Volume-variable heat treatment furnace

Abstract

The application discloses a variable-volume heat treatment furnace and belongs to the technical field of heat treatment furnaces. The variable-volume heat treatment furnace comprises a mounting ground, a track, a trolley and a heat treatment furnace body, a movable back wall is arranged on the trolley and located in the furnace body, and a driving assembly, an executing assembly and a pressing assembly are integrated in the movable back wall. The variable-volume heat treatment furnace can expand outward through the driving assembly and the executing assembly, so that the outer edges of the executing assembly are in close contact with the inner wall of the heat treatment furnace body and the positioning step block, and the downward pressure applied to the executing assembly by the pressing assembly forms a closed variable heating space in the heat treatment furnace body. The furnace volume can be adjusted according to the size of a workpiece, the effective heating area and the idle area are effectively isolated, the problem of energy waste caused by the fact that a large furnace is used to heat a small workpiece in the prior art is solved, and the heat treatment production efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of heat treatment furnace technology, and more particularly to a variable volume heat treatment furnace. Background Technology

[0002] Cart-type heat treatment furnaces are key equipment for heat treatment processes such as annealing, normalizing, quenching, and tempering of metallic materials and mechanical parts, and are especially widely used in the heat treatment of large castings, forgings, welded structural parts, and pressure vessels. Existing cart-type heat treatment furnaces typically consist of a fixed portal-shaped furnace body, a furnace door, and a car that can move along a track and also serves as the furnace bottom. During operation, the workpiece is placed on the car, and a traction mechanism drives the car into the furnace chamber. After the furnace door closes, a closed heating space is formed. To meet the processing needs of the largest workpieces in the factory, the effective heating zone of traditional heat treatment furnaces is usually designed and constructed according to the largest workpiece size. Therefore, once the equipment is installed, the physical depth and volume of its furnace chamber are fixed values.

[0003] However, in actual industrial production, the specifications, dimensions, and batch sizes of workpieces to be processed often exhibit diversity and fluctuation. When heat treatment is required for workpieces that are short in length, in small batches, or not fully loaded, the furnace space of existing heat treatment furnaces is not adjustable, and the workpieces only occupy a portion of the furnace space, resulting in a large amount of idle heating zone at the rear of the furnace. Under this condition of heating small parts in a large furnace, in order to maintain the process temperature, it is necessary to heat and hold the entire furnace space, increasing the energy consumption cost per unit product. Moreover, the ineffective space increases the heating time and reduces the production efficiency of heat treatment.

[0004] It should be noted that the information disclosed in this background section is only for understanding the background technology of this application concept, and therefore may include information that does not constitute prior art. Summary of the Invention

[0005] This invention provides a variable volume heat treatment furnace to solve the technical problem that trolley-type heat treatment furnaces, due to their fixed furnace volume, result in idle heating zones when processing non-full-load or short-sized workpieces, leading to long heating times.

[0006] This invention adopts the following technical solution: a variable volume heat treatment furnace. It includes a track and a trolley that can move along the track, with the furnace body mounted on top of the trolley. Its characteristic is that: The inner wall of the heat treatment furnace body is provided with several sets of positioning step blocks at intervals along the length direction, and the trolley is also provided with a movable rear wall located inside the heat treatment furnace body. The movable rear wall integrates drive components and execution components; The drive component is used to drive the execution component to expand outward, so that the outer edge of the execution component abuts against the inner wall of the heat treatment furnace and the positioning step block respectively, so as to form a closed variable heating space in the heat treatment furnace. The drive assembly includes a first cam and a second cam, and the actuation assembly includes a push rod corresponding to the drive of the first cam and the second cam; The first cam and the second cam both have inwardly recessed C-shaped locking grooves at their rounded tips, and the push rod has a sliding wheel rotatably mounted at its abutting end that cooperates with the locking grooves; The drive assembly is adapted to drive the first cam and the second cam to rotate to push the push rod into a sealed position, and the locking grooves with rounded tips respectively abut against the corresponding sliding wheels.

[0007] The above-mentioned at least one technical solution adopted in this invention can achieve the following beneficial effects: A variable-volume heat treatment furnace features C-shaped locking grooves with rounded transitions recessed at the rounded tips of the first and second cams. A sliding wheel is fitted at the abutting end of the push rod. When the furnace heats up, causing the sealing side plate and push rod to expand, the expansion is converted into a linear thermal expansion thrust along the push rod axis due to the limiting obstruction of the furnace inner wall. This thrust forces the sliding wheel to press deeper into the C-shaped locking groove. Utilizing the guiding effect of the rounded transition surface, the two tips of the locking groove generate a centripetal contraction and relative clamping force on the sliding wheel. This structure effectively transforms the destructive thermal stress that easily leads to cam reversal or motor overload in traditional rigid mechanisms into a stable relative clamping force within the structure. The stronger the thermal expansion thrust, the more secure the locking mechanism, thus improving the sealing reliability of the equipment under high-temperature conditions.

[0008] By setting a movable rear wall inside the heat treatment furnace on the trolley and using a drive assembly to drive the execution assembly to expand outward, the outer edge of the execution assembly is tightly abutted against the inner wall of the heat treatment furnace and the positioning step block. The movable rear wall can be positioned at different positions inside the heat treatment furnace according to the actual size of the workpiece to be processed, forming a variable-volume and completely enclosed heating space. This effectively isolates the effective heating area from the idle area at the rear of the furnace, preventing heat loss to the idle area. It solves the problem of large furnaces burning small parts when processing short-sized workpieces due to the fixed furnace volume, reduces heat waste, and shortens the heating time. Attached Figure Description

[0009] The accompanying drawings, which are provided to further illustrate the invention and constitute a part of this invention, are illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention.

[0010] In the attached diagram: Figure 1 This is an overall schematic diagram of a variable volume heat treatment furnace according to this application; Figure 2 for Figure 1 Overall schematic diagram of the intermediate heat treatment furnace; Figure 3 for Figure 2 A magnified view of a portion of point A in the middle; Figure 4 for Figure 2 Schematic diagram of partial cross-section structure; Figure 5 for Figure 4 A magnified view of a portion of point B in the middle; Figure 6 for Figure 2 Schematic diagram of the displacement structure of a heat treatment furnace; Figure 7 for Figure 6 A partial structural diagram; Figure 8 for Figure 7 A magnified view of a portion of point C in the middle; Figure 9 for Figure 7 A partial structural diagram; Figure 10 for Figure 9 A magnified view of a portion of point D in the middle; Figure 11 for Figure 9 A magnified view of a portion of point E in the middle; Figure 12 for Figure 9 A partial structural diagram; Figure 13 for Figure 12 The main view; Figure label: 1. Installation ground; 11. Heat treatment furnace body; 111. Positioning step block; 12. Trolley; 13. Track; 14. Traveling wheels; 15. Moving rear wall; 2. Furnace door lifting assembly; 21. Gantry frame; 22. Top beam; 23. Pulley beam; 24. Moving pulley; 25. Wire rope; 26. Furnace door body; 261. Lifting end; 27. Base; 28. Drum; 29. ​​Guide pulley; 210. Winch motor; 3. Drive assembly; 31. Support guard plate; 32. Support frame; 33. Horizontal plate; 34. Main drive shaft; 35. Transmission gear; 36. First cam; 3 7. Second cam; 38. Guide seat one; 39. Drive component; 310. Rack; 311. Guide plate; 312. Locking groove; 4. Actuating assembly; 41. Guide seat two; 42. Push rod; 421. Sliding wheel; 43. Step; 44. Connecting spring; 45. Sealing side plate; 46. Sealing box; 47. Sliding groove; 48. Sliding pin block; 49. Return spring; 410. Sealing top plate; 411. Movable groove; 412. Support spring; 5. Pressing assembly; 51. Crossbeam bracket; 53. Mounting frame; 54. Pressing rod; 55. Pressing spring; 56. Holding wheel. Detailed Implementation

[0011] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0012] The technical solutions provided by the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0013] Reference Figures 1-11 As shown, the present invention provides a variable volume heat treatment furnace, which mainly includes an installation ground 1, a trolley 12, a heat treatment furnace body 11, a movable rear wall 15 and a drive assembly 3, an execution assembly 4 and a clamping assembly 5 integrated on its side, as well as a furnace door lifting assembly 2 located at the front end.

[0014] like Figure 1 and Figure 2 As shown, two parallel tracks 13 are laid on the installation ground 1. The trolley 12 serves as the chassis for carrying the workpiece, and several sets of wheels 14 are installed on its bottom, enabling it to enter and exit the heat treatment area along the tracks 13. A fixed portal-shaped heat treatment furnace body 11 is installed above the trolley 12. Several sets of positioning step blocks 111 are spaced along the length of the inner wall of the heat treatment furnace body 11. These positioning step blocks 111 not only strengthen the furnace body structure, but also provide a precise positioning reference surface for the subsequent variable volume sealing.

[0015] like Figures 4-7As shown, the trolley 12 is also equipped with an independently movable rear wall 15. The movable rear wall 15 can be moved into the internal cavity of the heat treatment furnace body 11. When it is necessary to change the furnace volume, the movable rear wall 15 can be moved along the track 13 by the trolley 12 to a predetermined position, namely a set of positioning step blocks 111, to divide the heat treatment furnace body 11 into an effective heating zone and an idle zone. In order to ensure the sealing after separation, the movable rear wall 15 integrates a drive assembly 3, an execution assembly 4, and a clamping assembly 5 on its side.

[0016] like Figure 2 and Figures 4-5 As shown, the drive assembly 3 is the power source for the entire sealing operation. It includes a support plate 31 and a support frame 32 installed on the side of the movable rear wall 15. A horizontal plate 33 parallel to the surface of the movable rear wall 15 is fixed on the support frame 32. A horizontally arranged main drive shaft 34 is rotatably connected to the horizontal plate 33 via bearings. A first cam 36, a second cam 37, and a transmission gear 35 are sequentially fixed on the main drive shaft 34.

[0017] To drive the main drive shaft 34 to rotate, a guide seat 38 is fixed to the side of the movable rear wall 15. A vertical drive component 39 is inserted into the guide seat 38; in this embodiment, it is preferably an electric push rod. A vertical rack 310 is connected to the top of the drive component 39, and the rack 310 meshes with the transmission gear 35 fixed on the main drive shaft 34. To ensure the smooth movement of the rack 310 and prevent it from deflecting under force, a guide plate 311 is also fixed to the surface of the movable rear wall 15. The side of the rack 310 facing away from the tooth surface is embedded and slidably connected to the side groove of the guide plate 311. When the drive component 39 extends or retracts, it drives the rack 310 to move linearly up and down. Through meshing transmission, the linear motion is converted into the rotational motion of the transmission gear 35 and the main drive shaft 34.

[0018] like Figures 4-10 As shown, the actuator 4 is responsible for converting the rotational motion of the cam into a sealing action that expands outwards. The actuator 4 includes three sets of push units arranged in an inverted T-shape. Two sets of push units are arranged horizontally to the sides, and one set is arranged vertically upwards. Each push unit includes a guide seat 41 fixed to the movable rear wall 15, and a push rod 42 that slides through the guide seat 41. Each push rod 42 has a step 43 fixed on it, and a high-temperature resistant connecting spring 44 is fitted on the push rod 42. One end of the connecting spring 44 abuts against the side of the guide seat 41, and the other end abuts against the side of the step 43. The function of the connecting spring 44 is to provide an inward restoring force for the push rod 42, ensuring that the push rod 42 can automatically retract in the non-sealing state.

[0019] The first cam 36 has two rounded tips distributed at 180 degrees, which respectively engage with the ends of two sets of push rods 42 arranged horizontally on both sides. The second cam 37 has one rounded tip, which engages with the bottom end of a set of push rods 42 arranged vertically upwards. When the main drive shaft 34 rotates, the first cam 36 and the second cam 37 rotate synchronously, and their protruding parts simultaneously push the three sets of push rods 42, causing them to overcome the resistance of the connecting spring 44 and move synchronously to the left, right, and upwards respectively.

[0020] like Figures 8-11 As shown, a sealing plate is connected to the outer end of the push rod 42. Specifically, the outer ends of the two sets of horizontal push rods 42 are respectively connected to sealing side plates 45, and the top of the vertical push rod 42 is connected to a sealing top plate 410. When the push rod 42 is pushed outward, the outer edges of the sealing side plates 45 and the sealing top plate 410 will respectively abut tightly against the side wall and the top positioning step block 111 of the heat treatment furnace body 11, thereby forming a closed space.

[0021] To prevent mechanical jamming and accommodate thermal expansion and deformation, this invention incorporates a special design at the connection point. For example... Figure 8 As shown, the bottom surface of the sealing top plate 410 has a movable groove 411. The top end of the vertical push rod 42 is slidably connected to the movable groove 411 via a slider. A support spring 412 is provided in the movable groove 411, and the support spring 412 is connected between the upper end face of the slider and the inner wall of the movable groove 411. This floating connection allows the sealing top plate 410 to undergo a slight displacement relative to the push rod 42 when subjected to downward pressure, achieving flexible clamping.

[0022] like Figure 9 and Figure 11 As shown, an interference-resistant sliding connection is also used between the sealing side plate 45 and the sealing top plate 410. A sealing box 46 is embedded in the side wall of the sealing side plate 45, and a vertical sliding groove 47 is formed inside the sealing box 46. Sliding pins 48 are fixed at both ends of the sealing top plate 410, and the sliding pins 48 are slidably disposed within the sliding groove 47. A return spring 49 is also provided within the sliding groove 47, and the two end faces of the return spring 49 are respectively connected to the upper surface of the sliding pin 48 and the top surface of the inner wall of the sliding groove 47. When the drive assembly 3 resets, if the sealing top plate 410 is displaced downwards by gravity or the pressing assembly 5, the sliding pins 48 can slide freely within the sliding groove 47, causing the sealing side plate 45 to move downwards. At this time, a corresponding recessed groove is provided on the trolley 12 for the lower end of the sealing side plate 45 to extend into, thereby avoiding displacement interference and jamming caused by the rigid connection between the top plate and the side plate.

[0023] like Figure 8 and Figure 12As shown, to further improve the fit between the sealing top plate 410 and the positioning step block 111, a clamping assembly 5 is also provided on the movable rear wall 15. The clamping assembly 5 includes a crossbeam bracket 51 fixed on the movable rear wall 15, and a mounting frame 53 parallel to the sealing top plate 410 is fixed to one end of the crossbeam bracket 51. A clamping rod 54 is vertically and movably inserted through the mounting frame 53. The clamping rod 54 has a boss and a clamping spring 55 is fitted on it. The two ends of the clamping spring 55 abut against the boss and the top of the inner wall of the mounting frame 53, respectively. A pressure holding wheel 56 is rotatably mounted on the bottom end of the clamping rod 54. The pressure holding wheel 56 is adapted to abut against the upper surface of the sealing top plate 410. Under the action of the clamping spring 55, the pressure holding wheel 56 always applies a downward preload to the sealing top plate 410, forcing the sealing top plate 410 to fit tightly against the right-angle groove of the positioning step block 111, ensuring the sealing effect under high temperature environment.

[0024] like Figures 1-4 As shown, a furnace door lifting assembly 2 is provided at the front end of the heat treatment furnace body 11. It is used to control the opening and closing of the furnace opening. This assembly mainly consists of a support frame unit, a power drive unit, and a suspension actuator unit.

[0025] Specifically, the support frame unit includes a gantry frame 21 spanning above the track 13. The gantry frame 21 serves not only as the mounting base for the furnace door but also as a guide for the travel. A reinforced top beam 22 is welded to the top of the gantry frame 21 to bear the suspended load. A pulley beam 23 is suspended below the top beam 22, and two sets of movable pulleys 24 are installed side by side on the pulley beam 23. These two sets of movable pulleys 24 are symmetrically distributed about the centerline of the furnace door body 26 to ensure the balance of the lifting force.

[0026] The suspension actuator is based on a dual-wire rope synchronous traction structure. Lifting ends 261 (such as...) are welded to the upper left and right sides of the furnace door body 26. Figure 9 As shown, one end of each of the two high-strength steel wire ropes 25 is fixedly connected to the two lifting ends 261, realizing the dual-point lifting of the furnace door body 26. The steel wire ropes 25 extend upward through the movable pulley 24 on the pulley beam 23, and after changing the direction of force by the guide pulley 29 set on one side of the top of the gantry frame 21, they are led to the ground together.

[0027] The power drive unit is located on the ground on one side of the gantry 21, including a base 27 with a fixed foundation. A high-torque winch motor 210 is mounted on the base 27, and the motor output shaft is connected to a drum 28. The other ends of the two steel wire ropes 25 are wound side by side on the drum 28.

[0028] When the winch motor 210 starts rotating in the forward direction, it drives the drum 28 to rotate and wind up the wire rope 25. The wire rope 25 is guided by the guide pulley 29 and the movable pulley 24, and at the same time applies a vertical upward pulling force to the two lifting ends 261 on the furnace door body 26. Due to the use of double rope symmetrical traction, the furnace door body 26 can maintain an upward posture until the furnace opening is fully opened; conversely, when the motor reverses to release the rope, the furnace door body 26 descends by its own weight to achieve a seal.

[0029] Working Principle: Before heat treatment, the furnace door lifting assembly 2 is first controlled to operate. The winch motor 210 rotates forward to wind up the wire rope 25, and the furnace door 26 is raised through synchronous traction of the two ropes, opening the furnace opening. The trolley 12 moves out along the track 13, and the workpiece to be treated is placed on the trolley 12. At this time, the required heat treatment space is determined according to the actual length of the workpiece and the batch size. If the workpiece is short, the movable rear wall 15 slides along the track 13 on the trolley 12, allowing it to penetrate deeper into the heat treatment furnace body 11 until it stops at a set of positioning steps 111 that match the size of the workpiece. At this time, the movable rear wall 15 physically divides the furnace chamber into an effective heating zone at the front and an idle zone at the rear, completing the initial adjustment of the volume.

[0030] After the rear wall 15 is positioned, the drive component 39 in the drive assembly 3 is activated. The drive component 39 extends and drives the rack 310 to move upward in a straight line. Through meshing transmission, it forces the transmission gear 35 to drive the main drive shaft 34 to rotate. The first cam 36 (double rounded corner) and the second cam 37 (single rounded corner) on the main drive shaft 34 rotate synchronously, and their protruding parts push against the three sets of push rods 42 arranged in an inverted T-shape. The three sets of push rods 42 overcome the resistance of the high-temperature resistant connecting spring 44 and extend synchronously to the left, right and upward respectively. The sealing side plate 45 and sealing top plate 410 at the outer end of the push rod 42 expand outward until their outer edges tightly abut against the inner wall of the heat treatment furnace body 11 and the surface of the positioning step block 111, thereby structurally achieving an airtight seal of the effective heating zone and preventing heat loss to the rear idle area.

[0031] While the sealing plate contacts the furnace wall, the clamping assembly 5 comes into play. Under the preload of the clamping spring 55, the pressure roller 56 constantly applies downward pressure to the sealing top plate 410, forcing the sealing top plate 410 to move downward and fit tightly against the right-angle corner of the positioning step block 111. During this process, the movable groove 411 between the sealing top plate 410 and the push rod 42 and the support spring 412 structure allow the top plate to float relative to the push rod 42, avoiding damage caused by rigidity. At the same time, when the sealing top plate 410 moves downward, it slides in the sliding groove 47 of the sealing box 46 through the sliding pin block 48 and compresses the return spring 49, driving the two sets of sealing side plates 45 to adjust downward synchronously. The lower end of the side plate extends into the sinking groove of the trolley 12, effectively avoiding mechanical interference and jamming caused by thermal expansion or clamping action. After the heat treatment is completed, the drive component 39 retracts in the opposite direction, and each set of push rods 42 automatically retracts under the action of the connecting spring 44. The sealing plate detaches from the furnace wall, the moving rear wall 15 returns to its movable state, and the trolley 12 moves out to unload.

[0032] Reference Figures 12-13 As shown, in another embodiment of this invention, C-shaped locking grooves 312 are recessed inward at the rounded tips of the first cam 36 and the second cam 37, i.e., at the high point where the push rod 42 reaches the sealing position. The two tips of the opening of the C-shaped locking groove 312 are both designed with rounded corners. At the same time, a sliding wheel 421 that cooperates with the C-shaped locking groove 312 is rotatably installed at the end of the push rod 42 that abuts against the cam.

[0033] In contrast, if the highest point of the cam directly abuts the push rod 42 using a conventional smooth rounded end, refer to... Figure 9 The direction of heat impact indicated by the middle arrow is as follows: when the temperature inside the heat treatment furnace rises, and heat radiation and high-temperature airflow enter the gap between the movable rear wall 15 and the sealing side plate 45 from the side, the sealing side plate 45 and the push rod 42 will generate overall volume thermal expansion after absorbing heat. Although the heat impacts from the side perpendicular to the push rod 42, the radial direction of the push rod 42 is restricted by the external guide, and the outermost side of the sealing side plate 45 is blocked by the inner wall of the heat treatment furnace body 11. The expansion generated by the heat on the sealing side plate 45 and the push rod 42 cannot be released to the outside and radially, and can only be converted into a linear thermal expansion thrust extending backward (i.e. towards the cam direction) along the axis of the push rod 42.

[0034] If the highest point of the cam is a smooth, outward-convex shape, the linear thermal expansion thrust of the push rod 42 will act directly on the outer edge of the cam. Due to the limiting effect, this thrust is easily converted into torque that causes the cam to reverse, which can easily lead to motor overload.

[0035] In this embodiment, by forming a cam with a C-shaped locking groove 312, after the sliding wheel 421 at the end of the push rod 42 falls into the C-shaped locking groove 312, when the above-mentioned thermal expansion occurs, the push rod 42 generates a backward linear thermal expansion thrust due to the restriction at the front end. This thrust will force the sliding wheel 421 at the tail of the push rod 42 to press deeper into the bottom of the C-shaped locking groove 312. During this inward pressing process, since the two tips of the C-shaped locking groove 312 are designed with rounded corners, the two sides of the sliding wheel 421 will press inward along the rounded corner transition surfaces of the two tips. The two sides of the sliding wheel 421 are subjected to the inward pressing force, which can drive the two tips of the locking groove 312 to generate a centripetal contraction and relative clamping force on the sliding wheel 421 on the left and right sides.

[0036] Furthermore, since the two rounded tips of the first cam 36 are horizontally symmetrically distributed in the locked state, the C-shaped locking grooves 312 at both ends of the first cam 36 maintain a tight hold on the push rods 42 and sealing side plates 45 on both sides. Therefore, even when the left and right sides of the furnace are heated and expand simultaneously, the two opposing linear thermal expansion thrusts transmitted from the left and right sides will act on the same first cam 36 at the same time. These opposing forces form a counterforce and cancel each other out at the center of the first cam 36. This counterforce makes the sliding wheels 421 on both sides press deeper into the locking grooves 312, and the first cam 36 is in a self-locking equilibrium state. The expansion thrust can effectively limit the first cam 36 from reversing.

[0037] Meanwhile, since the second cam 37 supporting the upper sealing plate 410 and the first cam 36 are fixedly connected to the same main drive shaft 34, they form a coaxial linkage. Therefore, similarly, since the main drive shaft 34 is locked by the opposing forces on the first cam 36, and the second cam 37 forms a stable anti-torsional support, when the upper sealing plate 410 also experiences thermal expansion, generating a downward linear thermal expansion thrust, the downward thrust pressing against the second cam 37 cannot cause the main drive shaft 34 to rotate and retract. Instead, it is converted into a force that pushes the sliding wheel 421 into the C-shaped locking groove 312 of the second cam 37, thereby causing the sliding wheel 421 to also generate a clamping force. Therefore, the cam mechanism in this embodiment utilizes the opposing forces generated by the thermal expansion on both horizontal sides to lock the main drive shaft 34, thereby providing support for the thermal expansion thrust from above and effectively converting the three-dimensional thermal stress into a stable relative clamping force within the structure.

[0038] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A variable volume heat treatment furnace, comprising a track (13) and a trolley (12) movable along the track (13), wherein a heat treatment furnace body (11) is mounted on top of the trolley (12), characterized in that: The inner wall of the heat treatment furnace body (11) is provided with several sets of positioning step blocks (111) at intervals along the length direction, and the trolley (12) is also provided with a movable rear wall (15) located inside the heat treatment furnace body (11). The movable rear wall (15) integrates a drive component (3) and an execution component (4). The drive component (3) is used to drive the execution component (4) to expand outward, so that the outer edge of the execution component (4) abuts against the inner wall of the heat treatment furnace body (11) and the positioning step block (111) respectively, so as to form a closed variable heating space inside the heat treatment furnace body (11). The drive assembly (3) includes a first cam (36) and a second cam (37), and the actuation assembly (4) includes a push rod (42) corresponding to the drive of the first cam (36) and the second cam (37). The first cam (36) and the second cam (37) have C-shaped locking grooves (312) with their rounded tips recessed inward. The push rod (42) has a sliding wheel (421) that cooperates with the locking groove (312) rotatably mounted on its abutting end. The drive assembly (3) is adapted to drive the first cam (36) and the second cam (37) to rotate to push the push rod (42) into a sealed position, and the locking groove (312) at the rounded tip abuts against the corresponding sliding wheel (421).

2. The variable volume heat treatment furnace according to claim 1, characterized in that, The execution component (4) includes three sets of inverted T-shaped push units. Each push unit includes a guide seat (41) fixed on the movable rear wall (15) and a push rod (42) slidably inserted in the guide seat (41). A step (43) is fixed on the push rod (42). A high-temperature resistant connecting spring (44) is sleeved on the push rod (42). One end of the connecting spring (44) abuts against the side of the guide seat (41), and the other end abuts against the side of the step (43), which is used to provide the elastic force for the push rod (42) to reset. The execution component (4) also includes sealing side plates (45) connected to the outer ends of the two sets of push rods (42) arranged horizontally, and sealing top plates (410) connected to the top of the set of push rods (42) arranged vertically upward. The sealing side plates (45) and sealing top plates (410) are used to seal and contact the side wall and top of the heat treatment furnace body (11) respectively when pushed out.

3. A variable volume heat treatment furnace according to claim 2, characterized in that, A sealing box (46) is embedded in the side wall of the sealing side plate (45). A vertical sliding groove (47) is provided inside the sealing box (46). Sliding pins (48) extend downward from both ends of the sealing top plate (410). The sliding pins (48) are slidably disposed in the sliding groove (47). A return spring (49) is also provided in the sliding groove (47). The two ends of the return spring (49) are respectively connected to the top of the inner wall of the sliding groove (47) and the upper surface of the sliding pin (48). The trolley (12) is provided with a sinking groove that adapts to the downward movement of one end of the sealing side plate (45). The cooperation between the sliding groove (47) and the sliding pin block (48) allows the sealing side plate (45) to slide relative to the sliding pin block (48) when the drive assembly (3) drives the three sets of push units to reset synchronously, so as to avoid displacement interference between the sealing top plate (410) and the sealing side plate (45).

4. A variable volume heat treatment furnace according to claim 2, characterized in that, The bottom surface of the sealing top plate (410) is provided with a movable groove (411). The top end of the push rod (42) arranged vertically upward is slidably connected to the movable groove (411) through a slider. The movable groove (411) is also provided with a support spring (412). One end of the support spring (412) is connected to the inner wall of the movable groove (411), and the other end is connected to the upper end face of the slider.

5. A variable volume heat treatment furnace according to claim 2, characterized in that, It also includes a clamping assembly (5), which includes a beam bracket (51) fixed on the movable rear wall (15). One end of the beam bracket (51) is fixed with an installation frame (53) arranged parallel to the sealing top plate (410). A clamping rod (54) is vertically and movably installed through the installation frame (53). A clamping spring (55) and a boss are sleeved on the clamping rod (54). The two ends of the clamping spring (55) are respectively connected to the surface of the boss and the top of the inner wall of the installation frame (53). A pressure holding wheel (56) is rotatably installed at the bottom end of the clamping rod (54). The pressure holding wheel (56) abuts against the upper surface of the sealing top plate (410). The pressure holding wheel (56) is used to apply downward pressure to the sealing top plate (410) under the action of the clamping spring (55), so that the sealing top plate (410) is in close contact with the right angle groove of the positioning step block (111).

6. A variable volume heat treatment furnace according to claim 2, characterized in that, The drive assembly (3) includes a support plate (31) installed in the movable rear wall (15) and a support frame (32). A horizontal plate (33) parallel to the movable rear wall (15) is fixed on the support frame (32). A main drive shaft (34) is rotatably connected to the horizontal plate (33). The first cam (36) and the second cam (37) are sequentially fixedly sleeved on the main drive shaft (34). The first cam (36) has two rounded tips, which respectively engage with the ends of the push rods (42) of the two sets of push units arranged on both sides horizontally. The second cam (37) has one rounded tip, which engages with the end of the push rod (42) of the set of push units arranged vertically upward.

7. A variable volume heat treatment furnace according to claim 6, characterized in that, A transmission gear (35) is also fixedly sleeved on the main drive shaft (34). A guide seat (38) is also provided on the movable rear wall (15). A drive member (39) is slidably inserted in the guide seat (38). A rack (310) is connected to the top of the drive member (39). The rack (310) meshes with the transmission gear (35). A guide plate (311) is fixed on the surface of the movable rear wall (15). The side of the rack (310) away from the tooth surface is embedded and slidably connected to the side of the guide plate (311). The drive member (39) is used to drive the rack (310) to move linearly, thereby driving the transmission gear (35) to rotate.

8. A variable volume heat treatment furnace according to claim 6, characterized in that: The horizontal plate (33) is used to provide auxiliary support for the main drive shaft (34), and the support guard plate (31) is fixed to the back of the movable rear wall (15) to protect the drive assembly (3).

9. A variable volume heat treatment furnace according to claim 1, characterized in that, The front end of the heat treatment furnace body (11) is provided with a furnace door lifting assembly (2). The furnace door lifting assembly (2) includes a gantry frame (21) spanning above the track (13). The top of the gantry frame (21) is provided with a top beam (22). Below the top beam (22) is a pulley beam (23). Two sets of moving pulleys (24) are installed on the pulley beam (23) arranged side by side. Steel wire ropes (25) are respectively threaded on the two sets of moving pulleys (24). One end of the steel wire rope (25) is connected to the furnace door body (26) through the lifting end (261). The furnace door body (26) is used to close the front opening of the heat treatment furnace body (11). The lifting end (261) is fixedly connected to the furnace door body (26) and is respectively connected to one end of the corresponding steel wire rope (25).

10. A variable volume heat treatment furnace according to claim 9, characterized in that, A base (27) is installed on one side of the gantry frame (21). A winch motor (210) and a drum (28) driven by it are installed on the base (27). One end of the two wire ropes (25) are wound on the drum (28) through a guide pulley (29). The furnace door (26) is raised and lowered by the forward and reverse rotation of the winch motor (210).

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