A reciprocating saw

Abstract

The present invention relates to a reciprocating saw, belonging to the technical field of electric tools. The reciprocating saw comprises a housing with a gripping portion at one end and a driving mechanism at the other end, characterized in that: the motor output shaft of the driving mechanism is connected to a crankshaft whose two ends are supported in the housing through a rotating transmission mechanism, and between the two supporting ends of the crankshaft there is a first eccentric wheel which forms a rotating moving pair with the inner end slide groove of the reciprocating rod, and a second eccentric wheel which forms a rotating moving pair with the counterweight block, and the circumferential phases of the first eccentric wheel and the second eccentric wheel are opposite; the reciprocating rod and the counterweight block respectively form moving pairs that move in opposite directions with the housing. The crankshaft of the present invention is supported at both ends, so compared with the cantilever structure, the support is very stable and reliable, and is more conducive to shock absorption.

Description

Technical Field

[0001] The invention relates to a reciprocating saw, in particular to an electric reciprocating saw, belonging to the technical field of electric tools. Background Art

[0002] A reciprocating saw is a common electric tool that drives a saw blade to reciprocate to cut a workpiece. Its typical structure is disclosed in the European patent document with publication number EP3757427A1. The electric-driven reciprocating tool in the document includes a motor, a reciprocating motion mechanism, and a planetary gear assembly; the reciprocating motion mechanism converts the rotational power generated by the motor into the reciprocating linear motion of the saw blade. Since the conventional reciprocating motion mechanism is an unbalanced mechanism, there is a large vibration when the reciprocating saw is working. For this reason, a Chinese patent document with application number 201910110183.5 discloses a reciprocating saw, which, on the basis of the basic structure, is also designed with a balancing block with a phase opposite to that of the reciprocating motion mechanism, so it has the effect of suppressing vibration. However, the balancing block and the driving shaft of the reciprocating motion driving eccentric wheel are both cantilever structures supported at one end, and the stability and stability are poor, which has an adverse effect on the effect of suppressing vibration. Although it is well known that the cantilever structure with single-end support is far less stable and reliable than the simply supported structure with double-end support, the reciprocating motion and the balancing block mechanism have multiple rotating and moving sub-components that need to be mounted on the driving shaft, so the cantilever support is adopted, and its open end is convenient for assembly. The simply supported structure with double-end support will make it difficult or even impossible to complete the assembly of the assembly. Summary of the invention

[0003] The purpose of the present invention is to address the shortcomings of the above-mentioned prior art and to propose a reciprocating saw with a stable balancing block and an eccentric drive shaft support structure, which is easy to assemble and compact in structure, thereby further effectively improving the shock absorption performance and making the operation of the reciprocating saw more handy.

[0004] In order to achieve the above purpose, one of the basic technical solutions of the reciprocating saw of the present invention is to include: a housing with a gripping portion at one end and a driving mechanism at the other end, the motor output shaft of the driving mechanism being connected to a crankshaft supported at both ends in the housing through a rotary transmission mechanism, a first eccentric wheel constituting a rotary moving pair with an inner end slide groove of a reciprocating rod and a second eccentric wheel constituting a rotary moving pair with a counterweight block between the two supporting ends of the crankshaft, the circumferential phases of the first eccentric wheel and the second eccentric wheel being opposite; the reciprocating rod and the counterweight block respectively constitute a moving pair moving in opposite directions with the housing;

[0005] The crankshaft is an integral structure, and the distance between the two ends of the inner end slide groove of the reciprocating rod is greater than or equal to the sum of the center distance between the first eccentric wheel and the second eccentric wheel and the radius of the first eccentric wheel and the radius of the second eccentric wheel.

[0006] A further improvement of one of the technical solutions is that a gear box is fixedly installed on the housing near the output shaft, and the gear box is provided with an upper end recess for embedding an upper bearing; the gear box is fixedly connected to a counterweight box, and the counterweight box is provided with a lower end recess for embedding a lower bearing.

[0007] A further improvement of one of the technical solutions is that both ends of the inner end slide groove of the reciprocating rod are arc-shaped, a sliding plug extends from one side of the outer periphery of the slide groove, and the other side is fixedly connected to the cylindrical section, the sliding plug is adapted to the socket of the rear slide sleeve fixedly connected to the gear box to form a moving pair, and the cylindrical section is adapted to the through hole of the front slide sleeve fixedly connected to the gear box to form a moving pair.

[0008] A further improvement of one of the technical solutions is that the sum of the radius of the end cylindrical section of the crankshaft and the eccentricity of the first eccentric wheel is greater than the radius of the first eccentric wheel.

[0009] One of the technical solutions is further improved in that the diameters of the first eccentric wheel and the second eccentric wheel are equal, the two ends of the inner end slide groove of the reciprocating rod are arc-shaped, and the distance between the two ends of the arc of the inner end slide groove is greater than or equal to the sum of the center distance of the two eccentric wheels and their diameters.

[0010] Since the crankshaft is supported at both ends in one of the technical solutions of the present invention, the support is very stable and reliable compared with the cantilever structure, and is more conducive to shock absorption; and the reasonable design of the structural dimensions of the crankshaft eccentric wheel and the reciprocating rod slide groove makes the structure compact, and during assembly, as long as the relative positions of the crankshaft and the reciprocating rod are properly controlled, interference can be avoided and the two eccentric wheels can pass through the inner end slide groove as needed, so the assembly process can be as convenient as the cantilever structure.

[0011] The second basic technical solution of the reciprocating saw of the present invention is to include: a housing with a gripping portion at one end and a driving mechanism at the other end, the motor output shaft of the driving mechanism being connected to a crankshaft supported at both ends in the housing through a rotary transmission mechanism, a first eccentric shaft constituting a rotary moving pair with an inner end slide groove of a reciprocating rod and a second eccentric shaft constituting a rotary moving pair with a counterweight block between the two supporting ends of the crankshaft, the first eccentric shaft and the second eccentric shaft having opposite circumferential phases; the reciprocating rod and the counterweight block respectively constitute moving pairs moving in opposite directions with the housing;

[0012] The crankshaft is composed of crank support shafts at both ends and a crank pin in the middle. The crank support shaft is composed of a supporting shaft head and a crank with an eccentric hole. The crank pin is composed of a middle spacer and pins extending in opposite directions at both ends of the middle spacer. The two pins are respectively mounted as dynamic matching pin sleeves of the first eccentric shaft and the second eccentric shaft, and are pressed into the corresponding eccentric holes; the outer diameter of the pin sleeve is greater than or equal to the width of the crank and the middle spacer.

[0013] A further improvement of the second technical solution is that the crank pin is composed of a middle partition and two eccentric holes of the middle partition that press-fit pins extending in opposite directions, and the two pins are respectively mounted as dynamic matching pin sleeves of the first eccentric shaft and the second eccentric shaft.

[0014] A further improvement of the second technical solution is that the crank support shaft is composed of a supporting shaft head and a connected crank extending symmetrically from its end to both sides.

[0015] A further improvement of the second technical solution is that a gear box is fixedly installed on the housing near the output shaft, and the gear box is provided with an upper end recess for embedding an upper bearing; the gear box is fixedly connected to a counterweight box, and the counterweight box is provided with a lower end recess for embedding a lower bearing.

[0016] The second technical solution is further improved in that both ends of the inner end slide groove of the reciprocating rod are arc-shaped, a sliding plug extends from one side of the outer periphery of the slide groove, and the other side is fixedly connected to the cylindrical section, the sliding plug is adapted to the socket of the rear slide sleeve fixedly connected to the gear box to form a moving pair, and the cylindrical section is adapted to the through hole of the front slide sleeve fixedly connected to the gear box to form a moving pair.

[0017] Since the second technical solution of the present invention is also supported at both ends of the crankshaft, compared with the cantilever structure, the support is very stable and reliable, and is more conducive to shock absorption; and its crankshaft is combined in sections, so even if the eccentricity is large, the structure can be as compact as possible, and during assembly, as long as the pressing steps of the crankshaft are properly mastered, interference can be avoided, so that the two eccentric shafts respectively form corresponding rotary moving pairs with the inner end slide grooves and the counterweight blocks of the reciprocating rod, and the assembly process is also relatively simple, especially the pin shaft sliding sleeve changes the original sliding friction of the rotary moving pair into rolling friction, and the relative movement is lighter and smoother. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below in conjunction with the accompanying drawings.

[0019] Figure 1 It is a structural diagram of embodiment 1 of the present invention.

[0020] Figure 2 for Figure 1 Schematic diagram of the structure of the balancing weight and the eccentric driving part of the embodiment.

[0021] Figure 3 for Figure 2 Bottom view of .

[0022] Figure 4 for Figure 1 Schematic diagram of the three-dimensional exploded structure of the driving mechanism part of the embodiment.

[0023] Figure 5 It is a structural diagram of embodiment 2 of the present invention.

[0024] Figure 6 for Figure 5 Schematic diagram of the structure of the balancing weight and the eccentric driving part of the embodiment.

[0025] Figure 7 for Figure 6 Bottom view of .

[0026] Figure 8 for Figure 7 Schematic diagram of the three-dimensional structure.

[0027] Fig. 9 for Figure 8 Schematic diagram of the three-dimensional exploded structure of the crankshaft assembly.

[0028] Fig.10 for Figure 5 Schematic diagram of the three-dimensional exploded structure of the driving part of the embodiment. DETAILED DESCRIPTION

[0029] Embodiment 1

[0030] The reciprocating saw of this embodiment is as follows Figures 1 to 4 As shown, one end of the housing 1 is a gripping portion 1-1, and the other end is provided with a driving mechanism 2. The output shaft 2-2 of the motor 2-1 of the driving mechanism 2 is connected to the crankshaft 4 supported at both ends between the upper bearing 4-1 and the lower bearing 4-2 in the gear box 5 and the counterweight box 6 through a rotary transmission mechanism. Specifically, the housing 1 is fixedly mounted with a gear box 5 adjacent to the output shaft 2-2, and the gear box 5 is provided with an upper end recess 5-1 for embedding the upper bearing 4-1. The gear box 5 is fixedly connected to the counterweight box 6, and the counterweight box 6 is provided with a lower end recess 6-1 for embedding the lower bearing 4-2.

[0031] The rotary transmission mechanism includes a pinion 2-3 coaxial with the output shaft 2-2, and a large gear 4-3 coaxial with the support end of the crankshaft 4 and meshing with the pinion 2-3.

[0032] The crankshaft 4 is an integral structure, and between the two supporting ends, there is a first eccentric wheel 4-4 that forms a rotational movement pair with the inner end slot 7-2 of the reciprocating rod 7, and a second eccentric wheel 4-5 that forms a rotational movement pair with the counterweight block 8. The diameters of the first eccentric wheel 4-4 and the second eccentric wheel 4-5 are equal, and the circumferential phases are opposite. The outer end of the reciprocating rod 7 is installed with a tool chuck 7-1, and the two ends of the inner end slot 7-2 are arc-shaped, in the shape of a runway. The relationship between the radius r of the end cylindrical section connected to the upper bearing 4-1 of the crankshaft 4 and the eccentricity e of the first eccentric wheel and the radius R of the first eccentric wheel is e+r>R, so the radial dimension is as compact as possible. In addition, the distance L between the two ends of the arc of the inner end slot 7-1 of the reciprocating rod 7 is greater than (at least equal to) the sum l of the center distance of the two eccentric wheels and the radius and sum of the two eccentric wheels, which is not only conducive to the mutual motion balance, but also can make the two eccentric wheels 4-4, 4-5 and the two end cylindrical sections of the crankshaft have equal strength.

[0033] A sliding insert 7-3 extends from one side of the outer periphery of the slide groove 7-2, and the other side is fixedly connected to the cylindrical section 7-4. The sliding insert 7-3 is adapted to the insertion hole of the rear sliding sleeve 5-2 fixedly connected to the gear box 5 to form a moving pair, and the cylindrical section 7-4 is adapted to the through hole of the front sliding sleeve 5-3 fixedly connected to the gear box 5 to form a moving pair.

[0034] The assembly plan is carried out in the following steps:

[0035] The first step is to install the upper bearing 4-1 and the lower bearing 4-2 into the gear box 5 and the counterweight box 6 respectively;

[0036] Step 2: Press the large gear 4-3 onto the crankshaft 4, and insert the crankshaft 4 into the upper bearing 4-1;

[0037] Step 3: Insert the front sleeve 5-3 and the rear sleeve 5-2 onto the reciprocating rod 7, and rotate the crankshaft 4 to a position where the center line of the first eccentric wheel 4-4 and the second eccentric wheel 4-5 is consistent with the length direction of the slide groove 7-2 ( Figure 2 As shown), the reciprocating rod 7 is sleeved onto the first eccentric wheel 4-4 of the crankshaft 4;

[0038] Step 4: Install the front sliding sleeve 5-3 and the rear sliding sleeve 5-2 on the reciprocating rod 7 into the gear box 5 and fix them;

[0039] Step 5: Insert the counterweight 8 onto the second eccentric wheel 4-5 of the crankshaft 4, close the counterweight box 6, fix it to the gear box 5, and insert one end of the crankshaft 4 into the lower bearing 4-2.

[0040] It can be seen that after adopting this embodiment, since the crankshaft is supported at both ends, it is stable and reliable, and is more conducive to suppressing vibration during use. In addition, the structural relationship between the crankshaft eccentric wheel and the reciprocating rod slide slot size makes it possible to assemble as long as Figure 2 , Figure 3 As shown, by aligning the eccentric direction of the two eccentric wheels with the length direction of the inner end slot of the reciprocating rod, interference can be avoided, and the two eccentric wheels can pass through the inner end slot as needed, so as to achieve the same convenient installation as the cantilever structure. In addition, the two movable auxiliary structures at the front and rear of the reciprocating rod of this embodiment make its movement more stable and are also conducive to shock absorption.

[0041] Embodiment 2

[0042] The reciprocating saw of this embodiment is as follows Figures 5 to 10 As shown, the basic structure is the same as that of the first embodiment, the main difference is that the crankshaft 4 is not an integral structure, but is as shown in FIG. Fig. 9 As shown, the crank support shaft 4.1 and 4.6 at the upper and lower ends and the crank pin in the middle are combined. The crank support shaft 4.1 or 4.6 is respectively composed of a supporting shaft head and a connected crank extending symmetrically from its ends to both sides. The rotational inertia formed in this way is beneficial to shock absorption, and one side of the crank has an eccentric hole.

[0043] The crank pin is formed by pressing the middle septum 4.3 and the two eccentric holes of the middle septum with the upper and lower pins 4.2 and 4.4 extending in opposite directions. The upper and lower pins 4.2 and 4.4 are respectively mounted as the movable matching pin sleeves of the first eccentric shaft 4-4' and the second eccentric shaft 4-5'. The outer diameters of the two pin sleeves are greater than or equal to the width B of the crank and the middle septum.

[0044] The steps of assembly are: press the middle spacer 4.3 into the pins 4.2 and 4.4 respectively in reverse direction, then insert the pin sleeves 4-4' and 4-5' respectively, and finally press the crankshafts 4.1 and 4.6 respectively; after the press-fitting is completed, the support shaft heads at the ends of the crankshafts 4.1 and 4.6 are precision turned or ground to ensure the coaxiality of the two.

[0045] The test shows that the reciprocating saw of the above embodiment not only has a better damping effect during operation, but also is very convenient to assemble and has a compact structure. In particular, for the case of large eccentricity, the width of the inner end slide groove 7-2 on the reciprocating rod 7 is not affected by the eccentricity and can still maintain a small size. At the same time, the pin sleeves 4-4' and 4-5' matched with the inner end slide groove 7-2 have an outer diameter larger than the width of the support shaft 4.1, 4.6 and the middle spacer 4.3, so the reciprocating rod 7 is easy to be mounted on the pin sleeves 4-4' and 4-5', and at the same time, a rolling fit is formed, and the performance is better.

[0046] In addition to the above embodiments, the present invention may also have other implementation modes. Any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope required by the present invention.

Claims

1. A reciprocating saw comprising a housing having a gripping portion at one end and a driving mechanism at the other end, characterized in that: The motor output shaft of the driving mechanism is connected to the crankshaft whose two ends are supported in the housing through a rotary transmission mechanism. A first eccentric wheel and an inner end slot of the reciprocating rod are provided between the two supporting ends of the crankshaft, and a second eccentric wheel and a counterweight block are provided to form a rotary moving pair. The circumferential phases of the first eccentric wheel and the second eccentric wheel are opposite. The reciprocating rod and the counterweight block respectively form moving pairs with the housing that move in opposite directions. The crankshaft is an integral structure, and the distance between the two ends of the inner end slide groove of the reciprocating rod is greater than or equal to the sum of the center distance between the first eccentric wheel and the second eccentric wheel and the radius of the first eccentric wheel and the radius of the second eccentric wheel.

2. The reciprocating saw according to claim 1, characterized in that: The housing is fixedly mounted with a gear box adjacent to the output shaft, and the gear box is provided with an upper end recess for embedding an upper bearing; the gear box is fixedly connected with a counterweight box, and the counterweight box is provided with a lower end recess for embedding a lower bearing.

3. The reciprocating saw according to claim 2, characterized in that: Both ends of the inner end slide groove of the reciprocating rod are arc-shaped, a sliding plug extends from one side of the outer periphery of the slide groove, and the other side is fixedly connected to the cylindrical section, the sliding plug is adapted to the insertion hole of the rear slide sleeve fixedly connected to the gear box to form a moving pair, and the cylindrical section is adapted to the through hole of the front slide sleeve fixedly connected to the gear box to form a moving pair.

4. The reciprocating saw according to claim 3, characterized in that: The sum of the radius of the end cylindrical section of the crankshaft and the eccentricity of the first eccentric wheel is greater than the radius of the first eccentric wheel.

5. The reciprocating saw according to claim 4, characterized in that: The diameters of the first eccentric wheel and the second eccentric wheel are equal, the two ends of the inner end slide groove of the reciprocating rod are arc-shaped, and the distance between the arcs at the two ends of the inner end slide groove is greater than or equal to the sum of the center distance of the two eccentric wheels and their diameters.

6. A reciprocating saw comprising a housing having a gripping portion at one end and a drive mechanism at the other end, characterized in that: The motor output shaft of the driving mechanism is connected to the crankshaft whose two ends are supported in the housing through a rotary transmission mechanism. The crankshaft has a first eccentric shaft between the two supporting ends, which forms a rotary moving pair with the inner end slide groove of the reciprocating rod, and a second eccentric shaft which forms a rotary moving pair with the counterweight. The circumferential phases of the first eccentric shaft and the second eccentric shaft are opposite. The reciprocating rod and the counterweight respectively form moving pairs with the housing that move in opposite directions. The crankshaft is composed of crank support shafts at both ends and a crank pin in the middle. The crank support shaft is composed of a supporting shaft head and a crank with an eccentric hole. The crank pin is composed of a middle spacer and pins extending in opposite directions at both ends of the middle spacer. The two pins are respectively mounted as dynamic matching pin sleeves of the first eccentric wheel and the second eccentric wheel, and are pressed into the corresponding eccentric holes; the outer diameter of the pin sleeve is greater than or equal to the width of the crank and the middle spacer.

7. The reciprocating saw according to claim 6, characterized in that: The crank pin is formed by pressing a middle septum and two eccentric holes of the middle septum with pins extending in opposite directions, and the two pins are respectively mounted on the movable matching pin sleeves of the first eccentric shaft and the second eccentric shaft.

8. The reciprocating saw according to claim 7, characterized in that: The crank support shaft is composed of a supporting shaft head and a connected crank shaft symmetrically extending from the end thereof to both sides.

9. The reciprocating saw according to claim 8, characterized in that: The housing is fixedly mounted with a gear box adjacent to the output shaft, and the gear box is provided with an upper end recess for embedding an upper bearing; the gear box is fixedly connected with a counterweight box, and the counterweight box is provided with a lower end recess for embedding a lower bearing.

10. The reciprocating saw according to claim 9, characterized in that: Both ends of the inner end slide groove of the reciprocating rod are arc-shaped, a sliding plug extends from one side of the outer periphery of the slide groove, and the other side is fixedly connected to the cylindrical section, the sliding plug is adapted to the insertion hole of the rear slide sleeve fixedly connected to the gear box to form a moving pair, and the cylindrical section is adapted to the through hole of the front slide sleeve fixedly connected to the gear box to form a moving pair.

Images