Turning tool and turning device

Abstract

The utility model relates to the technical field of engine, disclose a kind of turning gear and turning gear, turning gear includes first engagement part and first fixed part, first engagement part is used to with the first inner spline tooth of first engine engagement, when first outer spline tooth and first inner spline tooth engagement, at least part of structure of first fixed part can be located outside first inner cavity.First engagement part is engaged with first inner spline tooth, i. e. complete the connection of turning gear and first engine, then use spanner etc. Rotating member clamps the part of structure of first fixed part located outside first inner cavity, and rotates the rotating member to drive turning gear overall rotation, and then sequentially drive first hydraulic pump shaft, hydraulic gear and intermediate gear wheel rotation, finally realize turning.This turning gear structure is simple, can realize and make the volume and weight of turning gear overall reduce, and need not additional fastener and engine connection, so that assembly is more convenient, to improve the turning efficiency.

Description

Technical Field

[0001] This utility model relates to the field of engine technology, and in particular to a turning tool and turning device. Background Technology

[0002] Existing turning tools contain too many parts and require fasteners to connect to the engine before turning can be performed, resulting in a large overall size, heavy weight, and cumbersome assembly, which in turn reduces the efficiency of turning.

[0003] Therefore, how to simplify the assembly process of the turning tool to improve the turning efficiency has become a technical problem that urgently needs to be solved in this field. Utility Model Content

[0004] The purpose of this invention is to at least solve the technical problem of how to simplify the assembly process of a turning wheel tool to improve turning wheel efficiency. This purpose is achieved through the following technical solution:

[0005] In a first aspect, this utility model proposes a turning tool suitable for an engine equipped with a hydraulic pump base. The engine includes a first engine, and a first internal spline tooth is provided in the first inner cavity of the first hydraulic pump shaft of the first engine. The turning tool extends along a first direction and includes: a first engaging part having a first external spline tooth for engaging with the first internal spline tooth; and a first fixing part fixedly connected to the first engaging part, wherein when the first external spline tooth engages with the first internal spline tooth, at least a portion of the structure of the first fixing part can be located outside the first inner cavity.

[0006] When this type of turning tool is in operation, it is first inserted into the first inner cavity of the first engine along the axial direction of the first inner cavity, so that the first external spline teeth of the turning tool mesh with the first internal spline teeth in the first cavity, thus completing the connection between the turning tool and the first engine. Since at least a part of the first fixing part is located outside the first inner cavity at this time, a wrench or other rotating component can be used to clamp the part of the first fixing part located outside the first inner cavity, and the rotating component can be rotated to drive the entire turning tool to rotate, thereby sequentially driving the first hydraulic pump shaft, hydraulic gear, and intermediate large gear to rotate, ultimately achieving turning. As can be seen from the above, this turning tool has a simple structure, which can reduce the overall size and weight of the turning tool, and does not require additional fasteners to connect to the engine, making assembly more convenient and thus improving the efficiency of turning.

[0007] In some embodiments of the utility model, the engine further includes a second engine, a second inner cavity of a second hydraulic pump shaft of the second engine is equipped with a second inner spline tooth, the turning gear further includes: a second meshing part, fixedly connected with the first fixed part, and located between the first meshing part and the first fixed part along the first direction, the second meshing part has a second outer spline tooth, the second outer spline tooth is used for meshing with the second inner spline tooth, and the second outer spline tooth is different from the first outer spline tooth in specification, and a second fixed part, fixedly connected with the first meshing part, and located between the second fixed part and the second meshing part along the first direction, and when the second outer spline tooth meshes with the second inner spline tooth, at least part of the structure of the second fixed part can be located outside the second inner cavity.

[0008] In some embodiments of the utility model, the turning gear further includes a limiting part, and the limiting part is located between the first meshing part and the first fixed part along the first direction, when the first outer spline tooth meshes with the first inner spline tooth, the limiting part is used for abutting against the end face of the first hydraulic pump shaft away from the hydraulic gear, and the first fixed part can be located outside the first inner cavity as a whole.

[0009] In some embodiments of the utility model, the limiting part is located between the first meshing part and the second meshing part along the first direction, when the second outer spline tooth meshes with the second inner spline tooth, the limiting part is used for abutting against the end face of the second hydraulic pump shaft away from the hydraulic gear, and the second fixed part can be located outside the second inner cavity as a whole.

[0010] In some embodiments of the utility model, the limiting part has a first limiting surface and a second limiting surface oppositely arranged along the first direction, when the first outer spline tooth meshes with the first inner spline tooth, the first limiting surface is used for abutting against the end face of the first hydraulic pump shaft away from the hydraulic gear, and when the second outer spline tooth meshes with the second inner spline tooth, the second limiting surface is used for abutting against the end face of the second hydraulic pump shaft away from the hydraulic.

[0011] In some embodiments of the utility model, the first fixed part is a first prism, and the first prism extends along the first direction.

[0012] In some embodiments of the utility model, the second fixed part is a second prism, and the second prism extends along the first direction.

[0013] In some embodiments of the utility model, the turning gear is an integral structure.

[0014] In the second aspect, the utility model provides a turning device, the turning device includes a rotating part and any one of the turning gears described above, and the rotating part is configured to be fixedly connected with the first fixed part to drive the whole turning gear to rotate.

[0015] In some embodiments of the utility model, the turning tool comprises a second engaging portion and a second fixing portion, and the rotating member is configured to be fixedly connected with the second fixing portion to drive the whole turning tool to rotate.

[0016] The above description is only a summary of the technical scheme of the present application, in order to more clearly understand the technical means of the present application, the content of the specification can be implemented, and in order to make the above and other purposes, characteristics and advantages of the present application more obvious and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0017] By reading the detailed description of the preferred embodiments below, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of illustrating the preferred embodiments and are not considered as limiting the present application. Moreover, the same reference numerals are used to represent the same components throughout the drawings. In the drawings:

[0018] Figure 1 Structure schematic view of the turning tool provided by the embodiment of the utility model at one angle;

[0019] Figure 2 Structure schematic view of the turning tool provided by the embodiment of the utility model at another angle;

[0020] Figure 3 Partial structure schematic view of the turning tool provided by the embodiment of the utility model and the first engine assembly.

[0021] The reference signs are as follows:

[0022] 1, turning tool;

[0023] 10, first engaging portion; 11, first external spline tooth;

[0024] 20, first fixing portion;

[0025] 30, second engaging portion; 31, second external spline tooth;

[0026] 40, second fixing portion;

[0027] 50, limiting portion; 51, first limiting surface; 52, second limiting surface;

[0028] A, first engine;

[0029] a, first internal spline tooth; b, first hydraulic pump shaft; c, first internal cavity; d, hydraulic pump seat; e, hydraulic gear. DETAILED DESCRIPTION

[0030] Exemplary embodiments of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings. While example embodiments of the present disclosure are shown in the drawings, it is understood that the present disclosure can be embodied in many forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0031] It is to be understood that the terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises", "comprising", "includes", "including" and the like are to be construed to be inclusive (i.e., to include both instances of open ended terms and instances of terms limiting to a specific number) unless otherwise indicated as otherwise limited by context. The methods described herein can be implemented as a method, an apparatus, a system, a computer program product, or any combination thereof.

[0032] Although the terms first, second, third, and the like can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can be only used to differentiate one element, component, region, layer or section from another region, layer or section. Terms such as "first", "second", and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

[0033] For the sake of description, spatial relative terms can be used herein for describing a relationship of one element or feature to another element or feature as illustrated in the figures, such as "inner", "outer", "inward", "outward", "lower", "below", "upper", "above", and the like. Such spatial relative terms can be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the example term "below" can encompass both an orientation of above and below. The device can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0034] Figure 1 A structural schematic view of the turning tool provided by the embodiment of the present application at one angle; Figure 2 A structural schematic view of the turning tool provided by the embodiment of the present application at another angle; Figure 3 A partial structural schematic view of the turning tool provided by the embodiment of the present application when assembled with the first engine.

[0035] As shown in the figure, Figures 1 to 3 The embodiment of the present application provides a turning tool 1, which is suitable for an engine equipped with a hydraulic pump seat d. The engine comprises a first engine A, and a first inner spline tooth a is arranged in a first inner cavity c of a first hydraulic pump shaft b of the first engine A. The turning tool 1 extends in a first direction. The turning tool 1 comprises: a first engaging part 10, which has a first outer spline tooth 11 for engaging with the first inner spline tooth a; and a first fixing part 20, which is fixedly connected with the first engaging part 10, and at least part of the structure of the first fixing part 20 can be located outside the first inner cavity c when the first outer spline tooth 11 engages with the first inner spline tooth a.

[0036] When the turning tool 1 works, the turning tool 1 is first inserted into the first inner cavity c of an engine (hereinafter referred to as the first engine A) in the axial direction of the first inner cavity c, so that the first outer spline tooth 11 of the turning tool 1 engages with the first inner spline tooth a in the first cavity, that is, the connection between the turning tool 1 and the first engine A is completed. Since at least part of the structure of the first fixing part 20 is located outside the first inner cavity c at this time, a wrench or the like rotating member can be used to clamp the part of the structure of the first fixing part 20 located outside the first inner cavity c, and the rotating member is rotated to drive the whole turning tool 1 to rotate, thereby sequentially driving the first hydraulic pump shaft b, the hydraulic gear e and the intermediate gear to rotate, and finally realizing turning.

[0037] From the above, the structure of the tool 1 is simple, the volume and weight of the tool 1 can be reduced, and the tool 1 is connected to the first engine A without additional fasteners, so that the assembly is more convenient, thereby improving the efficiency of the tool 1.

[0038] Reference Figures 1 to 3 According to an optional embodiment of the present application, the tool 1 is suitable for an engine equipped with a hydraulic pump seat d, and the engine further comprises a second engine, a second inner cavity of a second hydraulic pump shaft of the second engine is provided with a second internal spline tooth, and the tool 1 further comprises: a second engaging portion 30, which is fixedly connected with the first fixed portion 20 and located between the first engaging portion 10 and the first fixed portion 20 along the first direction; the second engaging portion 30 has a second external spline tooth 31, which is used for engaging with the second internal spline tooth, and the second external spline tooth is different in specification from the first external spline tooth 11; and a second fixed portion 40, which is fixedly connected with the first engaging portion 10, and the first engaging portion 10 is located between the second fixed portion 40 and the second engaging portion 30 along the first direction; and at least part of the structure of the second fixed portion 40 can be located outside the second inner cavity when the second external spline tooth 31 engages with the second internal spline tooth.

[0039] It is easy to understand that, since the specifications of the hydraulic pump shafts equipped by different engines are different, that is, the specifications (such as the outer diameter, the number of tooth rings, etc.) of the internal spline teeth in the inner cavities of different hydraulic pump shafts are different, so different specifications of the tool 1 are often required when the different engines are jacked.

[0040] In the embodiment, the second engaging portion 30 and the second fixed portion 40 are added to the tool 1, so that one tool 1 can be used for two specifications of engines.

[0041] Specifically, when the tool 1 needs to jack another engine (hereinafter referred to as a second engine), the tool 1 is first inserted into the second inner cavity along the axis direction of the second inner cavity, so that the second external spline tooth 31 of the tool 1 engages with the second internal spline tooth in the first cavity, that is, the connection between the tool 1 and the second engine is completed; since at least part of the structure of the second fixed portion 40 is located outside the second inner cavity, a wrench or the like rotating member can then be clamped to the part of the structure of the second fixed portion 40 located outside the second inner cavity, and the rotating member is rotated to drive the tool 1 to rotate, thereby sequentially driving the second hydraulic pump shaft, the hydraulic gear e and the intermediate gear to rotate, and finally achieving jacking.

[0042] That is, the tool 1 only needs to be simply adjusted in the assembly direction (such as the direction of the arrow A in the figure), and the tool 1 can be used for different specifications of engines. Figure 3As shown, the direction of the turning tool 1 is adjusted to exchange the front and back order of the first fixing part 20 and the second fixing part 40, so that one turning tool 1 is suitable for two different specifications of engines (i.e. the first engine A and the second engine, not shown in the figure), thereby improving the use scene of the turning tool 1, and also ensuring the turning efficiency of the turning tool 1.

[0043] In addition, it should be noted that the first fixing part 20 and the second fixing part 40 can not only be connected by a wrench or the like, but also can limit the position.

[0044] Specifically, the first fixing part 20 and the second fixing part 40 can extend in the first direction, as shown in Figure 1 and Figure 2 As shown, the following still takes the turning of the above-mentioned first engine A and the second engine as an example for description:

[0045] When the first engine A is turned, the first external spline tooth 11 of the turning tool 1 is inserted into the first inner cavity c to make the first external spline tooth 11 mesh with the first internal spline tooth a. Due to the existence of the second fixing part 40, the distance of the turning tool 1 as a whole inserted into the first inner cavity c in the axial direction of the first inner cavity c will be limited, thereby effectively ensuring that at least part of the structure of the first fixing part 20 can be located outside the first inner cavity c, and further ensuring that the wrench or the like can rotate the turning tool 1 as a whole through the first fixing part 20, thereby ensuring the working efficiency of the turning tool 1.

[0046] Similarly, when the second engine is turned, the assembly direction of the turning tool 1 is adjusted, the second external spline tooth 31 of the turning tool 1 is inserted into the second inner cavity to make the second external spline tooth 31 mesh with the second internal spline tooth. Due to the existence of the first fixing part 20, the distance of the turning tool 1 as a whole inserted into the second inner cavity in the axial direction of the second inner cavity will be limited, thereby effectively ensuring that at least part of the structure of the second fixing part 40 can be located outside the second inner cavity, and further ensuring that the wrench or the like can rotate the turning tool 1 as a whole through the second fixing part 40, thereby ensuring the working efficiency of the turning tool 1.

[0047] As shown in Figures 1 to 3 According to an optional embodiment of the utility model, the turning tool 1 further comprises a limiting part 50, which is located between the first engaging part 10 and the first fixing part 20 in the first direction. When the first external spline tooth 11 meshes with the first internal spline tooth a, the limiting part 50 is used to abut against the end face of the first hydraulic pump shaft b away from the hydraulic gear e, and the first fixing part 20 can be located outside the first inner cavity c as a whole.

[0048] In the embodiment, taking the first engine A as an example, if the length of the second fixed part 40 in the first direction is not enough, the first fixed part 20 may not be able to be finally out of the first cavity, so that the rotating tool 1 cannot be rotated by the wrench or the like, and the whole process of the turning is affected.

[0049] Therefore, the embodiment further provides the limiting part 50. When the first external spline tooth 11 is engaged with the first internal spline tooth a and the length of the second fixed part 40 in the first direction is not enough, the limiting part 50 can abut against the end face of the first hydraulic pump shaft b away from the hydraulic gear e, so that the first fixed part 20 can be located outside the first internal cavity c, and the convenience of connecting the wrench or the like with the first fixed part 20 is further improved, and the working efficiency of the turning is further ensured.

[0050] Continuing to refer to Figures 1 to 3 According to an optional embodiment of the utility model, along the first direction, the limiting part 50 is located between the first engaging part 10 and the second engaging part 30. When the second external spline tooth 31 is engaged with the second internal spline tooth, the limiting part 50 is used for abutting against the end face of the second hydraulic pump shaft away from the hydraulic gear e, and the second fixed part 40 can be located outside the second internal cavity.

[0051] In the embodiment, when the turning tool 1 is adapted to two different specifications of engines (i.e. the first engine A and the second engine), the turning process of the first engine A by the turning tool 1 is the same as before, and will not be repeated here. Taking the turning of the second engine by the turning tool 1 as an example, the turning process is described as follows:

[0052] If the length of the first fixed part 20 in the first direction is not enough, the second fixed part 40 may not be able to be finally out of the second cavity, so that the rotating tool 1 cannot be rotated by the wrench or the like, and the whole process of the turning is affected. However, due to the existence of the limiting part 50, when the second external spline tooth 31 is engaged with the second internal spline tooth and the length of the first fixed part 20 in the first direction is not enough, the limiting part 50 can abut against the end face of the second hydraulic pump shaft away from the hydraulic gear e, so that the second fixed part 40 can be located outside the second internal cavity, the convenience of connecting the wrench or the like with the second fixed part 40 is further improved, and the working efficiency of the turning is further ensured.

[0053] As Figures 1 to 3As shown, according to an optional embodiment of the utility model, the limiting part 50 has a first limiting surface 51 and a second limiting surface 52 arranged oppositely along the first direction; when the first external spline tooth 11 is engaged with the first internal spline tooth a, the first limiting surface 51 is used for abutting against the end surface of the first hydraulic pump shaft b on the side away from the hydraulic gear e; when the second external spline tooth 31 is engaged with the second internal spline tooth, the second limiting surface 52 is used for abutting against the end surface of the second hydraulic pump shaft on the side away from the hydraulic gear e.

[0054] In the embodiment, it is easy to understand that the abutment between the surfaces can well play the role of limiting, therefore, the embodiment is provided with the first limiting surface 51 and the second limiting surface 52 in the limiting part 50, the first limiting surface 51 is used for abutting against the end surface of the first hydraulic pump shaft b on the side away from the hydraulic gear e, so as to prevent the first fixed part 20 from being unable to explore the first cavity; the second limiting surface 52 is used for abutting against the end surface of the second hydraulic pump shaft on the side away from the hydraulic gear e, so as to prevent the second fixed part 40 from being unable to explore the second cavity.

[0055] It should be noted that the embodiment only specifically describes the structure playing the role of limiting in the limiting part 50, and in actual working conditions, the relative position between the turning tool 1 and the engine along the direction can be limited, and the structure playing the role of limiting in the limiting part 50 is not limited.

[0056] Reference Figure 1 And Figure 3 According to an optional embodiment of the utility model, the first fixed part 20 is a first prism, and the first prism extends along the first direction. The second fixed part 40 is a second prism, and the second prism extends along the first direction.

[0057] In the embodiment, it is easy to understand that since finally the rotating part needs to be connected with the first fixed part 20 or the second fixed part 40 during turning, and then the turning tool 1 is driven to rotate as a whole, and the wrench is a common tool capable of realizing this effect, and is very suitable for rotating the turning tool 1, therefore, the first fixed part 20 and the second fixed part 40 are set as prisms extending along the first direction, which is conducive to clamping the wrench.

[0058] Specifically, the prism can be a hexagonal prism, an octagonal prism or the like, and the specific shape is not limited.

[0059] According to an optional embodiment of the utility model, the turning tool 1 is an integral molding structure.

[0060] In the embodiment, it is easy to understand that the turning tool 1 has fewer components and high integration, and is convenient to set as an integral molding structure; and the integral turning tool 1 can be carried or assembled with the engine more conveniently, thereby further guaranteeing the efficiency of turning.

[0061] The utility model embodiment further provides a kind of turning gear, turning gear includes rotating member and above-mentioned any turning tool 1, rotating member is configured as can be fixedly connected with first fixed part 20 to drive turning tool 1 overall rotation.And when turning tool 1 includes second engaging portion 30 and second fixed part 40, rotating member is configured as can also be fixedly connected with second fixed part 40 to drive turning tool 1 overall rotation.

[0062] In the embodiment, the turning gear has the same beneficial effects as the above-mentioned any turning tool 1, and can improve the efficiency of turning. For details, refer to the analysis of the beneficial effects of the above-mentioned any turning tool 1, which will not be repeated here.

[0063] It is easy to understand that the rotating member is configured to be adapted to the first fixed part 20 and the second fixed part 40 at the same time (i.e. the rotating member can be connected with the first fixed part 20 alone or the second fixed part 40 alone, instead of being required to be connected with the first fixed part 20 and the second fixed part 40 at the same time), which further improves the convenience of turning.

[0064] The above is only a preferred specific embodiment of the utility model, but the protection scope of the utility model is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the utility model, which should be covered within the protection scope of the utility model. Therefore, the protection scope of the utility model should be subject to the protection scope of the claims.

Claims

1. A turning tool suitable for an engine equipped with a hydraulic pump base (d), the engine comprising a first engine (A), wherein a first internal spline (a) is provided in a first inner cavity (c) of a first hydraulic pump shaft (b) of the first engine (A), characterized in that, The turning tool (1) extends along a first direction, and the turning tool (1) includes: A first engaging portion (10), the first engaging portion (10) having a first external spline tooth (11), the first external spline tooth (11) being used to engage with the first internal spline tooth (a); and The first fixing part (20) is fixedly connected to the first engaging part (10), and when the first external spline tooth (11) engages with the first internal spline tooth (a), at least a portion of the structure of the first fixing part (20) can be located outside the first inner cavity (c).

2. The turning tool according to claim 1 is applicable to an engine equipped with a hydraulic pump base (d), the engine further comprising a second engine, wherein a second internal spline is provided in the second inner cavity of the second hydraulic pump shaft of the second engine, characterized in that, The turning tool also includes: A second engaging portion (30) is fixedly connected to the first fixing portion (20), and along the first direction, the second engaging portion (30) is located between the first engaging portion (10) and the first fixing portion (20); the second engaging portion (30) has a second external spline tooth (31), the second external spline tooth (31) is used to engage with the second internal spline tooth, and the specifications of the second external spline tooth are different from those of the first external spline tooth (11); and The second fixing part (40) is fixedly connected to the first engaging part (10). Along the first direction, the first engaging part (10) is located between the second fixing part (40) and the second engaging part (30). When the second external spline tooth (31) engages with the second internal spline tooth, at least a portion of the structure of the second fixing part (40) can be located outside the second inner cavity.

3. The turning tool according to claim 2, characterized in that, The turning tool also includes a limiting part (50), which is located between the first engaging part (10) and the first fixing part (20) along the first direction; When the first external spline tooth (11) meshes with the first internal spline tooth (a), the limiting part (50) is used to abut against the end face of the first hydraulic pump shaft (b) on the side opposite to the hydraulic gear (e), and the first fixing part (20) can be located entirely outside the first inner cavity.

4. The turning tool according to claim 3, characterized in that, Along the first direction, the limiting part (50) is located between the first engaging part (10) and the second engaging part (30); When the second external spline tooth (31) meshes with the second internal spline tooth, the limiting part (50) is used to abut against the end face of the second hydraulic pump shaft on the side opposite to the hydraulic gear (e), and the second fixing part (40) can be located entirely outside the second inner cavity.

5. The turning tool according to claim 4, characterized in that, The limiting part (50) has a first limiting surface (51) and a second limiting surface (52) disposed opposite to the first direction; When the first external spline tooth (11) meshes with the first internal spline tooth (a), the first limiting surface (51) abuts against the end face of the first hydraulic pump shaft (b) on the side away from the hydraulic gear (e); when the second external spline tooth (31) meshes with the second internal spline tooth, the second limiting surface (52) abuts against the end face of the second hydraulic pump shaft on the side away from the hydraulic gear (e).

6. The turning tool according to claim 1, characterized in that, The first fixing part (20) is a first prism, and the first prism extends along the first direction.

7. The turning tool according to claim 3, characterized in that, The second fixing part (40) is a second prism, and the second prism extends along the first direction.

8. The turning tool according to any one of claims 1-7, characterized in that, The turning tool is a one-piece molded structure.

9. A turning device, characterized in that, Includes a rotating component and a turning tool (1) as described in any one of claims 1-8, wherein the rotating component is configured to be fixedly connected to the first fixed part (20) to drive the turning tool (1) to rotate as a whole.

10. The turning gear device according to claim 9, characterized in that, The turning tool (1) includes a second engaging part (30) and a second fixing part (40), and the rotating member is configured to be fixedly connected to the second fixing part (40) to drive the turning tool (1) to rotate as a whole.

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