CN202846827U - A zero-degree demoulding plastic molding mold - Google Patents

Abstract

The utility model relates to a mould for injection moulding product zero degree drawing of patterns. The utility model relates to a zero degree drawing of patterns plastic forming die, comprises an upper die, the lower mould, the die carrier, reverse module of loosing core, second drive module and third drive module, first mounting hole has been seted up on the die core down, or first mounting hole has been seted up on die core and lower mould down, it is relative with the reverse position of loosing core that needs on injection moulding product in first mounting hole, reverse module of loosing core includes reverse core-pulling piece, reverse gliding the installing in first mounting hole of the piece of loosing core, the shape on the upper portion of reverse core-pulling piece suits with the shape that needs reverse position of loosing core on injection moulding product, second drive module can drive reverse core-pulling piece and slide towards injection moulding product's direction in first mounting hole, third drive module can drive reverse core-pulling piece and slide in the direction that injection moulding product was kept away from in first mounting hole. The mould can effectively solve the problem that the appearance surface of the product is scratched when the appearance surface of the product is subjected to zero-degree demoulding.

Description

A zero-degree demoulding plastic molding mold

technical field

The utility model relates to a mold, in particular to a mold used for zero-degree demoulding of injection molding products.

Background technique

As shown in Figure 1, it is the structural diagram of prior art plastic forming mold, and this mold comprises upper mold 3 ', lower mold 4 ' and ejection mechanism, upper mold 3 ' is provided with upper mold core 5 ', lower mold 4 ' A lower mold core 6' is arranged on the top. During mould-closing, the upper mold 3' and the lower mold 4' fit together, and the upper mold core 5' and the lower mold core 6' jointly form a sealed cavity 7' to form injection molded products. The ejector mechanism includes a ejector plate 8' and a plurality of ejector pins 9', and the ejector pins 9' are fixed on the ejector plate 8', and are pushed out by the ejector plate 8'. As shown in Figure 2, the ejector mechanism pushes the cooled and molded plastic product away from the lower core 6' when the mold is opened, thereby releasing the product from the mold. The appearance surface 1' of the injection molding product 10' produced by the existing plastic molding mold has a certain demoulding slope, which can ensure that the appearance surface 1' of the injection molding product 10' will not be scratched when the mold is opened. However, as shown in Figure 3 As shown, for some injection molded products 11', the appearance surface 2' is required to be set vertically. During molding, friction occurs between the upper mold core 5' and the appearance surface, which will scratch the appearance surface of the injection molded product, causing scratches and affecting the quality of the injection molded product.

Utility model content

The technical problem to be solved by the utility model is to provide a zero-degree demoulding plastic forming mold, which can effectively solve the problem that the product appearance surface is scratched when the product appearance surface is demoulded at zero degree.

The utility model relates to a zero-degree demoulding plastic molding mold, which comprises an upper mold, a lower mold and a mold frame, an upper mold core is fixedly installed in the upper mold, a lower mold core is fixedly installed in the lower mold, and the upper mold core and the lower mold are fixedly installed. There is a cavity between the cores, and the device also includes a reverse core-pulling module, a second driving module and a third driving module, and a first installation hole is opened on the lower mold core, or a first installation hole is opened on the lower mold core and the lower mold. One installation hole, the first installation hole is opposite to the part of the injection molding product that needs reverse core pulling, the first installation hole is connected to the cavity, the reverse core pulling module includes a reverse core pulling block, and the reverse core pulling block is slidably installed on In the first installation hole, the shape of the upper part of the reverse core-pulling block is adapted to the shape of the injection molded product that needs reverse core-pulling, and the second drive module can drive the reverse core-pulling block to face the injection molded product in the first installation hole The third driving module can drive the reverse core-pulling block to slide in the direction away from the injection molded product in the first installation hole.

The utility model is a zero-degree demoulding plastic forming mold, wherein the second driving module is driven by hydraulic pressure or spring, and the third driving module is driven by spring or hydraulic pressure.

The utility model is a zero-degree demoulding plastic forming mold, wherein the second driving module includes at least one second piston type oil cylinder body and a second cylinder body installation hole, a second high-pressure oil pipeline, and a second cylinder body installation hole Set on the formwork, the second high-pressure oil pipeline is opened on the formwork, the axis of each second cylinder mounting hole is parallel to the axis of the first mounting hole, and the upper end of each second cylinder mounting hole is in line with the first One installation hole communicates, and the lower end of each second cylinder installation hole communicates with the second high-pressure oil pipeline, and a second piston-type oil cylinder is installed slidingly in each second cylinder installation hole, and each second The upper end surface of the piston cylinder block is in contact with the lower end surface of the reverse core pulling block, and a seal is installed between the outer circumferential surface of each second piston cylinder body and the hole wall of the corresponding second cylinder body mounting hole. apron.

The utility model is a zero-degree demoulding plastic forming mold, wherein the third drive module includes at least one first spring, the first spring is a tension spring, each first spring is located in the first installation hole, each first The lower end of a spring is fixedly connected to the bottom surface of the first mounting hole, and the upper end of each first spring is fixedly connected to the bottom surface of the opposite core-pulling block.

The utility model is a zero-degree demoulding plastic forming mold, wherein the reverse core-pulling module also includes a mounting block, and a lower hole is opened on the lower surface of the lower mold, and each second cylinder mounting hole is connected with the lower hole through the lower hole. The first installation hole is connected, the diameter of the lower hole is larger than the diameter of the first installation hole, the installation block is slidably installed in the lower hole, and the upper end of the installation block is fixedly connected with the lower end of the reverse core pulling block, each second piston cylinder The upper end surface of the cylinder body is in contact with the lower end surface of the mounting block. The third drive module includes at least one first spring, the first spring is a compression spring, and at least one spring mounting hole is opened on the upper top surface of the lower hole. The first springs are all installed in a spring installation hole, and the lower end of each first spring is pressed on the upper surface of the installation block.

The utility model is a zero-degree demoulding plastic forming mold, wherein the reverse core-pulling block includes an upper block and a lower block, the lower end of the upper block is fixedly connected to the upper end of the lower block, and a first block is provided on the lower bottom surface of the upper block. Two mounting holes, the second mounting hole is a step hole, the reverse core-pulling module also includes a functional module, the functional module is slidably installed in the second mounting hole, the functional module includes a cutter and a connecting part, and the cutter is fixedly installed on the connecting part Above, the connection part is located in the large hole of the second installation hole, at least one second spring is installed between the upper end surface of the connection part and the step surface of the second installation hole, the second spring is a compression spring, the cutter and the mold The connection between the cavity and the runner gate is opposite, and the first cylinder mounting hole and the first high-pressure oil pipeline are opened on the upper surface of the lower block. The upper end of the first cylinder mounting hole communicates with the second mounting hole, and the first cylinder The axis of the body mounting hole is parallel to the axis of the second mounting hole, the lower end of the first cylinder mounting hole communicates with the first high-pressure oil pipeline, and the first piston type oil cylinder is installed slidingly in the first cylinder mounting hole, The outer peripheral surface of the first piston type oil cylinder body is sealed with the inner wall of the installation hole of the first cylinder body by a sealing rubber ring, and the upper end of the first piston type oil cylinder body is connected with the connecting part.

A zero-degree demoulding plastic forming mold of the utility model is different from the prior art in that the utility model is provided with a reverse core-pulling block, and the reverse core-pulling block is slidably installed in the first installation hole, and the reverse core-pulling block The shape of the upper part of the injection molding product is adapted to the shape of the reverse core-pulling part. The reverse core-pulling block can slide in the first mounting hole under the action of the second drive module and the third drive module, and the injection molding machine Before the molten material is injected into the mold, the second drive module drives the reverse core-pulling block to move upwards, so that the reverse core-pulling block is filled with the part of the injection molded product that needs reverse core-pulling. Before the mold is opened, the third drive module drives the reverse core-pulling block. Move down to the core-pulling block, so that the reverse core-pulling block leaves the injection molded product. When the reverse core-pulling block leaves the injection molded product, the injection molded product will shrink inward due to elasticity, so that the appearance surface of the injection molded product and the upper mold core The surface of the cavity is separated, so that after the mold is opened, the appearance surface of the injection molded product with a demoulding angle of zero will not be scratched, which effectively solves the problem of scratches on the appearance of the product.

Below in conjunction with accompanying drawing, the utility model is further described.

Description of drawings

Fig. 1 is a structural schematic diagram of a mold in a mold clamping state in the prior art (the appearance surface has a demoulding slope);

Fig. 2 is the structural representation of the mold of Fig. 1 when the mold is opened;

Fig. 3 is the structural representation of the upper and lower mold cores of the prior art mold (the demoulding slope of the appearance surface is zero degree);

Fig. 4 is a front sectional view of a zero-degree demoulding plastic molding mold of the present invention (the reverse core-pulling block contacts the plastic part, before the cutter works);

Figure 5 is a front sectional view of a zero-degree demoulding plastic molding mold of the present invention (when the reverse core-pulling block contacts the plastic part and the cutter is working);

Fig. 6 is a front sectional view of a zero-degree demoulding plastic molding mold of the present invention (the reverse core-pulling block is separated from the plastic part);

Fig. 7 is a top view of a piston-type cylinder block of a zero-degree demoulding plastic molding mold of the present invention;

Fig. 8 is a front view of a piston-type cylinder block of a zero-degree demoulding plastic molding mold of the present invention;

Fig. 9 is a front view of the third driving module of a zero-degree demoulding plastic molding mold of the present invention (the cylinder body is reset by a tension spring);

Fig. 10 is a front view of the third drive module of a zero-degree demoulding plastic molding mold of the present invention (the cylinder body is reset by high-pressure oil).

Detailed ways

Example 1:

As shown in Figure 4, a zero-degree demoulding plastic molding mold of the present invention includes an upper mold 1, a lower mold 2 and a mold frame 3, an upper mold core 4 is fixedly installed in the upper mold 1, and a mold core 4 is fixedly installed in the lower mold 2. Lower die core 5, lower die 2 are fixedly installed on the formwork 3. A cavity 6 is provided between the upper mold core 4 and the lower mold core 5 .

The device also includes a reverse core-pulling module 7, a second driving module and a third driving module. A first installation hole 8 is opened on the lower mold core 5 and the lower mold 2. The first installation hole 8 communicates with the cavity 6. The first installation hole 8 is opposite to the part of the injection molded product 9 that requires reverse core pulling. In the utility model The so-called part on the injection molding product that requires reverse core pulling refers to the cavity part formed by the inner surface opposite to the appearance surface of the injection molding product.

The reverse core-pulling module 7 includes a reverse core-pulling block 10 and a mounting block 16. The reverse core-pulling block 10 is slidably installed in the first mounting hole 8, and the outer circumferential surface of the reverse core-pulling block 10 is in contact with the first mounting hole. 8 is a clearance fit between the hole walls. In this embodiment, the first mounting hole 8 is a stepped hole with a small upper part and a larger lower part. A lower hole 17 coaxial with the first mounting hole 8 is also provided on the lower surface of the lower mold 2. The diameter of the lower hole 17 is larger than that of the first mounting hole 8. The diameter of the hole 8, the mounting block 16 is slidably installed in the lower hole 17, the outer peripheral surface of the mounting block 16 and the hole wall of the lower hole 17 are clearance fit, the upper end of the mounting block 16 and the lower end of the reverse core pulling block 10 Fixed connection. The shape of the upper part of the reverse core-pulling block 10 is adapted to the shape of the part on the injection molded product 9 that requires reverse core-pulling. The second driving module includes two second piston cylinders 11 , a second cylinder mounting hole 12 , and a second high-pressure oil pipeline 13 . The second cylinder mounting hole 12 is provided on the formwork 3, and the second high-pressure oil pipeline 13 is also provided on the formwork 3. The axis of each second cylinder mounting hole 12 is parallel to the axis of the first mounting hole 8. The upper ends of the second cylinder mounting holes 12 are communicated with the first mounting hole 8 through the lower hole 17, and the lower ends of each second cylinder mounting hole 12 are communicated with the second high-pressure oil pipeline 13, and each second cylinder is installed A second piston-type cylinder body 11 is installed slidingly in the hole 12, and the upper end surface of each second piston-type cylinder body 11 is in contact with the lower end surface of the mounting block 16, as shown in Fig. 7 and Fig. 8 , A sealing rubber ring 14 is installed between the outer peripheral surface of each second piston cylinder body 11 and the hole wall of the corresponding second cylinder body mounting hole 12 .

Wherein the third drive module includes three first springs 15, the first springs 15 are compression springs, and three spring mounting holes 18 are provided on the upper top surface of the lower hole 17, and the three spring mounting holes 18 are evenly distributed in the first mounting holes 8 around the large hole. Each first spring 15 is installed in a spring mounting hole 18 , and the lower end of each first spring 15 is pressed against the upper surface of the mounting block 16 .

Wherein the reverse core-pulling block 10 includes an upper block 19 and a lower block 20, the lower end of the upper block 19 is fixedly connected to the upper end of the lower block 20 with bolts, and a second mounting hole 21 is provided on the lower bottom surface of the upper block 19. The second installation hole 21 is a stepped hole with a small top and a large bottom. The reverse core-pulling module 7 also includes a functional module 22, which is slidably installed in the second installation hole 21. The functional module 22 includes a cutter 23 and a connecting part 24. , the cutter 23 is fixedly installed on the connecting portion 24, the connecting portion 24 is located in the large hole of the second mounting hole 21, and the outer peripheral surface of the connecting portion 24 and the large hole wall of the second mounting hole 21 are clearance fit . Three second springs 25 are installed between the upper end surface of the connecting portion 24 and the stepped surface of the second mounting hole 21 , the second springs 25 are compression springs, and the three second springs 25 are evenly distributed on the same circumference. The cutter 23 is opposite to the junction of the cavity 6 and the runner gate 26, and the upper surface of the lower block 20 is provided with a first cylinder mounting hole 27 and a first high-pressure oil pipeline 28, and the first cylinder mounting hole 27 The upper end communicates with the second mounting hole 21, the first cylinder mounting hole 27 is coaxial with the second mounting hole 21, the lower end of the first cylinder mounting hole 27 communicates with the first high-pressure oil pipeline 28, and the first cylinder mounting hole The first piston type oil cylinder body 29 is installed slidingly in 27, as shown in Fig. 7 and Fig. 8, the outer peripheral surface of the first piston type oil cylinder body 29 and the inner wall of the first cylinder body mounting hole 27 pass through the sealing rubber ring 14 is sealed, and the upper end of the first piston cylinder block 29 is connected with the connecting portion 24.

When a zero-degree demoulding plastic forming mold of the present invention is in use, first connect the high-pressure power oil source with the first high-pressure oil pipeline 28 and the second high-pressure oil pipeline 13; Melt, close the injection mold, connect the nozzle of the injection molding machine with the runner gate 26 and cavity 6 of the injection mold to form a closed cavity; before the material injection process of the injection molding machine starts, control the high-pressure power oil source to the second high-pressure oil pipeline Input pressure oil in 13, the pressure oil enters the second cylinder mounting hole 12 through the second high-pressure oil pipeline 13, and pushes the second piston cylinder 11 to move, and the two second piston cylinders 11 then push the reverse pumping The core block 10 moves into the cavity 6, and when the reverse core-pulling block 10 reaches the set position, the reverse core-pulling block 10 fills the part of the injection molded product 9 that needs reverse core-pulling, and then the injection molding machine melts The material is injected into the runner gate 26 of the injection mold at a certain pressure and speed; after being injected by the injection molding machine and pressure-holding for a certain period of time, as shown in Figure 5, the high-pressure power oil source is controlled to be input into the first high-pressure oil pipeline 28 Pressure oil, the pressure oil directly pushes the first piston cylinder body 29 to act through the first high pressure oil pipeline 28, and the first piston cylinder cylinder body 29 then pushes the cutter 23 of the functional module 22 to the cavity 6 and flow of the injection mold. The junction of the runner gate 26 moves so that the cutter 23 separates the injection molded product in the cavity 6 from the waste at the runner gate; after the injection molding machine is fully cooled, as shown in Figure 6, the first high-pressure oil pipeline 28 and The second high-pressure oil pipelines 13 are all depressurized, and the first spring 15 pushes the reverse core-pulling block 10 to move away from the cavity 6 of the injection mold. At the same time, the second spring 25 pushes the functional module 22 away from the injection mold. The direction of the cavity 6 moves, and finally demoulding.

In this embodiment, if the first installation hole is opened on the lower mold core, then the second driving module is installed on the lower mold.

In this embodiment, by setting a reverse core-pulling module and a functional module, it is possible to realize product demoulding and runner gate cutting when the demoulding slope of the product shape is zero degrees, and effectively solve the problem of scratches on the surface of the product , the principle is that when demolding, the reverse core-pulling block 10 has exited, and the injection molded part will undergo elastic deformation during demoulding, so that there will be a gap between the appearance surface 30 of the injection molded part and the mold cavity 6, thereby avoiding the appearance of the product. Scuffing, if the reverse core-pulling module 7 is not provided, the friction between the appearance surface 30 of the injection molded part and the cavity 6 of the mold is very large during demoulding, so the phenomenon of scuffing on the appearance of the product is easy to occur.

Example 2:

The difference between this embodiment and Embodiment 1 is that the third driving module includes three first springs 15. As shown in FIG. , the lower end of each first spring 15 is fixedly connected to the bottom surface of the first mounting hole 8 , and the upper end of each first spring 15 is fixedly connected to the bottom surface of the mounting block 16 .

Example 3:

The difference between this embodiment and Embodiment 1 is that the third drive module is driven by hydraulic pressure. As shown in Figure 10, the second piston cylinder block 11 includes two parts, a main body 31 and a connecting body 32. The diameter of the connecting body 32 is smaller than that of the main body 31, and the connecting body 32 is fixedly installed on the upper end surface of the main body 31. The second The cylinder mounting hole 12 includes two parts, a large hole 33 and a small hole 34. The large hole 33 is located below the small hole 34, wherein the body 31 of the second piston type cylinder block 11 is installed in the large hole of the second cylinder mounting hole 12. 33, the connecting body 32 passes through the small hole 34 of the second cylinder mounting hole 12, and contacts the lower end surface of the mounting block 16, wherein a sealing ring is arranged between the outer peripheral surface of the body 31 and the hole wall of the large hole 33 A sealing ring is also provided between the outer peripheral surface of the connecting body 32 and the wall of the small hole 34 , and the height of the body 31 is smaller than the depth of the large hole 33 . The 3rd driving module comprises the 3rd high-pressure oil pipeline 35, and the 3rd high-pressure oil pipeline 35 and the second high-pressure oil pipeline 13 are all opened on the formwork 3, wherein the second high-pressure oil pipeline 13 and the second cylinder mounting hole 12 are large The bottom end of the hole 33 communicates, and the third high-pressure oil pipeline 35 communicates with the top end of the large hole 33 . When working, the second high-pressure oil pipeline 13 and the third high-pressure oil pipeline 35 communicate with the two working oil ports of a two-position four-way electromagnetic reversing valve (not shown in the figure) respectively, and the two-position four-way electromagnetic reversing valve The oil inlet and oil return port of the valve are respectively connected with the high-pressure oil source and the oil tank. If the second piston type oil cylinder body 11 needs to move upwards and drive the reverse core-pulling block 10 to move upward, the two-position four-way electromagnetic commutation is controlled. valve, so that the second high-pressure oil pipeline 13 communicates with the high-pressure oil source, and the third high-pressure oil pipeline 35 communicates with the fuel tank, so that the upward movement of the second piston-type oil cylinder body 11 can be realized; when the cylinder body needs to be reset, control the two-position four Through the electromagnetic reversing valve, the third high-pressure oil pipeline 35 is communicated with the high-pressure oil source, and the second high-pressure oil pipeline 13 is communicated with the fuel tank, so that the second piston cylinder body 11 can move downward.

The above-mentioned embodiments are only described to the preferred implementation of the utility model, and are not limited to the scope of the utility model. Various modifications and improvements made should fall within the scope of protection determined by the claims of the utility model.

Claims (6)

1. zero degree demoulding plastic forming die, comprise patrix (1), counterdie (2) and mould bases (3), in patrix (1), be installed with upper mold core (4), in counterdie (2), be installed with lower mold core (5), between upper mold core (4) and lower mold core (5), be provided with die cavity (6), it is characterized in that: also comprise the module of oppositely loosing core (7), the second driver module and the 3rd driver module, offer the first installing hole (8) in lower mold core (5), perhaps offer the first installing hole (8) in lower mold core (5) and counterdie (2), the position that needs oppositely to loose core on the first installing hole (8) and the injecting products (9) is relative, the first installing hole (8) is communicated with die cavity (6), the module of oppositely loosing core (7) comprises the piece of oppositely loosing core (10), what the described piece (10) of oppositely loosing core slided is installed in the first installing hole (8), the shape at position of needing on the shape on top of piece (10) of oppositely loosing core and the injecting products (9) oppositely to loose core adapts, described the second driver module can drive the piece (10) of oppositely loosing core and slide towards the direction of injecting products (9) in the first installing hole (8), and described the 3rd driver module can drive piece (10) direction away from injecting products (9) in the first installing hole (8) of oppositely loosing core and slide.

2. a kind of zero degree demoulding plastic forming die according to claim 1, it is characterized in that: described the second driver module is hydraulic pressure or Spring driving, described the 3rd driver module is spring or hydraulic-driven.

3. a kind of zero degree demoulding plastic forming die according to claim 2, it is characterized in that: described the second driver module comprises at least one second ram cylinder cylinder body (11) and the second cylinder body installing hole (12), and the second hydraulic oil pipeline (13), described the second cylinder body installing hole (12) is opened on the mould bases (3), described the second hydraulic oil pipeline (13) is opened on the mould bases (3), the axis of described each the second cylinder body installing hole (12) is all parallel with the axis of the first installing hole (8), the upper end of each the second cylinder body installing hole (12) all is communicated with the first installing hole (8), the lower end of each the second cylinder body installing hole (12) is communicated with the second hydraulic oil pipeline (13), that all slides in described each second cylinder body installing hole (12) is equipped with second a ram cylinder cylinder body (11), the upper surface of described each the second ram cylinder cylinder body (11) all contacts with the lower surface of the piece of oppositely loosing core (10), between the hole wall of the outer circumference surface of each the second ram cylinder cylinder body (11) and corresponding the second cylinder body installing hole (12) O-ring seal (14) is installed.

4. a kind of zero degree demoulding plastic forming die according to claim 3, it is characterized in that: described the 3rd driver module comprises at least one the first spring (15), described the first spring (15) is extension spring, described every the first spring (15) all is positioned at the first installing hole (8), the lower end of every the first spring (15) is fixedly connected with the bottom surface of the first installing hole (8), and the upper end of every the first spring (15) is fixedly connected with the bottom surface of the piece of oppositely loosing core (10).

5. a kind of zero degree demoulding plastic forming die according to claim 3, it is characterized in that: the described module (7) of oppositely loosing core also comprises mounting blocks (16), also offer lower hole (17) on the lower surface of described counterdie (2), described each second cylinder body installing hole (12) all is communicated with the first installing hole (8) by lower hole (17), the diameter in described lower hole (17) is greater than the diameter of the first installing hole (8), under being installed in that described mounting blocks (16) slides in the hole (17), and the upper end of mounting blocks (16) is fixedly connected with the lower end of the piece of oppositely loosing core (10), the upper surface of each the second ram cylinder cylinder body (11) all contacts with the lower surface of mounting blocks (16), described the 3rd driver module comprises at least one the first spring (15), described the first spring (15) is stage clip, upper end face in lower hole (17) offers at least one spring mounting hole (18), described every the first spring (15) is installed in the spring mounting hole (18), and the lower end of described every the first spring (15) all is pressed on the upper surface of mounting blocks (16).

6. each described a kind of zero degree demoulding plastic forming die according to claim 1-5, it is characterized in that: the described piece (10) of oppositely loosing core comprises piece (19) and lower (20), the lower end of described upper piece (19) is fixedly connected on the upper end of lower (20), bottom surface upper (19) offers second installing hole (21), the second installing hole (21) is stepped hole, the described module (7) of oppositely loosing core also comprises functional module (22), what functional module (22) was slided is installed in the second installing hole (21), described functional module (22) comprises cutting knife (23) and connecting portion (24), described cutting knife (23) is fixedly mounted on the connecting portion (24), connecting portion (24) is positioned at the macropore of the second installing hole (21), between the step surface of the upper surface of connecting portion (24) and the second installing hole (21), at least one the second spring (25) is installed, the second spring (25) is stage clip, described cutting knife (23) is relative with the junction of die cavity (6) and runner cast gate (26), upper surface in described lower (20) offers the first cylinder body installing hole (27) and the first hydraulic oil pipeline (28), the upper end of described the first cylinder body installing hole (27) is communicated with the second installing hole (21), the axis of the first cylinder body installing hole (27) is parallel with the axis of the second installing hole (21), the lower end of the first cylinder body installing hole (27) is communicated with the first hydraulic oil pipeline (28), the first piston formula that the is equipped with cylinder block (29) that in the first cylinder body installing hole (27), slides, the inwall of the outer circumference surface of first piston formula cylinder block (29) and the first cylinder body installing hole (27) is by O-ring seal (14) sealing, and the upper end of first piston formula cylinder block (29) is connected with described connecting portion (24).

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