the like. The floating caliper disc brake is widely applied to automobiles due to the advantages of fast heat dissipation, light weight and the like. The floating caliper type disc brake comprises a transmission mechanism, a bracket and a caliper body arranged on the bracket, wherein a sliding pin is arranged on the bracket and penetrates through a sliding pin hole on the caliper body, and the transmission mechanism is connected with a brake block arranged on the caliper body. The combination of the caliper body and the component attached to the caliper body is sometimes referred to as a brake caliper assembly.

As disclosed in chinese patent literature, a floating air-pressure caliper disc brake without a bracket [ application number: CN 201110192286.4; publication number: CN 102252048A ]: comprises an installation plate, a clamp body, two guide pins, a screw, a brake block, a pressure spring and a pressure plate. A window is arranged in the middle of the clamp body, and the X surface and the Y surface of the window are surfaces for supporting and guiding the supporting block. The brake block comprises a back plate and friction plates, wherein two sides of the top of the back plate are provided with protruding hangers, the lower surfaces of the hangers are attached to the X surface of the clamp body window, and two side surfaces, located below the hangers, of the back plate are respectively attached to the Y surface of the clamp body window. Because the pressure spring is the elastic component, when the brake pad received great upwards external force, the easy vibration from top to bottom that appears of brake pad leads to brake pad installation stability variation.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a brake aiming at the problems in the prior art, and the technical problem to be solved is how to improve the installation stability of a brake block on a caliper body.

The purpose of the utility model can be realized by the following technical scheme:

the utility model provides a brake, includes the pincers body and brake pad, the installation department has on the pincers body, have the locating surface that pastes with the brake pad backplate and paste on the installation department, fixedly connected with clamp plate on the top of installation department, the top of backplate is connected with the elastic pressing strip, a serial communication port, convex horizontal sand grip that is banding has on the back of backplate, have the horizontal constant head tank that corresponds with horizontal sand grip on the locating surface, horizontal sand grip is embedded into in the horizontal constant head tank, the top surface of horizontal sand grip pastes and leans on the side of going up in horizontal constant head tank, the clamp plate supports and leans on the downside that makes the bottom surface of horizontal sand grip closely support in horizontal constant head tank on the elastic pressing strip.

The top surface of the transverse convex strip is attached to the upper side surface of the transverse positioning groove, the bottom surface of the transverse convex strip is attached to the lower side surface of the positioning groove, and the upper side surface and the lower side surface of the transverse positioning groove are used for positioning the brake block in the vertical direction, so that the brake block is prevented from vibrating vertically; the clamp plate supports and leans on the bottom surface that makes horizontal sand grip on the elastic pressing strip and closely supports the downside that leans on in horizontal constant head tank simultaneously, and horizontal sand grip and horizontal constant head tank are the strip, the area of contact between horizontal sand grip bottom surface and the horizontal constant head tank downside has been increased, guarantee to have sufficient frictional force between the bottom surface of horizontal sand grip and the downside of horizontal constant head tank, avoid horizontal sand grip roll-off in the horizontal constant head tank, and can also disperse the atress, avoid the structural damage that the atress concentrates and arouse, make the installation of brake pads on the pincers body stable. In addition, the transverse convex strips are arranged on the back face of the back plate in a protruding mode, so that the sectional areas of the transverse convex strips and the sectional areas of the joints of the transverse convex strips and the back plate are not limited by the thickness of the back plate, the structural strength of the transverse convex strips, particularly the structural strength of the joints of the transverse convex strips and the back plate, can be guaranteed, and the situation that the transverse convex strips deform to influence the stability of the installation of the brake block on the caliper body is avoided. Therefore, the brake improves the installation stability of the brake block on the caliper body.

In the above brake, the lateral ribs are symmetrically arranged about a center line of the back plate. Therefore, the stress of the transverse convex strips can be uniform, and the mounting stability of the brake block on the caliper body can be improved.

In the above brake, the left side surface and the right side surface of the transverse convex strip are respectively attached to the left side surface and the right side surface of the transverse positioning groove. The left side surface and the right side surface of the transverse positioning groove form positioning in the left-right direction of the brake block, so that the brake block is prevented from shaking left and right, and the brake block is stably installed on the caliper body.

In foretell stopper, still have the convex longitudinal raised line that is banding on the back of backplate, still set up the longitudinal positioning groove that corresponds with longitudinal raised line on the locating surface, longitudinal raised line is embedded into the longitudinal positioning groove, and the left surface and the right flank of longitudinal raised line paste respectively on the left surface and the right flank in longitudinal positioning groove.

The cooperation of longitudinal raised strip and longitudinal positioning groove forms the location to the brake pads left and right sides direction, avoids the brake pads to take place to rock from side to side, makes the brake pads installation stable on the pincers body. And longitudinal raised line and longitudinal positioning groove are the strip, have increased the area of contact of longitudinal raised line and longitudinal positioning groove side, dispersion atress that can be better, avoid the structural damage that the atress is concentrated and is aroused, also be favorable to making the brake block install stably on the pincers body.

In foretell stopper, the convex longitudinal direction sand grip that is the banding that is has on the locating surface, set up the longitudinal direction constant head tank that corresponds with longitudinal direction sand grip on the back of backplate, during longitudinal direction constant head tank was embedded into to longitudinal direction sand grip, and the left surface and the right flank of longitudinal direction sand grip lean on respectively on the left surface and the right flank of longitudinal direction constant head tank.

In the above brake, the longitudinal ribs are vertically connected to the middle portions of the transverse ribs. Therefore, the structural strength of the transverse convex strips and the longitudinal convex strips can be increased, and the stable installation of the brake block on the caliper body is facilitated.

In the above brake, two longitudinal ribs are symmetrically disposed on the upper and lower sides of the transverse rib. Therefore, the stress can be further dispersed, and the brake block can be stably installed on the caliper body.

In the above brake, the back surface of the transverse rib is flush with the back surface of the longitudinal rib. Therefore, the transverse convex strips and the longitudinal convex strips are convenient to process, and stress concentration caused by the existence of the steps can be avoided.

The utility model provides a brake, includes the pincers body and brake pad, the installation department has on the pincers body, have the locating surface that pastes with the brake pad backplate and paste on the installation department, fixedly connected with clamp plate on the top of installation department, the top of backplate is connected with the elastic pressing strip, a serial communication port, convex be banding horizontal sand grip on the locating surface, have the horizontal constant head tank that corresponds with horizontal sand grip on the back of backplate, horizontal sand grip is embedded into in the horizontal constant head tank, the bottom surface of horizontal sand grip pastes with the downside of horizontal constant head tank and pastes and lean on, the clamp plate supports to lean on the top surface that makes the side of going up of horizontal constant head tank closely to lean on in horizontal sand grip on the elastic pressing strip.

The upper side surface of the transverse positioning groove abuts against the top surface of the transverse convex strip, the lower side surface of the positioning groove abuts against the bottom surface of the transverse convex strip, and the top surface and the bottom surface of the transverse convex strip position the brake block in the vertical direction, so that the brake block is prevented from vibrating vertically; the clamp plate supports and leans on the top surface that makes the side of going up that makes transverse positioning groove closely to lean on in transverse convex strip on the elastic pressing strip simultaneously, and transverse convex strip and transverse positioning groove are the strip, the area of contact between transverse convex strip bottom surface and the transverse positioning groove downside has been increased, guarantee to have sufficient frictional force between the bottom surface of transverse convex strip and the downside of transverse positioning groove, avoid transverse convex strip roll-off in the transverse positioning groove, and can also disperse the atress, avoid the structural damage that the atress concentrates and arouse, make the installation of brake pads on the pincers body stable. In addition, the transverse convex strips are arranged on the caliper body in a protruding mode, so that the sectional areas of the transverse convex strips are not limited by the thickness of the back plate, the structural strength of the transverse convex strips can be guaranteed, and the problem that the transverse convex strips deform to influence the stability of the brake block mounted on the caliper body is avoided. Therefore, the brake improves the installation stability of the brake block on the caliper body.

In the brake, the back surface of the back plate is provided with a protruding strip-shaped longitudinal convex strip, the positioning surface is provided with a longitudinal positioning groove corresponding to the longitudinal convex strip, or the positioning surface is also provided with a protruding strip-shaped longitudinal convex strip, and the back surface of the back plate is also provided with a longitudinal positioning groove corresponding to the longitudinal convex strip; the longitudinal raised strips are embedded into the longitudinal positioning grooves, and the left side surface and the right side surface of the longitudinal raised strips are respectively attached to the left side surface and the right side surface of the longitudinal positioning grooves.

The cooperation of longitudinal raised strip and longitudinal positioning groove forms the location to the brake pads left and right sides direction, avoids the brake pads to take place to rock from side to side, makes the brake pads installation stable on the pincers body. And longitudinal raised line and longitudinal positioning groove are the strip, have increased the area of contact between longitudinal raised line and the longitudinal positioning groove side, dispersion atress that can be better, avoid the structural damage that the atress concentrates to cause, also be favorable to making the brake block install stably on the pincers body.

Compared with the prior art, the utility model has the following advantages:

the arrangement of the strip-shaped transverse protruding strips and the transverse positioning grooves realizes the upper and lower positioning of the brake block, avoids the brake block from vibrating up and down, increases the contact area, increases the friction force, and can also disperse the pressure to avoid stress concentration, thereby improving the installation stability of the brake block on the caliper body. The vertical protruding strips and the vertical positioning grooves are arranged, left and right positioning of the brake block is achieved, stress can be dispersed, and the installation stability of the brake block on the caliper body is improved.

Drawings

FIG. 1 is a perspective view of a first embodiment of the brake;

FIG. 2 is a perspective view of the brake of the present embodiment, showing the brake pad and caliper body separated from each other;

FIG. 3 is a cross-sectional view of the brake pad and caliper body at the connection point in the first embodiment of the brake;

FIG. 4 is a perspective view of the brake of the second embodiment of the present brake showing the brake pad and the caliper body;

FIG. 5 is a sectional view of the brake pad and caliper body at the junction thereof according to the second embodiment of the present brake.

In the figure, 1, a clamp body; 1a, an installation part; 1a1, a positioning surface; 1a2, transverse positioning groove; 1a3, longitudinal positioning groove; 1b, a transmission part; 1c, a bridge; 1d, mounting ports; 2. a brake pad; 2 a; a back plate; 2a1, transverse ribs; 2a2, longitudinal ribs; 2a3, bumps; 2b, a friction block; 2c, elastic pressing strips; 3. a pair of brake pads; 4. pressing a plate; 5. a bracket.

Detailed Description

The following are specific embodiments of the present invention and are further described with reference to the drawings, but the present invention is not limited to these embodiments.

Example one

As shown in fig. 1 to 3, a brake includes a caliper body 1 that can be placed across a brake disc, a brake pad 2 for braking in cooperation with an outer side surface of the brake disc, a counterpart brake pad 3 for braking in cooperation with an inner side surface of the brake disc, and a bracket 5. The caliper body 1 includes a mounting portion 1a for mounting the brake pad 2, a transmission portion 1b connected to the bracket 5, and a bridge portion 1c between the mounting portion 1a and the transmission portion 1 b. The mounting portion 1a and the transmission portion 1b are located inside and outside the brake disc, respectively, and the bridge portion 1c is located on the outer peripheral side of the brake disc. The brake pad 2 includes a backing plate 2a and a friction plate 2b, and the friction plate 2b can be brought into contact with a brake disc to perform braking. A transmission mechanism is arranged in the transmission part 1b, the paired brake blocks 3 are connected with the transmission mechanism and arranged in the bracket 5, and the bracket 5 is connected with the transmission part 1b in a sliding way. A sliding pin is fixedly connected in the pin hole of the bracket 5, a sliding pin hole is arranged on the transmission part 1b, and the sliding pin penetrates through the sliding pin hole. The bridge portion 1c has a mounting opening 1d formed in the top surface thereof, and the brake pad 2 and the counter brake pad 3 can be inserted into and removed from the mounting opening 1 d.

The top surface of the back plate 2a is connected with an elastic pressing strip 2c, the top surface of the back plate 2a is provided with a convex bulge 2a3, two bulges 2a3 are symmetrically arranged about the center line of the back plate 2a, two ends of the elastic pressing strip 2c are respectively fixed on the two bulges 2a3, the elastic pressing strip 2c is arched towards the direction away from the top surface of the back plate 2a, and the pressing plate 4 is pressed against the top of the elastic pressing strip 2 c. The top of the mounting part 1a is fixedly connected with a pressure plate 4, one end of the pressure plate 4 is inserted on the transmission part 1b, and the other end of the pressure plate 4 is fixedly connected on the top surface of the mounting part 1a through a bolt; or the two ends of the pressure plate 4 are fixedly connected to the transmission part 1b and the mounting part 1a through bolts respectively.

The mounting portion 1a has a positioning surface 1a1, and the back surface of the back plate 2a abuts against the positioning surface 1a 1. The back panel 2a has a protruding strip-shaped transverse rib 2a1 on the back surface, and the transverse rib 2a1 is symmetrically arranged about the center line of the back panel 2 a. The positioning surface 1a1 has transverse positioning slots 1a2 corresponding to the transverse ribs 2a1, and the transverse ribs 2a1 are embedded into the transverse positioning slots 1a 2. The top surface of the transverse convex strip 2a1 is abutted against the upper side surface of the transverse positioning slot 1a2, and the pressing plate 4 is abutted against the top of the elastic strip 2c, so that the bottom surface of the transverse convex strip 2a1 is tightly abutted against the lower side surface of the transverse positioning slot 1a 2. The left and right lateral surfaces of the lateral protruding strip 2a1 abut against the left and right lateral surfaces of the lateral positioning groove 1a2, respectively.

When the brake block 2 is installed, firstly, the paired brake block 3 and the brake block 2 are inserted through the installation opening 1d at the top of the caliper body 1, the paired brake block 3 is installed in the bracket 5, then the transverse convex strip 2a1 on the brake block 2 is embedded into the transverse positioning groove 1a2, the left side and the right side of the transverse convex strip 2a1 are respectively attached to the left side and the right side of the transverse positioning groove 1a2, the top surface and the bottom surface of the transverse convex strip 2a1 are respectively attached to the upper side and the lower side of the transverse positioning groove 1a2, the back surface of the back plate 2a of the brake block 2 is attached to the positioning surface 1a1 of the installation part 1a, then the pressing plate 4 is fixed on the top of the caliper body 1, and under the action of the pressing plate 4, the bottom surface of the transverse convex strip 2a1 is closely attached to the lower side of the transverse positioning groove 1a 2. The left and right side surfaces of the lateral positioning groove 1a2 position the brake pad 2 in the left-right direction, thereby preventing the brake pad 2 from shaking in the left-right direction. The upper and lower sides of the transverse positioning groove 1a2 are used for positioning the brake block 2 in the vertical direction, so that the brake block 2 is prevented from vibrating up and down. The clamp plate 4 supports and leans on the top that makes horizontal sand grip 2a1 the bottom surface closely to lean on in the downside of horizontal constant head tank 1a2 at elastic pressing strip 2c, and horizontal sand grip 2a1 and horizontal constant head tank 1a2 are the strip, the area of contact of the bottom surface of horizontal sand grip 2a1 and constant head tank downside has been increased, guarantee to have sufficient frictional force between the bottom surface of horizontal sand grip 2a1 and the downside of horizontal constant head tank 1a2, avoid horizontal sand grip 2a1 from the interior roll-off of horizontal constant head tank 1a2, and can also disperse the atress, avoid the structural damage that the atress concentrates and arouse, it is stable to make brake pad 2 install on pincers body 1. In addition, the transverse convex strips 2a1 are arranged on the back surface of the back plate 2a in a protruding mode, the cross section area of the transverse convex strips 2a1 and the cross section area of the connecting part of the transverse convex strips 2a1 and the back plate 2a are not limited by the thickness of the back plate 2a, so that the structural strength of the transverse convex strips 2a1, particularly the structural strength of the connecting part of the transverse convex strips 2a1 and the back plate 2a can be guaranteed, and the situation that the transverse convex strips 2a1 deform to influence the mounting stability of the brake pad 2 on the caliper body 1 is avoided. Therefore, the brake improves the mounting stability of the brake pad 2 on the caliper body 1.

Example two

As shown in fig. 4 and 5, in the first embodiment, the back panel 2a further has a protruding longitudinal rib 2a2 in a strip shape on the back surface, the longitudinal rib 2a2 is vertically connected to the middle of the transverse rib 2a1, and the back surface of the transverse rib 2a1 is flush with the back surface of the longitudinal rib 2a 2. The connecting part of the transverse convex strip 2a1 and the longitudinal convex strip 2a2 is provided with a fillet, which can avoid stress concentration and ensure the structural strength of the transverse convex strip 2a1 and the longitudinal convex strip 2a 2. The positioning surface 1a1 is further provided with a longitudinal positioning slot 1a3 corresponding to the longitudinal rib 2a2, the longitudinal rib 2a2 is embedded into the longitudinal positioning slot 1a3, and the left side surface and the right side surface of the longitudinal rib 2a2 are respectively attached to the left side surface and the right side surface of the longitudinal positioning slot 1a 3. The two longitudinal ribs 2a2 are symmetrically disposed on the upper and lower sides of the transverse rib 2a1, and correspondingly, the positioning surface 1a1 has two longitudinal positioning grooves 1a3 symmetrically disposed about the transverse positioning groove 1a 2.

EXAMPLE III

The transverse positioning grooves 1a2 are arranged on the back surface of the back plate 2a, the transverse protruding strips 2a1 are arranged on the positioning surface 1a1, the transverse protruding strips 2a1 are embedded into the transverse positioning grooves 1a2, the bottom surfaces of the transverse protruding strips 2a1 are attached to the lower side surfaces of the transverse positioning grooves 1a2, and the pressing plate 4 abuts against the elastic pressing strips 2c to enable the upper side surfaces of the transverse positioning grooves 1a2 to tightly abut against the top surfaces of the transverse protruding strips 2a 1. The other structure is the same as the first embodiment.

Example four

The transverse positioning grooves 1a2 and the longitudinal positioning grooves 1a3 are provided on the back surface of the back panel 2a, and the transverse protruding strips 2a1 and the longitudinal protruding strips 2a2 are provided on the positioning surface 1a 1. The transverse convex strip 2a1 is embedded into the transverse positioning slot 1a2, the bottom surface of the transverse convex strip 2a1 is abutted against the lower side surface of the transverse positioning slot 1a2, and the pressing plate 4 is abutted against the elastic pressing strip 2c to enable the upper side surface of the transverse positioning slot 1a2 to be tightly abutted against the top surface of the transverse convex strip 2a 1. The other structure is the same as the embodiment.

EXAMPLE five

The longitudinal positioning grooves 1a3 are disposed on the back surface of the back plate 2a, the longitudinal protruding strips 2a2 are disposed on the positioning surface 1a1, and the other structures are the same as those of the embodiment.

The specific embodiments described herein are merely illustrative of the spirit of the utility model. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the utility model as defined in the appended claims.

Claims

1. A brake, including pincers body (1) and brake pad (2), have installation department (1a) on pincers body (1), have locating surface (1a1) that leans on with brake pad (2) backplate (2a) on installation department (1a), fixedly connected with clamp plate (4) on the top of installation department (1a), the top of backplate (2a) is connected with elasticity layering (2c), characterized by, have protruding banding horizontal sand grip (2a1) that is on the back of backplate (2a), have horizontal constant head tank (1a2) that corresponds with horizontal sand grip (2a1) on locating surface (1a1), horizontal sand grip (2a1) is embedded into horizontal constant head tank (1a2), the top surface of horizontal sand grip (2a1) leans on the last side of horizontal constant head tank (1a2), clamp plate (4) lean on elasticity layering (2c) and make the bottom surface of horizontal sand grip (2a1) closely lean on in the horizontal constant head tank (1a2) and lean on (1a2) To the underside of the housing.

2. The brake of claim 1, characterized in that the transverse ribs (2a1) are arranged symmetrically with respect to the center line of the back plate (2 a).

3. The brake of claim 1, characterized in that the left and right lateral faces of the transverse rib (2a1) abut against the left and right lateral faces of the transverse detent groove (1a2), respectively.

4. The brake of any one of claims 1 to 3, characterized in that the back plate (2a) further has a protruding strip-shaped longitudinal rib (2a2) on the back surface thereof, the positioning surface (1a1) further has a longitudinal positioning groove (1a3) corresponding to the longitudinal rib (2a2), the longitudinal rib (2a2) is inserted into the longitudinal positioning groove (1a3), and the left side surface and the right side surface of the longitudinal rib (2a2) respectively abut against the left side surface and the right side surface of the longitudinal positioning groove (1a 3).

5. A brake according to any one of claims 1-3, characterized in that the positioning surface (1a1) has a protruding longitudinal rib (2a2) in the shape of a strip, the back surface of the back plate (2a) is provided with a longitudinal positioning slot (1a3) corresponding to the longitudinal rib (2a2), the longitudinal rib (2a2) is inserted into the longitudinal positioning slot (1a3), and the left side and the right side of the longitudinal rib (2a2) respectively abut against the left side and the right side of the longitudinal positioning slot (1a 3).

6. A brake according to claim 4, characterized in that the longitudinal ribs (2a2) are connected perpendicularly to the middle of the transverse ribs (2a 1).

7. A brake according to claim 4, characterized in that said longitudinal ribs (2a2) are two and symmetrically arranged on the upper and lower sides of the transverse rib (2a 1).

8. A brake according to claim 4, characterized in that the rear faces of the transverse ribs (2a1) are flush with the rear faces of the longitudinal ribs (2a 2).

9. The utility model provides a brake, includes pincers body (1) and brake pad (2), installation department (1a) has on pincers body (1), have locating surface (1a1) that leans on with brake pad (2) backplate (2a) on installation department (1a), fixedly connected with clamp plate (4) on the top of installation department (1a), elasticity layering (2c) is connected to the top of backplate (2a), its characterized in that, have convex lateral protrusion strip (2a1) that is on locating surface (1a1), have lateral positioning groove (1a2) that correspond with lateral protrusion strip (2a1) on the back of backplate (2a), lateral protrusion strip (2a1) is embedded into lateral positioning groove (1a2), the bottom surface of lateral protrusion strip (2a1) leans on with the downside of lateral positioning groove (1a2) to lean on, clamp plate (4) support and lean on the upside that makes lateral positioning groove (1a2) on elasticity layering (2c) closely to lean on in lateral positioning groove (1a2) Top surface of the strip (2a 1).

10. The brake of claim 9, characterized in that the back plate (2a) has a protruding longitudinal rib (2a2) in strip shape on its back surface, the positioning surface (1a1) has a longitudinal positioning groove (1a3) corresponding to the longitudinal rib (2a2), or the positioning surface (1a1) has a protruding longitudinal rib (2a2) in strip shape, the back plate (2a) has a longitudinal positioning groove (1a3) corresponding to the longitudinal rib (2a2) on its back surface; the longitudinal convex strip (2a2) is embedded into the longitudinal positioning groove (1a3), and the left side surface and the right side surface of the longitudinal convex strip (2a2) are respectively abutted against the left side surface and the right side surface of the longitudinal positioning groove (1a 3).